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linux-7.2.3/drivers/tty/hvc/Kconfig

@@ -0,0 +1,136 @@
+# SPDX-License-Identifier: GPL-2.0
+
+config HVC_DRIVER
+	bool
+	help
+	  Generic "hypervisor virtual console" infrastructure for various
+	  hypervisors (pSeries, iSeries, Xen).
+	  It will automatically be selected if one of the back-end console drivers
+	  is selected.
+
+config HVC_IRQ
+	bool
+
+config HVC_CONSOLE
+	bool "pSeries Hypervisor Virtual Console support"
+	depends on PPC_PSERIES
+	select HVC_DRIVER
+	select HVC_IRQ
+	help
+	  pSeries machines when partitioned support a hypervisor virtual
+	  console. This driver allows each pSeries partition to have a console
+	  which is accessed via the HMC.
+
+config HVC_OLD_HVSI
+	bool "Old driver for pSeries serial port (/dev/hvsi*)"
+	depends on HVC_CONSOLE
+
+config HVC_OPAL
+	bool "OPAL Console support"
+	depends on PPC_POWERNV
+	select HVC_DRIVER
+	select HVC_IRQ
+	default y
+	help
+	  PowerNV machines running under OPAL need that driver to get a console
+
+config HVC_RTAS
+	bool "IBM RTAS Console support"
+	depends on PPC_RTAS
+	select HVC_DRIVER
+	help
+	  IBM Console device driver which makes use of RTAS
+
+config HVC_IUCV
+	bool "z/VM IUCV Hypervisor console support (VM only)"
+	depends on S390 && NET
+	select HVC_DRIVER
+	select IUCV
+	default y
+	help
+	  This driver provides a Hypervisor console (HVC) back-end to access
+	  a Linux (console) terminal via a z/VM IUCV communication path.
+
+config HVC_XEN
+	bool "Xen Hypervisor Console support"
+	depends on XEN
+	select HVC_DRIVER
+	select HVC_IRQ
+	default y
+	help
+	  Xen virtual console device driver
+
+config HVC_XEN_FRONTEND
+	bool "Xen Hypervisor Multiple Consoles support"
+	depends on HVC_XEN
+	select XEN_XENBUS_FRONTEND
+	default y
+	help
+	  Xen driver for secondary virtual consoles
+
+config HVC_UDBG
+	bool "udbg based fake hypervisor console"
+	depends on PPC
+	select HVC_DRIVER
+	help
+	  This is meant to be used during HW bring up or debugging when
+	  no other console mechanism exist but udbg, to get you a quick
+	  console for userspace. Do NOT enable in production kernels.
+
+config HVC_DCC
+	bool "ARM JTAG DCC console"
+	depends on ARM || ARM64
+	select HVC_DRIVER
+	select SERIAL_CORE_CONSOLE
+	help
+	  This console uses the JTAG DCC on ARM to create a console under the HVC
+	  driver. This console is used through a JTAG only on ARM. If you don't have
+	  a JTAG then you probably don't want this option.
+
+config HVC_DCC_SERIALIZE_SMP
+	bool "Use DCC only on CPU core 0"
+	depends on SMP && HVC_DCC
+	help
+	  This is a DEBUG option to serialize all console input and output to CPU 0.
+	  Some external debuggers, do not handle reads/writes from/to DCC on more
+	  than one CPU core. Each core has its own DCC device registers, so when a
+	  CPU core reads or writes from/to DCC, it only accesses its own DCC device.
+	  Since kernel code can run on any CPU core, every time the kernel wants to
+	  write to the console, it might write to a different DCC.
+
+	  In SMP mode, external debuggers create multiple windows, and each window
+	  shows the DCC output only from that core's DCC. The result is that
+	  console output is either lost or scattered across windows.
+
+	  Enable this option only if you are sure that you do not need features like
+	  CPU hotplug to work. For example, during early chipset bringups without
+	  debug serial console support. If unsure, say N.
+
+config HVC_RISCV_SBI
+	bool "RISC-V SBI console support"
+	depends on RISCV_SBI && NONPORTABLE
+	select HVC_DRIVER
+	help
+	  This enables support for console output via RISC-V SBI calls, which
+	  is normally used only during boot to output printk.  This driver
+	  conflicts with real console drivers and should not be enabled on
+	  systems that directly access the console.
+
+	  If you don't know what do to here, say N.
+
+config HVCS
+	tristate "IBM Hypervisor Virtual Console Server support"
+	depends on PPC_PSERIES && HVC_CONSOLE
+	help
+	  Partitionable IBM Power5 ppc64 machines allow hosting of
+	  firmware virtual consoles from one Linux partition by
+	  another Linux partition.  This driver allows console data
+	  from Linux partitions to be accessed through TTY device
+	  interfaces in the device tree of a Linux partition running
+	  this driver.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called hvcs.  Additionally, this module
+	  will depend on arch specific APIs exported from hvcserver.ko
+	  which will also be compiled when this driver is built as a
+	  module.

linux-7.2.3/drivers/tty/hvc/Makefile

@@ -0,0 +1,13 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_HVC_CONSOLE)	+= hvc_vio.o hvsi_lib.o
+obj-$(CONFIG_HVC_OPAL)		+= hvc_opal.o hvsi_lib.o
+obj-$(CONFIG_HVC_OLD_HVSI)	+= hvsi.o
+obj-$(CONFIG_HVC_RTAS)		+= hvc_rtas.o
+obj-$(CONFIG_HVC_DCC)		+= hvc_dcc.o
+obj-$(CONFIG_HVC_DRIVER)	+= hvc_console.o
+obj-$(CONFIG_HVC_IRQ)		+= hvc_irq.o
+obj-$(CONFIG_HVC_XEN)		+= hvc_xen.o
+obj-$(CONFIG_HVC_IUCV)		+= hvc_iucv.o
+obj-$(CONFIG_HVC_UDBG)		+= hvc_udbg.o
+obj-$(CONFIG_HVC_RISCV_SBI)	+= hvc_riscv_sbi.o
+obj-$(CONFIG_HVCS)		+= hvcs.o

linux-7.2.3/drivers/tty/hvc/hvc_console.h

@@ -0,0 +1,113 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * hvc_console.h
+ * Copyright (C) 2005 IBM Corporation
+ *
+ * Author(s):
+ * 	Ryan S. Arnold <rsa@us.ibm.com>
+ *
+ * hvc_console header information:
+ *      moved here from arch/powerpc/include/asm/hvconsole.h
+ *      and drivers/char/hvc_console.c
+ */
+
+#ifndef HVC_CONSOLE_H
+#define HVC_CONSOLE_H
+#include <linux/kref.h>
+#include <linux/tty.h>
+#include <linux/spinlock.h>
+
+/*
+ * This is the max number of console adapters that can/will be found as
+ * console devices on first stage console init.  Any number beyond this range
+ * can't be used as a console device but is still a valid tty device.
+ */
+#define MAX_NR_HVC_CONSOLES	16
+
+/*
+ * The Linux TTY code does not support dynamic addition of tty derived devices
+ * so we need to know how many tty devices we might need when space is allocated
+ * for the tty device.  Since this driver supports hotplug of vty adapters we
+ * need to make sure we have enough allocated.
+ */
+#define HVC_ALLOC_TTY_ADAPTERS	8
+
+struct hvc_struct {
+	struct tty_port port;
+	spinlock_t lock;
+	int index;
+	int do_wakeup;
+	int outbuf_size;
+	int n_outbuf;
+	uint32_t vtermno;
+	const struct hv_ops *ops;
+	int irq_requested;
+	int data;
+	struct winsize ws;
+	struct work_struct tty_resize;
+	struct list_head next;
+	unsigned long flags;
+	u8 outbuf[] __aligned(sizeof(long));
+};
+
+/* implemented by a low level driver */
+struct hv_ops {
+	ssize_t (*get_chars)(uint32_t vtermno, u8 *buf, size_t count);
+	ssize_t (*put_chars)(uint32_t vtermno, const u8 *buf, size_t count);
+	int (*flush)(uint32_t vtermno, bool wait);
+
+	/* Callbacks for notification. Called in open, close and hangup */
+	int (*notifier_add)(struct hvc_struct *hp, int irq);
+	void (*notifier_del)(struct hvc_struct *hp, int irq);
+	void (*notifier_hangup)(struct hvc_struct *hp, int irq);
+
+	/* tiocmget/set implementation */
+	int (*tiocmget)(struct hvc_struct *hp);
+	int (*tiocmset)(struct hvc_struct *hp, unsigned int set, unsigned int clear);
+
+	/* Callbacks to handle tty ports */
+	void (*dtr_rts)(struct hvc_struct *hp, bool active);
+};
+
+/* Register a vterm and a slot index for use as a console (console_init) */
+extern int hvc_instantiate(uint32_t vtermno, int index,
+			   const struct hv_ops *ops);
+
+/* register a vterm for hvc tty operation (module_init or hotplug add) */
+extern struct hvc_struct * hvc_alloc(uint32_t vtermno, int data,
+				     const struct hv_ops *ops, int outbuf_size);
+/* remove a vterm from hvc tty operation (module_exit or hotplug remove) */
+extern void hvc_remove(struct hvc_struct *hp);
+
+/* data available */
+int hvc_poll(struct hvc_struct *hp);
+void hvc_kick(void);
+
+/* Resize hvc tty terminal window */
+extern void __hvc_resize(struct hvc_struct *hp, struct winsize ws);
+
+static inline void hvc_resize(struct hvc_struct *hp, struct winsize ws)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&hp->lock, flags);
+	__hvc_resize(hp, ws);
+	spin_unlock_irqrestore(&hp->lock, flags);
+}
+
+/* default notifier for irq based notification */
+extern int notifier_add_irq(struct hvc_struct *hp, int data);
+extern void notifier_del_irq(struct hvc_struct *hp, int data);
+extern void notifier_hangup_irq(struct hvc_struct *hp, int data);
+
+
+#if defined(CONFIG_XMON) && defined(CONFIG_SMP)
+#include <asm/xmon.h>
+#else
+static inline int cpus_are_in_xmon(void)
+{
+	return 0;
+}
+#endif
+
+#endif // HVC_CONSOLE_H

linux-7.2.3/drivers/tty/hvc/hvc_dcc.c

@@ -0,0 +1,309 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2010, 2014, 2022 The Linux Foundation. All rights reserved.  */
+
+#include <linux/console.h>
+#include <linux/cpu.h>
+#include <linux/cpumask.h>
+#include <linux/init.h>
+#include <linux/kfifo.h>
+#include <linux/serial.h>
+#include <linux/serial_core.h>
+#include <linux/smp.h>
+#include <linux/spinlock.h>
+
+#include <asm/dcc.h>
+#include <asm/processor.h>
+
+#include "hvc_console.h"
+
+/* DCC Status Bits */
+#define DCC_STATUS_RX		(1 << 30)
+#define DCC_STATUS_TX		(1 << 29)
+
+#define DCC_INBUF_SIZE		128
+#define DCC_OUTBUF_SIZE		1024
+
+/* Lock to serialize access to DCC fifo */
+static DEFINE_SPINLOCK(dcc_lock);
+
+static DEFINE_KFIFO(inbuf, u8, DCC_INBUF_SIZE);
+static DEFINE_KFIFO(outbuf, u8, DCC_OUTBUF_SIZE);
+
+static void dcc_uart_console_putchar(struct uart_port *port, u8 ch)
+{
+	while (__dcc_getstatus() & DCC_STATUS_TX)
+		cpu_relax();
+
+	__dcc_putchar(ch);
+}
+
+static void dcc_early_write(struct console *con, const char *s, unsigned n)
+{
+	struct earlycon_device *dev = con->data;
+
+	uart_console_write(&dev->port, s, n, dcc_uart_console_putchar);
+}
+
+static int __init dcc_early_console_setup(struct earlycon_device *device,
+					  const char *opt)
+{
+	unsigned int count = 0x4000000;
+
+	while (--count && (__dcc_getstatus() & DCC_STATUS_TX))
+		cpu_relax();
+
+	if (__dcc_getstatus() & DCC_STATUS_TX)
+		return -ENODEV;
+
+	device->con->write = dcc_early_write;
+
+	return 0;
+}
+
+EARLYCON_DECLARE(dcc, dcc_early_console_setup);
+
+static ssize_t hvc_dcc_put_chars(uint32_t vt, const u8 *buf, size_t count)
+{
+	size_t i;
+
+	for (i = 0; i < count; i++) {
+		while (__dcc_getstatus() & DCC_STATUS_TX)
+			cpu_relax();
+
+		__dcc_putchar(buf[i]);
+	}
+
+	return count;
+}
+
+static ssize_t hvc_dcc_get_chars(uint32_t vt, u8 *buf, size_t count)
+{
+	size_t i;
+
+	for (i = 0; i < count; ++i)
+		if (__dcc_getstatus() & DCC_STATUS_RX)
+			buf[i] = __dcc_getchar();
+		else
+			break;
+
+	return i;
+}
+
+/*
+ * Check if the DCC is enabled. If CONFIG_HVC_DCC_SERIALIZE_SMP is enabled,
+ * then we assume then this function will be called first on core0. That way,
+ * dcc_core0_available will be true only if it's available on core0.
+ */
+static bool hvc_dcc_check(void)
+{
+	unsigned long time = jiffies + (HZ / 10);
+	static bool dcc_core0_available;
+
+	/*
+	 * If we're not on core 0, but we previously confirmed that DCC is
+	 * active, then just return true.
+	 */
+	int cpu = get_cpu();
+
+	if (IS_ENABLED(CONFIG_HVC_DCC_SERIALIZE_SMP) && cpu && dcc_core0_available) {
+		put_cpu();
+		return true;
+	}
+
+	put_cpu();
+
+	/* Write a test character to check if it is handled */
+	__dcc_putchar('\n');
+
+	while (time_is_after_jiffies(time)) {
+		if (!(__dcc_getstatus() & DCC_STATUS_TX)) {
+			dcc_core0_available = true;
+			return true;
+		}
+	}
+
+	return false;
+}
+
+/*
+ * Workqueue function that writes the output FIFO to the DCC on core 0.
+ */
+static void dcc_put_work(struct work_struct *work)
+{
+	unsigned char ch;
+	unsigned long irqflags;
+
+	spin_lock_irqsave(&dcc_lock, irqflags);
+
+	/* While there's data in the output FIFO, write it to the DCC */
+	while (kfifo_get(&outbuf, &ch))
+		hvc_dcc_put_chars(0, &ch, 1);
+
+	/* While we're at it, check for any input characters */
+	while (!kfifo_is_full(&inbuf)) {
+		if (!hvc_dcc_get_chars(0, &ch, 1))
+			break;
+		kfifo_put(&inbuf, ch);
+	}
+
+	spin_unlock_irqrestore(&dcc_lock, irqflags);
+}
+
+static DECLARE_WORK(dcc_pwork, dcc_put_work);
+
+/*
+ * Workqueue function that reads characters from DCC and puts them into the
+ * input FIFO.
+ */
+static void dcc_get_work(struct work_struct *work)
+{
+	unsigned long irqflags;
+	u8 ch;
+
+	/*
+	 * Read characters from DCC and put them into the input FIFO, as
+	 * long as there is room and we have characters to read.
+	 */
+	spin_lock_irqsave(&dcc_lock, irqflags);
+
+	while (!kfifo_is_full(&inbuf)) {
+		if (!hvc_dcc_get_chars(0, &ch, 1))
+			break;
+		kfifo_put(&inbuf, ch);
+	}
+	spin_unlock_irqrestore(&dcc_lock, irqflags);
+}
+
+static DECLARE_WORK(dcc_gwork, dcc_get_work);
+
+/*
+ * Write characters directly to the DCC if we're on core 0 and the FIFO
+ * is empty, or write them to the FIFO if we're not.
+ */
+static ssize_t hvc_dcc0_put_chars(u32 vt, const u8 *buf, size_t count)
+{
+	unsigned long irqflags;
+	ssize_t len;
+
+	if (!IS_ENABLED(CONFIG_HVC_DCC_SERIALIZE_SMP))
+		return hvc_dcc_put_chars(vt, buf, count);
+
+	spin_lock_irqsave(&dcc_lock, irqflags);
+	if (smp_processor_id() || (!kfifo_is_empty(&outbuf))) {
+		len = kfifo_in(&outbuf, buf, count);
+		spin_unlock_irqrestore(&dcc_lock, irqflags);
+
+		/*
+		 * We just push data to the output FIFO, so schedule the
+		 * workqueue that will actually write that data to DCC.
+		 * CPU hotplug is disabled in dcc_init so CPU0 cannot be
+		 * offlined after the cpu online check.
+		 */
+		if (cpu_online(0))
+			schedule_work_on(0, &dcc_pwork);
+
+		return len;
+	}
+
+	/*
+	 * If we're already on core 0, and the FIFO is empty, then just
+	 * write the data to DCC.
+	 */
+	len = hvc_dcc_put_chars(vt, buf, count);
+	spin_unlock_irqrestore(&dcc_lock, irqflags);
+
+	return len;
+}
+
+/*
+ * Read characters directly from the DCC if we're on core 0 and the FIFO
+ * is empty, or read them from the FIFO if we're not.
+ */
+static ssize_t hvc_dcc0_get_chars(u32 vt, u8 *buf, size_t count)
+{
+	unsigned long irqflags;
+	ssize_t len;
+
+	if (!IS_ENABLED(CONFIG_HVC_DCC_SERIALIZE_SMP))
+		return hvc_dcc_get_chars(vt, buf, count);
+
+	spin_lock_irqsave(&dcc_lock, irqflags);
+
+	if (smp_processor_id() || (!kfifo_is_empty(&inbuf))) {
+		len = kfifo_out(&inbuf, buf, count);
+		spin_unlock_irqrestore(&dcc_lock, irqflags);
+
+		/*
+		 * If the FIFO was empty, there may be characters in the DCC
+		 * that we haven't read yet.  Schedule a workqueue to fill
+		 * the input FIFO, so that the next time this function is
+		 * called, we'll have data. CPU hotplug is disabled in dcc_init
+		 * so CPU0 cannot be offlined after the cpu online check.
+		 */
+		if (!len && cpu_online(0))
+			schedule_work_on(0, &dcc_gwork);
+
+		return len;
+	}
+
+	/*
+	 * If we're already on core 0, and the FIFO is empty, then just
+	 * read the data from DCC.
+	 */
+	len = hvc_dcc_get_chars(vt, buf, count);
+	spin_unlock_irqrestore(&dcc_lock, irqflags);
+
+	return len;
+}
+
+static const struct hv_ops hvc_dcc_get_put_ops = {
+	.get_chars = hvc_dcc0_get_chars,
+	.put_chars = hvc_dcc0_put_chars,
+};
+
+static int __init hvc_dcc_console_init(void)
+{
+	int ret;
+
+	if (!hvc_dcc_check())
+		return -ENODEV;
+
+	/* Returns -1 if error */
+	ret = hvc_instantiate(0, 0, &hvc_dcc_get_put_ops);
+
+	return ret < 0 ? -ENODEV : 0;
+}
+console_initcall(hvc_dcc_console_init);
+
+static int __init hvc_dcc_init(void)
+{
+	struct hvc_struct *p;
+
+	if (!hvc_dcc_check())
+		return -ENODEV;
+
+	if (IS_ENABLED(CONFIG_HVC_DCC_SERIALIZE_SMP)) {
+		pr_warn("\n");
+		pr_warn("********************************************************************\n");
+		pr_warn("**     NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE           **\n");
+		pr_warn("**                                                                **\n");
+		pr_warn("**  HVC_DCC_SERIALIZE_SMP SUPPORT HAS BEEN ENABLED IN THIS KERNEL **\n");
+		pr_warn("**                                                                **\n");
+		pr_warn("** This means that this is a DEBUG kernel and unsafe for          **\n");
+		pr_warn("** production use and has important feature like CPU hotplug      **\n");
+		pr_warn("** disabled.                                                      **\n");
+		pr_warn("**                                                                **\n");
+		pr_warn("** If you see this message and you are not debugging the          **\n");
+		pr_warn("** kernel, report this immediately to your vendor!                **\n");
+		pr_warn("**                                                                **\n");
+		pr_warn("**     NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE           **\n");
+		pr_warn("********************************************************************\n");
+
+		cpu_hotplug_disable();
+	}
+
+	p = hvc_alloc(0, 0, &hvc_dcc_get_put_ops, 128);
+
+	return PTR_ERR_OR_ZERO(p);
+}
+device_initcall(hvc_dcc_init);

linux-7.2.3/drivers/tty/hvc/hvc_irq.c

@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright IBM Corp. 2001,2008
+ *
+ * This file contains the IRQ specific code for hvc_console
+ *
+ */
+
+#include <linux/interrupt.h>
+
+#include "hvc_console.h"
+
+static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance)
+{
+	/* if hvc_poll request a repoll, then kick the hvcd thread */
+	if (hvc_poll(dev_instance))
+		hvc_kick();
+
+	/*
+	 * We're safe to always return IRQ_HANDLED as the hvcd thread will
+	 * iterate through each hvc_struct.
+	 */
+	return IRQ_HANDLED;
+}
+
+/*
+ * For IRQ based systems these callbacks can be used
+ */
+int notifier_add_irq(struct hvc_struct *hp, int irq)
+{
+	int rc;
+
+	if (!irq) {
+		hp->irq_requested = 0;
+		return 0;
+	}
+	rc = request_irq(irq, hvc_handle_interrupt, hp->flags,
+			"hvc_console", hp);
+	if (!rc)
+		hp->irq_requested = 1;
+	return rc;
+}
+
+void notifier_del_irq(struct hvc_struct *hp, int irq)
+{
+	if (!hp->irq_requested)
+		return;
+	free_irq(irq, hp);
+	hp->irq_requested = 0;
+}
+
+void notifier_hangup_irq(struct hvc_struct *hp, int irq)
+{
+	notifier_del_irq(hp, irq);
+}

linux-7.2.3/drivers/tty/hvc/hvc_opal.c

@@ -0,0 +1,417 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * opal driver interface to hvc_console.c
+ *
+ * Copyright 2011 Benjamin Herrenschmidt <benh@kernel.crashing.org>, IBM Corp.
+ */
+
+#undef DEBUG
+
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/console.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/export.h>
+#include <linux/interrupt.h>
+
+#include <asm/hvconsole.h>
+#include <asm/firmware.h>
+#include <asm/hvsi.h>
+#include <asm/udbg.h>
+#include <asm/opal.h>
+
+#include "hvc_console.h"
+
+static const char hvc_opal_name[] = "hvc_opal";
+
+static const struct of_device_id hvc_opal_match[] = {
+	{ .name = "serial", .compatible = "ibm,opal-console-raw" },
+	{ .name = "serial", .compatible = "ibm,opal-console-hvsi" },
+	{ },
+};
+
+typedef enum hv_protocol {
+	HV_PROTOCOL_RAW,
+	HV_PROTOCOL_HVSI
+} hv_protocol_t;
+
+struct hvc_opal_priv {
+	hv_protocol_t		proto;	/* Raw data or HVSI packets */
+	struct hvsi_priv	hvsi;	/* HVSI specific data */
+};
+static struct hvc_opal_priv *hvc_opal_privs[MAX_NR_HVC_CONSOLES];
+
+/* For early boot console */
+static struct hvc_opal_priv hvc_opal_boot_priv;
+static u32 hvc_opal_boot_termno;
+
+static const struct hv_ops hvc_opal_raw_ops = {
+	.get_chars = opal_get_chars,
+	.put_chars = opal_put_chars,
+	.flush = opal_flush_chars,
+	.notifier_add = notifier_add_irq,
+	.notifier_del = notifier_del_irq,
+	.notifier_hangup = notifier_hangup_irq,
+};
+
+static ssize_t hvc_opal_hvsi_get_chars(uint32_t vtermno, u8 *buf, size_t count)
+{
+	struct hvc_opal_priv *pv = hvc_opal_privs[vtermno];
+
+	if (WARN_ON(!pv))
+		return -ENODEV;
+
+	return hvsilib_get_chars(&pv->hvsi, buf, count);
+}
+
+static ssize_t hvc_opal_hvsi_put_chars(uint32_t vtermno, const u8 *buf,
+				       size_t count)
+{
+	struct hvc_opal_priv *pv = hvc_opal_privs[vtermno];
+
+	if (WARN_ON(!pv))
+		return -ENODEV;
+
+	return hvsilib_put_chars(&pv->hvsi, buf, count);
+}
+
+static int hvc_opal_hvsi_open(struct hvc_struct *hp, int data)
+{
+	struct hvc_opal_priv *pv = hvc_opal_privs[hp->vtermno];
+	int rc;
+
+	pr_devel("HVSI@%x: do open !\n", hp->vtermno);
+
+	rc = notifier_add_irq(hp, data);
+	if (rc)
+		return rc;
+
+	return hvsilib_open(&pv->hvsi, hp);
+}
+
+static void hvc_opal_hvsi_close(struct hvc_struct *hp, int data)
+{
+	struct hvc_opal_priv *pv = hvc_opal_privs[hp->vtermno];
+
+	pr_devel("HVSI@%x: do close !\n", hp->vtermno);
+
+	hvsilib_close(&pv->hvsi, hp);
+
+	notifier_del_irq(hp, data);
+}
+
+static void hvc_opal_hvsi_hangup(struct hvc_struct *hp, int data)
+{
+	struct hvc_opal_priv *pv = hvc_opal_privs[hp->vtermno];
+
+	pr_devel("HVSI@%x: do hangup !\n", hp->vtermno);
+
+	hvsilib_close(&pv->hvsi, hp);
+
+	notifier_hangup_irq(hp, data);
+}
+
+static int hvc_opal_hvsi_tiocmget(struct hvc_struct *hp)
+{
+	struct hvc_opal_priv *pv = hvc_opal_privs[hp->vtermno];
+
+	if (!pv)
+		return -EINVAL;
+	return pv->hvsi.mctrl;
+}
+
+static int hvc_opal_hvsi_tiocmset(struct hvc_struct *hp, unsigned int set,
+				unsigned int clear)
+{
+	struct hvc_opal_priv *pv = hvc_opal_privs[hp->vtermno];
+
+	pr_devel("HVSI@%x: Set modem control, set=%x,clr=%x\n",
+		 hp->vtermno, set, clear);
+
+	if (set & TIOCM_DTR)
+		hvsilib_write_mctrl(&pv->hvsi, 1);
+	else if (clear & TIOCM_DTR)
+		hvsilib_write_mctrl(&pv->hvsi, 0);
+
+	return 0;
+}
+
+static const struct hv_ops hvc_opal_hvsi_ops = {
+	.get_chars = hvc_opal_hvsi_get_chars,
+	.put_chars = hvc_opal_hvsi_put_chars,
+	.flush = opal_flush_chars,
+	.notifier_add = hvc_opal_hvsi_open,
+	.notifier_del = hvc_opal_hvsi_close,
+	.notifier_hangup = hvc_opal_hvsi_hangup,
+	.tiocmget = hvc_opal_hvsi_tiocmget,
+	.tiocmset = hvc_opal_hvsi_tiocmset,
+};
+
+static int hvc_opal_probe(struct platform_device *dev)
+{
+	const struct hv_ops *ops;
+	struct hvc_struct *hp;
+	struct hvc_opal_priv *pv;
+	hv_protocol_t proto;
+	unsigned int termno, irq, boot = 0;
+	const __be32 *reg;
+
+	if (of_device_is_compatible(dev->dev.of_node, "ibm,opal-console-raw")) {
+		proto = HV_PROTOCOL_RAW;
+		ops = &hvc_opal_raw_ops;
+	} else if (of_device_is_compatible(dev->dev.of_node,
+					   "ibm,opal-console-hvsi")) {
+		proto = HV_PROTOCOL_HVSI;
+		ops = &hvc_opal_hvsi_ops;
+	} else {
+		pr_err("hvc_opal: Unknown protocol for %pOF\n",
+		       dev->dev.of_node);
+		return -ENXIO;
+	}
+
+	reg = of_get_property(dev->dev.of_node, "reg", NULL);
+	termno = reg ? be32_to_cpup(reg) : 0;
+
+	/* Is it our boot one ? */
+	if (hvc_opal_privs[termno] == &hvc_opal_boot_priv) {
+		pv = hvc_opal_privs[termno];
+		boot = 1;
+	} else if (hvc_opal_privs[termno] == NULL) {
+		pv = kzalloc_obj(struct hvc_opal_priv);
+		if (!pv)
+			return -ENOMEM;
+		pv->proto = proto;
+		hvc_opal_privs[termno] = pv;
+		if (proto == HV_PROTOCOL_HVSI) {
+			/*
+			 * We want put_chars to be atomic to avoid mangling of
+			 * hvsi packets.
+			 */
+			hvsilib_init(&pv->hvsi,
+				     opal_get_chars, opal_put_chars_atomic,
+				     termno, 0);
+		}
+
+		/* Instanciate now to establish a mapping index==vtermno */
+		hvc_instantiate(termno, termno, ops);
+	} else {
+		pr_err("hvc_opal: Device %pOF has duplicate terminal number #%d\n",
+		       dev->dev.of_node, termno);
+		return -ENXIO;
+	}
+
+	pr_info("hvc%d: %s protocol on %pOF%s\n", termno,
+		proto == HV_PROTOCOL_RAW ? "raw" : "hvsi",
+		dev->dev.of_node,
+		boot ? " (boot console)" : "");
+
+	irq = irq_of_parse_and_map(dev->dev.of_node, 0);
+	if (!irq) {
+		pr_info("hvc%d: No interrupts property, using OPAL event\n",
+				termno);
+		irq = opal_event_request(ilog2(OPAL_EVENT_CONSOLE_INPUT));
+	}
+
+	if (!irq) {
+		pr_err("hvc_opal: Unable to map interrupt for device %pOF\n",
+			dev->dev.of_node);
+		return irq;
+	}
+
+	hp = hvc_alloc(termno, irq, ops, MAX_VIO_PUT_CHARS);
+	if (IS_ERR(hp))
+		return PTR_ERR(hp);
+
+	/* hvc consoles on powernv may need to share a single irq */
+	hp->flags = IRQF_SHARED;
+	dev_set_drvdata(&dev->dev, hp);
+
+	return 0;
+}
+
+static void hvc_opal_remove(struct platform_device *dev)
+{
+	struct hvc_struct *hp = dev_get_drvdata(&dev->dev);
+	int termno;
+
+	termno = hp->vtermno;
+	hvc_remove(hp);
+	if (hvc_opal_privs[termno] != &hvc_opal_boot_priv)
+		kfree(hvc_opal_privs[termno]);
+	hvc_opal_privs[termno] = NULL;
+}
+
+static struct platform_driver hvc_opal_driver = {
+	.probe		= hvc_opal_probe,
+	.remove		= hvc_opal_remove,
+	.driver		= {
+		.name	= hvc_opal_name,
+		.of_match_table	= hvc_opal_match,
+	}
+};
+
+static int __init hvc_opal_init(void)
+{
+	if (!firmware_has_feature(FW_FEATURE_OPAL))
+		return -ENODEV;
+
+	/* Register as a vio device to receive callbacks */
+	return platform_driver_register(&hvc_opal_driver);
+}
+device_initcall(hvc_opal_init);
+
+static void udbg_opal_putc(char c)
+{
+	unsigned int termno = hvc_opal_boot_termno;
+	int count = -1;
+
+	if (c == '\n')
+		udbg_opal_putc('\r');
+
+	do {
+		switch(hvc_opal_boot_priv.proto) {
+		case HV_PROTOCOL_RAW:
+			count = opal_put_chars(termno, &c, 1);
+			break;
+		case HV_PROTOCOL_HVSI:
+			count = hvc_opal_hvsi_put_chars(termno, &c, 1);
+			break;
+		}
+
+		/* This is needed for the cosole to flush
+		 * when there aren't any interrupts.
+		 */
+		opal_flush_console(termno);
+	} while(count == 0 || count == -EAGAIN);
+}
+
+static int udbg_opal_getc_poll(void)
+{
+	unsigned int termno = hvc_opal_boot_termno;
+	int rc = 0;
+	char c;
+
+	switch(hvc_opal_boot_priv.proto) {
+	case HV_PROTOCOL_RAW:
+		rc = opal_get_chars(termno, &c, 1);
+		break;
+	case HV_PROTOCOL_HVSI:
+		rc = hvc_opal_hvsi_get_chars(termno, &c, 1);
+		break;
+	}
+	if (!rc)
+		return -1;
+	return c;
+}
+
+static int udbg_opal_getc(void)
+{
+	int ch;
+	for (;;) {
+		ch = udbg_opal_getc_poll();
+		if (ch != -1)
+			return ch;
+	}
+}
+
+static void udbg_init_opal_common(void)
+{
+	udbg_putc = udbg_opal_putc;
+	udbg_getc = udbg_opal_getc;
+	udbg_getc_poll = udbg_opal_getc_poll;
+}
+
+void __init hvc_opal_init_early(void)
+{
+	struct device_node *stdout_node = of_node_get(of_stdout);
+	const __be32 *termno;
+	const struct hv_ops *ops;
+	u32 index;
+
+	/* If the console wasn't in /chosen, try /ibm,opal */
+	if (!stdout_node) {
+		struct device_node *opal, *np;
+
+		/* Current OPAL takeover doesn't provide the stdout
+		 * path, so we hard wire it
+		 */
+		opal = of_find_node_by_path("/ibm,opal/consoles");
+		if (opal) {
+			pr_devel("hvc_opal: Found consoles in new location\n");
+		} else {
+			opal = of_find_node_by_path("/ibm,opal");
+			if (opal)
+				pr_devel("hvc_opal: "
+					 "Found consoles in old location\n");
+		}
+		if (!opal)
+			return;
+		for_each_child_of_node(opal, np) {
+			if (of_node_name_eq(np, "serial")) {
+				stdout_node = np;
+				break;
+			}
+		}
+		of_node_put(opal);
+	}
+	if (!stdout_node)
+		return;
+	termno = of_get_property(stdout_node, "reg", NULL);
+	index = termno ? be32_to_cpup(termno) : 0;
+	if (index >= MAX_NR_HVC_CONSOLES)
+		return;
+	hvc_opal_privs[index] = &hvc_opal_boot_priv;
+
+	/* Check the protocol */
+	if (of_device_is_compatible(stdout_node, "ibm,opal-console-raw")) {
+		hvc_opal_boot_priv.proto = HV_PROTOCOL_RAW;
+		ops = &hvc_opal_raw_ops;
+		pr_devel("hvc_opal: Found RAW console\n");
+	}
+	else if (of_device_is_compatible(stdout_node,"ibm,opal-console-hvsi")) {
+		hvc_opal_boot_priv.proto = HV_PROTOCOL_HVSI;
+		ops = &hvc_opal_hvsi_ops;
+		hvsilib_init(&hvc_opal_boot_priv.hvsi,
+			     opal_get_chars, opal_put_chars_atomic,
+			     index, 1);
+		/* HVSI, perform the handshake now */
+		hvsilib_establish(&hvc_opal_boot_priv.hvsi);
+		pr_devel("hvc_opal: Found HVSI console\n");
+	} else
+		goto out;
+	hvc_opal_boot_termno = index;
+	udbg_init_opal_common();
+	add_preferred_console("hvc", index, NULL);
+	hvc_instantiate(index, index, ops);
+out:
+	of_node_put(stdout_node);
+}
+
+#ifdef CONFIG_PPC_EARLY_DEBUG_OPAL_RAW
+void __init udbg_init_debug_opal_raw(void)
+{
+	u32 index = CONFIG_PPC_EARLY_DEBUG_OPAL_VTERMNO;
+	hvc_opal_privs[index] = &hvc_opal_boot_priv;
+	hvc_opal_boot_priv.proto = HV_PROTOCOL_RAW;
+	hvc_opal_boot_termno = index;
+	udbg_init_opal_common();
+}
+#endif /* CONFIG_PPC_EARLY_DEBUG_OPAL_RAW */
+
+#ifdef CONFIG_PPC_EARLY_DEBUG_OPAL_HVSI
+void __init udbg_init_debug_opal_hvsi(void)
+{
+	u32 index = CONFIG_PPC_EARLY_DEBUG_OPAL_VTERMNO;
+	hvc_opal_privs[index] = &hvc_opal_boot_priv;
+	hvc_opal_boot_termno = index;
+	udbg_init_opal_common();
+	hvsilib_init(&hvc_opal_boot_priv.hvsi,
+		     opal_get_chars, opal_put_chars_atomic,
+		     index, 1);
+	hvsilib_establish(&hvc_opal_boot_priv.hvsi);
+}
+#endif /* CONFIG_PPC_EARLY_DEBUG_OPAL_HVSI */

linux-7.2.3/drivers/tty/hvc/hvc_riscv_sbi.c

@@ -0,0 +1,83 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2008 David Gibson, IBM Corporation
+ * Copyright (C) 2012 Regents of the University of California
+ * Copyright (C) 2017 SiFive
+ */
+
+#include <linux/console.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+
+#include <asm/sbi.h>
+
+#include "hvc_console.h"
+
+static ssize_t hvc_sbi_tty_put(uint32_t vtermno, const u8 *buf, size_t count)
+{
+	size_t i;
+
+	for (i = 0; i < count; i++)
+		sbi_console_putchar(buf[i]);
+
+	return i;
+}
+
+static ssize_t hvc_sbi_tty_get(uint32_t vtermno, u8 *buf, size_t count)
+{
+	size_t i;
+	int c;
+
+	for (i = 0; i < count; i++) {
+		c = sbi_console_getchar();
+		if (c < 0)
+			break;
+		buf[i] = c;
+	}
+
+	return i;
+}
+
+static const struct hv_ops hvc_sbi_v01_ops = {
+	.get_chars = hvc_sbi_tty_get,
+	.put_chars = hvc_sbi_tty_put,
+};
+
+static ssize_t hvc_sbi_dbcn_tty_put(uint32_t vtermno, const u8 *buf, size_t count)
+{
+	return sbi_debug_console_write(buf, count);
+}
+
+static ssize_t hvc_sbi_dbcn_tty_get(uint32_t vtermno, u8 *buf, size_t count)
+{
+	return sbi_debug_console_read(buf, count);
+}
+
+static const struct hv_ops hvc_sbi_dbcn_ops = {
+	.put_chars = hvc_sbi_dbcn_tty_put,
+	.get_chars = hvc_sbi_dbcn_tty_get,
+};
+
+static int __init hvc_sbi_init(void)
+{
+	int err;
+
+	if (sbi_debug_console_available) {
+		err = PTR_ERR_OR_ZERO(hvc_alloc(0, 0, &hvc_sbi_dbcn_ops, 256));
+		if (err)
+			return err;
+		hvc_instantiate(0, 0, &hvc_sbi_dbcn_ops);
+	} else if (IS_ENABLED(CONFIG_RISCV_SBI_V01)) {
+		err = PTR_ERR_OR_ZERO(hvc_alloc(0, 0, &hvc_sbi_v01_ops, 256));
+		if (err)
+			return err;
+		hvc_instantiate(0, 0, &hvc_sbi_v01_ops);
+	} else {
+		return -ENODEV;
+	}
+
+	return 0;
+}
+device_initcall(hvc_sbi_init);

linux-7.2.3/drivers/tty/hvc/hvc_rtas.c

@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * IBM RTAS driver interface to hvc_console.c
+ *
+ * (C) Copyright IBM Corporation 2001-2005
+ * (C) Copyright Red Hat, Inc. 2005
+ *
+ * Author(s): Maximino Augilar <IBM STI Design Center>
+ *	    : Ryan S. Arnold <rsa@us.ibm.com>
+ *	    : Utz Bacher <utz.bacher@de.ibm.com>
+ *	    : David Woodhouse <dwmw2@infradead.org>
+ *
+ *    inspired by drivers/char/hvc_console.c
+ *    written by Anton Blanchard and Paul Mackerras
+ */
+
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+
+#include <asm/irq.h>
+#include <asm/rtas.h>
+#include "hvc_console.h"
+
+#define hvc_rtas_cookie 0x67781e15
+static struct hvc_struct *hvc_rtas_dev;
+
+static int rtascons_put_char_token = RTAS_UNKNOWN_SERVICE;
+static int rtascons_get_char_token = RTAS_UNKNOWN_SERVICE;
+
+static ssize_t hvc_rtas_write_console(uint32_t vtermno, const u8 *buf,
+				      size_t count)
+{
+	size_t i;
+
+	for (i = 0; i < count; i++) {
+		if (rtas_call(rtascons_put_char_token, 1, 1, NULL, buf[i]))
+			break;
+	}
+
+	return i;
+}
+
+static ssize_t hvc_rtas_read_console(uint32_t vtermno, u8 *buf, size_t count)
+{
+	size_t i;
+	int c;
+
+	for (i = 0; i < count; i++) {
+		if (rtas_call(rtascons_get_char_token, 0, 2, &c))
+			break;
+
+		buf[i] = c;
+	}
+
+	return i;
+}
+
+static const struct hv_ops hvc_rtas_get_put_ops = {
+	.get_chars = hvc_rtas_read_console,
+	.put_chars = hvc_rtas_write_console,
+};
+
+static int __init hvc_rtas_init(void)
+{
+	struct hvc_struct *hp;
+
+	if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE)
+		rtascons_put_char_token = rtas_token("put-term-char");
+	if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE)
+		return -EIO;
+
+	if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE)
+		rtascons_get_char_token = rtas_token("get-term-char");
+	if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE)
+		return -EIO;
+
+	BUG_ON(hvc_rtas_dev);
+
+	/* Allocate an hvc_struct for the console device we instantiated
+	 * earlier.  Save off hp so that we can return it on exit */
+	hp = hvc_alloc(hvc_rtas_cookie, 0, &hvc_rtas_get_put_ops, 16);
+	if (IS_ERR(hp))
+		return PTR_ERR(hp);
+
+	hvc_rtas_dev = hp;
+
+	return 0;
+}
+device_initcall(hvc_rtas_init);
+
+/* This will happen prior to module init.  There is no tty at this time? */
+static int __init hvc_rtas_console_init(void)
+{
+	rtascons_put_char_token = rtas_token("put-term-char");
+	if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE)
+		return -EIO;
+
+	rtascons_get_char_token = rtas_token("get-term-char");
+	if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE)
+		return -EIO;
+
+	hvc_instantiate(hvc_rtas_cookie, 0, &hvc_rtas_get_put_ops);
+	add_preferred_console("hvc", 0, NULL);
+
+	return 0;
+}
+console_initcall(hvc_rtas_console_init);

linux-7.2.3/drivers/tty/hvc/hvc_udbg.c

@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * udbg interface to hvc_console.c
+ *
+ * (C) Copyright David Gibson, IBM Corporation 2008.
+ */
+
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/irq.h>
+
+#include <asm/udbg.h>
+
+#include "hvc_console.h"
+
+static struct hvc_struct *hvc_udbg_dev;
+
+static ssize_t hvc_udbg_put(uint32_t vtermno, const u8 *buf, size_t count)
+{
+	size_t i;
+
+	for (i = 0; i < count && udbg_putc; i++)
+		udbg_putc(buf[i]);
+
+	return i;
+}
+
+static ssize_t hvc_udbg_get(uint32_t vtermno, u8 *buf, size_t count)
+{
+	size_t i;
+	int c;
+
+	if (!udbg_getc_poll)
+		return 0;
+
+	for (i = 0; i < count; i++) {
+		if ((c = udbg_getc_poll()) == -1)
+			break;
+		buf[i] = c;
+	}
+
+	return i;
+}
+
+static const struct hv_ops hvc_udbg_ops = {
+	.get_chars = hvc_udbg_get,
+	.put_chars = hvc_udbg_put,
+};
+
+static int __init hvc_udbg_init(void)
+{
+	struct hvc_struct *hp;
+
+	if (!udbg_putc)
+		return -ENODEV;
+
+	BUG_ON(hvc_udbg_dev);
+
+	hp = hvc_alloc(0, 0, &hvc_udbg_ops, 16);
+	if (IS_ERR(hp))
+		return PTR_ERR(hp);
+
+	hvc_udbg_dev = hp;
+
+	return 0;
+}
+device_initcall(hvc_udbg_init);
+
+static int __init hvc_udbg_console_init(void)
+{
+	if (!udbg_putc)
+		return -ENODEV;
+
+	hvc_instantiate(0, 0, &hvc_udbg_ops);
+	add_preferred_console("hvc", 0, NULL);
+
+	return 0;
+}
+console_initcall(hvc_udbg_console_init);

linux-7.2.3/drivers/tty/hvc/hvc_vio.c

@@ -0,0 +1,475 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * vio driver interface to hvc_console.c
+ *
+ * This code was moved here to allow the remaining code to be reused as a
+ * generic polling mode with semi-reliable transport driver core to the
+ * console and tty subsystems.
+ *
+ *
+ * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
+ * Copyright (C) 2001 Paul Mackerras <paulus@au.ibm.com>, IBM
+ * Copyright (C) 2004 Benjamin Herrenschmidt <benh@kernel.crashing.org>, IBM Corp.
+ * Copyright (C) 2004 IBM Corporation
+ *
+ * Additional Author(s):
+ *  Ryan S. Arnold <rsa@us.ibm.com>
+ *
+ * TODO:
+ *
+ *   - handle error in sending hvsi protocol packets
+ *   - retry nego on subsequent sends ?
+ */
+
+#undef DEBUG
+
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/console.h>
+#include <linux/of.h>
+
+#include <asm/hvconsole.h>
+#include <asm/vio.h>
+#include <asm/hvsi.h>
+#include <asm/udbg.h>
+#include <asm/machdep.h>
+
+#include "hvc_console.h"
+
+static const char hvc_driver_name[] = "hvc_console";
+
+static const struct vio_device_id hvc_driver_table[] = {
+	{"serial", "hvterm1"},
+#ifndef HVC_OLD_HVSI
+	{"serial", "hvterm-protocol"},
+#endif
+	{ "", "" }
+};
+
+typedef enum hv_protocol {
+	HV_PROTOCOL_RAW,
+	HV_PROTOCOL_HVSI
+} hv_protocol_t;
+
+struct hvterm_priv {
+	u32			termno;	/* HV term number */
+	hv_protocol_t		proto;	/* Raw data or HVSI packets */
+	struct hvsi_priv	hvsi;	/* HVSI specific data */
+	spinlock_t		buf_lock;
+	u8			buf[SIZE_VIO_GET_CHARS];
+	size_t			left;
+	size_t			offset;
+};
+static struct hvterm_priv *hvterm_privs[MAX_NR_HVC_CONSOLES];
+/* For early boot console */
+static struct hvterm_priv hvterm_priv0;
+
+static ssize_t hvterm_raw_get_chars(uint32_t vtermno, u8 *buf, size_t count)
+{
+	struct hvterm_priv *pv = hvterm_privs[vtermno];
+	unsigned long i;
+	unsigned long flags;
+	size_t got;
+
+	if (WARN_ON(!pv))
+		return 0;
+
+	spin_lock_irqsave(&pv->buf_lock, flags);
+
+	if (pv->left == 0) {
+		pv->offset = 0;
+		pv->left = hvc_get_chars(pv->termno, pv->buf, count);
+
+		/*
+		 * Work around a HV bug where it gives us a null
+		 * after every \r.  -- paulus
+		 */
+		for (i = 1; i < pv->left; ++i) {
+			if (pv->buf[i] == 0 && pv->buf[i-1] == '\r') {
+				--pv->left;
+				if (i < pv->left) {
+					memmove(&pv->buf[i], &pv->buf[i+1],
+						pv->left - i);
+				}
+			}
+		}
+	}
+
+	got = min(count, pv->left);
+	memcpy(buf, &pv->buf[pv->offset], got);
+	pv->offset += got;
+	pv->left -= got;
+
+	spin_unlock_irqrestore(&pv->buf_lock, flags);
+
+	return got;
+}
+
+/**
+ * hvterm_raw_put_chars: send characters to firmware for given vterm adapter
+ * @vtermno: The virtual terminal number.
+ * @buf: The characters to send. Because of the underlying hypercall in
+ *       hvc_put_chars(), this buffer must be at least 16 bytes long, even if
+ *       you are sending fewer chars.
+ * @count: number of chars to send.
+ */
+static ssize_t hvterm_raw_put_chars(uint32_t vtermno, const u8 *buf,
+				    size_t count)
+{
+	struct hvterm_priv *pv = hvterm_privs[vtermno];
+
+	if (WARN_ON(!pv))
+		return 0;
+
+	return hvc_put_chars(pv->termno, buf, count);
+}
+
+static const struct hv_ops hvterm_raw_ops = {
+	.get_chars = hvterm_raw_get_chars,
+	.put_chars = hvterm_raw_put_chars,
+	.notifier_add = notifier_add_irq,
+	.notifier_del = notifier_del_irq,
+	.notifier_hangup = notifier_hangup_irq,
+};
+
+static ssize_t hvterm_hvsi_get_chars(uint32_t vtermno, u8 *buf, size_t count)
+{
+	struct hvterm_priv *pv = hvterm_privs[vtermno];
+
+	if (WARN_ON(!pv))
+		return 0;
+
+	return hvsilib_get_chars(&pv->hvsi, buf, count);
+}
+
+static ssize_t hvterm_hvsi_put_chars(uint32_t vtermno, const u8 *buf,
+				     size_t count)
+{
+	struct hvterm_priv *pv = hvterm_privs[vtermno];
+
+	if (WARN_ON(!pv))
+		return 0;
+
+	return hvsilib_put_chars(&pv->hvsi, buf, count);
+}
+
+static int hvterm_hvsi_open(struct hvc_struct *hp, int data)
+{
+	struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
+	int rc;
+
+	pr_devel("HVSI@%x: open !\n", pv->termno);
+
+	rc = notifier_add_irq(hp, data);
+	if (rc)
+		return rc;
+
+	return hvsilib_open(&pv->hvsi, hp);
+}
+
+static void hvterm_hvsi_close(struct hvc_struct *hp, int data)
+{
+	struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
+
+	pr_devel("HVSI@%x: do close !\n", pv->termno);
+
+	hvsilib_close(&pv->hvsi, hp);
+
+	notifier_del_irq(hp, data);
+}
+
+static void hvterm_hvsi_hangup(struct hvc_struct *hp, int data)
+{
+	struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
+
+	pr_devel("HVSI@%x: do hangup !\n", pv->termno);
+
+	hvsilib_close(&pv->hvsi, hp);
+
+	notifier_hangup_irq(hp, data);
+}
+
+static int hvterm_hvsi_tiocmget(struct hvc_struct *hp)
+{
+	struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
+
+	if (!pv)
+		return -EINVAL;
+	return pv->hvsi.mctrl;
+}
+
+static int hvterm_hvsi_tiocmset(struct hvc_struct *hp, unsigned int set,
+				unsigned int clear)
+{
+	struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
+
+	pr_devel("HVSI@%x: Set modem control, set=%x,clr=%x\n",
+		 pv->termno, set, clear);
+
+	if (set & TIOCM_DTR)
+		hvsilib_write_mctrl(&pv->hvsi, 1);
+	else if (clear & TIOCM_DTR)
+		hvsilib_write_mctrl(&pv->hvsi, 0);
+
+	return 0;
+}
+
+static const struct hv_ops hvterm_hvsi_ops = {
+	.get_chars = hvterm_hvsi_get_chars,
+	.put_chars = hvterm_hvsi_put_chars,
+	.notifier_add = hvterm_hvsi_open,
+	.notifier_del = hvterm_hvsi_close,
+	.notifier_hangup = hvterm_hvsi_hangup,
+	.tiocmget = hvterm_hvsi_tiocmget,
+	.tiocmset = hvterm_hvsi_tiocmset,
+};
+
+static void udbg_hvc_putc(char c)
+{
+	int count = -1;
+	unsigned char bounce_buffer[16];
+
+	if (!hvterm_privs[0])
+		return;
+
+	if (c == '\n')
+		udbg_hvc_putc('\r');
+
+	do {
+		switch(hvterm_privs[0]->proto) {
+		case HV_PROTOCOL_RAW:
+			/*
+			 * hvterm_raw_put_chars requires at least a 16-byte
+			 * buffer, so go via the bounce buffer
+			 */
+			bounce_buffer[0] = c;
+			count = hvterm_raw_put_chars(0, bounce_buffer, 1);
+			break;
+		case HV_PROTOCOL_HVSI:
+			count = hvterm_hvsi_put_chars(0, &c, 1);
+			break;
+		}
+	} while (count == 0 || count == -EAGAIN);
+}
+
+static int udbg_hvc_getc_poll(void)
+{
+	int rc = 0;
+	char c;
+
+	if (!hvterm_privs[0])
+		return -1;
+
+	switch(hvterm_privs[0]->proto) {
+	case HV_PROTOCOL_RAW:
+		rc = hvterm_raw_get_chars(0, &c, 1);
+		break;
+	case HV_PROTOCOL_HVSI:
+		rc = hvterm_hvsi_get_chars(0, &c, 1);
+		break;
+	}
+	if (!rc)
+		return -1;
+	return c;
+}
+
+static int udbg_hvc_getc(void)
+{
+	int ch;
+
+	if (!hvterm_privs[0])
+		return -1;
+
+	for (;;) {
+		ch = udbg_hvc_getc_poll();
+		if (ch == -1) {
+			/* This shouldn't be needed...but... */
+			volatile unsigned long delay;
+			for (delay=0; delay < 2000000; delay++)
+				;
+		} else {
+			return ch;
+		}
+	}
+}
+
+static int hvc_vio_probe(struct vio_dev *vdev,
+				   const struct vio_device_id *id)
+{
+	const struct hv_ops *ops;
+	struct hvc_struct *hp;
+	struct hvterm_priv *pv;
+	hv_protocol_t proto;
+	int i, termno = -1;
+
+	/* probed with invalid parameters. */
+	if (!vdev || !id)
+		return -EPERM;
+
+	if (of_device_is_compatible(vdev->dev.of_node, "hvterm1")) {
+		proto = HV_PROTOCOL_RAW;
+		ops = &hvterm_raw_ops;
+	} else if (of_device_is_compatible(vdev->dev.of_node, "hvterm-protocol")) {
+		proto = HV_PROTOCOL_HVSI;
+		ops = &hvterm_hvsi_ops;
+	} else {
+		pr_err("hvc_vio: Unknown protocol for %pOF\n", vdev->dev.of_node);
+		return -ENXIO;
+	}
+
+	pr_devel("hvc_vio_probe() device %pOF, using %s protocol\n",
+		 vdev->dev.of_node,
+		 proto == HV_PROTOCOL_RAW ? "raw" : "hvsi");
+
+	/* Is it our boot one ? */
+	if (hvterm_privs[0] == &hvterm_priv0 &&
+	    vdev->unit_address == hvterm_priv0.termno) {
+		pv = hvterm_privs[0];
+		termno = 0;
+		pr_devel("->boot console, using termno 0\n");
+	}
+	/* nope, allocate a new one */
+	else {
+		for (i = 0; i < MAX_NR_HVC_CONSOLES && termno < 0; i++)
+			if (!hvterm_privs[i])
+				termno = i;
+		pr_devel("->non-boot console, using termno %d\n", termno);
+		if (termno < 0)
+			return -ENODEV;
+		pv = kzalloc_obj(struct hvterm_priv);
+		if (!pv)
+			return -ENOMEM;
+		pv->termno = vdev->unit_address;
+		pv->proto = proto;
+		spin_lock_init(&pv->buf_lock);
+		hvterm_privs[termno] = pv;
+		hvsilib_init(&pv->hvsi, hvc_get_chars, hvc_put_chars,
+			     pv->termno, 0);
+	}
+
+	hp = hvc_alloc(termno, vdev->irq, ops, MAX_VIO_PUT_CHARS);
+	if (IS_ERR(hp))
+		return PTR_ERR(hp);
+	dev_set_drvdata(&vdev->dev, hp);
+
+	/* register udbg if it's not there already for console 0 */
+	if (hp->index == 0 && !udbg_putc) {
+		udbg_putc = udbg_hvc_putc;
+		udbg_getc = udbg_hvc_getc;
+		udbg_getc_poll = udbg_hvc_getc_poll;
+	}
+
+	return 0;
+}
+
+static struct vio_driver hvc_vio_driver = {
+	.id_table	= hvc_driver_table,
+	.probe		= hvc_vio_probe,
+	.name		= hvc_driver_name,
+	.driver = {
+		.suppress_bind_attrs	= true,
+	},
+};
+
+static int __init hvc_vio_init(void)
+{
+	int rc;
+
+	/* Register as a vio device to receive callbacks */
+	rc = vio_register_driver(&hvc_vio_driver);
+
+	return rc;
+}
+device_initcall(hvc_vio_init); /* after drivers/tty/hvc/hvc_console.c */
+
+void __init hvc_vio_init_early(void)
+{
+	const __be32 *termno;
+	const struct hv_ops *ops;
+
+	/* find the boot console from /chosen/stdout */
+	/* Check if it's a virtual terminal */
+	if (!of_node_name_prefix(of_stdout, "vty"))
+		return;
+	termno = of_get_property(of_stdout, "reg", NULL);
+	if (termno == NULL)
+		return;
+	hvterm_priv0.termno = of_read_number(termno, 1);
+	spin_lock_init(&hvterm_priv0.buf_lock);
+	hvterm_privs[0] = &hvterm_priv0;
+
+	/* Check the protocol */
+	if (of_device_is_compatible(of_stdout, "hvterm1")) {
+		hvterm_priv0.proto = HV_PROTOCOL_RAW;
+		ops = &hvterm_raw_ops;
+	}
+	else if (of_device_is_compatible(of_stdout, "hvterm-protocol")) {
+		hvterm_priv0.proto = HV_PROTOCOL_HVSI;
+		ops = &hvterm_hvsi_ops;
+		hvsilib_init(&hvterm_priv0.hvsi, hvc_get_chars, hvc_put_chars,
+			     hvterm_priv0.termno, 1);
+		/* HVSI, perform the handshake now */
+		hvsilib_establish(&hvterm_priv0.hvsi);
+	} else
+		return;
+	udbg_putc = udbg_hvc_putc;
+	udbg_getc = udbg_hvc_getc;
+	udbg_getc_poll = udbg_hvc_getc_poll;
+#ifdef HVC_OLD_HVSI
+	/* When using the old HVSI driver don't register the HVC
+	 * backend for HVSI, only do udbg
+	 */
+	if (hvterm_priv0.proto == HV_PROTOCOL_HVSI)
+		return;
+#endif
+	/* Check whether the user has requested a different console. */
+	if (!strstr(boot_command_line, "console="))
+		add_preferred_console("hvc", 0, NULL);
+	hvc_instantiate(0, 0, ops);
+}
+
+/* call this from early_init() for a working debug console on
+ * vterm capable LPAR machines
+ */
+#ifdef CONFIG_PPC_EARLY_DEBUG_LPAR
+void __init udbg_init_debug_lpar(void)
+{
+	/*
+	 * If we're running as a hypervisor then we definitely can't call the
+	 * hypervisor to print debug output (we *are* the hypervisor), so don't
+	 * register if we detect that MSR_HV=1.
+	 */
+	if (mfmsr() & MSR_HV)
+		return;
+
+	hvterm_privs[0] = &hvterm_priv0;
+	hvterm_priv0.termno = 0;
+	hvterm_priv0.proto = HV_PROTOCOL_RAW;
+	spin_lock_init(&hvterm_priv0.buf_lock);
+	udbg_putc = udbg_hvc_putc;
+	udbg_getc = udbg_hvc_getc;
+	udbg_getc_poll = udbg_hvc_getc_poll;
+}
+#endif /* CONFIG_PPC_EARLY_DEBUG_LPAR */
+
+#ifdef CONFIG_PPC_EARLY_DEBUG_LPAR_HVSI
+void __init udbg_init_debug_lpar_hvsi(void)
+{
+	/* See comment above in udbg_init_debug_lpar() */
+	if (mfmsr() & MSR_HV)
+		return;
+
+	hvterm_privs[0] = &hvterm_priv0;
+	hvterm_priv0.termno = CONFIG_PPC_EARLY_DEBUG_HVSI_VTERMNO;
+	hvterm_priv0.proto = HV_PROTOCOL_HVSI;
+	spin_lock_init(&hvterm_priv0.buf_lock);
+	udbg_putc = udbg_hvc_putc;
+	udbg_getc = udbg_hvc_getc;
+	udbg_getc_poll = udbg_hvc_getc_poll;
+	hvsilib_init(&hvterm_priv0.hvsi, hvc_get_chars, hvc_put_chars,
+		     hvterm_priv0.termno, 1);
+	hvsilib_establish(&hvterm_priv0.hvsi);
+}
+#endif /* CONFIG_PPC_EARLY_DEBUG_LPAR_HVSI */

linux-7.2.3/drivers/tty/hvc/hvc_xen.c

@@ -0,0 +1,794 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * xen console driver interface to hvc_console.c
+ *
+ * (c) 2007 Gerd Hoffmann <kraxel@suse.de>
+ */
+
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/irq.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/serial_core.h>
+
+#include <asm/io.h>
+#include <asm/xen/hypervisor.h>
+
+#include <xen/xen.h>
+#include <xen/interface/xen.h>
+#include <xen/hvm.h>
+#include <xen/grant_table.h>
+#include <xen/page.h>
+#include <xen/events.h>
+#include <xen/interface/io/console.h>
+#include <xen/interface/sched.h>
+#include <xen/hvc-console.h>
+#include <xen/xenbus.h>
+
+#include "hvc_console.h"
+
+#define HVC_COOKIE   0x58656e /* "Xen" in hex */
+
+struct xencons_info {
+	struct list_head list;
+	struct xenbus_device *xbdev;
+	struct xencons_interface *intf;
+	unsigned int evtchn;
+	XENCONS_RING_IDX out_cons;
+	unsigned int out_cons_same;
+	struct hvc_struct *hvc;
+	int irq;
+	int vtermno;
+	grant_ref_t gntref;
+	spinlock_t ring_lock;
+};
+
+static LIST_HEAD(xenconsoles);
+static DEFINE_SPINLOCK(xencons_lock);
+
+/* ------------------------------------------------------------------ */
+
+static bool xen_console_io = false;
+static int __initdata opt_console_io = -1;
+
+static int __init parse_xen_console_io(char *arg)
+{
+	bool val;
+	int ret;
+
+	ret = kstrtobool(arg, &val);
+	if (ret == 0)
+		opt_console_io = (int)val;
+
+	return ret;
+}
+early_param("xen_console_io", parse_xen_console_io);
+
+static struct xencons_info *vtermno_to_xencons(int vtermno)
+{
+	struct xencons_info *entry, *ret = NULL;
+	unsigned long flags;
+
+	spin_lock_irqsave(&xencons_lock, flags);
+	if (list_empty(&xenconsoles)) {
+		spin_unlock_irqrestore(&xencons_lock, flags);
+		return NULL;
+	}
+
+	list_for_each_entry(entry, &xenconsoles, list) {
+		if (entry->vtermno == vtermno) {
+			ret  = entry;
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&xencons_lock, flags);
+
+	return ret;
+}
+
+static inline int xenbus_devid_to_vtermno(int devid)
+{
+	return devid + HVC_COOKIE;
+}
+
+static inline void notify_daemon(struct xencons_info *cons)
+{
+	/* Use evtchn: this is called early, before irq is set up. */
+	notify_remote_via_evtchn(cons->evtchn);
+}
+
+static ssize_t __write_console(struct xencons_info *xencons,
+			       const u8 *data, size_t len)
+{
+	XENCONS_RING_IDX cons, prod;
+	struct xencons_interface *intf = xencons->intf;
+	unsigned long flags;
+	size_t sent = 0;
+
+	spin_lock_irqsave(&xencons->ring_lock, flags);
+	cons = intf->out_cons;
+	prod = intf->out_prod;
+	mb();			/* update queue values before going on */
+
+	if ((prod - cons) > sizeof(intf->out)) {
+		spin_unlock_irqrestore(&xencons->ring_lock, flags);
+		pr_err_once("xencons: Illegal ring page indices");
+		return -EINVAL;
+	}
+
+	while ((sent < len) && ((prod - cons) < sizeof(intf->out)))
+		intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++];
+
+	wmb();			/* write ring before updating pointer */
+	intf->out_prod = prod;
+	spin_unlock_irqrestore(&xencons->ring_lock, flags);
+
+	if (sent)
+		notify_daemon(xencons);
+	return sent;
+}
+
+static ssize_t domU_write_console(uint32_t vtermno, const u8 *data, size_t len)
+{
+	struct xencons_info *cons = vtermno_to_xencons(vtermno);
+	size_t ret = len;
+
+	if (cons == NULL)
+		return -EINVAL;
+
+	if (cons->intf->connection == XENCONSOLE_DISCONNECTED)
+		return -ENOTCONN;
+
+	/*
+	 * Make sure the whole buffer is emitted, polling if
+	 * necessary.  We don't ever want to rely on the hvc daemon
+	 * because the most interesting console output is when the
+	 * kernel is crippled.
+	 */
+	while (len) {
+		ssize_t sent = __write_console(cons, data, len);
+
+		if (sent < 0)
+			return sent;
+
+		data += sent;
+		len -= sent;
+
+		if (unlikely(len))
+			HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
+	}
+
+	return ret;
+}
+
+static ssize_t domU_read_console(uint32_t vtermno, u8 *buf, size_t len)
+{
+	struct xencons_interface *intf;
+	XENCONS_RING_IDX cons, prod;
+	struct xencons_info *xencons = vtermno_to_xencons(vtermno);
+	unsigned int eoiflag = 0;
+	unsigned long flags;
+	size_t recv = 0;
+
+	if (xencons == NULL)
+		return -EINVAL;
+	intf = xencons->intf;
+
+	spin_lock_irqsave(&xencons->ring_lock, flags);
+	cons = intf->in_cons;
+	prod = intf->in_prod;
+	mb();			/* get pointers before reading ring */
+
+	if ((prod - cons) > sizeof(intf->in)) {
+		spin_unlock_irqrestore(&xencons->ring_lock, flags);
+		pr_err_once("xencons: Illegal ring page indices");
+		return -EINVAL;
+	}
+
+	while (cons != prod && recv < len)
+		buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];
+
+	mb();			/* read ring before consuming */
+	intf->in_cons = cons;
+
+	/*
+	 * When to mark interrupt having been spurious:
+	 * - there was no new data to be read, and
+	 * - the backend did not consume some output bytes, and
+	 * - the previous round with no read data didn't see consumed bytes
+	 *   (we might have a race with an interrupt being in flight while
+	 *   updating xencons->out_cons, so account for that by allowing one
+	 *   round without any visible reason)
+	 */
+	if (intf->out_cons != xencons->out_cons) {
+		xencons->out_cons = intf->out_cons;
+		xencons->out_cons_same = 0;
+	}
+	if (!recv && xencons->out_cons_same++ > 1) {
+		eoiflag = XEN_EOI_FLAG_SPURIOUS;
+	}
+	spin_unlock_irqrestore(&xencons->ring_lock, flags);
+
+	if (recv) {
+		notify_daemon(xencons);
+	}
+
+	xen_irq_lateeoi(xencons->irq, eoiflag);
+
+	return recv;
+}
+
+static const struct hv_ops domU_hvc_ops = {
+	.get_chars = domU_read_console,
+	.put_chars = domU_write_console,
+	.notifier_add = notifier_add_irq,
+	.notifier_del = notifier_del_irq,
+	.notifier_hangup = notifier_hangup_irq,
+};
+
+static ssize_t dom0_read_console(uint32_t vtermno, u8 *buf, size_t len)
+{
+	return HYPERVISOR_console_io(CONSOLEIO_read, len, buf);
+}
+
+/*
+ * Either for a dom0 to write to the system console, or a domU with a
+ * debug version of Xen
+ */
+static ssize_t dom0_write_console(uint32_t vtermno, const u8 *str, size_t len)
+{
+	int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (u8 *)str);
+	if (rc < 0)
+		return rc;
+
+	return len;
+}
+
+static const struct hv_ops dom0_hvc_ops = {
+	.get_chars = dom0_read_console,
+	.put_chars = dom0_write_console,
+	.notifier_add = notifier_add_irq,
+	.notifier_del = notifier_del_irq,
+	.notifier_hangup = notifier_hangup_irq,
+};
+
+static int xen_hvm_console_init(void)
+{
+	int r;
+	uint64_t v = 0;
+	unsigned long gfn, flags;
+	struct xencons_info *info;
+
+	if (!xen_hvm_domain())
+		return -ENODEV;
+
+	info = vtermno_to_xencons(HVC_COOKIE);
+	if (!info) {
+		info = kzalloc_obj(struct xencons_info);
+		if (!info)
+			return -ENOMEM;
+		spin_lock_init(&info->ring_lock);
+	} else if (info->intf != NULL) {
+		/* already configured */
+		return 0;
+	}
+	/*
+	 * If the toolstack (or the hypervisor) hasn't set these values, the
+	 * default value is 0. Even though gfn = 0 and evtchn = 0 are
+	 * theoretically correct values, in practice they never are and they
+	 * mean that a legacy toolstack hasn't initialized the pv console correctly.
+	 */
+	r = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
+	if (r < 0 || v == 0)
+		goto err;
+	info->evtchn = v;
+	v = 0;
+	r = hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v);
+	if (r < 0 || v == 0)
+		goto err;
+	gfn = v;
+	info->intf = memremap(gfn << XEN_PAGE_SHIFT, XEN_PAGE_SIZE, MEMREMAP_WB);
+	if (info->intf == NULL)
+		goto err;
+	info->vtermno = HVC_COOKIE;
+
+	spin_lock_irqsave(&xencons_lock, flags);
+	list_add_tail(&info->list, &xenconsoles);
+	spin_unlock_irqrestore(&xencons_lock, flags);
+
+	return 0;
+err:
+	kfree(info);
+	return -ENODEV;
+}
+
+static int xencons_info_pv_init(struct xencons_info *info, int vtermno)
+{
+	spin_lock_init(&info->ring_lock);
+	info->evtchn = xen_start_info->console.domU.evtchn;
+	/* GFN == MFN for PV guest */
+	info->intf = gfn_to_virt(xen_start_info->console.domU.mfn);
+	info->vtermno = vtermno;
+
+	list_add_tail(&info->list, &xenconsoles);
+
+	return 0;
+}
+
+static int xen_pv_console_init(void)
+{
+	struct xencons_info *info;
+	unsigned long flags;
+
+	if (!xen_pv_domain())
+		return -ENODEV;
+
+	if (!xen_start_info->console.domU.evtchn)
+		return -ENODEV;
+
+	info = vtermno_to_xencons(HVC_COOKIE);
+	if (!info) {
+		info = kzalloc_obj(struct xencons_info);
+		if (!info)
+			return -ENOMEM;
+	} else if (info->intf != NULL) {
+		/* already configured */
+		return 0;
+	}
+	spin_lock_irqsave(&xencons_lock, flags);
+	xencons_info_pv_init(info, HVC_COOKIE);
+	spin_unlock_irqrestore(&xencons_lock, flags);
+
+	return 0;
+}
+
+static int xen_initial_domain_console_init(void)
+{
+	struct xencons_info *info;
+	unsigned long flags;
+
+	if (!xen_console_io)
+		return -ENODEV;
+
+	info = vtermno_to_xencons(HVC_COOKIE);
+	if (!info) {
+		info = kzalloc_obj(struct xencons_info);
+		if (!info)
+			return -ENOMEM;
+		spin_lock_init(&info->ring_lock);
+	}
+
+	info->irq = bind_virq_to_irq(VIRQ_CONSOLE, 0, false);
+	info->vtermno = HVC_COOKIE;
+
+	spin_lock_irqsave(&xencons_lock, flags);
+	list_add_tail(&info->list, &xenconsoles);
+	spin_unlock_irqrestore(&xencons_lock, flags);
+
+	return 0;
+}
+
+static void xen_console_update_evtchn(struct xencons_info *info)
+{
+	if (xen_hvm_domain()) {
+		uint64_t v = 0;
+		int err;
+
+		err = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
+		if (!err && v)
+			info->evtchn = v;
+	} else
+		info->evtchn = xen_start_info->console.domU.evtchn;
+}
+
+void xen_console_resume(void)
+{
+	struct xencons_info *info = vtermno_to_xencons(HVC_COOKIE);
+	if (info != NULL && info->irq) {
+		if (!xen_console_io)
+			xen_console_update_evtchn(info);
+		rebind_evtchn_irq(info->evtchn, info->irq);
+	}
+}
+
+#ifdef CONFIG_HVC_XEN_FRONTEND
+static void xencons_disconnect_backend(struct xencons_info *info)
+{
+	if (info->hvc != NULL)
+		hvc_remove(info->hvc);
+	info->hvc = NULL;
+	if (info->irq > 0) {
+		evtchn_put(info->evtchn);
+		info->irq = 0;
+		info->evtchn = 0;
+	}
+	/* evtchn_put() will also close it so this is only an error path */
+	if (info->evtchn > 0)
+		xenbus_free_evtchn(info->xbdev, info->evtchn);
+	info->evtchn = 0;
+	if (info->gntref > 0)
+		gnttab_free_grant_references(info->gntref);
+	info->gntref = 0;
+}
+
+static void xencons_free(struct xencons_info *info)
+{
+	free_page((unsigned long)info->intf);
+	info->intf = NULL;
+	info->vtermno = 0;
+	kfree(info);
+}
+
+static int xen_console_remove(struct xencons_info *info)
+{
+	unsigned long flags;
+
+	xencons_disconnect_backend(info);
+	spin_lock_irqsave(&xencons_lock, flags);
+	list_del(&info->list);
+	spin_unlock_irqrestore(&xencons_lock, flags);
+	if (info->xbdev != NULL)
+		xencons_free(info);
+	else {
+		if (xen_hvm_domain())
+			iounmap(info->intf);
+		kfree(info);
+	}
+	return 0;
+}
+
+static void xencons_remove(struct xenbus_device *dev)
+{
+	xen_console_remove(dev_get_drvdata(&dev->dev));
+}
+
+static int xencons_connect_backend(struct xenbus_device *dev,
+				  struct xencons_info *info)
+{
+	int ret, evtchn, devid, ref, irq;
+	struct xenbus_transaction xbt;
+	grant_ref_t gref_head;
+
+	ret = xenbus_alloc_evtchn(dev, &evtchn);
+	if (ret)
+		return ret;
+	info->evtchn = evtchn;
+	irq = bind_evtchn_to_irq_lateeoi(evtchn);
+	if (irq < 0)
+		return irq;
+	info->irq = irq;
+	devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
+	info->hvc = hvc_alloc(xenbus_devid_to_vtermno(devid),
+			irq, &domU_hvc_ops, 256);
+	if (IS_ERR(info->hvc))
+		return PTR_ERR(info->hvc);
+	ret = gnttab_alloc_grant_references(1, &gref_head);
+	if (ret < 0)
+		return ret;
+	info->gntref = gref_head;
+	ref = gnttab_claim_grant_reference(&gref_head);
+	if (ref < 0)
+		return ref;
+	gnttab_grant_foreign_access_ref(ref, info->xbdev->otherend_id,
+					virt_to_gfn(info->intf), 0);
+
+ again:
+	ret = xenbus_transaction_start(&xbt);
+	if (ret) {
+		xenbus_dev_fatal(dev, ret, "starting transaction");
+		return ret;
+	}
+	ret = xenbus_printf(xbt, dev->nodename, "ring-ref", "%d", ref);
+	if (ret)
+		goto error_xenbus;
+	ret = xenbus_printf(xbt, dev->nodename, "port", "%u",
+			    evtchn);
+	if (ret)
+		goto error_xenbus;
+	ret = xenbus_transaction_end(xbt, 0);
+	if (ret) {
+		if (ret == -EAGAIN)
+			goto again;
+		xenbus_dev_fatal(dev, ret, "completing transaction");
+		return ret;
+	}
+
+	xenbus_switch_state(dev, XenbusStateInitialised);
+	return 0;
+
+ error_xenbus:
+	xenbus_transaction_end(xbt, 1);
+	xenbus_dev_fatal(dev, ret, "writing xenstore");
+	return ret;
+}
+
+static int xencons_probe(struct xenbus_device *dev,
+				  const struct xenbus_device_id *id)
+{
+	int ret, devid;
+	struct xencons_info *info;
+	unsigned long flags;
+
+	devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
+	if (devid == 0)
+		return -ENODEV;
+
+	info = kzalloc_obj(struct xencons_info);
+	if (!info)
+		return -ENOMEM;
+	spin_lock_init(&info->ring_lock);
+	dev_set_drvdata(&dev->dev, info);
+	info->xbdev = dev;
+	info->vtermno = xenbus_devid_to_vtermno(devid);
+	info->intf = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
+	if (!info->intf)
+		goto error_nomem;
+
+	ret = xencons_connect_backend(dev, info);
+	if (ret < 0)
+		goto error;
+	spin_lock_irqsave(&xencons_lock, flags);
+	list_add_tail(&info->list, &xenconsoles);
+	spin_unlock_irqrestore(&xencons_lock, flags);
+
+	return 0;
+
+ error_nomem:
+	ret = -ENOMEM;
+	xenbus_dev_fatal(dev, ret, "allocating device memory");
+ error:
+	xencons_disconnect_backend(info);
+	xencons_free(info);
+	return ret;
+}
+
+static int xencons_resume(struct xenbus_device *dev)
+{
+	struct xencons_info *info = dev_get_drvdata(&dev->dev);
+
+	xencons_disconnect_backend(info);
+	memset(info->intf, 0, XEN_PAGE_SIZE);
+	return xencons_connect_backend(dev, info);
+}
+
+static void xencons_backend_changed(struct xenbus_device *dev,
+				   enum xenbus_state backend_state)
+{
+	switch (backend_state) {
+	case XenbusStateReconfiguring:
+	case XenbusStateReconfigured:
+	case XenbusStateInitialising:
+	case XenbusStateInitialised:
+	case XenbusStateUnknown:
+		break;
+
+	case XenbusStateInitWait:
+		break;
+
+	case XenbusStateConnected:
+		xenbus_switch_state(dev, XenbusStateConnected);
+		break;
+
+	case XenbusStateClosed:
+		if (dev->state == XenbusStateClosed)
+			break;
+		fallthrough;	/* Missed the backend's CLOSING state */
+	case XenbusStateClosing: {
+		struct xencons_info *info = dev_get_drvdata(&dev->dev);
+
+		/*
+		 * Don't tear down the evtchn and grant ref before the other
+		 * end has disconnected, but do stop userspace from trying
+		 * to use the device before we allow the backend to close.
+		 */
+		if (info->hvc) {
+			hvc_remove(info->hvc);
+			info->hvc = NULL;
+		}
+
+		xenbus_frontend_closed(dev);
+		break;
+	}
+	}
+}
+
+static const struct xenbus_device_id xencons_ids[] = {
+	{ "console" },
+	{ "" }
+};
+
+static struct xenbus_driver xencons_driver = {
+	.name = "xenconsole",
+	.ids = xencons_ids,
+	.probe = xencons_probe,
+	.remove = xencons_remove,
+	.resume = xencons_resume,
+	.otherend_changed = xencons_backend_changed,
+	.not_essential = true,
+};
+#endif /* CONFIG_HVC_XEN_FRONTEND */
+
+static int __init xen_hvc_init(void)
+{
+	int r;
+	struct xencons_info *info;
+	const struct hv_ops *ops;
+
+	if (!xen_domain())
+		return -ENODEV;
+
+	if (xen_console_io) {
+		ops = &dom0_hvc_ops;
+		r = xen_initial_domain_console_init();
+		if (r < 0)
+			goto register_fe;
+		info = vtermno_to_xencons(HVC_COOKIE);
+	} else {
+		ops = &domU_hvc_ops;
+		if (xen_hvm_domain())
+			r = xen_hvm_console_init();
+		else
+			r = xen_pv_console_init();
+		if (r < 0)
+			goto register_fe;
+
+		info = vtermno_to_xencons(HVC_COOKIE);
+		info->irq = bind_evtchn_to_irq_lateeoi(info->evtchn);
+	}
+	if (info->irq < 0)
+		info->irq = 0; /* NO_IRQ */
+	else
+		irq_set_noprobe(info->irq);
+
+	info->hvc = hvc_alloc(HVC_COOKIE, info->irq, ops, 256);
+	if (IS_ERR(info->hvc)) {
+		unsigned long flags;
+
+		r = PTR_ERR(info->hvc);
+		spin_lock_irqsave(&xencons_lock, flags);
+		list_del(&info->list);
+		spin_unlock_irqrestore(&xencons_lock, flags);
+		if (info->irq)
+			evtchn_put(info->evtchn);
+		kfree(info);
+		return r;
+	}
+
+	r = 0;
+ register_fe:
+#ifdef CONFIG_HVC_XEN_FRONTEND
+	r = xenbus_register_frontend(&xencons_driver);
+#endif
+	return r;
+}
+device_initcall(xen_hvc_init);
+
+static int __init xen_cons_init(void)
+{
+	const struct hv_ops *ops;
+
+	xen_console_io = opt_console_io >= 0 ? opt_console_io :
+					       xen_initial_domain();
+
+	if (!xen_domain())
+		return 0;
+
+	if (xen_console_io)
+		ops = &dom0_hvc_ops;
+	else {
+		int r;
+		ops = &domU_hvc_ops;
+
+		if (xen_hvm_domain())
+			r = xen_hvm_console_init();
+		else
+			r = xen_pv_console_init();
+		if (r < 0)
+			return r;
+	}
+
+	hvc_instantiate(HVC_COOKIE, 0, ops);
+	return 0;
+}
+console_initcall(xen_cons_init);
+
+#ifdef CONFIG_X86
+static void xen_hvm_early_write(uint32_t vtermno, const char *str, int len)
+{
+	if (xen_cpuid_base())
+		outsb(0xe9, str, len);
+}
+#else
+static void xen_hvm_early_write(uint32_t vtermno, const char *str, int len) { }
+#endif
+
+#ifdef CONFIG_EARLY_PRINTK
+static int __init xenboot_console_setup(struct console *console, char *string)
+{
+	static struct xencons_info xenboot;
+
+	if (xen_initial_domain() || !xen_pv_domain())
+		return 0;
+
+	return xencons_info_pv_init(&xenboot, 0);
+}
+
+static void xenboot_write_console(struct console *console, const char *string,
+				  unsigned len)
+{
+	unsigned int linelen, off = 0;
+	const char *pos;
+
+	if (dom0_write_console(0, string, len) >= 0)
+		return;
+
+	if (!xen_pv_domain()) {
+		xen_hvm_early_write(0, string, len);
+		return;
+	}
+
+	if (domU_write_console(0, "(early) ", 8) < 0)
+		return;
+	while (off < len && NULL != (pos = strchr(string+off, '\n'))) {
+		linelen = pos-string+off;
+		if (off + linelen > len)
+			break;
+		domU_write_console(0, string+off, linelen);
+		domU_write_console(0, "\r\n", 2);
+		off += linelen + 1;
+	}
+	if (off < len)
+		domU_write_console(0, string+off, len-off);
+}
+
+struct console xenboot_console = {
+	.name		= "xenboot",
+	.write		= xenboot_write_console,
+	.setup		= xenboot_console_setup,
+	.flags		= CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME,
+	.index		= -1,
+};
+#endif	/* CONFIG_EARLY_PRINTK */
+
+void xen_raw_console_write(const char *str)
+{
+	ssize_t len = strlen(str);
+	int rc = 0;
+
+	if (xen_domain()) {
+		rc = dom0_write_console(0, str, len);
+		if (rc != -ENOSYS || !xen_hvm_domain())
+			return;
+	}
+	xen_hvm_early_write(0, str, len);
+}
+
+void xen_raw_printk(const char *fmt, ...)
+{
+	static char buf[512];
+	va_list ap;
+
+	va_start(ap, fmt);
+	vsnprintf(buf, sizeof(buf), fmt, ap);
+	va_end(ap);
+
+	xen_raw_console_write(buf);
+}
+
+static void xenboot_earlycon_write(struct console *console,
+				  const char *string,
+				  unsigned len)
+{
+	dom0_write_console(0, string, len);
+}
+
+static int __init xenboot_earlycon_setup(struct earlycon_device *device,
+					    const char *opt)
+{
+	device->con->write = xenboot_earlycon_write;
+	return 0;
+}
+EARLYCON_DECLARE(xenboot, xenboot_earlycon_setup);

linux-7.2.3/drivers/tty/hvc/hvsi_lib.c

@@ -0,0 +1,426 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/types.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/console.h>
+#include <asm/hvsi.h>
+
+#include "hvc_console.h"
+
+static int hvsi_send_packet(struct hvsi_priv *pv, struct hvsi_header *packet)
+{
+	packet->seqno = cpu_to_be16(atomic_inc_return(&pv->seqno));
+
+	/* Assumes that always succeeds, works in practice */
+	return pv->put_chars(pv->termno, (u8 *)packet, packet->len);
+}
+
+static void hvsi_start_handshake(struct hvsi_priv *pv)
+{
+	struct hvsi_query q;
+
+	/* Reset state */
+	pv->established = 0;
+	atomic_set(&pv->seqno, 0);
+
+	pr_devel("HVSI@%x: Handshaking started\n", pv->termno);
+
+	/* Send version query */
+	q.hdr.type = VS_QUERY_PACKET_HEADER;
+	q.hdr.len = sizeof(struct hvsi_query);
+	q.verb = cpu_to_be16(VSV_SEND_VERSION_NUMBER);
+	hvsi_send_packet(pv, &q.hdr);
+}
+
+static int hvsi_send_close(struct hvsi_priv *pv)
+{
+	struct hvsi_control ctrl;
+
+	pv->established = 0;
+
+	ctrl.hdr.type = VS_CONTROL_PACKET_HEADER;
+	ctrl.hdr.len = sizeof(struct hvsi_control);
+	ctrl.verb = cpu_to_be16(VSV_CLOSE_PROTOCOL);
+	return hvsi_send_packet(pv, &ctrl.hdr);
+}
+
+static void hvsi_cd_change(struct hvsi_priv *pv, int cd)
+{
+	if (cd)
+		pv->mctrl |= TIOCM_CD;
+	else {
+		pv->mctrl &= ~TIOCM_CD;
+
+		/* We copy the existing hvsi driver semantics
+		 * here which are to trigger a hangup when
+		 * we get a carrier loss.
+		 * Closing our connection to the server will
+		 * do just that.
+		 */
+		if (!pv->is_console && pv->opened) {
+			pr_devel("HVSI@%x Carrier lost, hanging up !\n",
+				 pv->termno);
+			hvsi_send_close(pv);
+		}
+	}
+}
+
+static void hvsi_got_control(struct hvsi_priv *pv)
+{
+	struct hvsi_control *pkt = (struct hvsi_control *)pv->inbuf;
+
+	switch (be16_to_cpu(pkt->verb)) {
+	case VSV_CLOSE_PROTOCOL:
+		/* We restart the handshaking */
+		hvsi_start_handshake(pv);
+		break;
+	case VSV_MODEM_CTL_UPDATE:
+		/* Transition of carrier detect */
+		hvsi_cd_change(pv, be32_to_cpu(pkt->word) & HVSI_TSCD);
+		break;
+	}
+}
+
+static void hvsi_got_query(struct hvsi_priv *pv)
+{
+	struct hvsi_query *pkt = (struct hvsi_query *)pv->inbuf;
+	struct hvsi_query_response r;
+
+	/* We only handle version queries */
+	if (be16_to_cpu(pkt->verb) != VSV_SEND_VERSION_NUMBER)
+		return;
+
+	pr_devel("HVSI@%x: Got version query, sending response...\n",
+		 pv->termno);
+
+	/* Send version response */
+	r.hdr.type = VS_QUERY_RESPONSE_PACKET_HEADER;
+	r.hdr.len = sizeof(struct hvsi_query_response);
+	r.verb = cpu_to_be16(VSV_SEND_VERSION_NUMBER);
+	r.u.version = HVSI_VERSION;
+	r.query_seqno = pkt->hdr.seqno;
+	hvsi_send_packet(pv, &r.hdr);
+
+	/* Assume protocol is open now */
+	pv->established = 1;
+}
+
+static void hvsi_got_response(struct hvsi_priv *pv)
+{
+	struct hvsi_query_response *r =
+		(struct hvsi_query_response *)pv->inbuf;
+
+	switch(r->verb) {
+	case VSV_SEND_MODEM_CTL_STATUS:
+		hvsi_cd_change(pv, be32_to_cpu(r->u.mctrl_word) & HVSI_TSCD);
+		pv->mctrl_update = 1;
+		break;
+	}
+}
+
+static int hvsi_check_packet(struct hvsi_priv *pv)
+{
+	u8 len, type;
+
+	/* Check header validity. If it's invalid, we ditch
+	 * the whole buffer and hope we eventually resync
+	 */
+	if (pv->inbuf[0] < 0xfc) {
+		pv->inbuf_len = pv->inbuf_pktlen = 0;
+		return 0;
+	}
+	type = pv->inbuf[0];
+	len = pv->inbuf[1];
+
+	/* Packet incomplete ? */
+	if (pv->inbuf_len < len)
+		return 0;
+
+	pr_devel("HVSI@%x: Got packet type %x len %d bytes:\n",
+		 pv->termno, type, len);
+
+	/* We have a packet, yay ! Handle it */
+	switch(type) {
+	case VS_DATA_PACKET_HEADER:
+		pv->inbuf_pktlen = len - 4;
+		pv->inbuf_cur = 4;
+		return 1;
+	case VS_CONTROL_PACKET_HEADER:
+		hvsi_got_control(pv);
+		break;
+	case VS_QUERY_PACKET_HEADER:
+		hvsi_got_query(pv);
+		break;
+	case VS_QUERY_RESPONSE_PACKET_HEADER:
+		hvsi_got_response(pv);
+		break;
+	}
+
+	/* Swallow packet and retry */
+	pv->inbuf_len -= len;
+	memmove(pv->inbuf, &pv->inbuf[len], pv->inbuf_len);
+	return 1;
+}
+
+static int hvsi_get_packet(struct hvsi_priv *pv)
+{
+	/* If we have room in the buffer, ask HV for more */
+	if (pv->inbuf_len < HVSI_INBUF_SIZE)
+		pv->inbuf_len += pv->get_chars(pv->termno,
+					     &pv->inbuf[pv->inbuf_len],
+					     HVSI_INBUF_SIZE - pv->inbuf_len);
+	/*
+	 * If we have at least 4 bytes in the buffer, check for
+	 * a full packet and retry
+	 */
+	if (pv->inbuf_len >= 4)
+		return hvsi_check_packet(pv);
+	return 0;
+}
+
+ssize_t hvsilib_get_chars(struct hvsi_priv *pv, u8 *buf, size_t count)
+{
+	unsigned int tries;
+	size_t read = 0;
+
+	if (WARN_ON(!pv))
+		return -ENXIO;
+
+	/* If we aren't open, don't do anything in order to avoid races
+	 * with connection establishment. The hvc core will call this
+	 * before we have returned from notifier_add(), and we need to
+	 * avoid multiple users playing with the receive buffer
+	 */
+	if (!pv->opened)
+		return 0;
+
+	/* We try twice, once with what data we have and once more
+	 * after we try to fetch some more from the hypervisor
+	 */
+	for (tries = 1; count && tries < 2; tries++) {
+		/* Consume existing data packet */
+		if (pv->inbuf_pktlen) {
+			size_t l = min(count, pv->inbuf_pktlen);
+			memcpy(&buf[read], &pv->inbuf[pv->inbuf_cur], l);
+			pv->inbuf_cur += l;
+			pv->inbuf_pktlen -= l;
+			count -= l;
+			read += l;
+		}
+		if (count == 0)
+			break;
+
+		/* Data packet fully consumed, move down remaning data */
+		if (pv->inbuf_cur) {
+			pv->inbuf_len -= pv->inbuf_cur;
+			memmove(pv->inbuf, &pv->inbuf[pv->inbuf_cur],
+				pv->inbuf_len);
+			pv->inbuf_cur = 0;
+		}
+
+		/* Try to get another packet */
+		if (hvsi_get_packet(pv))
+			tries--;
+	}
+	if (!pv->established) {
+		pr_devel("HVSI@%x: returning -EPIPE\n", pv->termno);
+		return -EPIPE;
+	}
+	return read;
+}
+
+ssize_t hvsilib_put_chars(struct hvsi_priv *pv, const u8 *buf, size_t count)
+{
+	struct hvsi_data dp;
+	size_t adjcount = min_t(size_t, count, HVSI_MAX_OUTGOING_DATA);
+	int rc;
+
+	if (WARN_ON(!pv))
+		return -ENODEV;
+
+	dp.hdr.type = VS_DATA_PACKET_HEADER;
+	dp.hdr.len = adjcount + sizeof(struct hvsi_header);
+	memcpy(dp.data, buf, adjcount);
+	rc = hvsi_send_packet(pv, &dp.hdr);
+	if (rc <= 0)
+		return rc;
+	return adjcount;
+}
+
+static void maybe_msleep(unsigned long ms)
+{
+	/* During early boot, IRQs are disabled, use mdelay */
+	if (irqs_disabled())
+		mdelay(ms);
+	else
+		msleep(ms);
+}
+
+int hvsilib_read_mctrl(struct hvsi_priv *pv)
+{
+	struct hvsi_query q;
+	int rc, timeout;
+
+	pr_devel("HVSI@%x: Querying modem control status...\n",
+		 pv->termno);
+
+	pv->mctrl_update = 0;
+	q.hdr.type = VS_QUERY_PACKET_HEADER;
+	q.hdr.len = sizeof(struct hvsi_query);
+	q.verb = cpu_to_be16(VSV_SEND_MODEM_CTL_STATUS);
+	rc = hvsi_send_packet(pv, &q.hdr);
+	if (rc <= 0) {
+		pr_devel("HVSI@%x: Error %d...\n", pv->termno, rc);
+		return rc;
+	}
+
+	/* Try for up to 200ms */
+	for (timeout = 0; timeout < 20; timeout++) {
+		if (!pv->established)
+			return -ENXIO;
+		if (pv->mctrl_update)
+			return 0;
+		if (!hvsi_get_packet(pv))
+			maybe_msleep(10);
+	}
+	return -EIO;
+}
+
+int hvsilib_write_mctrl(struct hvsi_priv *pv, int dtr)
+{
+	struct hvsi_control ctrl;
+	unsigned short mctrl;
+
+	mctrl = pv->mctrl;
+	if (dtr)
+		mctrl |= TIOCM_DTR;
+	else
+		mctrl &= ~TIOCM_DTR;
+	if (mctrl == pv->mctrl)
+		return 0;
+	pv->mctrl = mctrl;
+
+	pr_devel("HVSI@%x: %s DTR...\n", pv->termno,
+		 dtr ? "Setting" : "Clearing");
+
+	ctrl.hdr.type = VS_CONTROL_PACKET_HEADER;
+	ctrl.hdr.len = sizeof(struct hvsi_control);
+	ctrl.verb = cpu_to_be16(VSV_SET_MODEM_CTL);
+	ctrl.mask = cpu_to_be32(HVSI_TSDTR);
+	ctrl.word = cpu_to_be32(dtr ? HVSI_TSDTR : 0);
+	return hvsi_send_packet(pv, &ctrl.hdr);
+}
+
+void hvsilib_establish(struct hvsi_priv *pv)
+{
+	int timeout;
+
+	pr_devel("HVSI@%x: Establishing...\n", pv->termno);
+
+	/* Try for up to 200ms, there can be a packet to
+	 * start the process waiting for us...
+	 */
+	for (timeout = 0; timeout < 20; timeout++) {
+		if (pv->established)
+			goto established;
+		if (!hvsi_get_packet(pv))
+			maybe_msleep(10);
+	}
+
+	/* Failed, send a close connection packet just
+	 * in case
+	 */
+	pr_devel("HVSI@%x:   ... sending close\n", pv->termno);
+
+	hvsi_send_close(pv);
+
+	/* Then restart handshake */
+
+	pr_devel("HVSI@%x:   ... restarting handshake\n", pv->termno);
+
+	hvsi_start_handshake(pv);
+
+	pr_devel("HVSI@%x:   ... waiting handshake\n", pv->termno);
+
+	/* Try for up to 400ms */
+	for (timeout = 0; timeout < 40; timeout++) {
+		if (pv->established)
+			goto established;
+		if (!hvsi_get_packet(pv))
+			maybe_msleep(10);
+	}
+
+	if (!pv->established) {
+		pr_devel("HVSI@%x: Timeout handshaking, giving up !\n",
+			 pv->termno);
+		return;
+	}
+ established:
+	/* Query modem control lines */
+
+	pr_devel("HVSI@%x:   ... established, reading mctrl\n", pv->termno);
+
+	hvsilib_read_mctrl(pv);
+
+	/* Set our own DTR */
+
+	pr_devel("HVSI@%x:   ... setting mctrl\n", pv->termno);
+
+	hvsilib_write_mctrl(pv, 1);
+
+	/* Set the opened flag so reads are allowed */
+	wmb();
+	pv->opened = 1;
+}
+
+int hvsilib_open(struct hvsi_priv *pv, struct hvc_struct *hp)
+{
+	pr_devel("HVSI@%x: open !\n", pv->termno);
+
+	/* Keep track of the tty data structure */
+	pv->tty = tty_port_tty_get(&hp->port);
+
+	hvsilib_establish(pv);
+
+	return 0;
+}
+
+void hvsilib_close(struct hvsi_priv *pv, struct hvc_struct *hp)
+{
+	unsigned long flags;
+
+	pr_devel("HVSI@%x: close !\n", pv->termno);
+
+	if (!pv->is_console) {
+		pr_devel("HVSI@%x: Not a console, tearing down\n",
+			 pv->termno);
+
+		/* Clear opened, synchronize with khvcd */
+		spin_lock_irqsave(&hp->lock, flags);
+		pv->opened = 0;
+		spin_unlock_irqrestore(&hp->lock, flags);
+
+		/* Clear our own DTR */
+		if (!pv->tty || (pv->tty->termios.c_cflag & HUPCL))
+			hvsilib_write_mctrl(pv, 0);
+
+		/* Tear down the connection */
+		hvsi_send_close(pv);
+	}
+
+	tty_kref_put(pv->tty);
+	pv->tty = NULL;
+}
+
+void hvsilib_init(struct hvsi_priv *pv,
+		  ssize_t (*get_chars)(uint32_t termno, u8 *buf, size_t count),
+		  ssize_t (*put_chars)(uint32_t termno, const u8 *buf,
+				       size_t count),
+		  int termno, int is_console)
+{
+	memset(pv, 0, sizeof(*pv));
+	pv->get_chars = get_chars;
+	pv->put_chars = put_chars;
+	pv->termno = termno;
+	pv->is_console = is_console;
+}