Resguardo inicial

linux-7.2.3/drivers/bus/mhi/ep/Kconfig

@@ -0,0 +1,10 @@
+config MHI_BUS_EP
+	tristate "Modem Host Interface (MHI) bus Endpoint implementation"
+	help
+	  Bus driver for MHI protocol. Modem Host Interface (MHI) is a
+	  communication protocol used by a host processor to control
+	  and communicate a modem device over a high speed peripheral
+	  bus or shared memory.
+
+	  MHI_BUS_EP implements the MHI protocol for the endpoint devices,
+	  such as SDX55 modem connected to the host machine over PCIe.

linux-7.2.3/drivers/bus/mhi/ep/Makefile

@@ -0,0 +1,2 @@
+obj-$(CONFIG_MHI_BUS_EP) += mhi_ep.o
+mhi_ep-y := main.o mmio.o ring.o sm.o

linux-7.2.3/drivers/bus/mhi/ep/internal.h

@@ -0,0 +1,222 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2022, Linaro Ltd.
+ *
+ */
+
+#ifndef _MHI_EP_INTERNAL_
+#define _MHI_EP_INTERNAL_
+
+#include <linux/bitfield.h>
+
+#include "../common.h"
+
+extern const struct bus_type mhi_ep_bus_type;
+
+#define MHI_REG_OFFSET				0x100
+#define BHI_REG_OFFSET				0x200
+
+/* MHI registers */
+#define EP_MHIREGLEN				(MHI_REG_OFFSET + MHIREGLEN)
+#define EP_MHIVER				(MHI_REG_OFFSET + MHIVER)
+#define EP_MHICFG				(MHI_REG_OFFSET + MHICFG)
+#define EP_CHDBOFF				(MHI_REG_OFFSET + CHDBOFF)
+#define EP_ERDBOFF				(MHI_REG_OFFSET + ERDBOFF)
+#define EP_BHIOFF				(MHI_REG_OFFSET + BHIOFF)
+#define EP_BHIEOFF				(MHI_REG_OFFSET + BHIEOFF)
+#define EP_DEBUGOFF				(MHI_REG_OFFSET + DEBUGOFF)
+#define EP_MHICTRL				(MHI_REG_OFFSET + MHICTRL)
+#define EP_MHISTATUS				(MHI_REG_OFFSET + MHISTATUS)
+#define EP_CCABAP_LOWER				(MHI_REG_OFFSET + CCABAP_LOWER)
+#define EP_CCABAP_HIGHER			(MHI_REG_OFFSET + CCABAP_HIGHER)
+#define EP_ECABAP_LOWER				(MHI_REG_OFFSET + ECABAP_LOWER)
+#define EP_ECABAP_HIGHER			(MHI_REG_OFFSET + ECABAP_HIGHER)
+#define EP_CRCBAP_LOWER				(MHI_REG_OFFSET + CRCBAP_LOWER)
+#define EP_CRCBAP_HIGHER			(MHI_REG_OFFSET + CRCBAP_HIGHER)
+#define EP_CRDB_LOWER				(MHI_REG_OFFSET + CRDB_LOWER)
+#define EP_CRDB_HIGHER				(MHI_REG_OFFSET + CRDB_HIGHER)
+#define EP_MHICTRLBASE_LOWER			(MHI_REG_OFFSET + MHICTRLBASE_LOWER)
+#define EP_MHICTRLBASE_HIGHER			(MHI_REG_OFFSET + MHICTRLBASE_HIGHER)
+#define EP_MHICTRLLIMIT_LOWER			(MHI_REG_OFFSET + MHICTRLLIMIT_LOWER)
+#define EP_MHICTRLLIMIT_HIGHER			(MHI_REG_OFFSET + MHICTRLLIMIT_HIGHER)
+#define EP_MHIDATABASE_LOWER			(MHI_REG_OFFSET + MHIDATABASE_LOWER)
+#define EP_MHIDATABASE_HIGHER			(MHI_REG_OFFSET + MHIDATABASE_HIGHER)
+#define EP_MHIDATALIMIT_LOWER			(MHI_REG_OFFSET + MHIDATALIMIT_LOWER)
+#define EP_MHIDATALIMIT_HIGHER			(MHI_REG_OFFSET + MHIDATALIMIT_HIGHER)
+
+/* MHI BHI registers */
+#define EP_BHI_INTVEC				(BHI_REG_OFFSET + BHI_INTVEC)
+#define EP_BHI_EXECENV				(BHI_REG_OFFSET + BHI_EXECENV)
+
+/* MHI Doorbell registers */
+#define CHDB_LOWER_n(n)				(0x400 + 0x8 * (n))
+#define CHDB_HIGHER_n(n)			(0x404 + 0x8 * (n))
+#define ERDB_LOWER_n(n)				(0x800 + 0x8 * (n))
+#define ERDB_HIGHER_n(n)			(0x804 + 0x8 * (n))
+
+#define MHI_CTRL_INT_STATUS			0x4
+#define MHI_CTRL_INT_STATUS_MSK			BIT(0)
+#define MHI_CTRL_INT_STATUS_CRDB_MSK		BIT(1)
+#define MHI_CHDB_INT_STATUS_n(n)		(0x28 + 0x4 * (n))
+#define MHI_ERDB_INT_STATUS_n(n)		(0x38 + 0x4 * (n))
+
+#define MHI_CTRL_INT_CLEAR			0x4c
+#define MHI_CTRL_INT_MMIO_WR_CLEAR		BIT(2)
+#define MHI_CTRL_INT_CRDB_CLEAR			BIT(1)
+#define MHI_CTRL_INT_CRDB_MHICTRL_CLEAR		BIT(0)
+
+#define MHI_CHDB_INT_CLEAR_n(n)			(0x70 + 0x4 * (n))
+#define MHI_CHDB_INT_CLEAR_n_CLEAR_ALL		GENMASK(31, 0)
+#define MHI_ERDB_INT_CLEAR_n(n)			(0x80 + 0x4 * (n))
+#define MHI_ERDB_INT_CLEAR_n_CLEAR_ALL		GENMASK(31, 0)
+
+/*
+ * Unlike the usual "masking" convention, writing "1" to a bit in this register
+ * enables the interrupt and writing "0" will disable it..
+ */
+#define MHI_CTRL_INT_MASK			0x94
+#define MHI_CTRL_INT_MASK_MASK			GENMASK(1, 0)
+#define MHI_CTRL_MHICTRL_MASK			BIT(0)
+#define MHI_CTRL_CRDB_MASK			BIT(1)
+
+#define MHI_CHDB_INT_MASK_n(n)			(0xb8 + 0x4 * (n))
+#define MHI_CHDB_INT_MASK_n_EN_ALL		GENMASK(31, 0)
+#define MHI_ERDB_INT_MASK_n(n)			(0xc8 + 0x4 * (n))
+#define MHI_ERDB_INT_MASK_n_EN_ALL		GENMASK(31, 0)
+
+#define NR_OF_CMD_RINGS				1
+#define MHI_MASK_ROWS_CH_DB			4
+#define MHI_MASK_ROWS_EV_DB			4
+#define MHI_MASK_CH_LEN				32
+#define MHI_MASK_EV_LEN				32
+
+/* Generic context */
+struct mhi_generic_ctx {
+	__le32 reserved0;
+	__le32 reserved1;
+	__le32 reserved2;
+
+	__le64 rbase __packed __aligned(4);
+	__le64 rlen __packed __aligned(4);
+	__le64 rp __packed __aligned(4);
+	__le64 wp __packed __aligned(4);
+};
+
+enum mhi_ep_ring_type {
+	RING_TYPE_CMD,
+	RING_TYPE_ER,
+	RING_TYPE_CH,
+};
+
+/* Ring element */
+union mhi_ep_ring_ctx {
+	struct mhi_cmd_ctxt cmd;
+	struct mhi_event_ctxt ev;
+	struct mhi_chan_ctxt ch;
+	struct mhi_generic_ctx generic;
+};
+
+struct mhi_ep_ring_item {
+	struct list_head node;
+	struct mhi_ep_ring *ring;
+};
+
+struct mhi_ep_ring {
+	struct mhi_ep_cntrl *mhi_cntrl;
+	union mhi_ep_ring_ctx *ring_ctx;
+	struct mhi_ring_element *ring_cache;
+	enum mhi_ep_ring_type type;
+	struct delayed_work intmodt_work;
+	u64 rbase;
+	size_t rd_offset;
+	size_t wr_offset;
+	size_t ring_size;
+	u32 db_offset_h;
+	u32 db_offset_l;
+	u32 ch_id;
+	u32 er_index;
+	u32 irq_vector;
+	u32 intmodt;
+	bool started;
+	bool irq_pending;
+};
+
+struct mhi_ep_cmd {
+	struct mhi_ep_ring ring;
+};
+
+struct mhi_ep_event {
+	struct mhi_ep_ring ring;
+};
+
+struct mhi_ep_state_transition {
+	struct list_head node;
+	enum mhi_state state;
+};
+
+struct mhi_ep_chan {
+	char *name;
+	struct mhi_ep_device *mhi_dev;
+	struct mhi_ep_ring ring;
+	struct mutex lock;
+	void (*xfer_cb)(struct mhi_ep_device *mhi_dev, struct mhi_result *result);
+	enum mhi_ch_state state;
+	enum dma_data_direction dir;
+	size_t rd_offset;
+	u64 tre_loc;
+	u32 tre_size;
+	u32 tre_bytes_left;
+	u32 chan;
+	bool skip_td;
+};
+
+/* MHI Ring related functions */
+void mhi_ep_ring_init(struct mhi_ep_ring *ring, enum mhi_ep_ring_type type, u32 id);
+void mhi_ep_ring_reset(struct mhi_ep_cntrl *mhi_cntrl, struct mhi_ep_ring *ring);
+int mhi_ep_ring_start(struct mhi_ep_cntrl *mhi_cntrl, struct mhi_ep_ring *ring,
+		      union mhi_ep_ring_ctx *ctx);
+size_t mhi_ep_ring_addr2offset(struct mhi_ep_ring *ring, u64 ptr);
+int mhi_ep_ring_add_element(struct mhi_ep_ring *ring, struct mhi_ring_element *element);
+void mhi_ep_ring_inc_index(struct mhi_ep_ring *ring);
+int mhi_ep_update_wr_offset(struct mhi_ep_ring *ring);
+
+/* MMIO related functions */
+u32 mhi_ep_mmio_read(struct mhi_ep_cntrl *mhi_cntrl, u32 offset);
+void mhi_ep_mmio_write(struct mhi_ep_cntrl *mhi_cntrl, u32 offset, u32 val);
+void mhi_ep_mmio_masked_write(struct mhi_ep_cntrl *mhi_cntrl, u32 offset, u32 mask, u32 val);
+u32 mhi_ep_mmio_masked_read(struct mhi_ep_cntrl *dev, u32 offset, u32 mask);
+void mhi_ep_mmio_enable_ctrl_interrupt(struct mhi_ep_cntrl *mhi_cntrl);
+void mhi_ep_mmio_disable_ctrl_interrupt(struct mhi_ep_cntrl *mhi_cntrl);
+void mhi_ep_mmio_enable_cmdb_interrupt(struct mhi_ep_cntrl *mhi_cntrl);
+void mhi_ep_mmio_disable_cmdb_interrupt(struct mhi_ep_cntrl *mhi_cntrl);
+void mhi_ep_mmio_enable_chdb(struct mhi_ep_cntrl *mhi_cntrl, u32 ch_id);
+void mhi_ep_mmio_disable_chdb(struct mhi_ep_cntrl *mhi_cntrl, u32 ch_id);
+void mhi_ep_mmio_enable_chdb_interrupts(struct mhi_ep_cntrl *mhi_cntrl);
+bool mhi_ep_mmio_read_chdb_status_interrupts(struct mhi_ep_cntrl *mhi_cntrl);
+void mhi_ep_mmio_mask_interrupts(struct mhi_ep_cntrl *mhi_cntrl);
+void mhi_ep_mmio_get_chc_base(struct mhi_ep_cntrl *mhi_cntrl);
+void mhi_ep_mmio_get_erc_base(struct mhi_ep_cntrl *mhi_cntrl);
+void mhi_ep_mmio_get_crc_base(struct mhi_ep_cntrl *mhi_cntrl);
+u64 mhi_ep_mmio_get_db(struct mhi_ep_ring *ring);
+void mhi_ep_mmio_set_env(struct mhi_ep_cntrl *mhi_cntrl, u32 value);
+void mhi_ep_mmio_clear_reset(struct mhi_ep_cntrl *mhi_cntrl);
+void mhi_ep_mmio_reset(struct mhi_ep_cntrl *mhi_cntrl);
+void mhi_ep_mmio_get_mhi_state(struct mhi_ep_cntrl *mhi_cntrl, enum mhi_state *state,
+			       bool *mhi_reset);
+void mhi_ep_mmio_init(struct mhi_ep_cntrl *mhi_cntrl);
+void mhi_ep_mmio_update_ner(struct mhi_ep_cntrl *mhi_cntrl);
+
+/* MHI EP core functions */
+int mhi_ep_send_state_change_event(struct mhi_ep_cntrl *mhi_cntrl, enum mhi_state state);
+int mhi_ep_send_ee_event(struct mhi_ep_cntrl *mhi_cntrl, enum mhi_ee_type exec_env);
+bool mhi_ep_check_mhi_state(struct mhi_ep_cntrl *mhi_cntrl, enum mhi_state cur_mhi_state,
+			    enum mhi_state mhi_state);
+int mhi_ep_set_mhi_state(struct mhi_ep_cntrl *mhi_cntrl, enum mhi_state mhi_state);
+int mhi_ep_set_m0_state(struct mhi_ep_cntrl *mhi_cntrl);
+int mhi_ep_set_m3_state(struct mhi_ep_cntrl *mhi_cntrl);
+int mhi_ep_set_ready_state(struct mhi_ep_cntrl *mhi_cntrl);
+void mhi_ep_handle_syserr(struct mhi_ep_cntrl *mhi_cntrl);
+void mhi_ep_resume_channels(struct mhi_ep_cntrl *mhi_cntrl);
+void mhi_ep_suspend_channels(struct mhi_ep_cntrl *mhi_cntrl);
+
+#endif

linux-7.2.3/drivers/bus/mhi/ep/mmio.c

@@ -0,0 +1,273 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2022 Linaro Ltd.
+ * Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/io.h>
+#include <linux/mhi_ep.h>
+
+#include "internal.h"
+
+u32 mhi_ep_mmio_read(struct mhi_ep_cntrl *mhi_cntrl, u32 offset)
+{
+	return readl(mhi_cntrl->mmio + offset);
+}
+
+void mhi_ep_mmio_write(struct mhi_ep_cntrl *mhi_cntrl, u32 offset, u32 val)
+{
+	writel(val, mhi_cntrl->mmio + offset);
+}
+
+void mhi_ep_mmio_masked_write(struct mhi_ep_cntrl *mhi_cntrl, u32 offset, u32 mask, u32 val)
+{
+	u32 regval;
+
+	regval = mhi_ep_mmio_read(mhi_cntrl, offset);
+	regval &= ~mask;
+	regval |= (val << __ffs(mask)) & mask;
+	mhi_ep_mmio_write(mhi_cntrl, offset, regval);
+}
+
+u32 mhi_ep_mmio_masked_read(struct mhi_ep_cntrl *dev, u32 offset, u32 mask)
+{
+	u32 regval;
+
+	regval = mhi_ep_mmio_read(dev, offset);
+	regval &= mask;
+	regval >>= __ffs(mask);
+
+	return regval;
+}
+
+void mhi_ep_mmio_get_mhi_state(struct mhi_ep_cntrl *mhi_cntrl, enum mhi_state *state,
+				bool *mhi_reset)
+{
+	u32 regval;
+
+	regval = mhi_ep_mmio_read(mhi_cntrl, EP_MHICTRL);
+	*state = FIELD_GET(MHICTRL_MHISTATE_MASK, regval);
+	*mhi_reset = !!FIELD_GET(MHICTRL_RESET_MASK, regval);
+}
+
+static void mhi_ep_mmio_set_chdb(struct mhi_ep_cntrl *mhi_cntrl, u32 ch_id, bool enable)
+{
+	u32 chid_mask, chid_shift, chdb_idx, val;
+
+	chid_shift = ch_id % 32;
+	chid_mask = BIT(chid_shift);
+	chdb_idx = ch_id / 32;
+
+	val = enable ? 1 : 0;
+
+	mhi_ep_mmio_masked_write(mhi_cntrl, MHI_CHDB_INT_MASK_n(chdb_idx), chid_mask, val);
+
+	/* Update the local copy of the channel mask */
+	mhi_cntrl->chdb[chdb_idx].mask &= ~chid_mask;
+	mhi_cntrl->chdb[chdb_idx].mask |= val << chid_shift;
+}
+
+void mhi_ep_mmio_enable_chdb(struct mhi_ep_cntrl *mhi_cntrl, u32 ch_id)
+{
+	mhi_ep_mmio_set_chdb(mhi_cntrl, ch_id, true);
+}
+
+void mhi_ep_mmio_disable_chdb(struct mhi_ep_cntrl *mhi_cntrl, u32 ch_id)
+{
+	mhi_ep_mmio_set_chdb(mhi_cntrl, ch_id, false);
+}
+
+static void mhi_ep_mmio_set_chdb_interrupts(struct mhi_ep_cntrl *mhi_cntrl, bool enable)
+{
+	u32 val, i;
+
+	val = enable ? MHI_CHDB_INT_MASK_n_EN_ALL : 0;
+
+	for (i = 0; i < MHI_MASK_ROWS_CH_DB; i++) {
+		mhi_ep_mmio_write(mhi_cntrl, MHI_CHDB_INT_MASK_n(i), val);
+		mhi_cntrl->chdb[i].mask = val;
+	}
+}
+
+void mhi_ep_mmio_enable_chdb_interrupts(struct mhi_ep_cntrl *mhi_cntrl)
+{
+	mhi_ep_mmio_set_chdb_interrupts(mhi_cntrl, true);
+}
+
+static void mhi_ep_mmio_mask_chdb_interrupts(struct mhi_ep_cntrl *mhi_cntrl)
+{
+	mhi_ep_mmio_set_chdb_interrupts(mhi_cntrl, false);
+}
+
+bool mhi_ep_mmio_read_chdb_status_interrupts(struct mhi_ep_cntrl *mhi_cntrl)
+{
+	bool chdb = false;
+	u32 i;
+
+	for (i = 0; i < MHI_MASK_ROWS_CH_DB; i++) {
+		mhi_cntrl->chdb[i].status = mhi_ep_mmio_read(mhi_cntrl, MHI_CHDB_INT_STATUS_n(i));
+		if (mhi_cntrl->chdb[i].status)
+			chdb = true;
+	}
+
+	/* Return whether a channel doorbell interrupt occurred or not */
+	return chdb;
+}
+
+static void mhi_ep_mmio_set_erdb_interrupts(struct mhi_ep_cntrl *mhi_cntrl, bool enable)
+{
+	u32 val, i;
+
+	val = enable ? MHI_ERDB_INT_MASK_n_EN_ALL : 0;
+
+	for (i = 0; i < MHI_MASK_ROWS_EV_DB; i++)
+		mhi_ep_mmio_write(mhi_cntrl, MHI_ERDB_INT_MASK_n(i), val);
+}
+
+static void mhi_ep_mmio_mask_erdb_interrupts(struct mhi_ep_cntrl *mhi_cntrl)
+{
+	mhi_ep_mmio_set_erdb_interrupts(mhi_cntrl, false);
+}
+
+void mhi_ep_mmio_enable_ctrl_interrupt(struct mhi_ep_cntrl *mhi_cntrl)
+{
+	mhi_ep_mmio_masked_write(mhi_cntrl, MHI_CTRL_INT_MASK,
+				  MHI_CTRL_MHICTRL_MASK, 1);
+}
+
+void mhi_ep_mmio_disable_ctrl_interrupt(struct mhi_ep_cntrl *mhi_cntrl)
+{
+	mhi_ep_mmio_masked_write(mhi_cntrl, MHI_CTRL_INT_MASK,
+				  MHI_CTRL_MHICTRL_MASK, 0);
+}
+
+void mhi_ep_mmio_enable_cmdb_interrupt(struct mhi_ep_cntrl *mhi_cntrl)
+{
+	mhi_ep_mmio_masked_write(mhi_cntrl, MHI_CTRL_INT_MASK,
+				  MHI_CTRL_CRDB_MASK, 1);
+}
+
+void mhi_ep_mmio_disable_cmdb_interrupt(struct mhi_ep_cntrl *mhi_cntrl)
+{
+	mhi_ep_mmio_masked_write(mhi_cntrl, MHI_CTRL_INT_MASK,
+				  MHI_CTRL_CRDB_MASK, 0);
+}
+
+void mhi_ep_mmio_mask_interrupts(struct mhi_ep_cntrl *mhi_cntrl)
+{
+	mhi_ep_mmio_disable_ctrl_interrupt(mhi_cntrl);
+	mhi_ep_mmio_disable_cmdb_interrupt(mhi_cntrl);
+	mhi_ep_mmio_mask_chdb_interrupts(mhi_cntrl);
+	mhi_ep_mmio_mask_erdb_interrupts(mhi_cntrl);
+}
+
+static void mhi_ep_mmio_clear_interrupts(struct mhi_ep_cntrl *mhi_cntrl)
+{
+	u32 i;
+
+	for (i = 0; i < MHI_MASK_ROWS_CH_DB; i++)
+		mhi_ep_mmio_write(mhi_cntrl, MHI_CHDB_INT_CLEAR_n(i),
+				   MHI_CHDB_INT_CLEAR_n_CLEAR_ALL);
+
+	for (i = 0; i < MHI_MASK_ROWS_EV_DB; i++)
+		mhi_ep_mmio_write(mhi_cntrl, MHI_ERDB_INT_CLEAR_n(i),
+				   MHI_ERDB_INT_CLEAR_n_CLEAR_ALL);
+
+	mhi_ep_mmio_write(mhi_cntrl, MHI_CTRL_INT_CLEAR,
+			   MHI_CTRL_INT_MMIO_WR_CLEAR |
+			   MHI_CTRL_INT_CRDB_CLEAR |
+			   MHI_CTRL_INT_CRDB_MHICTRL_CLEAR);
+}
+
+void mhi_ep_mmio_get_chc_base(struct mhi_ep_cntrl *mhi_cntrl)
+{
+	u32 regval;
+
+	regval = mhi_ep_mmio_read(mhi_cntrl, EP_CCABAP_HIGHER);
+	mhi_cntrl->ch_ctx_host_pa = regval;
+	mhi_cntrl->ch_ctx_host_pa <<= 32;
+
+	regval = mhi_ep_mmio_read(mhi_cntrl, EP_CCABAP_LOWER);
+	mhi_cntrl->ch_ctx_host_pa |= regval;
+}
+
+void mhi_ep_mmio_get_erc_base(struct mhi_ep_cntrl *mhi_cntrl)
+{
+	u32 regval;
+
+	regval = mhi_ep_mmio_read(mhi_cntrl, EP_ECABAP_HIGHER);
+	mhi_cntrl->ev_ctx_host_pa = regval;
+	mhi_cntrl->ev_ctx_host_pa <<= 32;
+
+	regval = mhi_ep_mmio_read(mhi_cntrl, EP_ECABAP_LOWER);
+	mhi_cntrl->ev_ctx_host_pa |= regval;
+}
+
+void mhi_ep_mmio_get_crc_base(struct mhi_ep_cntrl *mhi_cntrl)
+{
+	u32 regval;
+
+	regval = mhi_ep_mmio_read(mhi_cntrl, EP_CRCBAP_HIGHER);
+	mhi_cntrl->cmd_ctx_host_pa = regval;
+	mhi_cntrl->cmd_ctx_host_pa <<= 32;
+
+	regval = mhi_ep_mmio_read(mhi_cntrl, EP_CRCBAP_LOWER);
+	mhi_cntrl->cmd_ctx_host_pa |= regval;
+}
+
+u64 mhi_ep_mmio_get_db(struct mhi_ep_ring *ring)
+{
+	struct mhi_ep_cntrl *mhi_cntrl = ring->mhi_cntrl;
+	u64 db_offset;
+	u32 regval;
+
+	regval = mhi_ep_mmio_read(mhi_cntrl, ring->db_offset_h);
+	db_offset = regval;
+	db_offset <<= 32;
+
+	regval = mhi_ep_mmio_read(mhi_cntrl, ring->db_offset_l);
+	db_offset |= regval;
+
+	return db_offset;
+}
+
+void mhi_ep_mmio_set_env(struct mhi_ep_cntrl *mhi_cntrl, u32 value)
+{
+	mhi_ep_mmio_write(mhi_cntrl, EP_BHI_EXECENV, value);
+}
+
+void mhi_ep_mmio_clear_reset(struct mhi_ep_cntrl *mhi_cntrl)
+{
+	mhi_ep_mmio_masked_write(mhi_cntrl, EP_MHICTRL, MHICTRL_RESET_MASK, 0);
+}
+
+void mhi_ep_mmio_reset(struct mhi_ep_cntrl *mhi_cntrl)
+{
+	mhi_ep_mmio_write(mhi_cntrl, EP_MHICTRL, 0);
+	mhi_ep_mmio_write(mhi_cntrl, EP_MHISTATUS, 0);
+	mhi_ep_mmio_clear_interrupts(mhi_cntrl);
+}
+
+void mhi_ep_mmio_init(struct mhi_ep_cntrl *mhi_cntrl)
+{
+	u32 regval;
+
+	mhi_cntrl->chdb_offset = mhi_ep_mmio_read(mhi_cntrl, EP_CHDBOFF);
+	mhi_cntrl->erdb_offset = mhi_ep_mmio_read(mhi_cntrl, EP_ERDBOFF);
+
+	regval = mhi_ep_mmio_read(mhi_cntrl, EP_MHICFG);
+	mhi_cntrl->event_rings = FIELD_GET(MHICFG_NER_MASK, regval);
+	mhi_cntrl->hw_event_rings = FIELD_GET(MHICFG_NHWER_MASK, regval);
+
+	mhi_ep_mmio_reset(mhi_cntrl);
+}
+
+void mhi_ep_mmio_update_ner(struct mhi_ep_cntrl *mhi_cntrl)
+{
+	u32 regval;
+
+	regval = mhi_ep_mmio_read(mhi_cntrl, EP_MHICFG);
+	mhi_cntrl->event_rings = FIELD_GET(MHICFG_NER_MASK, regval);
+	mhi_cntrl->hw_event_rings = FIELD_GET(MHICFG_NHWER_MASK, regval);
+}

linux-7.2.3/drivers/bus/mhi/ep/ring.c

@@ -0,0 +1,234 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2022 Linaro Ltd.
+ * Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+ */
+
+#include <linux/mhi_ep.h>
+#include "internal.h"
+
+size_t mhi_ep_ring_addr2offset(struct mhi_ep_ring *ring, u64 ptr)
+{
+	return (ptr - ring->rbase) / sizeof(struct mhi_ring_element);
+}
+
+static u32 mhi_ep_ring_num_elems(struct mhi_ep_ring *ring)
+{
+	__le64 rlen;
+
+	memcpy_fromio(&rlen, (void __iomem *) &ring->ring_ctx->generic.rlen, sizeof(u64));
+
+	return le64_to_cpu(rlen) / sizeof(struct mhi_ring_element);
+}
+
+void mhi_ep_ring_inc_index(struct mhi_ep_ring *ring)
+{
+	ring->rd_offset = (ring->rd_offset + 1) % ring->ring_size;
+}
+
+static int __mhi_ep_cache_ring(struct mhi_ep_ring *ring, size_t end)
+{
+	struct mhi_ep_cntrl *mhi_cntrl = ring->mhi_cntrl;
+	struct device *dev = &mhi_cntrl->mhi_dev->dev;
+	struct mhi_ep_buf_info buf_info = {};
+	size_t start;
+	int ret;
+
+	/* Don't proceed in the case of event ring. This happens during mhi_ep_ring_start(). */
+	if (ring->type == RING_TYPE_ER)
+		return 0;
+
+	/* No need to cache the ring if write pointer is unmodified */
+	if (ring->wr_offset == end)
+		return 0;
+
+	start = ring->wr_offset;
+	if (start < end) {
+		buf_info.size = (end - start) * sizeof(struct mhi_ring_element);
+		buf_info.host_addr = ring->rbase + (start * sizeof(struct mhi_ring_element));
+		buf_info.dev_addr = &ring->ring_cache[start];
+
+		ret = mhi_cntrl->read_sync(mhi_cntrl, &buf_info);
+		if (ret)
+			return ret;
+	} else {
+		buf_info.size = (ring->ring_size - start) * sizeof(struct mhi_ring_element);
+		buf_info.host_addr = ring->rbase + (start * sizeof(struct mhi_ring_element));
+		buf_info.dev_addr = &ring->ring_cache[start];
+
+		ret = mhi_cntrl->read_sync(mhi_cntrl, &buf_info);
+		if (ret)
+			return ret;
+
+		if (end) {
+			buf_info.host_addr = ring->rbase;
+			buf_info.dev_addr = &ring->ring_cache[0];
+			buf_info.size = end * sizeof(struct mhi_ring_element);
+
+			ret = mhi_cntrl->read_sync(mhi_cntrl, &buf_info);
+			if (ret)
+				return ret;
+		}
+	}
+
+	dev_dbg(dev, "Cached ring: start %zu end %zu size %zu\n", start, end, buf_info.size);
+
+	return 0;
+}
+
+static int mhi_ep_cache_ring(struct mhi_ep_ring *ring, u64 wr_ptr)
+{
+	size_t wr_offset;
+	int ret;
+
+	wr_offset = mhi_ep_ring_addr2offset(ring, wr_ptr);
+
+	/* Cache the host ring till write offset */
+	ret = __mhi_ep_cache_ring(ring, wr_offset);
+	if (ret)
+		return ret;
+
+	ring->wr_offset = wr_offset;
+
+	return 0;
+}
+
+int mhi_ep_update_wr_offset(struct mhi_ep_ring *ring)
+{
+	u64 wr_ptr;
+
+	wr_ptr = mhi_ep_mmio_get_db(ring);
+
+	return mhi_ep_cache_ring(ring, wr_ptr);
+}
+
+/* TODO: Support for adding multiple ring elements to the ring */
+int mhi_ep_ring_add_element(struct mhi_ep_ring *ring, struct mhi_ring_element *el)
+{
+	struct mhi_ep_cntrl *mhi_cntrl = ring->mhi_cntrl;
+	struct device *dev = &mhi_cntrl->mhi_dev->dev;
+	struct mhi_ep_buf_info buf_info = {};
+	size_t old_offset = 0;
+	u32 num_free_elem;
+	__le64 rp;
+	int ret;
+
+	ret = mhi_ep_update_wr_offset(ring);
+	if (ret) {
+		dev_err(dev, "Error updating write pointer\n");
+		return ret;
+	}
+
+	if (ring->rd_offset < ring->wr_offset)
+		num_free_elem = (ring->wr_offset - ring->rd_offset) - 1;
+	else
+		num_free_elem = ((ring->ring_size - ring->rd_offset) + ring->wr_offset) - 1;
+
+	/* Check if there is space in ring for adding at least an element */
+	if (!num_free_elem) {
+		dev_err(dev, "No space left in the ring\n");
+		return -ENOSPC;
+	}
+
+	old_offset = ring->rd_offset;
+
+	dev_dbg(dev, "Adding an element to ring at offset (%zu)\n", ring->rd_offset);
+	buf_info.host_addr = ring->rbase + (old_offset * sizeof(*el));
+	buf_info.dev_addr = el;
+	buf_info.size = sizeof(*el);
+
+	ret = mhi_cntrl->write_sync(mhi_cntrl, &buf_info);
+	if (ret)
+		return ret;
+
+	mhi_ep_ring_inc_index(ring);
+
+	/* Update rp in ring context */
+	rp = cpu_to_le64(ring->rd_offset * sizeof(*el) + ring->rbase);
+	memcpy_toio((void __iomem *) &ring->ring_ctx->generic.rp, &rp, sizeof(u64));
+
+	return ret;
+}
+
+void mhi_ep_ring_init(struct mhi_ep_ring *ring, enum mhi_ep_ring_type type, u32 id)
+{
+	ring->type = type;
+	if (ring->type == RING_TYPE_CMD) {
+		ring->db_offset_h = EP_CRDB_HIGHER;
+		ring->db_offset_l = EP_CRDB_LOWER;
+	} else if (ring->type == RING_TYPE_CH) {
+		ring->db_offset_h = CHDB_HIGHER_n(id);
+		ring->db_offset_l = CHDB_LOWER_n(id);
+		ring->ch_id = id;
+	} else {
+		ring->db_offset_h = ERDB_HIGHER_n(id);
+		ring->db_offset_l = ERDB_LOWER_n(id);
+	}
+}
+
+static void mhi_ep_raise_irq(struct work_struct *work)
+{
+	struct mhi_ep_ring *ring = container_of(work, struct mhi_ep_ring, intmodt_work.work);
+	struct mhi_ep_cntrl *mhi_cntrl = ring->mhi_cntrl;
+
+	mhi_cntrl->raise_irq(mhi_cntrl, ring->irq_vector);
+	WRITE_ONCE(ring->irq_pending, false);
+}
+
+int mhi_ep_ring_start(struct mhi_ep_cntrl *mhi_cntrl, struct mhi_ep_ring *ring,
+			union mhi_ep_ring_ctx *ctx)
+{
+	struct device *dev = &mhi_cntrl->mhi_dev->dev;
+	__le64 val;
+	int ret;
+
+	ring->mhi_cntrl = mhi_cntrl;
+	ring->ring_ctx = ctx;
+	ring->ring_size = mhi_ep_ring_num_elems(ring);
+	memcpy_fromio(&val, (void __iomem *) &ring->ring_ctx->generic.rbase, sizeof(u64));
+	ring->rbase = le64_to_cpu(val);
+
+	if (ring->type == RING_TYPE_CH)
+		ring->er_index = le32_to_cpu(ring->ring_ctx->ch.erindex);
+
+	if (ring->type == RING_TYPE_ER) {
+		ring->irq_vector = le32_to_cpu(ring->ring_ctx->ev.msivec);
+		ring->intmodt = FIELD_GET(EV_CTX_INTMODT_MASK,
+					  le32_to_cpu(ring->ring_ctx->ev.intmod));
+
+		INIT_DELAYED_WORK(&ring->intmodt_work, mhi_ep_raise_irq);
+	}
+
+	/* During ring init, both rp and wp are equal */
+	memcpy_fromio(&val, (void __iomem *) &ring->ring_ctx->generic.rp, sizeof(u64));
+	ring->rd_offset = mhi_ep_ring_addr2offset(ring, le64_to_cpu(val));
+	ring->wr_offset = mhi_ep_ring_addr2offset(ring, le64_to_cpu(val));
+
+	/* Allocate ring cache memory for holding the copy of host ring */
+	ring->ring_cache = kzalloc_objs(struct mhi_ring_element,
+					ring->ring_size);
+	if (!ring->ring_cache)
+		return -ENOMEM;
+
+	memcpy_fromio(&val, (void __iomem *) &ring->ring_ctx->generic.wp, sizeof(u64));
+	ret = mhi_ep_cache_ring(ring, le64_to_cpu(val));
+	if (ret) {
+		dev_err(dev, "Failed to cache ring\n");
+		kfree(ring->ring_cache);
+		return ret;
+	}
+
+	ring->started = true;
+
+	return 0;
+}
+
+void mhi_ep_ring_reset(struct mhi_ep_cntrl *mhi_cntrl, struct mhi_ep_ring *ring)
+{
+	if (ring->type == RING_TYPE_ER)
+		cancel_delayed_work_sync(&ring->intmodt_work);
+
+	ring->started = false;
+	kfree(ring->ring_cache);
+	ring->ring_cache = NULL;
+}

linux-7.2.3/drivers/bus/mhi/ep/sm.c

@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2022 Linaro Ltd.
+ * Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+ */
+
+#include <linux/errno.h>
+#include <linux/mhi_ep.h>
+#include "internal.h"
+
+bool __must_check mhi_ep_check_mhi_state(struct mhi_ep_cntrl *mhi_cntrl,
+					 enum mhi_state cur_mhi_state,
+					 enum mhi_state mhi_state)
+{
+	if (mhi_state == MHI_STATE_SYS_ERR)
+		return true;    /* Allowed in any state */
+
+	if (mhi_state == MHI_STATE_READY)
+		return cur_mhi_state == MHI_STATE_RESET;
+
+	if (mhi_state == MHI_STATE_M0)
+		return cur_mhi_state == MHI_STATE_M3 || cur_mhi_state == MHI_STATE_READY;
+
+	if (mhi_state == MHI_STATE_M3)
+		return cur_mhi_state == MHI_STATE_M0;
+
+	return false;
+}
+
+int mhi_ep_set_mhi_state(struct mhi_ep_cntrl *mhi_cntrl, enum mhi_state mhi_state)
+{
+	struct device *dev = &mhi_cntrl->mhi_dev->dev;
+
+	if (!mhi_ep_check_mhi_state(mhi_cntrl, mhi_cntrl->mhi_state, mhi_state)) {
+		dev_err(dev, "MHI state change to %s from %s is not allowed!\n",
+			mhi_state_str(mhi_state),
+			mhi_state_str(mhi_cntrl->mhi_state));
+		return -EACCES;
+	}
+
+	/* TODO: Add support for M1 and M2 states */
+	if (mhi_state == MHI_STATE_M1 || mhi_state == MHI_STATE_M2) {
+		dev_err(dev, "MHI state (%s) not supported\n", mhi_state_str(mhi_state));
+		return -EOPNOTSUPP;
+	}
+
+	mhi_ep_mmio_masked_write(mhi_cntrl, EP_MHISTATUS, MHISTATUS_MHISTATE_MASK, mhi_state);
+	mhi_cntrl->mhi_state = mhi_state;
+
+	if (mhi_state == MHI_STATE_READY)
+		mhi_ep_mmio_masked_write(mhi_cntrl, EP_MHISTATUS, MHISTATUS_READY_MASK, 1);
+
+	if (mhi_state == MHI_STATE_SYS_ERR)
+		mhi_ep_mmio_masked_write(mhi_cntrl, EP_MHISTATUS, MHISTATUS_SYSERR_MASK, 1);
+
+	return 0;
+}
+
+int mhi_ep_set_m0_state(struct mhi_ep_cntrl *mhi_cntrl)
+{
+	struct device *dev = &mhi_cntrl->mhi_dev->dev;
+	enum mhi_state old_state;
+	int ret;
+
+	/* If MHI is in M3, resume suspended channels */
+	mutex_lock(&mhi_cntrl->state_lock);
+
+	old_state = mhi_cntrl->mhi_state;
+	if (old_state == MHI_STATE_M3)
+		mhi_ep_resume_channels(mhi_cntrl);
+
+	ret = mhi_ep_set_mhi_state(mhi_cntrl, MHI_STATE_M0);
+	if (ret) {
+		mhi_ep_handle_syserr(mhi_cntrl);
+		goto err_unlock;
+	}
+
+	/* Signal host that the device moved to M0 */
+	ret = mhi_ep_send_state_change_event(mhi_cntrl, MHI_STATE_M0);
+	if (ret) {
+		dev_err(dev, "Failed sending M0 state change event\n");
+		goto err_unlock;
+	}
+
+	if (old_state == MHI_STATE_READY) {
+		/* Send AMSS EE event to host */
+		ret = mhi_ep_send_ee_event(mhi_cntrl, MHI_EE_AMSS);
+		if (ret) {
+			dev_err(dev, "Failed sending AMSS EE event\n");
+			goto err_unlock;
+		}
+	}
+
+err_unlock:
+	mutex_unlock(&mhi_cntrl->state_lock);
+
+	return ret;
+}
+
+int mhi_ep_set_m3_state(struct mhi_ep_cntrl *mhi_cntrl)
+{
+	struct device *dev = &mhi_cntrl->mhi_dev->dev;
+	int ret;
+
+	mutex_lock(&mhi_cntrl->state_lock);
+
+	ret = mhi_ep_set_mhi_state(mhi_cntrl, MHI_STATE_M3);
+	if (ret) {
+		mhi_ep_handle_syserr(mhi_cntrl);
+		goto err_unlock;
+	}
+
+	mhi_ep_suspend_channels(mhi_cntrl);
+
+	/* Signal host that the device moved to M3 */
+	ret = mhi_ep_send_state_change_event(mhi_cntrl, MHI_STATE_M3);
+	if (ret) {
+		dev_err(dev, "Failed sending M3 state change event\n");
+		goto err_unlock;
+	}
+
+err_unlock:
+	mutex_unlock(&mhi_cntrl->state_lock);
+
+	return ret;
+}
+
+int mhi_ep_set_ready_state(struct mhi_ep_cntrl *mhi_cntrl)
+{
+	struct device *dev = &mhi_cntrl->mhi_dev->dev;
+	enum mhi_state mhi_state;
+	int ret, is_ready;
+
+	mutex_lock(&mhi_cntrl->state_lock);
+
+	/* Ensure that the MHISTATUS is set to RESET by host */
+	mhi_state = mhi_ep_mmio_masked_read(mhi_cntrl, EP_MHISTATUS, MHISTATUS_MHISTATE_MASK);
+	is_ready = mhi_ep_mmio_masked_read(mhi_cntrl, EP_MHISTATUS, MHISTATUS_READY_MASK);
+
+	if (mhi_state != MHI_STATE_RESET || is_ready) {
+		dev_err(dev, "READY state transition failed. MHI host not in RESET state\n");
+		ret = -EIO;
+		goto err_unlock;
+	}
+
+	ret = mhi_ep_set_mhi_state(mhi_cntrl, MHI_STATE_READY);
+	if (ret)
+		mhi_ep_handle_syserr(mhi_cntrl);
+
+err_unlock:
+	mutex_unlock(&mhi_cntrl->state_lock);
+
+	return ret;
+}