[PATCH v7 1/7] dt-bindings: Add a binding for Mediatek SCP

[PATCH v7 1/7] dt-bindings: Add a binding for Mediatek SCP

[Peter Shih]

From: Erin Lo <erin.lo@mediatek.com>

Add a DT binding documentation of SCP for the
MT8183 SoC from Mediatek.

Signed-off-by: Erin Lo <erin.lo@mediatek.com>
Signed-off-by: Pi-Hsun Shih <pihsun@chromium.org>
Reviewed-by: Rob Herring <robh@kernel.org>
---
Changes from v6:
 - No change.

Changes from v5:
 - Remove dependency on CONFIG_RPMSG_MTK_SCP.

Changes from v4:
 - Add detail of more properties.
 - Document the usage of mtk,rpmsg-name in subnode from the new design.

Changes from v3:
 - No change.

Changes from v2:
 - No change. I realized that for this patch series, there's no need to
   add anything under the mt8183-scp node (neither the mt8183-rpmsg or
   the cros-ec-rpmsg) for them to work, since mt8183-rpmsg is added
   directly as a rproc_subdev by code, and cros-ec-rpmsg is dynamically
   created by SCP name service.

Changes from v1:
 - No change.
---
 .../bindings/remoteproc/mtk,scp.txt           | 36 +++++++++++++++++++
 1 file changed, 36 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/remoteproc/mtk,scp.txt

diff --git a/Documentation/devicetree/bindings/remoteproc/mtk,scp.txt b/Documentation/devicetree/bindings/remoteproc/mtk,scp.txt
new file mode 100644
index 000000000000..3ba668bab14b
--- /dev/null
+++ b/Documentation/devicetree/bindings/remoteproc/mtk,scp.txt
@@ -0,0 +1,36 @@
+Mediatek SCP Bindings
+----------------------------------------
+
+This binding provides support for ARM Cortex M4 Co-processor found on some
+Mediatek SoCs.
+
+Required properties:
+- compatible		Should be "mediatek,mt8183-scp"
+- reg			Should contain the address ranges for the two memory
+			regions, SRAM and CFG.
+- reg-names		Contains the corresponding names for the two memory
+			regions. These should be named "sram" & "cfg".
+- clocks		Clock for co-processor (See: ../clock/clock-bindings.txt)
+- clock-names		Contains the corresponding name for the clock. This
+			should be named "main".
+
+Subnodes
+--------
+
+Subnodes of the SCP represent rpmsg devices. The names of the devices are not
+important. The properties of these nodes are defined by the individual bindings
+for the rpmsg devices - but must contain the following property:
+
+- mtk,rpmsg-name	Contains the name for the rpmsg device. Used to match
+			the subnode to rpmsg device announced by SCP.
+
+Example:
+
+	scp: scp@10500000 {
+		compatible = "mediatek,mt8183-scp";
+		reg = <0 0x10500000 0 0x80000>,
+		      <0 0x105c0000 0 0x5000>;
+		reg-names = "sram", "cfg";
+		clocks = <&infracfg CLK_INFRA_SCPSYS>;
+		clock-names = "main";
+	};
-- 
2.21.0.392.gf8f6787159e-goog

[PATCH v7 2/7] remoteproc/mediatek: add SCP support for mt8183

[Peter Shih]

From: Erin Lo <erin.lo@mediatek.com>

Provide a basic driver to control Cortex M4 co-processor

Signed-off-by: Erin Lo <erin.lo@mediatek.com>
Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Signed-off-by: Pi-Hsun Shih <pihsun@chromium.org>
---
Changes from v6:
 - No change.

Changes from v5:
 - Changed some space to tab.

Changes from v4:
 - Rename most function from mtk_scp_* to scp_*.
 - Change the irq to threaded handler.
 - Load ELF file instead of plain binary file as firmware by default
   (Squashed patch 6 in v4 into this patch).

Changes from v3:
 - Fix some issue found by checkpatch.
 - Make writes aligned in scp_ipi_send.

Changes from v2:
 - Squash patch 3 from v2 (separate the ipi interface) into this patch.
 - Remove unused name argument from scp_ipi_register.
 - Add scp_ipi_unregister for proper cleanup.
 - Move IPI ids in sync with firmware.
 - Add mb() in proper place, and correctly clear the run->signaled.

Changes from v1:
 - Extract functions and rename variables in mtk_scp.c.
---
 drivers/remoteproc/Kconfig            |   9 +
 drivers/remoteproc/Makefile           |   1 +
 drivers/remoteproc/mtk_common.h       |  75 ++++
 drivers/remoteproc/mtk_scp.c          | 496 ++++++++++++++++++++++++++
 drivers/remoteproc/mtk_scp_ipi.c      | 162 +++++++++
 include/linux/platform_data/mtk_scp.h | 135 +++++++
 6 files changed, 878 insertions(+)
 create mode 100644 drivers/remoteproc/mtk_common.h
 create mode 100644 drivers/remoteproc/mtk_scp.c
 create mode 100644 drivers/remoteproc/mtk_scp_ipi.c
 create mode 100644 include/linux/platform_data/mtk_scp.h

diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
index f0abd2608044..92bd20d6b9cd 100644
--- a/drivers/remoteproc/Kconfig
+++ b/drivers/remoteproc/Kconfig
@@ -22,6 +22,15 @@ config IMX_REMOTEPROC
 
 	  It's safe to say N here.
 
+config MTK_SCP
+	tristate "Mediatek SCP support"
+	depends on ARCH_MEDIATEK
+	help
+	  Say y here to support Mediatek's System Companion Processor (SCP) via
+	  the remote processor framework.
+
+	  It's safe to say N here.
+
 config OMAP_REMOTEPROC
 	tristate "OMAP remoteproc support"
 	depends on ARCH_OMAP4 || SOC_OMAP5
diff --git a/drivers/remoteproc/Makefile b/drivers/remoteproc/Makefile
index ce5d061e92be..16b3e5e7a81c 100644
--- a/drivers/remoteproc/Makefile
+++ b/drivers/remoteproc/Makefile
@@ -10,6 +10,7 @@ remoteproc-y				+= remoteproc_sysfs.o
 remoteproc-y				+= remoteproc_virtio.o
 remoteproc-y				+= remoteproc_elf_loader.o
 obj-$(CONFIG_IMX_REMOTEPROC)		+= imx_rproc.o
+obj-$(CONFIG_MTK_SCP)			+= mtk_scp.o mtk_scp_ipi.o
 obj-$(CONFIG_OMAP_REMOTEPROC)		+= omap_remoteproc.o
 obj-$(CONFIG_WKUP_M3_RPROC)		+= wkup_m3_rproc.o
 obj-$(CONFIG_DA8XX_REMOTEPROC)		+= da8xx_remoteproc.o
diff --git a/drivers/remoteproc/mtk_common.h b/drivers/remoteproc/mtk_common.h
new file mode 100644
index 000000000000..7504ae1bc0ef
--- /dev/null
+++ b/drivers/remoteproc/mtk_common.h
@@ -0,0 +1,75 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2018 MediaTek Inc.
+ */
+
+#ifndef __RPROC_MTK_COMMON_H
+#define __RPROC_MTK_COMMON_H
+
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/remoteproc.h>
+
+#define MT8183_SW_RSTN			0x0
+#define MT8183_SW_RSTN_BIT		BIT(0)
+#define MT8183_SCP_TO_HOST		0x1C
+#define MT8183_SCP_IPC_INT_BIT		BIT(0)
+#define MT8183_SCP_WDT_INT_BIT		BIT(8)
+#define MT8183_HOST_TO_SCP		0x28
+#define MT8183_HOST_IPC_INT_BIT		BIT(0)
+#define MT8183_SCP_SRAM_PDN		0x402C
+
+#define SCP_FW_VER_LEN		32
+
+struct scp_run {
+	u32 signaled;
+	s8 fw_ver[SCP_FW_VER_LEN];
+	u32 dec_capability;
+	u32 enc_capability;
+	wait_queue_head_t wq;
+};
+
+struct scp_ipi_desc {
+	scp_ipi_handler_t handler;
+	void *priv;
+};
+
+struct mtk_scp {
+	struct device *dev;
+	struct rproc *rproc;
+	struct clk *clk;
+	void __iomem *reg_base;
+	void __iomem *sram_base;
+	size_t sram_size;
+
+	struct share_obj *recv_buf;
+	struct share_obj *send_buf;
+	struct scp_run run;
+	struct mutex lock; /* for protecting mtk_scp data structure */
+	struct scp_ipi_desc ipi_desc[SCP_IPI_MAX];
+	bool ipi_id_ack[SCP_IPI_MAX];
+	wait_queue_head_t ack_wq;
+
+	void __iomem *cpu_addr;
+	phys_addr_t phys_addr;
+	size_t dram_size;
+};
+
+/**
+ * struct share_obj - SRAM buffer shared with
+ *		      AP and SCP
+ *
+ * @id:		IPI id
+ * @len:	share buffer length
+ * @share_buf:	share buffer data
+ */
+struct share_obj {
+	s32 id;
+	u32 len;
+	u8 share_buf[288];
+};
+
+void scp_memcpy_aligned(void *dst, const void *src, unsigned int len);
+
+#endif
diff --git a/drivers/remoteproc/mtk_scp.c b/drivers/remoteproc/mtk_scp.c
new file mode 100644
index 000000000000..a84d69ae6c53
--- /dev/null
+++ b/drivers/remoteproc/mtk_scp.c
@@ -0,0 +1,496 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright (c) 2018 MediaTek Inc.
+
+#include <asm/barrier.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/platform_data/mtk_scp.h>
+#include <linux/platform_device.h>
+#include <linux/remoteproc.h>
+
+#include "mtk_common.h"
+#include "remoteproc_internal.h"
+
+#define MAX_CODE_SIZE 0x500000
+#define SCP_FW_BASE 0x800
+
+struct platform_device *scp_get_pdev(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *scp_node;
+	struct platform_device *scp_pdev;
+
+	scp_node = of_parse_phandle(dev->of_node, "mediatek,scp", 0);
+	if (!scp_node) {
+		dev_err(dev, "can't get SCP node\n");
+		return NULL;
+	}
+
+	scp_pdev = of_find_device_by_node(scp_node);
+	if (WARN_ON(!scp_pdev)) {
+		dev_err(dev, "SCP pdev failed\n");
+		of_node_put(scp_node);
+		return NULL;
+	}
+
+	return scp_pdev;
+}
+EXPORT_SYMBOL_GPL(scp_get_pdev);
+
+static void scp_wdt_handler(struct mtk_scp *scp)
+{
+	rproc_report_crash(scp->rproc, RPROC_WATCHDOG);
+}
+
+static void scp_init_ipi_handler(void *data, unsigned int len, void *priv)
+{
+	struct mtk_scp *scp = (struct mtk_scp *)priv;
+	struct scp_run *run = (struct scp_run *)data;
+
+	scp->run.signaled = run->signaled;
+	strncpy(scp->run.fw_ver, run->fw_ver, SCP_FW_VER_LEN);
+	scp->run.dec_capability = run->dec_capability;
+	scp->run.enc_capability = run->enc_capability;
+	wake_up_interruptible(&scp->run.wq);
+}
+
+static void scp_ipi_handler(struct mtk_scp *scp)
+{
+	struct share_obj *rcv_obj = scp->recv_buf;
+	struct scp_ipi_desc *ipi_desc = scp->ipi_desc;
+	u8 tmp_data[288];
+
+	if (rcv_obj->id >= SCP_IPI_MAX || !ipi_desc[rcv_obj->id].handler) {
+		dev_err(scp->dev, "No such ipi id = %d\n", rcv_obj->id);
+		return;
+	}
+
+	memcpy_fromio(tmp_data, &rcv_obj->share_buf, rcv_obj->len);
+	ipi_desc[rcv_obj->id].handler(tmp_data,
+				      rcv_obj->len,
+				      ipi_desc[rcv_obj->id].priv);
+	scp->ipi_id_ack[rcv_obj->id] = true;
+	wake_up(&scp->ack_wq);
+}
+
+static int scp_ipi_init(struct mtk_scp *scp)
+{
+	size_t send_offset = SCP_FW_BASE - sizeof(struct share_obj);
+	size_t recv_offset = send_offset - sizeof(struct share_obj);
+
+	/* Disable SCP to host interrupt */
+	writel(MT8183_SCP_IPC_INT_BIT, scp->reg_base + MT8183_SCP_TO_HOST);
+
+	/* shared buffer initialization */
+	scp->recv_buf = (__force struct share_obj *)(scp->sram_base +
+						recv_offset);
+	scp->send_buf = (__force struct share_obj *)(scp->sram_base +
+						send_offset);
+	memset_io(scp->recv_buf, 0, sizeof(scp->recv_buf));
+	memset_io(scp->send_buf, 0, sizeof(scp->send_buf));
+
+	return 0;
+}
+
+static void scp_reset_assert(const struct mtk_scp *scp)
+{
+	u32 val;
+
+	val = readl(scp->reg_base + MT8183_SW_RSTN);
+	val &= ~MT8183_SW_RSTN_BIT;
+	writel(val, scp->reg_base + MT8183_SW_RSTN);
+}
+
+static void scp_reset_deassert(const struct mtk_scp *scp)
+{
+	u32 val;
+
+	val = readl(scp->reg_base + MT8183_SW_RSTN);
+	val |= MT8183_SW_RSTN_BIT;
+	writel(val, scp->reg_base + MT8183_SW_RSTN);
+}
+
+static irqreturn_t scp_irq_handler(int irq, void *priv)
+{
+	struct mtk_scp *scp = priv;
+	u32 scp_to_host;
+
+	scp_to_host = readl(scp->reg_base + MT8183_SCP_TO_HOST);
+	if (scp_to_host & MT8183_SCP_IPC_INT_BIT) {
+		scp_ipi_handler(scp);
+	} else {
+		dev_err(scp->dev, "SCP watchdog timeout! 0x%x", scp_to_host);
+		scp_wdt_handler(scp);
+	}
+
+	/*
+	 * Ensure that all writes to SRAM are committed before another
+	 * interrupt.
+	 */
+	mb();
+	/* SCP won't send another interrupt until we set SCP_TO_HOST to 0. */
+	writel(MT8183_SCP_IPC_INT_BIT | MT8183_SCP_WDT_INT_BIT,
+	       scp->reg_base + MT8183_SCP_TO_HOST);
+
+	return IRQ_HANDLED;
+}
+
+int scp_elf_load_segments(struct rproc *rproc, const struct firmware *fw)
+{
+	struct device *dev = &rproc->dev;
+	struct elf32_hdr *ehdr;
+	struct elf32_phdr *phdr;
+	int i, ret = 0;
+	const u8 *elf_data = fw->data;
+
+	ehdr = (struct elf32_hdr *)elf_data;
+	phdr = (struct elf32_phdr *)(elf_data + ehdr->e_phoff);
+
+	/* go through the available ELF segments */
+	for (i = 0; i < ehdr->e_phnum; i++, phdr++) {
+		u32 da = phdr->p_paddr;
+		u32 memsz = phdr->p_memsz;
+		u32 filesz = phdr->p_filesz;
+		u32 offset = phdr->p_offset;
+		void __iomem *ptr;
+
+		if (phdr->p_type != PT_LOAD)
+			continue;
+
+		dev_dbg(dev, "phdr: type %d da 0x%x memsz 0x%x filesz 0x%x\n",
+			phdr->p_type, da, memsz, filesz);
+
+		if (filesz > memsz) {
+			dev_err(dev, "bad phdr filesz 0x%x memsz 0x%x\n",
+				filesz, memsz);
+			ret = -EINVAL;
+			break;
+		}
+
+		if (offset + filesz > fw->size) {
+			dev_err(dev, "truncated fw: need 0x%x avail 0x%zx\n",
+				offset + filesz, fw->size);
+			ret = -EINVAL;
+			break;
+		}
+
+		/* grab the kernel address for this device address */
+		ptr = rproc_da_to_va(rproc, da, memsz);
+		if (!ptr) {
+			dev_err(dev, "bad phdr da 0x%x mem 0x%x\n", da, memsz);
+			ret = -EINVAL;
+			break;
+		}
+
+		/* put the segment where the remote processor expects it */
+		if (phdr->p_filesz)
+			scp_memcpy_aligned(ptr, elf_data + phdr->p_offset,
+					   filesz);
+	}
+
+	return ret;
+}
+
+static int scp_load(struct rproc *rproc, const struct firmware *fw)
+{
+	const struct mtk_scp *scp = rproc->priv;
+	struct device *dev = scp->dev;
+	int ret;
+
+	/* Hold SCP in reset while loading FW. */
+	scp_reset_assert(scp);
+
+	ret = clk_prepare_enable(scp->clk);
+	if (ret) {
+		scp_reset_deassert(scp);
+		dev_err(dev, "failed to enable clocks\n");
+		return ret;
+	}
+
+	/* Turn on the power of SCP's SRAM before using it. */
+	writel(0x0, scp->reg_base + MT8183_SCP_SRAM_PDN);
+
+	return scp_elf_load_segments(rproc, fw);
+}
+
+static int scp_start(struct rproc *rproc)
+{
+	struct mtk_scp *scp = (struct mtk_scp *)rproc->priv;
+	struct device *dev = scp->dev;
+	struct scp_run *run;
+	int ret;
+
+	ret = clk_prepare_enable(scp->clk);
+	if (ret) {
+		dev_err(dev, "failed to enable clocks\n");
+		return ret;
+	}
+
+	run = &scp->run;
+	run->signaled = false;
+
+	scp_reset_deassert(scp);
+
+	ret = wait_event_interruptible_timeout(
+					run->wq,
+					run->signaled,
+					msecs_to_jiffies(2000));
+
+	if (ret == 0) {
+		dev_err(dev, "wait SCP initialization timeout!\n");
+		ret = -ETIME;
+		goto stop;
+	}
+	if (ret == -ERESTARTSYS) {
+		dev_err(dev, "wait SCP interrupted by a signal!\n");
+		goto stop;
+	}
+	dev_info(dev, "SCP is ready. FW version %s\n", run->fw_ver);
+
+	return 0;
+
+stop:
+	scp_reset_assert(scp);
+	clk_disable_unprepare(scp->clk);
+	return ret;
+}
+
+static void *scp_da_to_va(struct rproc *rproc, u64 da, int len)
+{
+	struct mtk_scp *scp = (struct mtk_scp *)rproc->priv;
+	int offset;
+
+	if (da < scp->sram_size) {
+		offset = da;
+		if (offset >= 0 && ((offset + len) < scp->sram_size))
+			return (__force void *)(scp->sram_base + offset);
+	} else if (da >= scp->sram_size &&
+		   da < (scp->sram_size + MAX_CODE_SIZE)) {
+		offset = da - scp->sram_size;
+		if (offset >= 0 && (offset + len) < MAX_CODE_SIZE)
+			return scp->cpu_addr + offset;
+	} else {
+		offset = da - scp->phys_addr;
+		if (offset >= 0 &&
+		    (offset + len) < (scp->dram_size - MAX_CODE_SIZE))
+			return scp->cpu_addr + offset;
+	}
+
+	return NULL;
+}
+
+static int scp_stop(struct rproc *rproc)
+{
+	struct mtk_scp *scp = (struct mtk_scp *)rproc->priv;
+
+	scp_reset_assert(scp);
+	clk_disable_unprepare(scp->clk);
+
+	return 0;
+}
+
+static const struct rproc_ops scp_ops = {
+	.start		= scp_start,
+	.stop		= scp_stop,
+	.load		= scp_load,
+	.da_to_va	= scp_da_to_va,
+};
+
+unsigned int scp_get_vdec_hw_capa(struct platform_device *pdev)
+{
+	struct mtk_scp *scp = platform_get_drvdata(pdev);
+
+	return scp->run.dec_capability;
+}
+EXPORT_SYMBOL_GPL(scp_get_vdec_hw_capa);
+
+unsigned int scp_get_venc_hw_capa(struct platform_device *pdev)
+{
+	struct mtk_scp *scp = platform_get_drvdata(pdev);
+
+	return scp->run.enc_capability;
+}
+EXPORT_SYMBOL_GPL(scp_get_venc_hw_capa);
+
+void *scp_mapping_dm_addr(struct platform_device *pdev, u32 mem_addr)
+{
+	struct mtk_scp *scp = platform_get_drvdata(pdev);
+	void *ptr;
+
+	ptr = scp_da_to_va(scp->rproc, mem_addr, 0);
+	if (!ptr)
+		return ERR_PTR(-EINVAL);
+
+	return ptr;
+}
+EXPORT_SYMBOL_GPL(scp_mapping_dm_addr);
+
+static int scp_map_memory_region(struct mtk_scp *scp)
+{
+	struct device_node *node;
+	struct resource r;
+	int ret;
+
+	node = of_parse_phandle(scp->dev->of_node, "memory-region", 0);
+	if (!node) {
+		dev_err(scp->dev, "no memory-region specified\n");
+		return -EINVAL;
+	}
+
+	ret = of_address_to_resource(node, 0, &r);
+	if (ret)
+		return ret;
+
+	scp->phys_addr = r.start;
+	scp->dram_size = resource_size(&r);
+	scp->cpu_addr =
+		devm_ioremap_wc(scp->dev, scp->phys_addr, scp->dram_size);
+
+	if (!scp->cpu_addr) {
+		dev_err(scp->dev, "unable to map memory region: %pa+%zx\n",
+			&r.start, scp->dram_size);
+		return -EBUSY;
+	}
+
+	return 0;
+}
+
+static int scp_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct mtk_scp *scp;
+	struct rproc *rproc;
+	struct resource *res;
+	char *fw_name = "scp.img";
+	int ret;
+
+	rproc = rproc_alloc(dev,
+			    np->name,
+			    &scp_ops,
+			    fw_name,
+			    sizeof(*scp));
+	if (!rproc) {
+		dev_err(dev, "unable to allocate remoteproc\n");
+		return -ENOMEM;
+	}
+
+	scp = (struct mtk_scp *)rproc->priv;
+	scp->rproc = rproc;
+	scp->dev = dev;
+	platform_set_drvdata(pdev, scp);
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "sram");
+	scp->sram_base = devm_ioremap_resource(dev, res);
+	if (IS_ERR((__force void *)scp->sram_base)) {
+		dev_err(dev, "Failed to parse and map sram memory\n");
+		ret = PTR_ERR((__force void *)scp->sram_base);
+		goto free_rproc;
+	}
+	scp->sram_size = resource_size(res);
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "cfg");
+	scp->reg_base = devm_ioremap_resource(dev, res);
+	if (IS_ERR((__force void *)scp->reg_base)) {
+		dev_err(dev, "Failed to parse and map cfg memory\n");
+		ret = PTR_ERR((__force void *)scp->reg_base);
+		goto free_rproc;
+	}
+
+	ret = scp_map_memory_region(scp);
+	if (ret)
+		goto free_rproc;
+
+	scp->clk = devm_clk_get(dev, "main");
+	if (IS_ERR(scp->clk)) {
+		dev_err(dev, "Failed to get clock\n");
+		ret = PTR_ERR(scp->clk);
+		goto free_rproc;
+	}
+
+	ret = clk_prepare_enable(scp->clk);
+	if (ret) {
+		dev_err(dev, "failed to enable clocks\n");
+		goto free_rproc;
+	}
+
+	ret = scp_ipi_init(scp);
+	clk_disable_unprepare(scp->clk);
+	if (ret) {
+		dev_err(dev, "Failed to init ipi\n");
+		goto free_rproc;
+	}
+
+	/* register SCP initialization IPI */
+	ret = scp_ipi_register(pdev,
+			       SCP_IPI_INIT,
+			       scp_init_ipi_handler,
+			       scp);
+	if (ret) {
+		dev_err(dev, "Failed to register IPI_SCP_INIT\n");
+		goto free_rproc;
+	}
+
+	mutex_init(&scp->lock);
+
+	init_waitqueue_head(&scp->run.wq);
+	init_waitqueue_head(&scp->ack_wq);
+
+	ret = devm_request_threaded_irq(dev, platform_get_irq(pdev, 0), NULL,
+					scp_irq_handler, IRQF_ONESHOT,
+					pdev->name, scp);
+
+	if (ret) {
+		dev_err(dev, "failed to request irq\n");
+		goto destroy_mutex;
+	}
+
+	ret = rproc_add(rproc);
+	if (ret)
+		goto destroy_mutex;
+
+	return ret;
+
+destroy_mutex:
+	mutex_destroy(&scp->lock);
+free_rproc:
+	rproc_free(rproc);
+
+	return ret;
+}
+
+static int scp_remove(struct platform_device *pdev)
+{
+	struct mtk_scp *scp = platform_get_drvdata(pdev);
+
+	rproc_del(scp->rproc);
+	rproc_free(scp->rproc);
+
+	return 0;
+}
+
+static const struct of_device_id mtk_scp_of_match[] = {
+	{ .compatible = "mediatek,mt8183-scp"},
+	{},
+};
+MODULE_DEVICE_TABLE(of, mtk_scp_of_match);
+
+static struct platform_driver mtk_scp_driver = {
+	.probe = scp_probe,
+	.remove = scp_remove,
+	.driver = {
+		.name = "mtk-scp",
+		.of_match_table = of_match_ptr(mtk_scp_of_match),
+	},
+};
+
+module_platform_driver(mtk_scp_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("MediaTek SCP control driver");
diff --git a/drivers/remoteproc/mtk_scp_ipi.c b/drivers/remoteproc/mtk_scp_ipi.c
new file mode 100644
index 000000000000..f5d271c0f623
--- /dev/null
+++ b/drivers/remoteproc/mtk_scp_ipi.c
@@ -0,0 +1,162 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright (c) 2018 MediaTek Inc.
+
+#include <asm/barrier.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_data/mtk_scp.h>
+#include <linux/platform_device.h>
+
+#include "mtk_common.h"
+
+int scp_ipi_register(struct platform_device *pdev,
+		     enum scp_ipi_id id,
+		     scp_ipi_handler_t handler,
+		     void *priv)
+{
+	struct mtk_scp *scp = platform_get_drvdata(pdev);
+	struct scp_ipi_desc *ipi_desc;
+
+	if (!scp) {
+		dev_err(&pdev->dev, "scp device is not ready\n");
+		return -EPROBE_DEFER;
+	}
+
+	if (WARN_ON(id < 0) || WARN_ON(id >= SCP_IPI_MAX) ||
+	    WARN_ON(handler == NULL))
+		return -EINVAL;
+
+	ipi_desc = scp->ipi_desc;
+	ipi_desc[id].handler = handler;
+	ipi_desc[id].priv = priv;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(scp_ipi_register);
+
+void scp_ipi_unregister(struct platform_device *pdev, enum scp_ipi_id id)
+{
+	struct mtk_scp *scp = platform_get_drvdata(pdev);
+	struct scp_ipi_desc *ipi_desc;
+
+	if (!scp)
+		return;
+
+	if (WARN_ON(id < 0) || WARN_ON(id >= SCP_IPI_MAX))
+		return;
+
+	ipi_desc = scp->ipi_desc;
+	ipi_desc[id].handler = NULL;
+	ipi_desc[id].priv = NULL;
+}
+EXPORT_SYMBOL_GPL(scp_ipi_unregister);
+
+/*
+ * Copy src to dst, where dst is in SCP SRAM region.
+ * Since AP access of SCP SRAM don't support byte write, this always write a
+ * full word at a time, and may cause some extra bytes to be written at the
+ * beginning & ending of dst.
+ */
+void scp_memcpy_aligned(void *dst, const void *src, unsigned int len)
+{
+	void *ptr;
+	u32 val;
+	unsigned int i = 0;
+
+	if (!IS_ALIGNED((unsigned long)dst, 4)) {
+		ptr = (void *)ALIGN_DOWN((unsigned long)dst, 4);
+		i = 4 - (dst - ptr);
+		val = readl_relaxed(ptr);
+		memcpy((u8 *)&val + (4 - i), src, i);
+		writel_relaxed(val, ptr);
+	}
+
+	while (i + 4 <= len) {
+		val = *((u32 *)(src + i));
+		writel_relaxed(val, dst + i);
+		i += 4;
+	}
+	if (i < len) {
+		val = readl_relaxed(dst + i);
+		memcpy(&val, src + i, len - i);
+		writel_relaxed(val, dst + i);
+	}
+}
+EXPORT_SYMBOL_GPL(scp_memcpy_aligned);
+
+int scp_ipi_send(struct platform_device *pdev,
+		 enum scp_ipi_id id,
+		 void *buf,
+		 unsigned int len,
+		 unsigned int wait)
+{
+	struct mtk_scp *scp = platform_get_drvdata(pdev);
+	struct share_obj *send_obj = scp->send_buf;
+	unsigned long timeout;
+	int ret;
+
+	if (WARN_ON(id <= SCP_IPI_INIT) || WARN_ON(id >= SCP_IPI_MAX) ||
+	    WARN_ON(len > sizeof(send_obj->share_buf)) || WARN_ON(!buf))
+		return -EINVAL;
+
+	mutex_lock(&scp->lock);
+
+	ret = clk_prepare_enable(scp->clk);
+	if (ret) {
+		dev_err(scp->dev, "failed to enable clock\n");
+		return ret;
+	}
+
+	 /* Wait until SCP receives the last command */
+	timeout = jiffies + msecs_to_jiffies(2000);
+	do {
+		if (time_after(jiffies, timeout)) {
+			dev_err(scp->dev, "%s: IPI timeout!\n", __func__);
+			ret = -EIO;
+			mutex_unlock(&scp->lock);
+			goto clock_disable;
+		}
+	} while (readl(scp->reg_base + MT8183_HOST_TO_SCP));
+
+	scp_memcpy_aligned(send_obj->share_buf, buf, len);
+
+	send_obj->len = len;
+	send_obj->id = id;
+
+	scp->ipi_id_ack[id] = false;
+	/*
+	 * Ensure that all writes to SRAM are committed before sending the
+	 * interrupt to SCP.
+	 */
+	mb();
+	/* send the command to SCP */
+	writel(MT8183_HOST_IPC_INT_BIT, scp->reg_base + MT8183_HOST_TO_SCP);
+
+	mutex_unlock(&scp->lock);
+
+	if (wait) {
+		/* wait for SCP's ACK */
+		timeout = msecs_to_jiffies(wait);
+		ret = wait_event_timeout(scp->ack_wq,
+					 scp->ipi_id_ack[id],
+					 timeout);
+		scp->ipi_id_ack[id] = false;
+		if (WARN(!ret,
+			 "scp ipi %d ack time out !", id))
+			ret = -EIO;
+		else
+			ret = 0;
+	}
+
+clock_disable:
+	clk_disable_unprepare(scp->clk);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(scp_ipi_send);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("MediaTek scp IPI interface");
diff --git a/include/linux/platform_data/mtk_scp.h b/include/linux/platform_data/mtk_scp.h
new file mode 100644
index 000000000000..dfda05051235
--- /dev/null
+++ b/include/linux/platform_data/mtk_scp.h
@@ -0,0 +1,135 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2018 MediaTek Inc.
+ */
+
+#ifndef _MTK_SCP_H
+#define _MTK_SCP_H
+
+#include <linux/platform_device.h>
+
+typedef void (*scp_ipi_handler_t) (void *data,
+				   unsigned int len,
+				   void *priv);
+
+/**
+ * enum ipi_id - the id of inter-processor interrupt
+ *
+ * @SCP_IPI_INIT:	 The interrupt from scp is to notfiy kernel
+ *			 SCP initialization completed.
+ *			 IPI_SCP_INIT is sent from SCP when firmware is
+ *			 loaded. AP doesn't need to send IPI_SCP_INIT
+ *			 command to SCP.
+ *			 For other IPI below, AP should send the request
+ *			 to SCP to trigger the interrupt.
+ * @SCP_IPI_MAX:	 The maximum IPI number
+ */
+
+enum scp_ipi_id {
+	SCP_IPI_INIT = 0,
+	SCP_IPI_VDEC_H264,
+	SCP_IPI_VDEC_VP8,
+	SCP_IPI_VDEC_VP9,
+	SCP_IPI_VENC_H264,
+	SCP_IPI_VENC_VP8,
+	SCP_IPI_MDP,
+	SCP_IPI_CROS_HOST_CMD,
+	SCP_IPI_MAX,
+};
+
+/**
+ * scp_ipi_register - register an ipi function
+ *
+ * @pdev:	SCP platform device
+ * @id:		IPI ID
+ * @handler:	IPI handler
+ * @priv:	private data for IPI handler
+ *
+ * Register an ipi function to receive ipi interrupt from SCP.
+ *
+ * Return: Return 0 if ipi registers successfully, otherwise it is failed.
+ */
+int scp_ipi_register(struct platform_device *pdev,
+		     enum scp_ipi_id id,
+		     scp_ipi_handler_t handler,
+		     void *priv);
+
+/**
+ * scp_ipi_unregister - unregister an ipi function
+ *
+ * @pdev:	SCP platform device
+ * @id:		IPI ID
+ *
+ * Unregister an ipi function to receive ipi interrupt from SCP.
+ */
+void scp_ipi_unregister(struct platform_device *pdev, enum scp_ipi_id id);
+
+/**
+ * scp_ipi_send - send data from AP to scp.
+ *
+ * @pdev:	SCP platform device
+ * @id:		IPI ID
+ * @buf:	the data buffer
+ * @len:	the data buffer length
+ * @wait:	1: need ack
+ *
+ * This function is thread-safe. When this function returns,
+ * SCP has received the data and starts the processing.
+ * When the processing completes, IPI handler registered
+ * by scp_ipi_register will be called in interrupt context.
+ *
+ * Return: Return 0 if sending data successfully, otherwise it is failed.
+ **/
+int scp_ipi_send(struct platform_device *pdev,
+		 enum scp_ipi_id id,
+		 void *buf,
+		 unsigned int len,
+		 unsigned int wait);
+
+/**
+ * scp_get_pdev - get SCP's platform device
+ *
+ * @pdev:	the platform device of the module requesting SCP platform
+ *		device for using SCP API.
+ *
+ * Return: Return NULL if it is failed.
+ * otherwise it is SCP's platform device
+ **/
+struct platform_device *scp_get_pdev(struct platform_device *pdev);
+
+/**
+ * scp_get_vdec_hw_capa - get video decoder hardware capability
+ *
+ * @pdev:	SCP platform device
+ *
+ * Return: video decoder hardware capability
+ **/
+unsigned int scp_get_vdec_hw_capa(struct platform_device *pdev);
+
+/**
+ * scp_get_venc_hw_capa - get video encoder hardware capability
+ *
+ * @pdev:	SCP platform device
+ *
+ * Return: video encoder hardware capability
+ **/
+unsigned int scp_get_venc_hw_capa(struct platform_device *pdev);
+
+/**
+ * scp_mapping_dm_addr - Mapping SRAM/DRAM to kernel virtual address
+ *
+ * @pdev:	SCP platform device
+ * @mem_addr:	SCP views memory address
+ *
+ * Mapping the SCP's SRAM address /
+ * DMEM (Data Extended Memory) memory address /
+ * Working buffer memory address to
+ * kernel virtual address.
+ *
+ * Return: Return ERR_PTR(-EINVAL) if mapping failed,
+ * otherwise the mapped kernel virtual address
+ **/
+void *scp_mapping_dm_addr(struct platform_device *pdev,
+			  u32 mem_addr);
+
+#endif /* _MTK_SCP_H */
-- 
2.21.0.392.gf8f6787159e-goog

[PATCH v7 3/7] remoteproc: mt8183: add reserved memory manager API

[Peter Shih]

From: Erin Lo <erin.lo@mediatek.com>

Add memory table mapping API for other driver to lookup
reserved physical and virtual memory

Signed-off-by: Erin Lo <erin.lo@mediatek.com>
Signed-off-by: Pi-Hsun Shih <pihsun@chromium.org>
---
Changes from v6:
 - No change.

Changes from v5:
 - No change.

Changes from v4:
 - New patch.
---
 drivers/remoteproc/mtk_scp.c          | 111 ++++++++++++++++++++++++++
 include/linux/platform_data/mtk_scp.h |  20 +++++
 2 files changed, 131 insertions(+)

diff --git a/drivers/remoteproc/mtk_scp.c b/drivers/remoteproc/mtk_scp.c
index a84d69ae6c53..ca45cb729bd3 100644
--- a/drivers/remoteproc/mtk_scp.c
+++ b/drivers/remoteproc/mtk_scp.c
@@ -331,6 +331,113 @@ void *scp_mapping_dm_addr(struct platform_device *pdev, u32 mem_addr)
 }
 EXPORT_SYMBOL_GPL(scp_mapping_dm_addr);
 
+#if SCP_RESERVED_MEM
+phys_addr_t scp_mem_base_phys;
+phys_addr_t scp_mem_base_virt;
+phys_addr_t scp_mem_size;
+
+static struct scp_reserve_mblock scp_reserve_mblock[] = {
+	{
+		.num = SCP_ISP_MEM_ID,
+		.start_phys = 0x0,
+		.start_virt = 0x0,
+		.size = 0x1400000,  /*20MB*/
+	},
+};
+
+static int scp_reserve_mem_init(struct mtk_scp *scp)
+{
+	enum scp_reserve_mem_id_t id;
+	phys_addr_t accumlate_memory_size = 0;
+
+	scp_mem_base_phys = (phys_addr_t) (scp->phys_addr + MAX_CODE_SIZE);
+	scp_mem_size = (phys_addr_t) (scp->dram_size - MAX_CODE_SIZE);
+
+	dev_info(scp->dev,
+		 "phys:0x%llx - 0x%llx (0x%llx)\n",
+		 scp_mem_base_phys,
+		 scp_mem_base_phys + scp_mem_size,
+		 scp_mem_size);
+	accumlate_memory_size = 0;
+	for (id = 0; id < SCP_NUMS_MEM_ID; id++) {
+		scp_reserve_mblock[id].start_phys =
+			scp_mem_base_phys + accumlate_memory_size;
+		accumlate_memory_size += scp_reserve_mblock[id].size;
+		dev_info(scp->dev,
+			 "[reserve_mem:%d]: phys:0x%llx - 0x%llx (0x%llx)\n",
+			 id, scp_reserve_mblock[id].start_phys,
+			 scp_reserve_mblock[id].start_phys +
+				 scp_reserve_mblock[id].size,
+			 scp_reserve_mblock[id].size);
+	}
+	return 0;
+}
+
+static int scp_reserve_memory_ioremap(struct mtk_scp *scp)
+{
+	enum scp_reserve_mem_id_t id;
+	phys_addr_t accumlate_memory_size = 0;
+
+	scp_mem_base_virt = (phys_addr_t)(size_t)ioremap_wc(scp_mem_base_phys,
+							    scp_mem_size);
+
+	dev_info(scp->dev,
+		 "virt:0x%llx - 0x%llx (0x%llx)\n",
+		(phys_addr_t)scp_mem_base_virt,
+		(phys_addr_t)scp_mem_base_virt + (phys_addr_t)scp_mem_size,
+		scp_mem_size);
+	for (id = 0; id < SCP_NUMS_MEM_ID; id++) {
+		scp_reserve_mblock[id].start_virt =
+			scp_mem_base_virt + accumlate_memory_size;
+		accumlate_memory_size += scp_reserve_mblock[id].size;
+	}
+	/* the reserved memory should be larger then expected memory
+	 * or scp_reserve_mblock does not match dts
+	 */
+	WARN_ON(accumlate_memory_size > scp_mem_size);
+#ifdef DEBUG
+	for (id = 0; id < NUMS_MEM_ID; id++) {
+		dev_info(scp->dev,
+			 "[mem_reserve-%d] phys:0x%llx,virt:0x%llx,size:0x%llx\n",
+			 id,
+			 scp_get_reserve_mem_phys(id),
+			 scp_get_reserve_mem_virt(id),
+			 scp_get_reserve_mem_size(id));
+	}
+#endif
+	return 0;
+}
+phys_addr_t scp_get_reserve_mem_phys(enum scp_reserve_mem_id_t id)
+{
+	if (id >= SCP_NUMS_MEM_ID) {
+		pr_err("[SCP] no reserve memory for %d", id);
+		return 0;
+	} else
+		return scp_reserve_mblock[id].start_phys;
+}
+EXPORT_SYMBOL_GPL(scp_get_reserve_mem_phys);
+
+phys_addr_t scp_get_reserve_mem_virt(enum scp_reserve_mem_id_t id)
+{
+	if (id >= SCP_NUMS_MEM_ID) {
+		pr_err("[SCP] no reserve memory for %d", id);
+		return 0;
+	} else
+		return scp_reserve_mblock[id].start_virt;
+}
+EXPORT_SYMBOL_GPL(scp_get_reserve_mem_virt);
+
+phys_addr_t scp_get_reserve_mem_size(enum scp_reserve_mem_id_t id)
+{
+	if (id >= SCP_NUMS_MEM_ID) {
+		pr_err("[SCP] no reserve memory for %d", id);
+		return 0;
+	} else
+		return scp_reserve_mblock[id].size;
+}
+EXPORT_SYMBOL_GPL(scp_get_reserve_mem_size);
+#endif
+
 static int scp_map_memory_region(struct mtk_scp *scp)
 {
 	struct device_node *node;
@@ -358,6 +465,10 @@ static int scp_map_memory_region(struct mtk_scp *scp)
 		return -EBUSY;
 	}
 
+#if SCP_RESERVED_MEM
+	scp_reserve_mem_init(scp);
+	scp_reserve_memory_ioremap(scp);
+#endif
 	return 0;
 }
 
diff --git a/include/linux/platform_data/mtk_scp.h b/include/linux/platform_data/mtk_scp.h
index dfda05051235..7625eede2e58 100644
--- a/include/linux/platform_data/mtk_scp.h
+++ b/include/linux/platform_data/mtk_scp.h
@@ -132,4 +132,24 @@ unsigned int scp_get_venc_hw_capa(struct platform_device *pdev);
 void *scp_mapping_dm_addr(struct platform_device *pdev,
 			  u32 mem_addr);
 
+#define SCP_RESERVED_MEM	(1)
+#if SCP_RESERVED_MEM
+/* scp reserve memory ID definition*/
+enum scp_reserve_mem_id_t {
+	SCP_ISP_MEM_ID,
+	SCP_NUMS_MEM_ID,
+};
+
+struct scp_reserve_mblock {
+	enum scp_reserve_mem_id_t num;
+	u64 start_phys;
+	u64 start_virt;
+	u64 size;
+};
+
+extern phys_addr_t scp_get_reserve_mem_phys(enum scp_reserve_mem_id_t id);
+extern phys_addr_t scp_get_reserve_mem_virt(enum scp_reserve_mem_id_t id);
+extern phys_addr_t scp_get_reserve_mem_size(enum scp_reserve_mem_id_t id);
+#endif
+
 #endif /* _MTK_SCP_H */
-- 
2.21.0.392.gf8f6787159e-goog

[PATCH v7 4/7] rpmsg: add rpmsg support for mt8183 SCP.

[Peter Shih]

From: Pi-Hsun Shih <pihsun@chromium.org>

Add a simple rpmsg support for mt8183 SCP, that use IPI / IPC directly.

Signed-off-by: Pi-Hsun Shih <pihsun@chromium.org>
---
Changes from v6:
 - Decouple mtk_rpmsg from mtk_scp by putting all necessary informations
   (name service IPI id, register/unregister/send functions) into a
   struct, and pass it to the mtk_rpmsg_create_rproc_subdev function.

Changes from v5:
 - CONFIG_MTK_SCP now selects CONFIG_RPMSG_MTK_SCP, and the dummy
   implementation for mtk_rpmsg_{create,destroy}_rproc_subdev when
   CONFIG_RPMSG_MTK_SCP is not defined is removed.

Changes from v4:
 - Match and fill the device tree node to the created rpmsg subdevice,
   so the rpmsg subdevice can utilize the properties and subnodes on
   device tree (This is similar to what drivers/rpmsg/qcom_smd.c does).

Changes from v3:
 - Change from unprepare to stop, to stop the rpmsg driver before the
   rproc is stopped, avoiding problem that some rpmsg would fail after
   rproc is stopped.
 - Add missing spin_lock_init, and use destroy_ept instead of kref_put.

Changes from v2:
 - Unregiser IPI handler on unprepare.
 - Lock the channel list on operations.
 - Move SCP_IPI_NS_SERVICE to 0xFF.

Changes from v1:
 - Do cleanup properly in mtk_rpmsg.c, which also removes the problem of
   short-lived work items.
 - Fix several issues checkpatch found.
---
 drivers/remoteproc/Kconfig            |   1 +
 drivers/remoteproc/mtk_common.h       |   2 +
 drivers/remoteproc/mtk_scp.c          |  38 ++-
 drivers/remoteproc/mtk_scp_ipi.c      |   1 +
 drivers/rpmsg/Kconfig                 |   9 +
 drivers/rpmsg/Makefile                |   1 +
 drivers/rpmsg/mtk_rpmsg.c             | 396 ++++++++++++++++++++++++++
 include/linux/platform_data/mtk_scp.h |   4 +-
 include/linux/rpmsg/mtk_rpmsg.h       |  30 ++
 9 files changed, 477 insertions(+), 5 deletions(-)
 create mode 100644 drivers/rpmsg/mtk_rpmsg.c
 create mode 100644 include/linux/rpmsg/mtk_rpmsg.h

diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
index 92bd20d6b9cd..01182936f4fa 100644
--- a/drivers/remoteproc/Kconfig
+++ b/drivers/remoteproc/Kconfig
@@ -25,6 +25,7 @@ config IMX_REMOTEPROC
 config MTK_SCP
 	tristate "Mediatek SCP support"
 	depends on ARCH_MEDIATEK
+	select RPMSG_MTK_SCP
 	help
 	  Say y here to support Mediatek's System Companion Processor (SCP) via
 	  the remote processor framework.
diff --git a/drivers/remoteproc/mtk_common.h b/drivers/remoteproc/mtk_common.h
index 7504ae1bc0ef..19a907810271 100644
--- a/drivers/remoteproc/mtk_common.h
+++ b/drivers/remoteproc/mtk_common.h
@@ -54,6 +54,8 @@ struct mtk_scp {
 	void __iomem *cpu_addr;
 	phys_addr_t phys_addr;
 	size_t dram_size;
+
+	struct rproc_subdev *rpmsg_subdev;
 };
 
 /**
diff --git a/drivers/remoteproc/mtk_scp.c b/drivers/remoteproc/mtk_scp.c
index ca45cb729bd3..2c4847fcae10 100644
--- a/drivers/remoteproc/mtk_scp.c
+++ b/drivers/remoteproc/mtk_scp.c
@@ -13,6 +13,7 @@
 #include <linux/platform_data/mtk_scp.h>
 #include <linux/platform_device.h>
 #include <linux/remoteproc.h>
+#include <linux/rpmsg/mtk_rpmsg.h>
 
 #include "mtk_common.h"
 #include "remoteproc_internal.h"
@@ -472,6 +473,31 @@ static int scp_map_memory_region(struct mtk_scp *scp)
 	return 0;
 }
 
+static struct mtk_rpmsg_info mtk_scp_rpmsg_info = {
+	.send_ipi = scp_ipi_send,
+	.register_ipi = scp_ipi_register,
+	.unregister_ipi = scp_ipi_unregister,
+	.ns_ipi_id = SCP_IPI_NS_SERVICE,
+};
+
+static void scp_add_rpmsg_subdev(struct mtk_scp *scp)
+{
+	scp->rpmsg_subdev =
+		mtk_rpmsg_create_rproc_subdev(to_platform_device(scp->dev),
+					      &mtk_scp_rpmsg_info);
+	if (scp->rpmsg_subdev)
+		rproc_add_subdev(scp->rproc, scp->rpmsg_subdev);
+}
+
+static void scp_remove_rpmsg_subdev(struct mtk_scp *scp)
+{
+	if (scp->rpmsg_subdev) {
+		rproc_remove_subdev(scp->rproc, scp->rpmsg_subdev);
+		mtk_rpmsg_destroy_rproc_subdev(scp->rpmsg_subdev);
+		scp->rpmsg_subdev = NULL;
+	}
+}
+
 static int scp_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -553,22 +579,25 @@ static int scp_probe(struct platform_device *pdev)
 	init_waitqueue_head(&scp->run.wq);
 	init_waitqueue_head(&scp->ack_wq);
 
+	scp_add_rpmsg_subdev(scp);
+
 	ret = devm_request_threaded_irq(dev, platform_get_irq(pdev, 0), NULL,
 					scp_irq_handler, IRQF_ONESHOT,
 					pdev->name, scp);
 
 	if (ret) {
 		dev_err(dev, "failed to request irq\n");
-		goto destroy_mutex;
+		goto remove_subdev;
 	}
 
 	ret = rproc_add(rproc);
 	if (ret)
-		goto destroy_mutex;
+		goto remove_subdev;
 
-	return ret;
+	return 0;
 
-destroy_mutex:
+remove_subdev:
+	scp_remove_rpmsg_subdev(scp);
 	mutex_destroy(&scp->lock);
 free_rproc:
 	rproc_free(rproc);
@@ -580,6 +609,7 @@ static int scp_remove(struct platform_device *pdev)
 {
 	struct mtk_scp *scp = platform_get_drvdata(pdev);
 
+	scp_remove_rpmsg_subdev(scp);
 	rproc_del(scp->rproc);
 	rproc_free(scp->rproc);
 
diff --git a/drivers/remoteproc/mtk_scp_ipi.c b/drivers/remoteproc/mtk_scp_ipi.c
index f5d271c0f623..10b0cbda7aee 100644
--- a/drivers/remoteproc/mtk_scp_ipi.c
+++ b/drivers/remoteproc/mtk_scp_ipi.c
@@ -99,6 +99,7 @@ int scp_ipi_send(struct platform_device *pdev,
 	int ret;
 
 	if (WARN_ON(id <= SCP_IPI_INIT) || WARN_ON(id >= SCP_IPI_MAX) ||
+	    WARN_ON(id == SCP_IPI_NS_SERVICE) ||
 	    WARN_ON(len > sizeof(send_obj->share_buf)) || WARN_ON(!buf))
 		return -EINVAL;
 
diff --git a/drivers/rpmsg/Kconfig b/drivers/rpmsg/Kconfig
index d0322b41eca5..85e3cc075cb4 100644
--- a/drivers/rpmsg/Kconfig
+++ b/drivers/rpmsg/Kconfig
@@ -15,6 +15,15 @@ config RPMSG_CHAR
 	  in /dev. They make it possible for user-space programs to send and
 	  receive rpmsg packets.
 
+config RPMSG_MTK_SCP
+	tristate "MediaTek SCP"
+	depends on MTK_SCP
+	select RPMSG
+	help
+	  Say y here to enable support providing communication channels to
+	  remote processors in MediaTek platforms.
+	  This use IPI and IPC to communicate with remote processors.
+
 config RPMSG_QCOM_GLINK_NATIVE
 	tristate
 	select RPMSG
diff --git a/drivers/rpmsg/Makefile b/drivers/rpmsg/Makefile
index 9aa859502d27..ae92a7fb08f6 100644
--- a/drivers/rpmsg/Makefile
+++ b/drivers/rpmsg/Makefile
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_RPMSG)		+= rpmsg_core.o
 obj-$(CONFIG_RPMSG_CHAR)	+= rpmsg_char.o
+obj-$(CONFIG_RPMSG_MTK_SCP)	+= mtk_rpmsg.o
 obj-$(CONFIG_RPMSG_QCOM_GLINK_RPM) += qcom_glink_rpm.o
 obj-$(CONFIG_RPMSG_QCOM_GLINK_NATIVE) += qcom_glink_native.o
 obj-$(CONFIG_RPMSG_QCOM_GLINK_SMEM) += qcom_glink_smem.o
diff --git a/drivers/rpmsg/mtk_rpmsg.c b/drivers/rpmsg/mtk_rpmsg.c
new file mode 100644
index 000000000000..e5e988941ea6
--- /dev/null
+++ b/drivers/rpmsg/mtk_rpmsg.c
@@ -0,0 +1,396 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright 2018 Google LLC.
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/remoteproc.h>
+#include <linux/rpmsg/mtk_rpmsg.h>
+#include <linux/workqueue.h>
+
+#include "rpmsg_internal.h"
+
+struct mtk_rpmsg_rproc_subdev {
+	struct platform_device *pdev;
+	struct mtk_rpmsg_info *info;
+	struct rpmsg_endpoint *ns_ept;
+	struct rproc_subdev subdev;
+
+	struct work_struct register_work;
+	struct list_head channels;
+	struct mutex channels_lock;
+};
+
+#define to_mtk_subdev(d) container_of(d, struct mtk_rpmsg_rproc_subdev, subdev)
+
+struct mtk_rpmsg_channel_info {
+	struct rpmsg_channel_info info;
+	bool registered;
+	struct list_head list;
+};
+
+/**
+ * struct rpmsg_ns_msg - dynamic name service announcement message
+ * @name: name of remote service that is published
+ * @addr: address of remote service that is published
+ *
+ * This message is sent across to publish a new service. When we receive these
+ * messages, an appropriate rpmsg channel (i.e device) is created. In turn, the
+ * ->probe() handler of the appropriate rpmsg driver will be invoked
+ *  (if/as-soon-as one is registered).
+ */
+struct rpmsg_ns_msg {
+	char name[RPMSG_NAME_SIZE];
+	u32 addr;
+} __packed;
+
+struct mtk_rpmsg_device {
+	struct rpmsg_device rpdev;
+	struct mtk_rpmsg_rproc_subdev *mtk_subdev;
+};
+
+struct mtk_rpmsg_endpoint {
+	struct rpmsg_endpoint ept;
+	struct mtk_rpmsg_rproc_subdev *mtk_subdev;
+};
+
+#define to_mtk_rpmsg_device(r) container_of(r, struct mtk_rpmsg_device, rpdev)
+#define to_mtk_rpmsg_endpoint(r) container_of(r, struct mtk_rpmsg_endpoint, ept)
+
+static const struct rpmsg_endpoint_ops mtk_rpmsg_endpoint_ops;
+
+static void __ept_release(struct kref *kref)
+{
+	struct rpmsg_endpoint *ept = container_of(kref, struct rpmsg_endpoint,
+						  refcount);
+	kfree(to_mtk_rpmsg_endpoint(ept));
+}
+
+static void mtk_rpmsg_ipi_handler(void *data, unsigned int len, void *priv)
+{
+	struct mtk_rpmsg_endpoint *mept = priv;
+	struct rpmsg_endpoint *ept = &mept->ept;
+	int ret;
+
+	ret = (*ept->cb)(ept->rpdev, data, len, ept->priv, ept->addr);
+	if (ret)
+		dev_warn(&ept->rpdev->dev, "rpmsg handler return error = %d",
+			 ret);
+}
+
+static struct rpmsg_endpoint *
+__rpmsg_create_ept(struct mtk_rpmsg_rproc_subdev *mtk_subdev,
+		   struct rpmsg_device *rpdev, rpmsg_rx_cb_t cb, void *priv,
+		   u32 id)
+{
+	struct mtk_rpmsg_endpoint *mept;
+	struct rpmsg_endpoint *ept;
+	struct platform_device *pdev = mtk_subdev->pdev;
+	int ret;
+
+	mept = kzalloc(sizeof(*mept), GFP_KERNEL);
+	if (!mept)
+		return NULL;
+	mept->mtk_subdev = mtk_subdev;
+
+	ept = &mept->ept;
+	kref_init(&ept->refcount);
+
+	ept->rpdev = rpdev;
+	ept->cb = cb;
+	ept->priv = priv;
+	ept->ops = &mtk_rpmsg_endpoint_ops;
+	ept->addr = id;
+
+	ret = mtk_subdev->info->register_ipi(pdev, id, mtk_rpmsg_ipi_handler,
+					     mept);
+	if (ret) {
+		dev_err(&pdev->dev, "IPI register failed, id = %d", id);
+		kref_put(&ept->refcount, __ept_release);
+		return NULL;
+	}
+
+	return ept;
+}
+
+static struct rpmsg_endpoint *
+mtk_rpmsg_create_ept(struct rpmsg_device *rpdev, rpmsg_rx_cb_t cb, void *priv,
+		     struct rpmsg_channel_info chinfo)
+{
+	struct mtk_rpmsg_rproc_subdev *mtk_subdev =
+		to_mtk_rpmsg_device(rpdev)->mtk_subdev;
+
+	return __rpmsg_create_ept(mtk_subdev, rpdev, cb, priv, chinfo.src);
+}
+
+static void mtk_rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
+{
+	struct mtk_rpmsg_rproc_subdev *mtk_subdev =
+		to_mtk_rpmsg_endpoint(ept)->mtk_subdev;
+
+	mtk_subdev->info->unregister_ipi(mtk_subdev->pdev, ept->addr);
+	kref_put(&ept->refcount, __ept_release);
+}
+
+static int mtk_rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
+{
+	struct mtk_rpmsg_rproc_subdev *mtk_subdev =
+		to_mtk_rpmsg_endpoint(ept)->mtk_subdev;
+
+	return mtk_subdev->info->send_ipi(mtk_subdev->pdev, ept->addr, data,
+					  len, 0);
+}
+
+static int mtk_rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
+{
+	struct mtk_rpmsg_rproc_subdev *mtk_subdev =
+		to_mtk_rpmsg_endpoint(ept)->mtk_subdev;
+
+	/*
+	 * TODO: This currently is same as mtk_rpmsg_send, and wait until SCP
+	 * received the last command.
+	 */
+	return mtk_subdev->info->send_ipi(mtk_subdev->pdev, ept->addr, data,
+					  len, 0);
+}
+
+static const struct rpmsg_endpoint_ops mtk_rpmsg_endpoint_ops = {
+	.destroy_ept = mtk_rpmsg_destroy_ept,
+	.send = mtk_rpmsg_send,
+	.trysend = mtk_rpmsg_trysend,
+};
+
+static void mtk_rpmsg_release_device(struct device *dev)
+{
+	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+	struct mtk_rpmsg_device *mdev = to_mtk_rpmsg_device(rpdev);
+
+	kfree(mdev);
+}
+
+static const struct rpmsg_device_ops mtk_rpmsg_device_ops = {
+	.create_ept = mtk_rpmsg_create_ept,
+};
+
+static struct device_node *
+mtk_rpmsg_match_device_subnode(struct device_node *node, const char *channel)
+{
+	struct device_node *child;
+	const char *name;
+	int ret;
+
+	for_each_available_child_of_node(node, child) {
+		ret = of_property_read_string(child, "mtk,rpmsg-name", &name);
+		if (ret)
+			continue;
+
+		if (strcmp(name, channel) == 0)
+			return child;
+	}
+
+	return NULL;
+}
+
+static int mtk_rpmsg_register_device(struct mtk_rpmsg_rproc_subdev *mtk_subdev,
+				     struct rpmsg_channel_info *info)
+{
+	struct rpmsg_device *rpdev;
+	struct mtk_rpmsg_device *mdev;
+	struct platform_device *pdev = mtk_subdev->pdev;
+	int ret;
+
+	mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
+	if (!mdev)
+		return -ENOMEM;
+
+	mdev->mtk_subdev = mtk_subdev;
+
+	rpdev = &mdev->rpdev;
+	rpdev->ops = &mtk_rpmsg_device_ops;
+	rpdev->src = info->src;
+	rpdev->dst = info->dst;
+	strncpy(rpdev->id.name, info->name, RPMSG_NAME_SIZE);
+
+	rpdev->dev.of_node =
+		mtk_rpmsg_match_device_subnode(pdev->dev.of_node, info->name);
+	rpdev->dev.parent = &pdev->dev;
+	rpdev->dev.release = mtk_rpmsg_release_device;
+
+	ret = rpmsg_register_device(rpdev);
+	if (ret) {
+		kfree(mdev);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void mtk_register_device_work_function(struct work_struct *register_work)
+{
+	struct mtk_rpmsg_rproc_subdev *subdev = container_of(
+		register_work, struct mtk_rpmsg_rproc_subdev, register_work);
+	struct platform_device *pdev = subdev->pdev;
+	struct mtk_rpmsg_channel_info *info;
+	int ret;
+
+	mutex_lock(&subdev->channels_lock);
+	list_for_each_entry(info, &subdev->channels, list) {
+		if (info->registered)
+			continue;
+
+		ret = mtk_rpmsg_register_device(subdev, &info->info);
+		if (ret) {
+			dev_err(&pdev->dev, "Can't create rpmsg_device\n");
+			continue;
+		}
+
+		info->registered = true;
+	}
+	mutex_unlock(&subdev->channels_lock);
+}
+
+static int mtk_rpmsg_create_device(struct mtk_rpmsg_rproc_subdev *mtk_subdev,
+				   char *name, u32 addr)
+{
+	struct mtk_rpmsg_channel_info *info;
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	strncpy(info->info.name, name, RPMSG_NAME_SIZE);
+	info->info.src = addr;
+	info->info.dst = RPMSG_ADDR_ANY;
+	mutex_lock(&mtk_subdev->channels_lock);
+	list_add(&info->list, &mtk_subdev->channels);
+	mutex_unlock(&mtk_subdev->channels_lock);
+
+	schedule_work(&mtk_subdev->register_work);
+	return 0;
+}
+
+static int mtk_rpmsg_ns_cb(struct rpmsg_device *rpdev, void *data, int len,
+			   void *priv, u32 src)
+{
+	struct rpmsg_ns_msg *msg = data;
+	struct mtk_rpmsg_rproc_subdev *mtk_subdev = priv;
+	struct device *dev = &mtk_subdev->pdev->dev;
+
+	int ret;
+
+	if (len != sizeof(*msg)) {
+		dev_err(dev, "malformed ns msg (%d)\n", len);
+		return -EINVAL;
+	}
+
+	/*
+	 * the name service ept does _not_ belong to a real rpmsg channel,
+	 * and is handled by the rpmsg bus itself.
+	 * for sanity reasons, make sure a valid rpdev has _not_ sneaked
+	 * in somehow.
+	 */
+	if (rpdev) {
+		dev_err(dev, "anomaly: ns ept has an rpdev handle\n");
+		return -EINVAL;
+	}
+
+	/* don't trust the remote processor for null terminating the name */
+	msg->name[RPMSG_NAME_SIZE - 1] = '\0';
+
+	dev_info(dev, "creating channel %s addr 0x%x\n", msg->name, msg->addr);
+
+	ret = mtk_rpmsg_create_device(mtk_subdev, msg->name, msg->addr);
+	if (ret) {
+		dev_err(dev, "create rpmsg device failed\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+int mtk_rpmsg_prepare(struct rproc_subdev *subdev)
+{
+	struct mtk_rpmsg_rproc_subdev *mtk_subdev = to_mtk_subdev(subdev);
+
+	/* a dedicated endpoint handles the name service msgs */
+	if (mtk_subdev->info->ns_ipi_id >= 0) {
+		mtk_subdev->ns_ept =
+			__rpmsg_create_ept(mtk_subdev, NULL, mtk_rpmsg_ns_cb,
+					   mtk_subdev,
+					   mtk_subdev->info->ns_ipi_id);
+		if (!mtk_subdev->ns_ept) {
+			dev_err(&mtk_subdev->pdev->dev,
+				"failed to create name service endpoint\n");
+			return -ENOMEM;
+		}
+	}
+
+	return 0;
+}
+
+void mtk_rpmsg_stop(struct rproc_subdev *subdev, bool crashed)
+{
+	struct mtk_rpmsg_channel_info *info, *next;
+	struct mtk_rpmsg_rproc_subdev *mtk_subdev = to_mtk_subdev(subdev);
+	struct device *dev = &mtk_subdev->pdev->dev;
+
+	if (mtk_subdev->ns_ept)
+		mtk_rpmsg_destroy_ept(mtk_subdev->ns_ept);
+	cancel_work_sync(&mtk_subdev->register_work);
+
+	mutex_lock(&mtk_subdev->channels_lock);
+	list_for_each_entry(info, &mtk_subdev->channels, list) {
+		if (!info->registered)
+			continue;
+		if (rpmsg_unregister_device(dev, &info->info)) {
+			dev_warn(
+				dev,
+				"rpmsg_unregister_device failed for %s.%d.%d\n",
+				info->info.name, info->info.src,
+				info->info.dst);
+		}
+	}
+
+	list_for_each_entry_safe(info, next,
+				 &mtk_subdev->channels, list) {
+		list_del(&info->list);
+		kfree(info);
+	}
+	mutex_unlock(&mtk_subdev->channels_lock);
+}
+
+struct rproc_subdev *
+mtk_rpmsg_create_rproc_subdev(struct platform_device *pdev,
+			      struct mtk_rpmsg_info *info)
+{
+	struct mtk_rpmsg_rproc_subdev *mtk_subdev;
+
+	mtk_subdev = kzalloc(sizeof(*mtk_subdev), GFP_KERNEL);
+	if (!mtk_subdev)
+		return NULL;
+
+	mtk_subdev->pdev = pdev;
+	mtk_subdev->subdev.prepare = mtk_rpmsg_prepare;
+	mtk_subdev->subdev.stop = mtk_rpmsg_stop;
+	mtk_subdev->info = info;
+	INIT_LIST_HEAD(&mtk_subdev->channels);
+	INIT_WORK(&mtk_subdev->register_work,
+		  mtk_register_device_work_function);
+	mutex_init(&mtk_subdev->channels_lock);
+
+	return &mtk_subdev->subdev;
+}
+EXPORT_SYMBOL_GPL(mtk_rpmsg_create_rproc_subdev);
+
+void mtk_rpmsg_destroy_rproc_subdev(struct rproc_subdev *subdev)
+{
+	struct mtk_rpmsg_rproc_subdev *mtk_subdev = to_mtk_subdev(subdev);
+
+	kfree(mtk_subdev);
+}
+EXPORT_SYMBOL_GPL(mtk_rpmsg_destroy_rproc_subdev);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("MediaTek scp rpmsg driver");
diff --git a/include/linux/platform_data/mtk_scp.h b/include/linux/platform_data/mtk_scp.h
index 7625eede2e58..e26e5f6146e6 100644
--- a/include/linux/platform_data/mtk_scp.h
+++ b/include/linux/platform_data/mtk_scp.h
@@ -34,9 +34,11 @@ enum scp_ipi_id {
 	SCP_IPI_VENC_VP8,
 	SCP_IPI_MDP,
 	SCP_IPI_CROS_HOST_CMD,
-	SCP_IPI_MAX,
+	SCP_IPI_NS_SERVICE = 0xFF,
+	SCP_IPI_MAX = 0x100,
 };
 
+
 /**
  * scp_ipi_register - register an ipi function
  *
diff --git a/include/linux/rpmsg/mtk_rpmsg.h b/include/linux/rpmsg/mtk_rpmsg.h
new file mode 100644
index 000000000000..90f848696161
--- /dev/null
+++ b/include/linux/rpmsg/mtk_rpmsg.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright 2018 Google LLC.
+ */
+
+#ifndef __LINUX_RPMSG_MTK_RPMSG_H
+#define __LINUX_RPMSG_MTK_RPMSG_H
+
+#include <linux/device.h>
+#include <linux/remoteproc.h>
+
+typedef void (*ipi_handler_t)(void *data, unsigned int len, void *priv);
+
+/* TODO: Document */
+struct mtk_rpmsg_info {
+	int (*register_ipi)(struct platform_device *pdev, u32 id,
+			    ipi_handler_t handler, void *priv);
+	void (*unregister_ipi)(struct platform_device *pdev, u32 id);
+	int (*send_ipi)(struct platform_device *pdev, u32 id,
+			void *buf, unsigned int len, unsigned int wait);
+	int ns_ipi_id;
+};
+
+struct rproc_subdev *
+mtk_rpmsg_create_rproc_subdev(struct platform_device *pdev,
+			      struct mtk_rpmsg_info *info);
+
+void mtk_rpmsg_destroy_rproc_subdev(struct rproc_subdev *subdev);
+
+#endif
-- 
2.21.0.392.gf8f6787159e-goog

[PATCH v7 5/7] dt-bindings: Add binding for cros-ec-rpmsg.

[Peter Shih]

From: Pi-Hsun Shih <pihsun@chromium.org>

Add a DT binding documentation for ChromeOS EC driver over rpmsg.

Signed-off-by: Pi-Hsun Shih <pihsun@chromium.org>
---
Changes from v6:
 - No change.

Changes from v5:
 - New patch.
---
 Documentation/devicetree/bindings/mfd/cros-ec.txt | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/mfd/cros-ec.txt b/Documentation/devicetree/bindings/mfd/cros-ec.txt
index 6245c9b1a68b..4860eabd0f72 100644
--- a/Documentation/devicetree/bindings/mfd/cros-ec.txt
+++ b/Documentation/devicetree/bindings/mfd/cros-ec.txt
@@ -3,7 +3,7 @@ ChromeOS Embedded Controller
 Google's ChromeOS EC is a Cortex-M device which talks to the AP and
 implements various function such as keyboard and battery charging.
 
-The EC can be connect through various means (I2C, SPI, LPC) and the
+The EC can be connect through various means (I2C, SPI, LPC, RPMSG) and the
 compatible string used depends on the interface. Each connection method has
 its own driver which connects to the top level interface-agnostic EC driver.
 Other Linux driver (such as cros-ec-keyb for the matrix keyboard) connect to
@@ -17,6 +17,9 @@ Required properties (SPI):
 - compatible: "google,cros-ec-spi"
 - reg: SPI chip select
 
+Required properties (RPMSG):
+- compatible: "google,cros-ec-rpmsg"
+
 Optional properties (SPI):
 - google,cros-ec-spi-pre-delay: Some implementations of the EC need a little
   time to wake up from sleep before they can receive SPI transfers at a high
-- 
2.21.0.392.gf8f6787159e-goog

Re: [PATCH v7 5/7] dt-bindings: Add binding for cros-ec-rpmsg.

[Rob Herring]

On Wed, Mar 27, 2019 at 01:14:47PM +0800, Peter Shih wrote:
> From: Pi-Hsun Shih <pihsun@chromium.org>
> 
> Add a DT binding documentation for ChromeOS EC driver over rpmsg.
> 
> Signed-off-by: Pi-Hsun Shih <pihsun@chromium.org>
> ---
> Changes from v6:
>  - No change.
> 
> Changes from v5:
>  - New patch.
> ---
>  Documentation/devicetree/bindings/mfd/cros-ec.txt | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)

Acked-by: Rob Herring <robh@kernel.org>

[PATCH v7 6/7] platform/chrome: cros_ec: add EC host command support using rpmsg.

[Peter Shih]

From: Pi-Hsun Shih <pihsun@chromium.org>

Add EC host command support through rpmsg.

Signed-off-by: Pi-Hsun Shih <pihsun@chromium.org>
---
Changes from v6:
 - Make data for response aligned to 4 bytes.

Changes from v5:
 - Change commit title.
 - Add documents for some structs, and fix all warning from
   scripts/kernel-doc.
 - Miscellaneous fixes based on feedback.

Changes from v4:
 - Change from work queue to completion.
 - Change from matching using rpmsg id to device tree compatible, to
   support EC subdevices.

Changes from v3:
 - Add host event support by adding an extra bytes at the start of IPC
   message to indicate the type of the message (host event or host
   command), since there's no additional irq that can be used for host
   event.

Changes from v2:
 - Wait for ipi ack instead of depends on the behavior in mtk-rpmsg.

Changes from v1:
 - Code format fix based on feedback for cros_ec_rpmsg.c.
 - Extract feature detection for SCP into separate patch (Patch 6).
---
 drivers/platform/chrome/Kconfig         |   9 +
 drivers/platform/chrome/Makefile        |   1 +
 drivers/platform/chrome/cros_ec_rpmsg.c | 265 ++++++++++++++++++++++++
 3 files changed, 275 insertions(+)
 create mode 100644 drivers/platform/chrome/cros_ec_rpmsg.c

diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
index 9186d81a51cc..5c48aa6da2f8 100644
--- a/drivers/platform/chrome/Kconfig
+++ b/drivers/platform/chrome/Kconfig
@@ -59,6 +59,15 @@ config CROS_EC_I2C
 	  a checksum. Failing accesses will be retried three times to
 	  improve reliability.
 
+config CROS_EC_RPMSG
+	tristate "ChromeOS Embedded Controller (rpmsg)"
+	depends on MFD_CROS_EC && RPMSG && OF
+	help
+	  If you say Y here, you get support for talking to the ChromeOS EC
+	  through rpmsg. This uses a simple byte-level protocol with a
+	  checksum. Also since there's no addition EC-to-host interrupt, this
+	  use a byte in message to distinguish host event from host command.
+
 config CROS_EC_SPI
 	tristate "ChromeOS Embedded Controller (SPI)"
 	depends on MFD_CROS_EC && SPI
diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
index 1e2f0029b597..4b69d795720d 100644
--- a/drivers/platform/chrome/Makefile
+++ b/drivers/platform/chrome/Makefile
@@ -4,6 +4,7 @@ obj-$(CONFIG_CHROMEOS_LAPTOP)		+= chromeos_laptop.o
 obj-$(CONFIG_CHROMEOS_PSTORE)		+= chromeos_pstore.o
 obj-$(CONFIG_CHROMEOS_TBMC)		+= chromeos_tbmc.o
 obj-$(CONFIG_CROS_EC_I2C)		+= cros_ec_i2c.o
+obj-$(CONFIG_CROS_EC_RPMSG)		+= cros_ec_rpmsg.o
 obj-$(CONFIG_CROS_EC_SPI)		+= cros_ec_spi.o
 cros_ec_lpcs-objs			:= cros_ec_lpc.o cros_ec_lpc_reg.o
 cros_ec_lpcs-$(CONFIG_CROS_EC_LPC_MEC)	+= cros_ec_lpc_mec.o
diff --git a/drivers/platform/chrome/cros_ec_rpmsg.c b/drivers/platform/chrome/cros_ec_rpmsg.c
new file mode 100644
index 000000000000..2ecae806cfc5
--- /dev/null
+++ b/drivers/platform/chrome/cros_ec_rpmsg.c
@@ -0,0 +1,265 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright 2018 Google LLC.
+
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mfd/cros_ec.h>
+#include <linux/mfd/cros_ec_commands.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/rpmsg.h>
+#include <linux/slab.h>
+
+#define EC_MSG_TIMEOUT_MS 200
+#define HOST_COMMAND_MARK 1
+#define HOST_EVENT_MARK 2
+
+/**
+ * struct cros_ec_rpmsg_response - rpmsg message format from from EC.
+ *
+ * @type:	The type of message, should be either HOST_COMMAND_MARK or
+ *		HOST_EVENT_MARK, representing that the message is a response to
+ *		host command, or a host event.
+ * @data:	ec_host_response for host command.
+ */
+struct cros_ec_rpmsg_response {
+	u8 type;
+	u8 data[] __aligned(4);
+};
+
+/**
+ * struct cros_ec_rpmsg - information about a EC over rpmsg.
+ *
+ * @rpdev:	rpmsg device we are connected to
+ * @xfer_ack:	completion for host command transfer.
+ * @host_event_work:	Work struct for pending host event.
+ */
+struct cros_ec_rpmsg {
+	struct rpmsg_device *rpdev;
+	struct completion xfer_ack;
+	struct work_struct host_event_work;
+};
+
+/**
+ * cros_ec_cmd_xfer_rpmsg - Transfer a message over rpmsg and receive the reply
+ *
+ * @ec_dev: ChromeOS EC device
+ * @ec_msg: Message to transfer
+ *
+ * This is only used for old EC proto version, and is not supported for this
+ * driver.
+ *
+ * Return: number of bytes of the reply on success or negative error code.
+ */
+static int cros_ec_cmd_xfer_rpmsg(struct cros_ec_device *ec_dev,
+				  struct cros_ec_command *ec_msg)
+{
+	return -EINVAL;
+}
+
+/**
+ * cros_ec_pkt_xfer_rpmsg - Transfer a packet over rpmsg and receive the reply
+ *
+ * @ec_dev: ChromeOS EC device
+ * @ec_msg: Message to transfer
+ *
+ * Return: number of bytes of the reply on success or negative error code.
+ */
+static int cros_ec_pkt_xfer_rpmsg(struct cros_ec_device *ec_dev,
+				  struct cros_ec_command *ec_msg)
+{
+	struct ec_host_response *response;
+	struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
+	struct rpmsg_device *rpdev = ec_rpmsg->rpdev;
+	int len;
+	u8 sum;
+	int ret;
+	int i;
+	unsigned long timeout;
+
+	ec_msg->result = 0;
+	len = cros_ec_prepare_tx(ec_dev, ec_msg);
+	dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
+
+	reinit_completion(&ec_rpmsg->xfer_ack);
+	ret = rpmsg_send(rpdev->ept, ec_dev->dout, len);
+	if (ret) {
+		dev_err(ec_dev->dev, "rpmsg send failed\n");
+		return ret;
+	}
+
+	timeout = msecs_to_jiffies(EC_MSG_TIMEOUT_MS);
+	ret = wait_for_completion_timeout(&ec_rpmsg->xfer_ack, timeout);
+	if (!ret) {
+		dev_err(ec_dev->dev, "rpmsg send timeout\n");
+		return -EIO;
+	}
+
+	/* check response error code */
+	response = (struct ec_host_response *)ec_dev->din;
+	ec_msg->result = response->result;
+
+	ret = cros_ec_check_result(ec_dev, ec_msg);
+	if (ret)
+		goto exit;
+
+	if (response->data_len > ec_msg->insize) {
+		dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
+			response->data_len, ec_msg->insize);
+		ret = -EMSGSIZE;
+		goto exit;
+	}
+
+	/* copy response packet payload and compute checksum */
+	memcpy(ec_msg->data, ec_dev->din + sizeof(*response),
+	       response->data_len);
+
+	sum = 0;
+	for (i = 0; i < sizeof(*response) + response->data_len; i++)
+		sum += ec_dev->din[i];
+
+	if (sum) {
+		dev_err(ec_dev->dev, "bad packet checksum, calculated %x\n",
+			sum);
+		ret = -EBADMSG;
+		goto exit;
+	}
+
+	ret = response->data_len;
+exit:
+	if (ec_msg->command == EC_CMD_REBOOT_EC)
+		msleep(EC_REBOOT_DELAY_MS);
+
+	return ret;
+}
+
+static void
+cros_ec_rpmsg_host_event_function(struct work_struct *host_event_work)
+{
+	struct cros_ec_rpmsg *ec_rpmsg = container_of(
+		host_event_work, struct cros_ec_rpmsg, host_event_work);
+	struct cros_ec_device *ec_dev = dev_get_drvdata(&ec_rpmsg->rpdev->dev);
+	bool wake_event = true;
+	int ret;
+
+	ret = cros_ec_get_next_event(ec_dev, &wake_event);
+
+	/*
+	 * Signal only if wake host events or any interrupt if
+	 * cros_ec_get_next_event() returned an error (default value for
+	 * wake_event is true)
+	 */
+	if (wake_event && device_may_wakeup(ec_dev->dev))
+		pm_wakeup_event(ec_dev->dev, 0);
+
+	if (ret > 0)
+		blocking_notifier_call_chain(&ec_dev->event_notifier,
+					     0, ec_dev);
+}
+
+static int cros_ec_rpmsg_callback(struct rpmsg_device *rpdev, void *data,
+				  int len, void *priv, u32 src)
+{
+	struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
+	struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
+	struct cros_ec_rpmsg_response *resp;
+
+	if (!len) {
+		dev_warn(ec_dev->dev, "rpmsg received empty response");
+		return -EINVAL;
+	}
+
+	resp = data;
+	len -= offsetof(struct cros_ec_rpmsg_response, data);
+	if (resp->type == HOST_COMMAND_MARK) {
+		if (len > ec_dev->din_size) {
+			dev_warn(
+				ec_dev->dev,
+				"received length %d > din_size %d, truncating",
+				len, ec_dev->din_size);
+			len = ec_dev->din_size;
+		}
+
+		memcpy(ec_dev->din, resp->data, len);
+		complete(&ec_rpmsg->xfer_ack);
+	} else if (resp->type == HOST_EVENT_MARK) {
+		schedule_work(&ec_rpmsg->host_event_work);
+	} else {
+		dev_warn(ec_dev->dev, "rpmsg received invalid type = %d",
+			 resp->type);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int cros_ec_rpmsg_probe(struct rpmsg_device *rpdev)
+{
+	struct device *dev = &rpdev->dev;
+	struct cros_ec_device *ec_dev;
+	struct cros_ec_rpmsg *ec_rpmsg;
+	int ret;
+
+	ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
+	if (!ec_dev)
+		return -ENOMEM;
+
+	ec_rpmsg = devm_kzalloc(dev, sizeof(*ec_rpmsg), GFP_KERNEL);
+	if (!ec_rpmsg)
+		return -ENOMEM;
+
+	ec_dev->dev = dev;
+	ec_dev->priv = ec_rpmsg;
+	ec_dev->cmd_xfer = cros_ec_cmd_xfer_rpmsg;
+	ec_dev->pkt_xfer = cros_ec_pkt_xfer_rpmsg;
+	ec_dev->phys_name = dev_name(&rpdev->dev);
+	ec_dev->din_size = sizeof(struct ec_host_response) +
+			   sizeof(struct ec_response_get_protocol_info);
+	ec_dev->dout_size = sizeof(struct ec_host_request);
+	dev_set_drvdata(dev, ec_dev);
+
+	ec_rpmsg->rpdev = rpdev;
+	init_completion(&ec_rpmsg->xfer_ack);
+	INIT_WORK(&ec_rpmsg->host_event_work,
+		  cros_ec_rpmsg_host_event_function);
+
+	ret = cros_ec_register(ec_dev);
+	if (ret) {
+		dev_err(dev, "cannot register EC\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static void cros_ec_rpmsg_remove(struct rpmsg_device *rpdev)
+{
+	struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
+	struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
+
+	cancel_work_sync(&ec_rpmsg->host_event_work);
+}
+
+static const struct of_device_id cros_ec_rpmsg_of_match[] = {
+	{ .compatible = "google,cros-ec-rpmsg", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, cros_ec_rpmsg_of_match);
+
+static struct rpmsg_driver cros_ec_driver_rpmsg = {
+	.drv = {
+		.name   = KBUILD_MODNAME,
+		.of_match_table = cros_ec_rpmsg_of_match,
+	},
+	.probe		= cros_ec_rpmsg_probe,
+	.remove		= cros_ec_rpmsg_remove,
+	.callback	= cros_ec_rpmsg_callback,
+};
+
+module_rpmsg_driver(cros_ec_driver_rpmsg);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("ChromeOS EC multi function device (rpmsg)");
-- 
2.21.0.392.gf8f6787159e-goog

Re: [PATCH v7 6/7] platform/chrome: cros_ec: add EC host command support using rpmsg.

[Enric Balletbo Serra]

Hi

Thanks for sending this upstream, Some few comments and questions
below. Apart from these LGTM.

Missatge de Peter Shih <pihsun@chromium.org> del dia dc., 27 de març
2019 a les 6:17:
>
> From: Pi-Hsun Shih <pihsun@chromium.org>
>
> Add EC host command support through rpmsg.
>
> Signed-off-by: Pi-Hsun Shih <pihsun@chromium.org>
> ---
> Changes from v6:
>  - Make data for response aligned to 4 bytes.
>
> Changes from v5:
>  - Change commit title.
>  - Add documents for some structs, and fix all warning from
>    scripts/kernel-doc.
>  - Miscellaneous fixes based on feedback.
>
> Changes from v4:
>  - Change from work queue to completion.
>  - Change from matching using rpmsg id to device tree compatible, to
>    support EC subdevices.
>
> Changes from v3:
>  - Add host event support by adding an extra bytes at the start of IPC
>    message to indicate the type of the message (host event or host
>    command), since there's no additional irq that can be used for host
>    event.
>
> Changes from v2:
>  - Wait for ipi ack instead of depends on the behavior in mtk-rpmsg.
>
> Changes from v1:
>  - Code format fix based on feedback for cros_ec_rpmsg.c.
>  - Extract feature detection for SCP into separate patch (Patch 6).
> ---
>  drivers/platform/chrome/Kconfig         |   9 +
>  drivers/platform/chrome/Makefile        |   1 +
>  drivers/platform/chrome/cros_ec_rpmsg.c | 265 ++++++++++++++++++++++++
>  3 files changed, 275 insertions(+)
>  create mode 100644 drivers/platform/chrome/cros_ec_rpmsg.c
>
> diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
> index 9186d81a51cc..5c48aa6da2f8 100644
> --- a/drivers/platform/chrome/Kconfig
> +++ b/drivers/platform/chrome/Kconfig
> @@ -59,6 +59,15 @@ config CROS_EC_I2C
>           a checksum. Failing accesses will be retried three times to
>           improve reliability.
>
> +config CROS_EC_RPMSG
> +       tristate "ChromeOS Embedded Controller (rpmsg)"
> +       depends on MFD_CROS_EC && RPMSG && OF
> +       help
> +         If you say Y here, you get support for talking to the ChromeOS EC
> +         through rpmsg. This uses a simple byte-level protocol with a
> +         checksum. Also since there's no addition EC-to-host interrupt, this
> +         use a byte in message to distinguish host event from host command.
> +
>  config CROS_EC_SPI
>         tristate "ChromeOS Embedded Controller (SPI)"
>         depends on MFD_CROS_EC && SPI
> diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
> index 1e2f0029b597..4b69d795720d 100644
> --- a/drivers/platform/chrome/Makefile
> +++ b/drivers/platform/chrome/Makefile
> @@ -4,6 +4,7 @@ obj-$(CONFIG_CHROMEOS_LAPTOP)           += chromeos_laptop.o
>  obj-$(CONFIG_CHROMEOS_PSTORE)          += chromeos_pstore.o
>  obj-$(CONFIG_CHROMEOS_TBMC)            += chromeos_tbmc.o
>  obj-$(CONFIG_CROS_EC_I2C)              += cros_ec_i2c.o
> +obj-$(CONFIG_CROS_EC_RPMSG)            += cros_ec_rpmsg.o
>  obj-$(CONFIG_CROS_EC_SPI)              += cros_ec_spi.o
>  cros_ec_lpcs-objs                      := cros_ec_lpc.o cros_ec_lpc_reg.o
>  cros_ec_lpcs-$(CONFIG_CROS_EC_LPC_MEC) += cros_ec_lpc_mec.o
> diff --git a/drivers/platform/chrome/cros_ec_rpmsg.c b/drivers/platform/chrome/cros_ec_rpmsg.c
> new file mode 100644
> index 000000000000..2ecae806cfc5
> --- /dev/null
> +++ b/drivers/platform/chrome/cros_ec_rpmsg.c
> @@ -0,0 +1,265 @@
> +// SPDX-License-Identifier: GPL-2.0
> +//
> +// Copyright 2018 Google LLC.
> +
> +#include <linux/completion.h>
> +#include <linux/delay.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/mfd/cros_ec.h>
> +#include <linux/mfd/cros_ec_commands.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/rpmsg.h>
> +#include <linux/slab.h>
> +
> +#define EC_MSG_TIMEOUT_MS 200
> +#define HOST_COMMAND_MARK 1
> +#define HOST_EVENT_MARK 2
> +
> +/**
> + * struct cros_ec_rpmsg_response - rpmsg message format from from EC.
> + *
> + * @type:      The type of message, should be either HOST_COMMAND_MARK or
> + *             HOST_EVENT_MARK, representing that the message is a response to
> + *             host command, or a host event.
> + * @data:      ec_host_response for host command.
> + */
> +struct cros_ec_rpmsg_response {
> +       u8 type;
> +       u8 data[] __aligned(4);
> +};
> +
> +/**
> + * struct cros_ec_rpmsg - information about a EC over rpmsg.
> + *
> + * @rpdev:     rpmsg device we are connected to
> + * @xfer_ack:  completion for host command transfer.
> + * @host_event_work:   Work struct for pending host event.
> + */
> +struct cros_ec_rpmsg {
> +       struct rpmsg_device *rpdev;
> +       struct completion xfer_ack;
> +       struct work_struct host_event_work;
> +};
> +
> +/**
> + * cros_ec_cmd_xfer_rpmsg - Transfer a message over rpmsg and receive the reply
> + *
> + * @ec_dev: ChromeOS EC device
> + * @ec_msg: Message to transfer
> + *
> + * This is only used for old EC proto version, and is not supported for this
> + * driver.
> + *
> + * Return: number of bytes of the reply on success or negative error code.
> + */
> +static int cros_ec_cmd_xfer_rpmsg(struct cros_ec_device *ec_dev,
> +                                 struct cros_ec_command *ec_msg)
> +{
> +       return -EINVAL;
> +}
> +
> +/**
> + * cros_ec_pkt_xfer_rpmsg - Transfer a packet over rpmsg and receive the reply
> + *
> + * @ec_dev: ChromeOS EC device
> + * @ec_msg: Message to transfer
> + *
> + * Return: number of bytes of the reply on success or negative error code.
> + */
> +static int cros_ec_pkt_xfer_rpmsg(struct cros_ec_device *ec_dev,
> +                                 struct cros_ec_command *ec_msg)
> +{
> +       struct ec_host_response *response;
> +       struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
> +       struct rpmsg_device *rpdev = ec_rpmsg->rpdev;
> +       int len;
> +       u8 sum;
> +       int ret;
> +       int i;
> +       unsigned long timeout;
> +
> +       ec_msg->result = 0;
> +       len = cros_ec_prepare_tx(ec_dev, ec_msg);
> +       dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
> +
> +       reinit_completion(&ec_rpmsg->xfer_ack);
> +       ret = rpmsg_send(rpdev->ept, ec_dev->dout, len);
> +       if (ret) {
> +               dev_err(ec_dev->dev, "rpmsg send failed\n");
> +               return ret;
> +       }
> +
> +       timeout = msecs_to_jiffies(EC_MSG_TIMEOUT_MS);
> +       ret = wait_for_completion_timeout(&ec_rpmsg->xfer_ack, timeout);
> +       if (!ret) {
> +               dev_err(ec_dev->dev, "rpmsg send timeout\n");
> +               return -EIO;
> +       }
> +
> +       /* check response error code */
> +       response = (struct ec_host_response *)ec_dev->din;
> +       ec_msg->result = response->result;
> +
> +       ret = cros_ec_check_result(ec_dev, ec_msg);
> +       if (ret)
> +               goto exit;
> +
> +       if (response->data_len > ec_msg->insize) {
> +               dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
> +                       response->data_len, ec_msg->insize);
> +               ret = -EMSGSIZE;
> +               goto exit;
> +       }
> +
> +       /* copy response packet payload and compute checksum */
> +       memcpy(ec_msg->data, ec_dev->din + sizeof(*response),
> +              response->data_len);
> +
> +       sum = 0;
> +       for (i = 0; i < sizeof(*response) + response->data_len; i++)
> +               sum += ec_dev->din[i];
> +
> +       if (sum) {
> +               dev_err(ec_dev->dev, "bad packet checksum, calculated %x\n",
> +                       sum);
> +               ret = -EBADMSG;
> +               goto exit;
> +       }
> +
> +       ret = response->data_len;
> +exit:
> +       if (ec_msg->command == EC_CMD_REBOOT_EC)
> +               msleep(EC_REBOOT_DELAY_MS);
> +
> +       return ret;
> +}
> +
> +static void
> +cros_ec_rpmsg_host_event_function(struct work_struct *host_event_work)
> +{
> +       struct cros_ec_rpmsg *ec_rpmsg = container_of(
> +               host_event_work, struct cros_ec_rpmsg, host_event_work);
> +       struct cros_ec_device *ec_dev = dev_get_drvdata(&ec_rpmsg->rpdev->dev);
> +       bool wake_event = true;
> +       int ret;
> +
> +       ret = cros_ec_get_next_event(ec_dev, &wake_event);
> +
> +       /*
> +        * Signal only if wake host events or any interrupt if
> +        * cros_ec_get_next_event() returned an error (default value for
> +        * wake_event is true)
> +        */
> +       if (wake_event && device_may_wakeup(ec_dev->dev))
> +               pm_wakeup_event(ec_dev->dev, 0);
> +
> +       if (ret > 0)
> +               blocking_notifier_call_chain(&ec_dev->event_notifier,
> +                                            0, ec_dev);
> +}
> +
> +static int cros_ec_rpmsg_callback(struct rpmsg_device *rpdev, void *data,
> +                                 int len, void *priv, u32 src)
> +{
> +       struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
> +       struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
> +       struct cros_ec_rpmsg_response *resp;
> +
> +       if (!len) {
> +               dev_warn(ec_dev->dev, "rpmsg received empty response");

Is this is unlikely to happen?

> +               return -EINVAL;
> +       }
> +
> +       resp = data;
> +       len -= offsetof(struct cros_ec_rpmsg_response, data);
> +       if (resp->type == HOST_COMMAND_MARK) {
> +               if (len > ec_dev->din_size) {
> +                       dev_warn(
> +                               ec_dev->dev,
> +                               "received length %d > din_size %d, truncating",
> +                               len, ec_dev->din_size);

How often this warning appears? Should be this a dev_dbg?

> +                       len = ec_dev->din_size;
> +               }
> +
> +               memcpy(ec_dev->din, resp->data, len);
> +               complete(&ec_rpmsg->xfer_ack);
> +       } else if (resp->type == HOST_EVENT_MARK) {
> +               schedule_work(&ec_rpmsg->host_event_work);
> +       } else {
> +               dev_warn(ec_dev->dev, "rpmsg received invalid type = %d",
> +                        resp->type);

Is this is unlikely to happen?

> +               return -EINVAL;
> +       }
> +
> +       return 0;
> +}
> +
> +static int cros_ec_rpmsg_probe(struct rpmsg_device *rpdev)
> +{
> +       struct device *dev = &rpdev->dev;
> +       struct cros_ec_device *ec_dev;
> +       struct cros_ec_rpmsg *ec_rpmsg;
> +       int ret;
> +
> +       ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
> +       if (!ec_dev)
> +               return -ENOMEM;
> +
> +       ec_rpmsg = devm_kzalloc(dev, sizeof(*ec_rpmsg), GFP_KERNEL);
> +       if (!ec_rpmsg)
> +               return -ENOMEM;
> +
> +       ec_dev->dev = dev;
> +       ec_dev->priv = ec_rpmsg;
> +       ec_dev->cmd_xfer = cros_ec_cmd_xfer_rpmsg;
> +       ec_dev->pkt_xfer = cros_ec_pkt_xfer_rpmsg;
> +       ec_dev->phys_name = dev_name(&rpdev->dev);
> +       ec_dev->din_size = sizeof(struct ec_host_response) +
> +                          sizeof(struct ec_response_get_protocol_info);
> +       ec_dev->dout_size = sizeof(struct ec_host_request);
> +       dev_set_drvdata(dev, ec_dev);
> +
> +       ec_rpmsg->rpdev = rpdev;
> +       init_completion(&ec_rpmsg->xfer_ack);
> +       INIT_WORK(&ec_rpmsg->host_event_work,
> +                 cros_ec_rpmsg_host_event_function);
> +
> +       ret = cros_ec_register(ec_dev);
> +       if (ret) {
> +               dev_err(dev, "cannot register EC\n");
> +               return ret;
> +       }
> +
> +       return 0;

cros_ec_register returns 0 on success and prints an error message if
something went wrong. Remove the above and just do:

return cros_ec_register(ec_dev);


> +}
> +
> +static void cros_ec_rpmsg_remove(struct rpmsg_device *rpdev)
> +{
> +       struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
> +       struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
> +
> +       cancel_work_sync(&ec_rpmsg->host_event_work);
> +}
> +
> +static const struct of_device_id cros_ec_rpmsg_of_match[] = {
> +       { .compatible = "google,cros-ec-rpmsg", },
> +       { }
> +};
> +MODULE_DEVICE_TABLE(of, cros_ec_rpmsg_of_match);
> +
> +static struct rpmsg_driver cros_ec_driver_rpmsg = {
> +       .drv = {
> +               .name   = KBUILD_MODNAME,
> +               .of_match_table = cros_ec_rpmsg_of_match,
> +       },
> +       .probe          = cros_ec_rpmsg_probe,
> +       .remove         = cros_ec_rpmsg_remove,
> +       .callback       = cros_ec_rpmsg_callback,
> +};
> +
> +module_rpmsg_driver(cros_ec_driver_rpmsg);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("ChromeOS EC multi function device (rpmsg)");
> --
> 2.21.0.392.gf8f6787159e-goog
>

Re: [PATCH v7 6/7] platform/chrome: cros_ec: add EC host command support using rpmsg.

[Pi-Hsun Shih]

Hi,

On Thu, Mar 28, 2019 at 7:16 PM Enric Balletbo Serra
<eballetbo@gmail.com> wrote:
>
> Hi
>
> Thanks for sending this upstream, Some few comments and questions
> below. Apart from these LGTM.
>
> Missatge de Peter Shih <pihsun@chromium.org> del dia dc., 27 de març
> 2019 a les 6:17:
> >
> > From: Pi-Hsun Shih <pihsun@chromium.org>
> >
> > Add EC host command support through rpmsg.
> >
> > Signed-off-by: Pi-Hsun Shih <pihsun@chromium.org>
> > ---
> > ...
> > diff --git a/drivers/platform/chrome/cros_ec_rpmsg.c b/drivers/platform/chrome/cros_ec_rpmsg.c
> > new file mode 100644
> > index 000000000000..2ecae806cfc5
> > --- /dev/null
> > +++ b/drivers/platform/chrome/cros_ec_rpmsg.c
> > ...
> > +static int cros_ec_rpmsg_callback(struct rpmsg_device *rpdev, void *data,
> > +                                 int len, void *priv, u32 src)
> > +{
> > +       struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
> > +       struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
> > +       struct cros_ec_rpmsg_response *resp;
> > +
> > +       if (!len) {
> > +               dev_warn(ec_dev->dev, "rpmsg received empty response");
>
> Is this is unlikely to happen?

Yes this should not happen unless the firmware is broken. Should I
change this to `if(unlikely(!len))`, or use dev_err instead ?

>
> > +               return -EINVAL;
> > +       }
> > +
> > +       resp = data;
> > +       len -= offsetof(struct cros_ec_rpmsg_response, data);
> > +       if (resp->type == HOST_COMMAND_MARK) {
> > +               if (len > ec_dev->din_size) {
> > +                       dev_warn(
> > +                               ec_dev->dev,
> > +                               "received length %d > din_size %d, truncating",
> > +                               len, ec_dev->din_size);
>
> How often this warning appears? Should be this a dev_dbg?

This also should not happen unless the firmware is broken, so I think
it's better to have a warning here when there's something wrong.

>
> > +                       len = ec_dev->din_size;
> > +               }
> > +
> > +               memcpy(ec_dev->din, resp->data, len);
> > +               complete(&ec_rpmsg->xfer_ack);
> > +       } else if (resp->type == HOST_EVENT_MARK) {
> > +               schedule_work(&ec_rpmsg->host_event_work);
> > +       } else {
> > +               dev_warn(ec_dev->dev, "rpmsg received invalid type = %d",
> > +                        resp->type);
>
> Is this is unlikely to happen?

Same as above, this should not happen unless the firmware is broken.

>
> > +               return -EINVAL;
> > +       }
> > +
> > +       return 0;
> > +}
> > +
> > +static int cros_ec_rpmsg_probe(struct rpmsg_device *rpdev)
> > +{
> > +       struct device *dev = &rpdev->dev;
> > +       struct cros_ec_device *ec_dev;
> > +       struct cros_ec_rpmsg *ec_rpmsg;
> > +       int ret;
> > +
> > +       ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
> > +       if (!ec_dev)
> > +               return -ENOMEM;
> > +
> > +       ec_rpmsg = devm_kzalloc(dev, sizeof(*ec_rpmsg), GFP_KERNEL);
> > +       if (!ec_rpmsg)
> > +               return -ENOMEM;
> > +
> > +       ec_dev->dev = dev;
> > +       ec_dev->priv = ec_rpmsg;
> > +       ec_dev->cmd_xfer = cros_ec_cmd_xfer_rpmsg;
> > +       ec_dev->pkt_xfer = cros_ec_pkt_xfer_rpmsg;
> > +       ec_dev->phys_name = dev_name(&rpdev->dev);
> > +       ec_dev->din_size = sizeof(struct ec_host_response) +
> > +                          sizeof(struct ec_response_get_protocol_info);
> > +       ec_dev->dout_size = sizeof(struct ec_host_request);
> > +       dev_set_drvdata(dev, ec_dev);
> > +
> > +       ec_rpmsg->rpdev = rpdev;
> > +       init_completion(&ec_rpmsg->xfer_ack);
> > +       INIT_WORK(&ec_rpmsg->host_event_work,
> > +                 cros_ec_rpmsg_host_event_function);
> > +
> > +       ret = cros_ec_register(ec_dev);
> > +       if (ret) {
> > +               dev_err(dev, "cannot register EC\n");
> > +               return ret;
> > +       }
> > +
> > +       return 0;
>
> cros_ec_register returns 0 on success and prints an error message if
> something went wrong. Remove the above and just do:
>
> return cros_ec_register(ec_dev);
>

Ack, would change this in v7.

>
> > +}
> > +
> > +static void cros_ec_rpmsg_remove(struct rpmsg_device *rpdev)
> > +{
> > +       struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
> > +       struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
> > +
> > +       cancel_work_sync(&ec_rpmsg->host_event_work);
> > +}
> > +
> > +static const struct of_device_id cros_ec_rpmsg_of_match[] = {
> > +       { .compatible = "google,cros-ec-rpmsg", },
> > +       { }
> > +};
> > +MODULE_DEVICE_TABLE(of, cros_ec_rpmsg_of_match);
> > +
> > +static struct rpmsg_driver cros_ec_driver_rpmsg = {
> > +       .drv = {
> > +               .name   = KBUILD_MODNAME,
> > +               .of_match_table = cros_ec_rpmsg_of_match,
> > +       },
> > +       .probe          = cros_ec_rpmsg_probe,
> > +       .remove         = cros_ec_rpmsg_remove,
> > +       .callback       = cros_ec_rpmsg_callback,
> > +};
> > +
> > +module_rpmsg_driver(cros_ec_driver_rpmsg);
> > +
> > +MODULE_LICENSE("GPL v2");
> > +MODULE_DESCRIPTION("ChromeOS EC multi function device (rpmsg)");
> > --
> > 2.21.0.392.gf8f6787159e-goog
> >

Re: [PATCH v7 6/7] platform/chrome: cros_ec: add EC host command support using rpmsg.

[Enric Balletbo Serra]

Hi,

Missatge de Pi-Hsun Shih <pihsun@chromium.org> del dia dc., 10 d’abr.
2019 a les 9:13:
>
> Hi,
>
> On Thu, Mar 28, 2019 at 7:16 PM Enric Balletbo Serra
> <eballetbo@gmail.com> wrote:
> >
> > Hi
> >
> > Thanks for sending this upstream, Some few comments and questions
> > below. Apart from these LGTM.
> >
> > Missatge de Peter Shih <pihsun@chromium.org> del dia dc., 27 de març
> > 2019 a les 6:17:
> > >
> > > From: Pi-Hsun Shih <pihsun@chromium.org>
> > >
> > > Add EC host command support through rpmsg.
> > >
> > > Signed-off-by: Pi-Hsun Shih <pihsun@chromium.org>
> > > ---
> > > ...
> > > diff --git a/drivers/platform/chrome/cros_ec_rpmsg.c b/drivers/platform/chrome/cros_ec_rpmsg.c
> > > new file mode 100644
> > > index 000000000000..2ecae806cfc5
> > > --- /dev/null
> > > +++ b/drivers/platform/chrome/cros_ec_rpmsg.c
> > > ...
> > > +static int cros_ec_rpmsg_callback(struct rpmsg_device *rpdev, void *data,
> > > +                                 int len, void *priv, u32 src)
> > > +{
> > > +       struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
> > > +       struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
> > > +       struct cros_ec_rpmsg_response *resp;
> > > +
> > > +       if (!len) {
> > > +               dev_warn(ec_dev->dev, "rpmsg received empty response");
> >
> > Is this is unlikely to happen?
>
> Yes this should not happen unless the firmware is broken. Should I
> change this to `if(unlikely(!len))`, or use dev_err instead ?
>
> >
> > > +               return -EINVAL;
> > > +       }
> > > +
> > > +       resp = data;
> > > +       len -= offsetof(struct cros_ec_rpmsg_response, data);
> > > +       if (resp->type == HOST_COMMAND_MARK) {
> > > +               if (len > ec_dev->din_size) {
> > > +                       dev_warn(
> > > +                               ec_dev->dev,
> > > +                               "received length %d > din_size %d, truncating",
> > > +                               len, ec_dev->din_size);
> >
> > How often this warning appears? Should be this a dev_dbg?
>
> This also should not happen unless the firmware is broken, so I think
> it's better to have a warning here when there's something wrong.
>

Ok, fine with me.

> >
> > > +                       len = ec_dev->din_size;
> > > +               }
> > > +
> > > +               memcpy(ec_dev->din, resp->data, len);
> > > +               complete(&ec_rpmsg->xfer_ack);
> > > +       } else if (resp->type == HOST_EVENT_MARK) {
> > > +               schedule_work(&ec_rpmsg->host_event_work);
> > > +       } else {
> > > +               dev_warn(ec_dev->dev, "rpmsg received invalid type = %d",
> > > +                        resp->type);
> >
> > Is this is unlikely to happen?
>
> Same as above, this should not happen unless the firmware is broken.
>
> >
> > > +               return -EINVAL;
> > > +       }
> > > +
> > > +       return 0;
> > > +}
> > > +
> > > +static int cros_ec_rpmsg_probe(struct rpmsg_device *rpdev)
> > > +{
> > > +       struct device *dev = &rpdev->dev;
> > > +       struct cros_ec_device *ec_dev;
> > > +       struct cros_ec_rpmsg *ec_rpmsg;
> > > +       int ret;
> > > +
> > > +       ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
> > > +       if (!ec_dev)
> > > +               return -ENOMEM;
> > > +
> > > +       ec_rpmsg = devm_kzalloc(dev, sizeof(*ec_rpmsg), GFP_KERNEL);
> > > +       if (!ec_rpmsg)
> > > +               return -ENOMEM;
> > > +
> > > +       ec_dev->dev = dev;
> > > +       ec_dev->priv = ec_rpmsg;
> > > +       ec_dev->cmd_xfer = cros_ec_cmd_xfer_rpmsg;
> > > +       ec_dev->pkt_xfer = cros_ec_pkt_xfer_rpmsg;
> > > +       ec_dev->phys_name = dev_name(&rpdev->dev);
> > > +       ec_dev->din_size = sizeof(struct ec_host_response) +
> > > +                          sizeof(struct ec_response_get_protocol_info);
> > > +       ec_dev->dout_size = sizeof(struct ec_host_request);
> > > +       dev_set_drvdata(dev, ec_dev);
> > > +
> > > +       ec_rpmsg->rpdev = rpdev;
> > > +       init_completion(&ec_rpmsg->xfer_ack);
> > > +       INIT_WORK(&ec_rpmsg->host_event_work,
> > > +                 cros_ec_rpmsg_host_event_function);
> > > +
> > > +       ret = cros_ec_register(ec_dev);
> > > +       if (ret) {
> > > +               dev_err(dev, "cannot register EC\n");
> > > +               return ret;
> > > +       }
> > > +
> > > +       return 0;
> >
> > cros_ec_register returns 0 on success and prints an error message if
> > something went wrong. Remove the above and just do:
> >
> > return cros_ec_register(ec_dev);
> >
>
> Ack, would change this in v7.
>

Will wait for v7.

Thanks,
 Enric

> >
> > > +}
> > > +
> > > +static void cros_ec_rpmsg_remove(struct rpmsg_device *rpdev)
> > > +{
> > > +       struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
> > > +       struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
> > > +
> > > +       cancel_work_sync(&ec_rpmsg->host_event_work);
> > > +}
> > > +
> > > +static const struct of_device_id cros_ec_rpmsg_of_match[] = {
> > > +       { .compatible = "google,cros-ec-rpmsg", },
> > > +       { }
> > > +};
> > > +MODULE_DEVICE_TABLE(of, cros_ec_rpmsg_of_match);
> > > +
> > > +static struct rpmsg_driver cros_ec_driver_rpmsg = {
> > > +       .drv = {
> > > +               .name   = KBUILD_MODNAME,
> > > +               .of_match_table = cros_ec_rpmsg_of_match,
> > > +       },
> > > +       .probe          = cros_ec_rpmsg_probe,
> > > +       .remove         = cros_ec_rpmsg_remove,
> > > +       .callback       = cros_ec_rpmsg_callback,
> > > +};
> > > +
> > > +module_rpmsg_driver(cros_ec_driver_rpmsg);
> > > +
> > > +MODULE_LICENSE("GPL v2");
> > > +MODULE_DESCRIPTION("ChromeOS EC multi function device (rpmsg)");
> > > --
> > > 2.21.0.392.gf8f6787159e-goog
> > >

[PATCH v7 7/7] cros_ec: differentiate SCP from EC by feature bit.

[Peter Shih]

From: Pi-Hsun Shih <pihsun@chromium.org>

Since a SCP and EC would both exist on a system, and use the cros_ec_dev
driver, we need to differentiate between them for the userspace, or they
would both be registered at /dev/cros_ec, causing a conflict.

Signed-off-by: Pi-Hsun Shih <pihsun@chromium.org>
---
Changes from v6:
 - No change.

Changes from v5:
 - No change.

Changes from v4:
 - No change.

Changes from v3:
 - No change.

Changes from v2:
 - No change.

Changes from v1:
 - New patch extracted from Patch 5.
---
 drivers/mfd/cros_ec_dev.c            | 10 ++++++++++
 include/linux/mfd/cros_ec.h          |  1 +
 include/linux/mfd/cros_ec_commands.h |  2 ++
 3 files changed, 13 insertions(+)

diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
index d275deaecb12..da2f2145d31d 100644
--- a/drivers/mfd/cros_ec_dev.c
+++ b/drivers/mfd/cros_ec_dev.c
@@ -418,6 +418,16 @@ static int ec_device_probe(struct platform_device *pdev)
 	device_initialize(&ec->class_dev);
 	cdev_init(&ec->cdev, &fops);
 
+	/* check whether this is actually a SCP rather than an EC */
+	if (cros_ec_check_features(ec, EC_FEATURE_SCP)) {
+		dev_info(dev, "SCP detected.\n");
+		/*
+		 * Help userspace differentiating ECs from SCP,
+		 * regardless of the probing order.
+		 */
+		ec_platform->ec_name = CROS_EC_DEV_SCP_NAME;
+	}
+
 	/*
 	 * Add the class device
 	 * Link to the character device for creating the /dev entry
diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
index 8f2a8918bfa3..a971399bad82 100644
--- a/include/linux/mfd/cros_ec.h
+++ b/include/linux/mfd/cros_ec.h
@@ -24,6 +24,7 @@
 
 #define CROS_EC_DEV_NAME "cros_ec"
 #define CROS_EC_DEV_PD_NAME "cros_pd"
+#define CROS_EC_DEV_SCP_NAME "cros_scp"
 
 /*
  * The EC is unresponsive for a time after a reboot command.  Add a
diff --git a/include/linux/mfd/cros_ec_commands.h b/include/linux/mfd/cros_ec_commands.h
index fc91082d4c35..3e5da6e93b2f 100644
--- a/include/linux/mfd/cros_ec_commands.h
+++ b/include/linux/mfd/cros_ec_commands.h
@@ -856,6 +856,8 @@ enum ec_feature_code {
 	EC_FEATURE_RTC = 27,
 	/* EC supports CEC commands */
 	EC_FEATURE_CEC = 35,
+	/* The MCU exposes a SCP */
+	EC_FEATURE_SCP = 39,
 };
 
 #define EC_FEATURE_MASK_0(event_code) (1UL << (event_code % 32))
-- 
2.21.0.392.gf8f6787159e-goog

Re: [PATCH v7 7/7] cros_ec: differentiate SCP from EC by feature bit.

[Enric Balletbo Serra]

Hi,

Thanks for submitting this upstream. Some few comments below.

Please prepend the subsystem for the commit. I.e:

mfd: cros_ec: differentiate SCP from EC by feature bit.

Missatge de Peter Shih <pihsun@chromium.org> del dia dc., 27 de març
2019 a les 6:18:
>
> From: Pi-Hsun Shih <pihsun@chromium.org>
>
> Since a SCP and EC would both exist on a system, and use the cros_ec_dev

Could you also explain what an SCP is?

> driver, we need to differentiate between them for the userspace, or they
> would both be registered at /dev/cros_ec, causing a conflict.
>
> Signed-off-by: Pi-Hsun Shih <pihsun@chromium.org>
> ---
> Changes from v6:
>  - No change.
>
> Changes from v5:
>  - No change.
>
> Changes from v4:
>  - No change.
>
> Changes from v3:
>  - No change.
>
> Changes from v2:
>  - No change.
>
> Changes from v1:
>  - New patch extracted from Patch 5.
> ---
>  drivers/mfd/cros_ec_dev.c            | 10 ++++++++++
>  include/linux/mfd/cros_ec.h          |  1 +
>  include/linux/mfd/cros_ec_commands.h |  2 ++
>  3 files changed, 13 insertions(+)
>
> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> index d275deaecb12..da2f2145d31d 100644
> --- a/drivers/mfd/cros_ec_dev.c
> +++ b/drivers/mfd/cros_ec_dev.c
> @@ -418,6 +418,16 @@ static int ec_device_probe(struct platform_device *pdev)
>         device_initialize(&ec->class_dev);
>         cdev_init(&ec->cdev, &fops);
>
> +       /* check whether this is actually a SCP rather than an EC */

Capitalize the phrase.

> +       if (cros_ec_check_features(ec, EC_FEATURE_SCP)) {
> +               dev_info(dev, "SCP detected.\n");

dev_info(dev, "CrOS SCP MCU detected.\n")

To be coherent with other messages like this that are already sent upstream.

> +               /*
> +                * Help userspace differentiating ECs from SCP,
> +                * regardless of the probing order.
> +                */
> +               ec_platform->ec_name = CROS_EC_DEV_SCP_NAME;
> +       }
> +
>         /*
>          * Add the class device
>          * Link to the character device for creating the /dev entry
> diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
> index 8f2a8918bfa3..a971399bad82 100644
> --- a/include/linux/mfd/cros_ec.h
> +++ b/include/linux/mfd/cros_ec.h
> @@ -24,6 +24,7 @@
>
>  #define CROS_EC_DEV_NAME "cros_ec"
>  #define CROS_EC_DEV_PD_NAME "cros_pd"
> +#define CROS_EC_DEV_SCP_NAME "cros_scp"
>
>  /*
>   * The EC is unresponsive for a time after a reboot command.  Add a
> diff --git a/include/linux/mfd/cros_ec_commands.h b/include/linux/mfd/cros_ec_commands.h
> index fc91082d4c35..3e5da6e93b2f 100644
> --- a/include/linux/mfd/cros_ec_commands.h
> +++ b/include/linux/mfd/cros_ec_commands.h

Remove this change and base your work on top of [1]

> @@ -856,6 +856,8 @@ enum ec_feature_code {
>         EC_FEATURE_RTC = 27,
>         /* EC supports CEC commands */
>         EC_FEATURE_CEC = 35,
> +       /* The MCU exposes a SCP */
> +       EC_FEATURE_SCP = 39,
>  };
>
>  #define EC_FEATURE_MASK_0(event_code) (1UL << (event_code % 32))
> --
> 2.21.0.392.gf8f6787159e-goog
>
Thanks,
 Enric

[1] https://lkml.org/lkml/2019/2/27/723