remoteproc: stm32: add an ST stm32_rproc driver

This patch introduces a new remoteproc driver to control Cortex-M4
co-processor of the STM32 family.
It provides with the following features:
- start and stop
- dedicated co-processor memory regions registration
- coredump and recovery

Signed-off-by: Fabien Dessenne <[e-mail]>
Signed-off-by: Ludovic Barre <[e-mail]>
Signed-off-by: Loic Pallardy <[e-mail]>
Signed-off-by: Arnaud Pouliquen <[e-mail]>
[bjorn: Fixup of dev_dbg types and cast of int to pointer in mbox send]
Signed-off-by: Bjorn Andersson <[e-mail]>

drivers/remoteproc/Kconfig

···
 config ST_SLIM_REMOTEPROC
 	tristate
 
+config STM32_RPROC
+	tristate "STM32 remoteproc support"
+	depends on ARCH_STM32
+	depends on REMOTEPROC
+	select MAILBOX
+	help
+	  Say y here to support STM32 MCU processors via the
+	  remote processor framework.
+
+	  You want to say y here in order to enable AMP
+	  use-cases to run on your platform (dedicated firmware could be
+	  offloaded to remote MCU processors using this framework).
+
+	  This can be either built-in or a loadable module.
+
 endif # REMOTEPROC
 
 endmenu

drivers/remoteproc/Makefile

···
 qcom_wcnss_pil-y			+= qcom_wcnss_iris.o
 obj-$(CONFIG_ST_REMOTEPROC)		+= st_remoteproc.o
 obj-$(CONFIG_ST_SLIM_REMOTEPROC)	+= st_slim_rproc.o
+obj-$(CONFIG_STM32_RPROC)		+= stm32_rproc.o

drivers/remoteproc/stm32_rproc.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) STMicroelectronics 2018 - All Rights Reserved
+ * Authors: Ludovic Barre <[e-mail]> for STMicroelectronics.
+ *          Fabien Dessenne <[e-mail]> for STMicroelectronics.
+ */
+
+#include <linux/arm-smccc.h>
+#include <linux/dma-mapping.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/mailbox_client.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/of_reserved_mem.h>
+#include <linux/regmap.h>
+#include <linux/remoteproc.h>
+#include <linux/reset.h>
+
+#include "remoteproc_internal.h"
+
+#define HOLD_BOOT		0
+#define RELEASE_BOOT		1
+
+#define MBOX_NB_VQ		2
+#define MBOX_NB_MBX		3
+
+#define STM32_SMC_RCC		0x82001000
+#define STM32_SMC_REG_WRITE	0x1
+
+#define STM32_MBX_VQ0		"vq0"
+#define STM32_MBX_VQ1		"vq1"
+#define STM32_MBX_SHUTDOWN	"shutdown"
+
+struct stm32_syscon {
+	struct regmap *map;
+	u32 reg;
+	u32 mask;
+};
+
+struct stm32_rproc_mem {
+	char name[20];
+	void __iomem *cpu_addr;
+	phys_addr_t bus_addr;
+	u32 dev_addr;
+	size_t size;
+};
+
+struct stm32_rproc_mem_ranges {
+	u32 dev_addr;
+	u32 bus_addr;
+	u32 size;
+};
+
+struct stm32_mbox {
+	const unsigned char name[10];
+	struct mbox_chan *chan;
+	struct mbox_client client;
+	int vq_id;
+};
+
+struct stm32_rproc {
+	struct reset_control *rst;
+	struct stm32_syscon hold_boot;
+	struct stm32_syscon pdds;
+	u32 nb_rmems;
+	struct stm32_rproc_mem *rmems;
+	struct stm32_mbox mb[MBOX_NB_MBX];
+	bool secured_soc;
+};
+
+static int stm32_rproc_pa_to_da(struct rproc *rproc, phys_addr_t pa, u64 *da)
+{
+	unsigned int i;
+	struct stm32_rproc *ddata = rproc->priv;
+	struct stm32_rproc_mem *p_mem;
+
+	for (i = 0; i < ddata->nb_rmems; i++) {
+		p_mem = &ddata->rmems[i];
+
+		if (pa < p_mem->bus_addr ||
+		    pa >= p_mem->bus_addr + p_mem->size)
+			continue;
+		*da = pa - p_mem->bus_addr + p_mem->dev_addr;
+		dev_dbg(rproc->dev.parent, "pa %pa to da %llx\n", &pa, *da);
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static int stm32_rproc_mem_alloc(struct rproc *rproc,
+				 struct rproc_mem_entry *mem)
+{
+	struct device *dev = rproc->dev.parent;
+	void *va;
+
+	dev_dbg(dev, "map memory: %pa+%x\n", &mem->dma, mem->len);
+	va = ioremap_wc(mem->dma, mem->len);
+	if (IS_ERR_OR_NULL(va)) {
+		dev_err(dev, "Unable to map memory region: %pa+%x\n",
+			&mem->dma, mem->len);
+		return -ENOMEM;
+	}
+
+	/* Update memory entry va */
+	mem->va = va;
+
+	return 0;
+}
+
+static int stm32_rproc_mem_release(struct rproc *rproc,
+				   struct rproc_mem_entry *mem)
+{
+	dev_dbg(rproc->dev.parent, "unmap memory: %pa\n", &mem->dma);
+	iounmap(mem->va);
+
+	return 0;
+}
+
+static int stm32_rproc_of_memory_translations(struct rproc *rproc)
+{
+	struct device *parent, *dev = rproc->dev.parent;
+	struct stm32_rproc *ddata = rproc->priv;
+	struct device_node *np;
+	struct stm32_rproc_mem *p_mems;
+	struct stm32_rproc_mem_ranges *mem_range;
+	int cnt, array_size, i, ret = 0;
+
+	parent = dev->parent;
+	np = parent->of_node;
+
+	cnt = of_property_count_elems_of_size(np, "dma-ranges",
+					      sizeof(*mem_range));
+	if (cnt <= 0) {
+		dev_err(dev, "%s: dma-ranges property not defined\n", __func__);
+		return -EINVAL;
+	}
+
+	p_mems = devm_kcalloc(dev, cnt, sizeof(*p_mems), GFP_KERNEL);
+	if (!p_mems)
+		return -ENOMEM;
+	mem_range = kcalloc(cnt, sizeof(*mem_range), GFP_KERNEL);
+	if (!mem_range)
+		return -ENOMEM;
+
+	array_size = cnt * sizeof(struct stm32_rproc_mem_ranges) / sizeof(u32);
+
+	ret = of_property_read_u32_array(np, "dma-ranges",
+					 (u32 *)mem_range, array_size);
+	if (ret) {
+		dev_err(dev, "error while get dma-ranges property: %x\n", ret);
+		goto free_mem;
+	}
+
+	for (i = 0; i < cnt; i++) {
+		p_mems[i].bus_addr = mem_range[i].bus_addr;
+		p_mems[i].dev_addr = mem_range[i].dev_addr;
+		p_mems[i].size     = mem_range[i].size;
+
+		dev_dbg(dev, "memory range[%i]: da %#x, pa %pa, size %#zx:\n",
+			i, p_mems[i].dev_addr, &p_mems[i].bus_addr,
+			p_mems[i].size);
+	}
+
+	ddata->rmems = p_mems;
+	ddata->nb_rmems = cnt;
+
+free_mem:
+	kfree(mem_range);
+	return ret;
+}
+
+static int stm32_rproc_mbox_idx(struct rproc *rproc, const unsigned char *name)
+{
+	struct stm32_rproc *ddata = rproc->priv;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(ddata->mb); i++) {
+		if (!strncmp(ddata->mb[i].name, name, strlen(name)))
+			return i;
+	}
+	dev_err(&rproc->dev, "mailbox %s not found\n", name);
+
+	return -EINVAL;
+}
+
+static int stm32_rproc_elf_load_rsc_table(struct rproc *rproc,
+					  const struct firmware *fw)
+{
+	if (rproc_elf_load_rsc_table(rproc, fw))
+		dev_warn(&rproc->dev, "no resource table found for this firmware\n");
+
+	return 0;
+}
+
+static int stm32_rproc_parse_fw(struct rproc *rproc, const struct firmware *fw)
+{
+	struct device *dev = rproc->dev.parent;
+	struct device_node *np = dev->of_node;
+	struct of_phandle_iterator it;
+	struct rproc_mem_entry *mem;
+	struct reserved_mem *rmem;
+	u64 da;
+	int index = 0;
+
+	/* Register associated reserved memory regions */
+	of_phandle_iterator_init(&it, np, "memory-region", NULL, 0);
+	while (of_phandle_iterator_next(&it) == 0) {
+		rmem = of_reserved_mem_lookup(it.node);
+		if (!rmem) {
+			dev_err(dev, "unable to acquire memory-region\n");
+			return -EINVAL;
+		}
+
+		if (stm32_rproc_pa_to_da(rproc, rmem->base, &da) < 0) {
+			dev_err(dev, "memory region not valid %pa\n",
+				&rmem->base);
+			return -EINVAL;
+		}
+
+		/*  No need to map vdev buffer */
+		if (strcmp(it.node->name, "vdev0buffer")) {
+			/* Register memory region */
+			mem = rproc_mem_entry_init(dev, NULL,
+						   (dma_addr_t)rmem->base,
+						   rmem->size, da,
+						   stm32_rproc_mem_alloc,
+						   stm32_rproc_mem_release,
+						   it.node->name);
+
+			if (mem)
+				rproc_coredump_add_segment(rproc, da,
+							   rmem->size);
+		} else {
+			/* Register reserved memory for vdev buffer alloc */
+			mem = rproc_of_resm_mem_entry_init(dev, index,
+							   rmem->size,
+							   rmem->base,
+							   it.node->name);
+		}
+
+		if (!mem)
+			return -ENOMEM;
+
+		rproc_add_carveout(rproc, mem);
+		index++;
+	}
+
+	return stm32_rproc_elf_load_rsc_table(rproc, fw);
+}
+
+static irqreturn_t stm32_rproc_wdg(int irq, void *data)
+{
+	struct rproc *rproc = data;
+
+	rproc_report_crash(rproc, RPROC_WATCHDOG);
+
+	return IRQ_HANDLED;
+}
+
+static void stm32_rproc_mb_callback(struct mbox_client *cl, void *data)
+{
+	struct rproc *rproc = dev_get_drvdata(cl->dev);
+	struct stm32_mbox *mb = container_of(cl, struct stm32_mbox, client);
+
+	if (rproc_vq_interrupt(rproc, mb->vq_id) == IRQ_NONE)
+		dev_dbg(&rproc->dev, "no message found in vq%d\n", mb->vq_id);
+}
+
+static void stm32_rproc_free_mbox(struct rproc *rproc)
+{
+	struct stm32_rproc *ddata = rproc->priv;
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(ddata->mb); i++) {
+		if (ddata->mb[i].chan)
+			mbox_free_channel(ddata->mb[i].chan);
+		ddata->mb[i].chan = NULL;
+	}
+}
+
+static const struct stm32_mbox stm32_rproc_mbox[MBOX_NB_MBX] = {
+	{
+		.name = STM32_MBX_VQ0,
+		.vq_id = 0,
+		.client = {
+			.rx_callback = stm32_rproc_mb_callback,
+			.tx_block = false,
+		},
+	},
+	{
+		.name = STM32_MBX_VQ1,
+		.vq_id = 1,
+		.client = {
+			.rx_callback = stm32_rproc_mb_callback,
+			.tx_block = false,
+		},
+	},
+	{
+		.name = STM32_MBX_SHUTDOWN,
+		.vq_id = -1,
+		.client = {
+			.tx_block = true,
+			.tx_done = NULL,
+			.tx_tout = 500, /* 500 ms time out */
+		},
+	}
+};
+
+static void stm32_rproc_request_mbox(struct rproc *rproc)
+{
+	struct stm32_rproc *ddata = rproc->priv;
+	struct device *dev = &rproc->dev;
+	unsigned int i;
+	const unsigned char *name;
+	struct mbox_client *cl;
+
+	/* Initialise mailbox structure table */
+	memcpy(ddata->mb, stm32_rproc_mbox, sizeof(stm32_rproc_mbox));
+
+	for (i = 0; i < MBOX_NB_MBX; i++) {
+		name = ddata->mb[i].name;
+
+		cl = &ddata->mb[i].client;
+		cl->dev = dev->parent;
+
+		ddata->mb[i].chan = mbox_request_channel_byname(cl, name);
+		if (IS_ERR(ddata->mb[i].chan)) {
+			dev_warn(dev, "cannot get %s mbox\n", name);
+			ddata->mb[i].chan = NULL;
+		}
+	}
+}
+
+static int stm32_rproc_set_hold_boot(struct rproc *rproc, bool hold)
+{
+	struct stm32_rproc *ddata = rproc->priv;
+	struct stm32_syscon hold_boot = ddata->hold_boot;
+	struct arm_smccc_res smc_res;
+	int val, err;
+
+	val = hold ? HOLD_BOOT : RELEASE_BOOT;
+
+	if (ddata->secured_soc) {
+		arm_smccc_smc(STM32_SMC_RCC, STM32_SMC_REG_WRITE,
+			      hold_boot.reg, val, 0, 0, 0, 0, &smc_res);
+		err = smc_res.a0;
+	} else {
+		err = regmap_update_bits(hold_boot.map, hold_boot.reg,
+					 hold_boot.mask, val);
+	}
+
+	if (err)
+		dev_err(&rproc->dev, "failed to set hold boot\n");
+
+	return err;
+}
+
+static void stm32_rproc_add_coredump_trace(struct rproc *rproc)
+{
+	struct rproc_debug_trace *trace;
+	struct rproc_dump_segment *segment;
+	bool already_added;
+
+	list_for_each_entry(trace, &rproc->traces, node) {
+		already_added = false;
+
+		list_for_each_entry(segment, &rproc->dump_segments, node) {
+			if (segment->da == trace->trace_mem.da) {
+				already_added = true;
+				break;
+			}
+		}
+
+		if (!already_added)
+			rproc_coredump_add_segment(rproc, trace->trace_mem.da,
+						   trace->trace_mem.len);
+	}
+}
+
+static int stm32_rproc_start(struct rproc *rproc)
+{
+	int err;
+
+	stm32_rproc_add_coredump_trace(rproc);
+
+	err = stm32_rproc_set_hold_boot(rproc, false);
+	if (err)
+		return err;
+
+	return stm32_rproc_set_hold_boot(rproc, true);
+}
+
+static int stm32_rproc_stop(struct rproc *rproc)
+{
+	struct stm32_rproc *ddata = rproc->priv;
+	int err, dummy_data, idx;
+
+	/* request shutdown of the remote processor */
+	if (rproc->state != RPROC_OFFLINE) {
+		idx = stm32_rproc_mbox_idx(rproc, STM32_MBX_SHUTDOWN);
+		if (idx >= 0 && ddata->mb[idx].chan) {
+			/* a dummy data is sent to allow to block on transmit */
+			err = mbox_send_message(ddata->mb[idx].chan,
+						&dummy_data);
+			if (err < 0)
+				dev_warn(&rproc->dev, "warning: remote FW shutdown without ack\n");
+		}
+	}
+
+	err = stm32_rproc_set_hold_boot(rproc, true);
+	if (err)
+		return err;
+
+	err = reset_control_assert(ddata->rst);
+	if (err) {
+		dev_err(&rproc->dev, "failed to assert the reset\n");
+		return err;
+	}
+
+	/* to allow platform Standby power mode, set remote proc Deep Sleep */
+	if (ddata->pdds.map) {
+		err = regmap_update_bits(ddata->pdds.map, ddata->pdds.reg,
+					 ddata->pdds.mask, 1);
+		if (err) {
+			dev_err(&rproc->dev, "failed to set pdds\n");
+			return err;
+		}
+	}
+
+	return 0;
+}
+
+static void stm32_rproc_kick(struct rproc *rproc, int vqid)
+{
+	struct stm32_rproc *ddata = rproc->priv;
+	unsigned int i;
+	int err;
+
+	if (WARN_ON(vqid >= MBOX_NB_VQ))
+		return;
+
+	for (i = 0; i < MBOX_NB_MBX; i++) {
+		if (vqid != ddata->mb[i].vq_id)
+			continue;
+		if (!ddata->mb[i].chan)
+			return;
+		err = mbox_send_message(ddata->mb[i].chan, (void *)(long)vqid);
+		if (err < 0)
+			dev_err(&rproc->dev, "%s: failed (%s, err:%d)\n",
+				__func__, ddata->mb[i].name, err);
+		return;
+	}
+}
+
+static struct rproc_ops st_rproc_ops = {
+	.start		= stm32_rproc_start,
+	.stop		= stm32_rproc_stop,
+	.kick		= stm32_rproc_kick,
+	.load		= rproc_elf_load_segments,
+	.parse_fw	= stm32_rproc_parse_fw,
+	.find_loaded_rsc_table = rproc_elf_find_loaded_rsc_table,
+	.sanity_check	= rproc_elf_sanity_check,
+	.get_boot_addr	= rproc_elf_get_boot_addr,
+};
+
+static const struct of_device_id stm32_rproc_match[] = {
+	{ .compatible = "st,stm32mp1-m4" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, stm32_rproc_match);
+
+static int stm32_rproc_get_syscon(struct device_node *np, const char *prop,
+				  struct stm32_syscon *syscon)
+{
+	int err = 0;
+
+	syscon->map = syscon_regmap_lookup_by_phandle(np, prop);
+	if (IS_ERR(syscon->map)) {
+		err = PTR_ERR(syscon->map);
+		syscon->map = NULL;
+		goto out;
+	}
+
+	err = of_property_read_u32_index(np, prop, 1, &syscon->reg);
+	if (err)
+		goto out;
+
+	err = of_property_read_u32_index(np, prop, 2, &syscon->mask);
+
+out:
+	return err;
+}
+
+static int stm32_rproc_parse_dt(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct rproc *rproc = platform_get_drvdata(pdev);
+	struct stm32_rproc *ddata = rproc->priv;
+	struct stm32_syscon tz;
+	unsigned int tzen;
+	int err, irq;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq > 0) {
+		err = devm_request_irq(dev, irq, stm32_rproc_wdg, 0,
+				       dev_name(dev), rproc);
+		if (err) {
+			dev_err(dev, "failed to request wdg irq\n");
+			return err;
+		}
+
+		dev_info(dev, "wdg irq registered\n");
+	}
+
+	ddata->rst = devm_reset_control_get_by_index(dev, 0);
+	if (IS_ERR(ddata->rst)) {
+		dev_err(dev, "failed to get mcu reset\n");
+		return PTR_ERR(ddata->rst);
+	}
+
+	/*
+	 * if platform is secured the hold boot bit must be written by
+	 * smc call and read normally.
+	 * if not secure the hold boot bit could be read/write normally
+	 */
+	err = stm32_rproc_get_syscon(np, "st,syscfg-tz", &tz);
+	if (err) {
+		dev_err(dev, "failed to get tz syscfg\n");
+		return err;
+	}
+
+	err = regmap_read(tz.map, tz.reg, &tzen);
+	if (err) {
+		dev_err(&rproc->dev, "failed to read tzen\n");
+		return err;
+	}
+	ddata->secured_soc = tzen & tz.mask;
+
+	err = stm32_rproc_get_syscon(np, "st,syscfg-holdboot",
+				     &ddata->hold_boot);
+	if (err) {
+		dev_err(dev, "failed to get hold boot\n");
+		return err;
+	}
+
+	err = stm32_rproc_get_syscon(np, "st,syscfg-pdds", &ddata->pdds);
+	if (err)
+		dev_warn(dev, "failed to get pdds\n");
+
+	rproc->auto_boot = of_property_read_bool(np, "st,auto-boot");
+
+	return stm32_rproc_of_memory_translations(rproc);
+}
+
+static int stm32_rproc_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct stm32_rproc *ddata;
+	struct device_node *np = dev->of_node;
+	struct rproc *rproc;
+	int ret;
+
+	ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(32));
+	if (ret)
+		return ret;
+
+	rproc = rproc_alloc(dev, np->name, &st_rproc_ops, NULL, sizeof(*ddata));
+	if (!rproc)
+		return -ENOMEM;
+
+	rproc->has_iommu = false;
+	ddata = rproc->priv;
+
+	platform_set_drvdata(pdev, rproc);
+
+	ret = stm32_rproc_parse_dt(pdev);
+	if (ret)
+		goto free_rproc;
+
+	stm32_rproc_request_mbox(rproc);
+
+	ret = rproc_add(rproc);
+	if (ret)
+		goto free_mb;
+
+	return 0;
+
+free_mb:
+	stm32_rproc_free_mbox(rproc);
+free_rproc:
+	rproc_free(rproc);
+	return ret;
+}
+
+static int stm32_rproc_remove(struct platform_device *pdev)
+{
+	struct rproc *rproc = platform_get_drvdata(pdev);
+
+	if (atomic_read(&rproc->power) > 0)
+		rproc_shutdown(rproc);
+
+	rproc_del(rproc);
+	stm32_rproc_free_mbox(rproc);
+	rproc_free(rproc);
+
+	return 0;
+}
+
+static struct platform_driver stm32_rproc_driver = {
+	.probe = stm32_rproc_probe,
+	.remove = stm32_rproc_remove,
+	.driver = {
+		.name = "stm32-rproc",
+		.of_match_table = of_match_ptr(stm32_rproc_match),
+	},
+};
+module_platform_driver(stm32_rproc_driver);
+
+MODULE_DESCRIPTION("STM32 Remote Processor Control Driver");
+MODULE_AUTHOR("Ludovic Barre <[e-mail]>");
+MODULE_AUTHOR("Fabien Dessenne <[e-mail]>");
+MODULE_LICENSE("GPL v2");
+