drivers/remoteproc/stm32_rproc.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) STMicroelectronics 2018 - All Rights Reserved
 * Authors: Ludovic Barre <ludovic.barre@st.com> for STMicroelectronics.
 *          Fabien Dessenne <fabien.dessenne@st.com> 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/pm_wakeirq.h>
#include <linux/regmap.h>
#include <linux/remoteproc.h>
#include <linux/reset.h>
#include <linux/slab.h>
#include <linux/workqueue.h>

#include "remoteproc_internal.h"

#define HOLD_BOOT		0
#define RELEASE_BOOT		1

#define MBOX_NB_VQ		2
#define MBOX_NB_MBX		4

#define STM32_SMC_RCC		0x82001000
#define STM32_SMC_REG_WRITE	0x1

#define STM32_MBX_VQ0		"vq0"
#define STM32_MBX_VQ0_ID	0
#define STM32_MBX_VQ1		"vq1"
#define STM32_MBX_VQ1_ID	1
#define STM32_MBX_SHUTDOWN	"shutdown"
#define STM32_MBX_DETACH	"detach"

#define RSC_TBL_SIZE		1024

#define M4_STATE_OFF		0
#define M4_STATE_INI		1
#define M4_STATE_CRUN		2
#define M4_STATE_CSTOP		3
#define M4_STATE_STANDBY	4
#define M4_STATE_CRASH		5

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;
	struct work_struct vq_work;
	int vq_id;
};

struct stm32_rproc {
	struct reset_control *rst;
	struct stm32_syscon hold_boot;
	struct stm32_syscon pdds;
	struct stm32_syscon m4_state;
	struct stm32_syscon rsctbl;
	int wdg_irq;
	u32 nb_rmems;
	struct stm32_rproc_mem *rmems;
	struct stm32_mbox mb[MBOX_NB_MBX];
	struct workqueue_struct *workqueue;
	bool secured_soc;
	void __iomem *rsc_va;
};

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 platform_device *pdev,
					      struct stm32_rproc *ddata)
{
	struct device *parent, *dev = &pdev->dev;
	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_prepare(struct rproc *rproc)
{
	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) {
			of_node_put(it.node);
			dev_err(dev, "unable to acquire memory-region\n");
			return -EINVAL;
		}

		if (stm32_rproc_pa_to_da(rproc, rmem->base, &da) < 0) {
			of_node_put(it.node);
			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) {
			of_node_put(it.node);
			return -ENOMEM;
		}

		rproc_add_carveout(rproc, mem);
		index++;
	}

	return 0;
}

static int stm32_rproc_parse_fw(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 irqreturn_t stm32_rproc_wdg(int irq, void *data)
{
	struct platform_device *pdev = data;
	struct rproc *rproc = platform_get_drvdata(pdev);

	rproc_report_crash(rproc, RPROC_WATCHDOG);

	return IRQ_HANDLED;
}

static void stm32_rproc_mb_vq_work(struct work_struct *work)
{
	struct stm32_mbox *mb = container_of(work, struct stm32_mbox, vq_work);
	struct rproc *rproc = dev_get_drvdata(mb->client.dev);

	mutex_lock(&rproc->lock);

	if (rproc->state != RPROC_RUNNING)
		goto unlock_mutex;

	if (rproc_vq_interrupt(rproc, mb->vq_id) == IRQ_NONE)
		dev_dbg(&rproc->dev, "no message found in vq%d\n", mb->vq_id);

unlock_mutex:
	mutex_unlock(&rproc->lock);
}

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);
	struct stm32_rproc *ddata = rproc->priv;

	queue_work(ddata->workqueue, &mb->vq_work);
}

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 = STM32_MBX_VQ0_ID,
		.client = {
			.rx_callback = stm32_rproc_mb_callback,
			.tx_block = false,
		},
	},
	{
		.name = STM32_MBX_VQ1,
		.vq_id = STM32_MBX_VQ1_ID,
		.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 */
		},
	},
	{
		.name = STM32_MBX_DETACH,
		.vq_id = -1,
		.client = {
			.tx_block = true,
			.tx_done = NULL,
			.tx_tout = 200, /* 200 ms time out to detach should be fair enough */
		},
	}
};

static int stm32_rproc_request_mbox(struct rproc *rproc)
{
	struct stm32_rproc *ddata = rproc->priv;
	struct device *dev = &rproc->dev;
	unsigned int i;
	int j;
	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)) {
			if (PTR_ERR(ddata->mb[i].chan) == -EPROBE_DEFER) {
				dev_err_probe(dev->parent,
					      PTR_ERR(ddata->mb[i].chan),
					      "failed to request mailbox %s\n",
					      name);
				goto err_probe;
			}
			dev_warn(dev, "cannot get %s mbox\n", name);
			ddata->mb[i].chan = NULL;
		}
		if (ddata->mb[i].vq_id >= 0) {
			INIT_WORK(&ddata->mb[i].vq_work,
				  stm32_rproc_mb_vq_work);
		}
	}

	return 0;

err_probe:
	for (j = i - 1; j >= 0; j--)
		if (ddata->mb[j].chan)
			mbox_free_channel(ddata->mb[j].chan);
	return -EPROBE_DEFER;
}

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 (IS_ENABLED(CONFIG_HAVE_ARM_SMCCC) && 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)
{
	struct stm32_rproc *ddata = rproc->priv;
	int err;

	stm32_rproc_add_coredump_trace(rproc);

	/* clear remote proc Deep Sleep */
	if (ddata->pdds.map) {
		err = regmap_update_bits(ddata->pdds.map, ddata->pdds.reg,
					 ddata->pdds.mask, 0);
		if (err) {
			dev_err(&rproc->dev, "failed to clear pdds\n");
			return err;
		}
	}

	err = stm32_rproc_set_hold_boot(rproc, false);
	if (err)
		return err;

	return stm32_rproc_set_hold_boot(rproc, true);
}

static int stm32_rproc_attach(struct rproc *rproc)
{
	stm32_rproc_add_coredump_trace(rproc);

	return stm32_rproc_set_hold_boot(rproc, true);
}

static int stm32_rproc_detach(struct rproc *rproc)
{
	struct stm32_rproc *ddata = rproc->priv;
	int err, idx;

	/* Inform the remote processor of the detach */
	idx = stm32_rproc_mbox_idx(rproc, STM32_MBX_DETACH);
	if (idx >= 0 && ddata->mb[idx].chan) {
		err = mbox_send_message(ddata->mb[idx].chan, "stop");
		if (err < 0)
			dev_warn(&rproc->dev, "warning: remote FW detach without ack\n");
	}

	/* Allow remote processor to auto-reboot */
	return stm32_rproc_set_hold_boot(rproc, false);
}

static int stm32_rproc_stop(struct rproc *rproc)
{
	struct stm32_rproc *ddata = rproc->priv;
	int err, idx;

	/* request shutdown of the remote processor */
	if (rproc->state != RPROC_OFFLINE && rproc->state != RPROC_CRASHED) {
		idx = stm32_rproc_mbox_idx(rproc, STM32_MBX_SHUTDOWN);
		if (idx >= 0 && ddata->mb[idx].chan) {
			err = mbox_send_message(ddata->mb[idx].chan, "detach");
			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;
		}
	}

	/* update coprocessor state to OFF if available */
	if (ddata->m4_state.map) {
		err = regmap_update_bits(ddata->m4_state.map,
					 ddata->m4_state.reg,
					 ddata->m4_state.mask,
					 M4_STATE_OFF);
		if (err) {
			dev_err(&rproc->dev, "failed to set copro state\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, "kick");
		if (err < 0)
			dev_err(&rproc->dev, "%s: failed (%s, err:%d)\n",
				__func__, ddata->mb[i].name, err);
		return;
	}
}

static int stm32_rproc_da_to_pa(struct rproc *rproc,
				u64 da, phys_addr_t *pa)
{
	struct stm32_rproc *ddata = rproc->priv;
	struct device *dev = rproc->dev.parent;
	struct stm32_rproc_mem *p_mem;
	unsigned int i;

	for (i = 0; i < ddata->nb_rmems; i++) {
		p_mem = &ddata->rmems[i];

		if (da < p_mem->dev_addr ||
		    da >= p_mem->dev_addr + p_mem->size)
			continue;

		*pa = da - p_mem->dev_addr + p_mem->bus_addr;
		dev_dbg(dev, "da %llx to pa %pap\n", da, pa);

		return 0;
	}

	dev_err(dev, "can't translate da %llx\n", da);

	return -EINVAL;
}

static struct resource_table *
stm32_rproc_get_loaded_rsc_table(struct rproc *rproc, size_t *table_sz)
{
	struct stm32_rproc *ddata = rproc->priv;
	struct device *dev = rproc->dev.parent;
	phys_addr_t rsc_pa;
	u32 rsc_da;
	int err;

	/* The resource table has already been mapped, nothing to do */
	if (ddata->rsc_va)
		goto done;

	err = regmap_read(ddata->rsctbl.map, ddata->rsctbl.reg, &rsc_da);
	if (err) {
		dev_err(dev, "failed to read rsc tbl addr\n");
		return ERR_PTR(-EINVAL);
	}

	if (!rsc_da)
		/* no rsc table */
		return ERR_PTR(-ENOENT);

	err = stm32_rproc_da_to_pa(rproc, rsc_da, &rsc_pa);
	if (err)
		return ERR_PTR(err);

	ddata->rsc_va = devm_ioremap_wc(dev, rsc_pa, RSC_TBL_SIZE);
	if (IS_ERR_OR_NULL(ddata->rsc_va)) {
		dev_err(dev, "Unable to map memory region: %pa+%zx\n",
			&rsc_pa, RSC_TBL_SIZE);
		ddata->rsc_va = NULL;
		return ERR_PTR(-ENOMEM);
	}

done:
	/*
	 * Assuming the resource table fits in 1kB is fair.
	 * Notice for the detach, that this 1 kB memory area has to be reserved in the coprocessor
	 * firmware for the resource table. On detach, the remoteproc core re-initializes this
	 * entire area by overwriting it with the initial values stored in rproc->clean_table.
	 */
	*table_sz = RSC_TBL_SIZE;
	return (struct resource_table *)ddata->rsc_va;
}

static const struct rproc_ops st_rproc_ops = {
	.prepare	= stm32_rproc_prepare,
	.start		= stm32_rproc_start,
	.stop		= stm32_rproc_stop,
	.attach		= stm32_rproc_attach,
	.detach		= stm32_rproc_detach,
	.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,
	.get_loaded_rsc_table = stm32_rproc_get_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 stm32_rproc *ddata, bool *auto_boot)
{
	struct device *dev = &pdev->dev;
	struct device_node *np = dev->of_node;
	struct stm32_syscon tz;
	unsigned int tzen;
	int err, irq;

	irq = platform_get_irq(pdev, 0);
	if (irq == -EPROBE_DEFER)
		return dev_err_probe(dev, irq, "failed to get interrupt\n");

	if (irq > 0) {
		err = devm_request_irq(dev, irq, stm32_rproc_wdg, 0,
				       dev_name(dev), pdev);
		if (err)
			return dev_err_probe(dev, err,
					     "failed to request wdg irq\n");

		ddata->wdg_irq = irq;

		if (of_property_read_bool(np, "wakeup-source")) {
			device_init_wakeup(dev, true);
			dev_pm_set_wake_irq(dev, irq);
		}

		dev_info(dev, "wdg irq registered\n");
	}

	ddata->rst = devm_reset_control_get_by_index(dev, 0);
	if (IS_ERR(ddata->rst))
		return dev_err_probe(dev, PTR_ERR(ddata->rst),
				     "failed to get mcu_reset\n");

	/*
	 * 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(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_info(dev, "failed to get pdds\n");

	*auto_boot = of_property_read_bool(np, "st,auto-boot");

	/*
	 * See if we can check the M4 status, i.e if it was started
	 * from the boot loader or not.
	 */
	err = stm32_rproc_get_syscon(np, "st,syscfg-m4-state",
				     &ddata->m4_state);
	if (err) {
		/* remember this */
		ddata->m4_state.map = NULL;
		/* no coprocessor state syscon (optional) */
		dev_warn(dev, "m4 state not supported\n");

		/* no need to go further */
		return 0;
	}

	/* See if we can get the resource table */
	err = stm32_rproc_get_syscon(np, "st,syscfg-rsc-tbl",
				     &ddata->rsctbl);
	if (err) {
		/* no rsc table syscon (optional) */
		dev_warn(dev, "rsc tbl syscon not supported\n");
	}

	return 0;
}

static int stm32_rproc_get_m4_status(struct stm32_rproc *ddata,
				     unsigned int *state)
{
	/* See stm32_rproc_parse_dt() */
	if (!ddata->m4_state.map) {
		/*
		 * We couldn't get the coprocessor's state, assume
		 * it is not running.
		 */
		*state = M4_STATE_OFF;
		return 0;
	}

	return regmap_read(ddata->m4_state.map, ddata->m4_state.reg, state);
}

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;
	unsigned int state;
	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;

	ddata = rproc->priv;

	rproc_coredump_set_elf_info(rproc, ELFCLASS32, EM_NONE);

	ret = stm32_rproc_parse_dt(pdev, ddata, &rproc->auto_boot);
	if (ret)
		goto free_rproc;

	ret = stm32_rproc_of_memory_translations(pdev, ddata);
	if (ret)
		goto free_rproc;

	ret = stm32_rproc_get_m4_status(ddata, &state);
	if (ret)
		goto free_rproc;

	if (state == M4_STATE_CRUN)
		rproc->state = RPROC_DETACHED;

	rproc->has_iommu = false;
	ddata->workqueue = create_workqueue(dev_name(dev));
	if (!ddata->workqueue) {
		dev_err(dev, "cannot create workqueue\n");
		ret = -ENOMEM;
		goto free_resources;
	}

	platform_set_drvdata(pdev, rproc);

	ret = stm32_rproc_request_mbox(rproc);
	if (ret)
		goto free_wkq;

	ret = rproc_add(rproc);
	if (ret)
		goto free_mb;

	return 0;

free_mb:
	stm32_rproc_free_mbox(rproc);
free_wkq:
	destroy_workqueue(ddata->workqueue);
free_resources:
	rproc_resource_cleanup(rproc);
free_rproc:
	if (device_may_wakeup(dev)) {
		dev_pm_clear_wake_irq(dev);
		device_init_wakeup(dev, false);
	}
	rproc_free(rproc);
	return ret;
}

static int stm32_rproc_remove(struct platform_device *pdev)
{
	struct rproc *rproc = platform_get_drvdata(pdev);
	struct stm32_rproc *ddata = rproc->priv;
	struct device *dev = &pdev->dev;

	if (atomic_read(&rproc->power) > 0)
		rproc_shutdown(rproc);

	rproc_del(rproc);
	stm32_rproc_free_mbox(rproc);
	destroy_workqueue(ddata->workqueue);

	if (device_may_wakeup(dev)) {
		dev_pm_clear_wake_irq(dev);
		device_init_wakeup(dev, false);
	}
	rproc_free(rproc);

	return 0;
}

static int __maybe_unused stm32_rproc_suspend(struct device *dev)
{
	struct rproc *rproc = dev_get_drvdata(dev);
	struct stm32_rproc *ddata = rproc->priv;

	if (device_may_wakeup(dev))
		return enable_irq_wake(ddata->wdg_irq);

	return 0;
}

static int __maybe_unused stm32_rproc_resume(struct device *dev)
{
	struct rproc *rproc = dev_get_drvdata(dev);
	struct stm32_rproc *ddata = rproc->priv;

	if (device_may_wakeup(dev))
		return disable_irq_wake(ddata->wdg_irq);

	return 0;
}

static SIMPLE_DEV_PM_OPS(stm32_rproc_pm_ops,
			 stm32_rproc_suspend, stm32_rproc_resume);

static struct platform_driver stm32_rproc_driver = {
	.probe = stm32_rproc_probe,
	.remove = stm32_rproc_remove,
	.driver = {
		.name = "stm32-rproc",
		.pm = &stm32_rproc_pm_ops,
		.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 <ludovic.barre@st.com>");
MODULE_AUTHOR("Fabien Dessenne <fabien.dessenne@st.com>");
MODULE_LICENSE("GPL v2");