drivers/remoteproc/stm32_rproc.c

root/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.h>
#include <linux/of_reserved_mem.h>
#include <linux/platform_device.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 reset_control *hold_boot_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 hold_boot_smc;
        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: %pad+%zx\n", &mem->dma, mem->len);
        va = (__force void *)ioremap_wc(mem->dma, mem->len);
        if (IS_ERR_OR_NULL(va)) {
                dev_err(dev, "Unable to map memory region: %pad+0x%zx\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((__force __iomem void *)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 = kzalloc_objs(*mem_range, cnt);
        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 rproc_mem_entry *mem;
        u64 da;
        int index = 0, mr = 0;

        /* Register associated reserved memory regions */
        while (1) {
                struct resource res;
                int ret;

                ret = of_reserved_mem_region_to_resource(np, mr++, &res);
                if (ret)
                        return 0;

                if (stm32_rproc_pa_to_da(rproc, res.start, &da) < 0) {
                        dev_err(dev, "memory region not valid %pR\n", &res);
                        return -EINVAL;
                }

                /*  No need to map vdev buffer */
                if (!strstarts(res.name, "vdev0buffer")) {
                        /* Register memory region */
                        mem = rproc_mem_entry_init(dev, NULL,
                                                   (dma_addr_t)res.start,
                                                   resource_size(&res), da,
                                                   stm32_rproc_mem_alloc,
                                                   stm32_rproc_mem_release,
                                                   "%.*s", strchrnul(res.name, '@') - res.name,
                                                   res.name);
                        if (mem)
                                rproc_coredump_add_segment(rproc, da,
                                                           resource_size(&res));
                } else {
                        /* Register reserved memory for vdev buffer alloc */
                        mem = rproc_of_resm_mem_entry_init(dev, index,
                                                           resource_size(&res),
                                                           res.start,
                                                           "vdev0buffer");
                }

                if (!mem) {
                        return -ENOMEM;
                }

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

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 && rproc->state != RPROC_ATTACHED)
                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;

        /*
         * Three ways to manage the hold boot
         * - using SCMI: the hold boot is managed as a reset,
         * - using Linux(no SCMI): the hold boot is managed as a syscon register
         * - using SMC call (deprecated): use SMC reset interface
         */

        val = hold ? HOLD_BOOT : RELEASE_BOOT;

        if (ddata->hold_boot_rst) {
                /* Use the SCMI reset controller */
                if (!hold)
                        err = reset_control_deassert(ddata->hold_boot_rst);
                else
                        err =  reset_control_assert(ddata->hold_boot_rst);
        } else if (IS_ENABLED(CONFIG_HAVE_ARM_SMCCC) && ddata->hold_boot_smc) {
                /* Use the SMC call */
                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 {
                /* Use syscon */
                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+%x\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 (__force 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_optional(pdev, 0);
        if (irq == -EPROBE_DEFER)
                return irq;

        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_optional(dev, "mcu_rst");
        if (!ddata->rst) {
                /* Try legacy fallback method: get it by index */
                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");

        /*
         * Three ways to manage the hold boot
         * - using SCMI: the hold boot is managed as a reset
         *    The DT "reset-mames" property should be defined with 2 items:
         *        reset-names = "mcu_rst", "hold_boot";
         * - using SMC call (deprecated): use SMC reset interface
         *    The DT "reset-mames" property is optional, "st,syscfg-tz" is required
         * - default(no SCMI, no SMC): the hold boot is managed as a syscon register
         *    The DT "reset-mames" property is optional, "st,syscfg-holdboot" is required
         */

        ddata->hold_boot_rst = devm_reset_control_get_optional(dev, "hold_boot");
        if (IS_ERR(ddata->hold_boot_rst))
                return dev_err_probe(dev, PTR_ERR(ddata->hold_boot_rst),
                                     "failed to get hold_boot reset\n");

        if (!ddata->hold_boot_rst && IS_ENABLED(CONFIG_HAVE_ARM_SMCCC)) {
                /* Manage the MCU_BOOT using SMC call */
                err = stm32_rproc_get_syscon(np, "st,syscfg-tz", &tz);
                if (!err) {
                        err = regmap_read(tz.map, tz.reg, &tzen);
                        if (err) {
                                dev_err(dev, "failed to read tzen\n");
                                return err;
                        }
                        ddata->hold_boot_smc = tzen & tz.mask;
                }
        }

        if (!ddata->hold_boot_rst && !ddata->hold_boot_smc) {
                /* Default: hold boot manage it through the syscon controller */
                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;
        const char *fw_name;
        struct rproc *rproc;
        unsigned int state;
        int ret;

        ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(32));
        if (ret)
                return ret;

        /* Look for an optional firmware name */
        ret = rproc_of_parse_firmware(dev, 0, &fw_name);
        if (ret < 0 && ret != -EINVAL)
                return ret;

        rproc = devm_rproc_alloc(dev, np->name, &st_rproc_ops, fw_name, 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);
        }
        return ret;
}

static void 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);
        }
}

static int 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 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 DEFINE_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 = pm_ptr(&stm32_rproc_pm_ops),
                .of_match_table = 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");