ste_modem_rproc.c

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/*
 * Copyright (C) ST-Ericsson AB 2012
 * Author: Sjur Brændeland <[email protected]>
 * License terms:  GNU General Public License (GPL), version 2
 */

#include <linux/module.h>
#include <linux/dma-mapping.h>
#include <linux/remoteproc.h>
#include <linux/ste_modem_shm.h>
#include "remoteproc_internal.h"

#define SPROC_FW_SIZE (50 * 4096)
#define SPROC_MAX_TOC_ENTRIES 32
#define SPROC_MAX_NOTIFY_ID 14
#define SPROC_RESOURCE_NAME "rsc-table"
#define SPROC_MODEM_NAME "ste-modem"
#define SPROC_MODEM_FIRMWARE SPROC_MODEM_NAME "-fw.bin"

#define sproc_dbg(sproc, fmt, ...) \
    dev_dbg(&sproc->mdev->pdev.dev, fmt, ##__VA_ARGS__)
#define sproc_err(sproc, fmt, ...) \
    dev_err(&sproc->mdev->pdev.dev, fmt, ##__VA_ARGS__)

/* STE-modem control structure */
struct sproc {
    struct rproc *rproc;
    struct ste_modem_device *mdev;
    int error;
    void *fw_addr;
    size_t fw_size;
    dma_addr_t fw_dma_addr;
};

/* STE-Modem firmware entry */
struct ste_toc_entry {
    __le32 start;
    __le32 size;
    __le32 flags;
    __le32 entry_point;
    __le32 load_addr;
    char name[12];
};

/*
 * The Table Of Content is located at the start of the firmware image and
 * at offset zero in the shared memory region. The resource table typically
 * contains the initial boot image (boot strap) and other information elements
 * such as remoteproc resource table. Each entry is identified by a unique
 * name.
 */
struct ste_toc {
    struct ste_toc_entry table[SPROC_MAX_TOC_ENTRIES];
};

/* Loads the firmware to shared memory. */
static int sproc_load_segments(struct rproc *rproc, const struct firmware *fw)
{
    struct sproc *sproc = rproc->priv;

    memcpy(sproc->fw_addr, fw->data, fw->size);

    return 0;
}

/* Find the entry for resource table in the Table of Content */
static struct ste_toc_entry *sproc_find_rsc_entry(const struct firmware *fw)
{
    int i;
    struct ste_toc *toc;

    if (!fw)
        return NULL;

    toc = (void *)fw->data;

    /* Search the table for the resource table */
    for (i = 0; i < SPROC_MAX_TOC_ENTRIES &&
            toc->table[i].start != 0xffffffff; i++) {

        if (!strncmp(toc->table[i].name, SPROC_RESOURCE_NAME,
                 sizeof(toc->table[i].name))) {
            if (toc->table[i].start > fw->size)
                return NULL;
            return &toc->table[i];
        }
    }

    return NULL;
}

/* Find the resource table inside the remote processor's firmware. */
static struct resource_table *
sproc_find_rsc_table(struct rproc *rproc, const struct firmware *fw,
             int *tablesz)
{
    struct sproc *sproc = rproc->priv;
    struct resource_table *table;
    struct ste_toc_entry *entry;

    entry = sproc_find_rsc_entry(fw);
    if (!entry) {
        sproc_err(sproc, "resource table not found in fw\n");
        return NULL;
    }

    table = (void *)(fw->data + entry->start);

    /* sanity check size and offset of resource table */
    if (entry->start > SPROC_FW_SIZE ||
        entry->size > SPROC_FW_SIZE ||
        fw->size > SPROC_FW_SIZE ||
        entry->start + entry->size > fw->size ||
        sizeof(struct resource_table) > entry->size) {
        sproc_err(sproc, "bad size of fw or resource table\n");
        return NULL;
    }

    /* we don't support any version beyond the first */
    if (table->ver != 1) {
        sproc_err(sproc, "unsupported fw ver: %d\n", table->ver);
        return NULL;
    }

    /* make sure reserved bytes are zeroes */
    if (table->reserved[0] || table->reserved[1]) {
        sproc_err(sproc, "non zero reserved bytes\n");
        return NULL;
    }

    /* make sure the offsets array isn't truncated */
    if (table->num > SPROC_MAX_TOC_ENTRIES ||
        table->num * sizeof(table->offset[0]) +
        sizeof(struct resource_table) > entry->size) {
        sproc_err(sproc, "resource table incomplete\n");
        return NULL;
    }

    /* If the fw size has grown, release the previous fw allocation */
    if (SPROC_FW_SIZE < fw->size) {
        sproc_err(sproc, "Insufficient space for fw (%d < %zd)\n",
              SPROC_FW_SIZE, fw->size);
        return NULL;
    }

    sproc->fw_size = fw->size;
    *tablesz = entry->size;

    return table;
}

/* STE modem firmware handler operations */
const struct rproc_fw_ops sproc_fw_ops = {
    .load = sproc_load_segments,
    .find_rsc_table = sproc_find_rsc_table,
};

/* Kick the modem with specified notification id */
static void sproc_kick(struct rproc *rproc, int vqid)
{
    struct sproc *sproc = rproc->priv;

    sproc_dbg(sproc, "kick vqid:%d\n", vqid);

    /*
     * We need different notification IDs for RX and TX so add
     * an offset on TX notification IDs.
     */
    sproc->mdev->ops.kick(sproc->mdev, vqid + SPROC_MAX_NOTIFY_ID);
}

/* Received a kick from a modem, kick the virtqueue */
static void sproc_kick_callback(struct ste_modem_device *mdev, int vqid)
{
    struct sproc *sproc = mdev->drv_data;

    if (rproc_vq_interrupt(sproc->rproc, vqid) == IRQ_NONE)
        sproc_dbg(sproc, "no message was found in vqid %d\n", vqid);
}

struct ste_modem_dev_cb sproc_dev_cb = {
    .kick = sproc_kick_callback,
};

/* Start the STE modem */
static int sproc_start(struct rproc *rproc)
{
    struct sproc *sproc = rproc->priv;
    int i, err;

    sproc_dbg(sproc, "start ste-modem\n");

    /* Sanity test the max_notifyid */
    if (rproc->max_notifyid > SPROC_MAX_NOTIFY_ID) {
        sproc_err(sproc, "Notification IDs too high:%d\n",
              rproc->max_notifyid);
        return -EINVAL;
    }

    /* Subscribe to notifications */
    for (i = 0; i < rproc->max_notifyid; i++) {
        err = sproc->mdev->ops.kick_subscribe(sproc->mdev, i);
        if (err) {
            sproc_err(sproc,
                  "subscription of kicks failed:%d\n", err);
            return err;
        }
    }

    /* Request modem start-up*/
    return sproc->mdev->ops.power(sproc->mdev, true);
}

/* Stop the STE modem */
static int sproc_stop(struct rproc *rproc)
{
    struct sproc *sproc = rproc->priv;
    sproc_dbg(sproc, "stop ste-modem\n");

    return sproc->mdev->ops.power(sproc->mdev, false);
}

static struct rproc_ops sproc_ops = {
    .start      = sproc_start,
    .stop       = sproc_stop,
    .kick       = sproc_kick,
};

/* STE modem device is unregistered */
static int sproc_drv_remove(struct platform_device *pdev)
{
    struct ste_modem_device *mdev =
        container_of(pdev, struct ste_modem_device, pdev);
    struct sproc *sproc = mdev->drv_data;

    sproc_dbg(sproc, "remove ste-modem\n");

    /* Reset device callback functions */
    sproc->mdev->ops.setup(sproc->mdev, NULL);

    /* Unregister as remoteproc device */
    rproc_del(sproc->rproc);
    rproc_put(sproc->rproc);

    mdev->drv_data = NULL;

    return 0;
}

/* Handle probe of a modem device */
static int sproc_probe(struct platform_device *pdev)
{
    struct ste_modem_device *mdev =
        container_of(pdev, struct ste_modem_device, pdev);
    struct sproc *sproc;
    struct rproc *rproc;
    int err;

    dev_dbg(&mdev->pdev.dev, "probe ste-modem\n");

    if (!mdev->ops.setup || !mdev->ops.kick || !mdev->ops.kick_subscribe ||
        !mdev->ops.power) {
        dev_err(&mdev->pdev.dev, "invalid mdev ops\n");
        return -EINVAL;
    }

    rproc = rproc_alloc(&mdev->pdev.dev, mdev->pdev.name, &sproc_ops,
                SPROC_MODEM_FIRMWARE, sizeof(*sproc));
    if (!rproc)
        return -ENOMEM;

    sproc = rproc->priv;
    sproc->mdev = mdev;
    sproc->rproc = rproc;
    mdev->drv_data = sproc;

    /* Provide callback functions to modem device */
    sproc->mdev->ops.setup(sproc->mdev, &sproc_dev_cb);

    /* Set the STE-modem specific firmware handler */
    rproc->fw_ops = &sproc_fw_ops;

    /*
     * STE-modem requires the firmware to be located
     * at the start of the shared memory region. So we need to
     * reserve space for firmware at the start.
     */
    sproc->fw_addr = dma_alloc_coherent(rproc->dev.parent, SPROC_FW_SIZE,
                        &sproc->fw_dma_addr,
                        GFP_KERNEL);
    if (!sproc->fw_addr) {
        sproc_err(sproc, "Cannot allocate memory for fw\n");
        err = -ENOMEM;
        goto free_rproc;
    }

    /* Register as a remoteproc device */
    err = rproc_add(rproc);
    if (err)
        goto free_rproc;

    return 0;

free_rproc:
    /* Reset device data upon error */
    mdev->drv_data = NULL;
    rproc_put(rproc);
    return err;
}

static struct platform_driver sproc_driver = {
    .driver = {
        .name   = SPROC_MODEM_NAME,
        .owner  = THIS_MODULE,
    },
    .probe  = sproc_probe,
    .remove = sproc_drv_remove,
};

module_platform_driver(sproc_driver);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("STE Modem driver using the Remote Processor Framework");