sigmadsp.c

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/*
 * Load Analog Devices SigmaStudio firmware files
 *
 * Copyright 2009-2011 Analog Devices Inc.
 *
 * Licensed under the GPL-2 or later.
 */

#include <linux/crc32.h>
#include <linux/delay.h>
#include <linux/firmware.h>
#include <linux/kernel.h>
#include <linux/i2c.h>
#include <linux/regmap.h>
#include <linux/module.h>

#include "sigmadsp.h"

#define SIGMA_MAGIC "ADISIGM"

struct sigma_firmware_header {
    unsigned char magic[7];
    u8 version;
    __le32 crc;
} __packed;

enum {
    SIGMA_ACTION_WRITEXBYTES = 0,
    SIGMA_ACTION_WRITESINGLE,
    SIGMA_ACTION_WRITESAFELOAD,
    SIGMA_ACTION_DELAY,
    SIGMA_ACTION_PLLWAIT,
    SIGMA_ACTION_NOOP,
    SIGMA_ACTION_END,
};

struct sigma_action {
    u8 instr;
    u8 len_hi;
    __le16 len;
    __be16 addr;
    unsigned char payload[];
} __packed;

struct sigma_firmware {
    const struct firmware *fw;
    size_t pos;

    void *control_data;
    int (*write)(void *control_data, const struct sigma_action *sa,
            size_t len);
};

static inline u32 sigma_action_len(struct sigma_action *sa)
{
    return (sa->len_hi << 16) | le16_to_cpu(sa->len);
}

static size_t sigma_action_size(struct sigma_action *sa)
{
    size_t payload = 0;

    switch (sa->instr) {
    case SIGMA_ACTION_WRITEXBYTES:
    case SIGMA_ACTION_WRITESINGLE:
    case SIGMA_ACTION_WRITESAFELOAD:
        payload = sigma_action_len(sa);
        break;
    default:
        break;
    }

    payload = ALIGN(payload, 2);

    return payload + sizeof(struct sigma_action);
}

/*
 * Returns a negative error value in case of an error, 0 if processing of
 * the firmware should be stopped after this action, 1 otherwise.
 */
static int
process_sigma_action(struct sigma_firmware *ssfw, struct sigma_action *sa)
{
    size_t len = sigma_action_len(sa);
    int ret;

    pr_debug("%s: instr:%i addr:%#x len:%zu\n", __func__,
        sa->instr, sa->addr, len);

    switch (sa->instr) {
    case SIGMA_ACTION_WRITEXBYTES:
    case SIGMA_ACTION_WRITESINGLE:
    case SIGMA_ACTION_WRITESAFELOAD:
        ret = ssfw->write(ssfw->control_data, sa, len);
        if (ret < 0)
            return -EINVAL;
        break;
    case SIGMA_ACTION_DELAY:
        udelay(len);
        len = 0;
        break;
    case SIGMA_ACTION_END:
        return 0;
    default:
        return -EINVAL;
    }

    return 1;
}

static int
process_sigma_actions(struct sigma_firmware *ssfw)
{
    struct sigma_action *sa;
    size_t size;
    int ret;

    while (ssfw->pos + sizeof(*sa) <= ssfw->fw->size) {
        sa = (struct sigma_action *)(ssfw->fw->data + ssfw->pos);

        size = sigma_action_size(sa);
        ssfw->pos += size;
        if (ssfw->pos > ssfw->fw->size || size == 0)
            break;

        ret = process_sigma_action(ssfw, sa);

        pr_debug("%s: action returned %i\n", __func__, ret);

        if (ret <= 0)
            return ret;
    }

    if (ssfw->pos != ssfw->fw->size)
        return -EINVAL;

    return 0;
}

static int _process_sigma_firmware(struct device *dev,
    struct sigma_firmware *ssfw, const char *name)
{
    int ret;
    struct sigma_firmware_header *ssfw_head;
    const struct firmware *fw;
    u32 crc;

    pr_debug("%s: loading firmware %s\n", __func__, name);

    /* first load the blob */
    ret = request_firmware(&fw, name, dev);
    if (ret) {
        pr_debug("%s: request_firmware() failed with %i\n", __func__, ret);
        return ret;
    }
    ssfw->fw = fw;

    /* then verify the header */
    ret = -EINVAL;

    /*
     * Reject too small or unreasonable large files. The upper limit has been
     * chosen a bit arbitrarily, but it should be enough for all practical
     * purposes and having the limit makes it easier to avoid integer
     * overflows later in the loading process.
     */
    if (fw->size < sizeof(*ssfw_head) || fw->size >= 0x4000000) {
        dev_err(dev, "Failed to load firmware: Invalid size\n");
        goto done;
    }

    ssfw_head = (void *)fw->data;
    if (memcmp(ssfw_head->magic, SIGMA_MAGIC, ARRAY_SIZE(ssfw_head->magic))) {
        dev_err(dev, "Failed to load firmware: Invalid magic\n");
        goto done;
    }

    crc = crc32(0, fw->data + sizeof(*ssfw_head),
            fw->size - sizeof(*ssfw_head));
    pr_debug("%s: crc=%x\n", __func__, crc);
    if (crc != le32_to_cpu(ssfw_head->crc)) {
        dev_err(dev, "Failed to load firmware: Wrong crc checksum: expected %x got %x\n",
            le32_to_cpu(ssfw_head->crc), crc);
        goto done;
    }

    ssfw->pos = sizeof(*ssfw_head);

    /* finally process all of the actions */
    ret = process_sigma_actions(ssfw);

 done:
    release_firmware(fw);

    pr_debug("%s: loaded %s\n", __func__, name);

    return ret;
}

#if IS_ENABLED(CONFIG_I2C)

static int sigma_action_write_i2c(void *control_data,
    const struct sigma_action *sa, size_t len)
{
    return i2c_master_send(control_data, (const unsigned char *)&sa->addr,
        len);
}

int process_sigma_firmware(struct i2c_client *client, const char *name)
{
    struct sigma_firmware ssfw;

    ssfw.control_data = client;
    ssfw.write = sigma_action_write_i2c;

    return _process_sigma_firmware(&client->dev, &ssfw, name);
}
EXPORT_SYMBOL(process_sigma_firmware);

#endif

#if IS_ENABLED(CONFIG_REGMAP)

static int sigma_action_write_regmap(void *control_data,
    const struct sigma_action *sa, size_t len)
{
    return regmap_raw_write(control_data, le16_to_cpu(sa->addr),
        sa->payload, len - 2);
}

int process_sigma_firmware_regmap(struct device *dev, struct regmap *regmap,
    const char *name)
{
    struct sigma_firmware ssfw;

    ssfw.control_data = regmap;
    ssfw.write = sigma_action_write_regmap;

    return _process_sigma_firmware(dev, &ssfw, name);
}
EXPORT_SYMBOL(process_sigma_firmware_regmap);

#endif

MODULE_LICENSE("GPL");