/*
 * 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, be16_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");