Merge tag 'io_uring-5.11-2021-01-16' of git://git.kernel.dk/linux-block

[linux/fpc-iii.git] / drivers / memory / brcmstb_dpfe.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * DDR PHY Front End (DPFE) driver for Broadcom set top box SoCs
 *
 * Copyright (c) 2017 Broadcom
 */

/*
 * This driver provides access to the DPFE interface of Broadcom STB SoCs.
 * The firmware running on the DCPU inside the DDR PHY can provide current
 * information about the system's RAM, for instance the DRAM refresh rate.
 * This can be used as an indirect indicator for the DRAM's temperature.
 * Slower refresh rate means cooler RAM, higher refresh rate means hotter
 * RAM.
 *
 * Throughout the driver, we use readl_relaxed() and writel_relaxed(), which
 * already contain the appropriate le32_to_cpu()/cpu_to_le32() calls.
 *
 * Note regarding the loading of the firmware image: we use be32_to_cpu()
 * and le_32_to_cpu(), so we can support the following four cases:
 *     - LE kernel + LE firmware image (the most common case)
 *     - LE kernel + BE firmware image
 *     - BE kernel + LE firmware image
 *     - BE kernel + BE firmware image
 *
 * The DPCU always runs in big endian mode. The firmware image, however, can
 * be in either format. Also, communication between host CPU and DCPU is
 * always in little endian.
 */

#include <linux/delay.h>
#include <linux/firmware.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>

#define DRVNAME                 "brcmstb-dpfe"

/* DCPU register offsets */
#define REG_DCPU_RESET          0x0
#define REG_TO_DCPU_MBOX        0x10
#define REG_TO_HOST_MBOX        0x14

/* Macros to process offsets returned by the DCPU */
#define DRAM_MSG_ADDR_OFFSET    0x0
#define DRAM_MSG_TYPE_OFFSET    0x1c
#define DRAM_MSG_ADDR_MASK      ((1UL << DRAM_MSG_TYPE_OFFSET) - 1)
#define DRAM_MSG_TYPE_MASK      ((1UL << \
                                 (BITS_PER_LONG - DRAM_MSG_TYPE_OFFSET)) - 1)

/* Message RAM */
#define DCPU_MSG_RAM_START      0x100
#define DCPU_MSG_RAM(x)         (DCPU_MSG_RAM_START + (x) * sizeof(u32))

/* DRAM Info Offsets & Masks */
#define DRAM_INFO_INTERVAL      0x0
#define DRAM_INFO_MR4           0x4
#define DRAM_INFO_ERROR         0x8
#define DRAM_INFO_MR4_MASK      0xff
#define DRAM_INFO_MR4_SHIFT     24      /* We need to look at byte 3 */

/* DRAM MR4 Offsets & Masks */
#define DRAM_MR4_REFRESH        0x0     /* Refresh rate */
#define DRAM_MR4_SR_ABORT       0x3     /* Self Refresh Abort */
#define DRAM_MR4_PPRE           0x4     /* Post-package repair entry/exit */
#define DRAM_MR4_TH_OFFS        0x5     /* Thermal Offset; vendor specific */
#define DRAM_MR4_TUF            0x7     /* Temperature Update Flag */

#define DRAM_MR4_REFRESH_MASK   0x7
#define DRAM_MR4_SR_ABORT_MASK  0x1
#define DRAM_MR4_PPRE_MASK      0x1
#define DRAM_MR4_TH_OFFS_MASK   0x3
#define DRAM_MR4_TUF_MASK       0x1

/* DRAM Vendor Offsets & Masks (API v2) */
#define DRAM_VENDOR_MR5         0x0
#define DRAM_VENDOR_MR6         0x4
#define DRAM_VENDOR_MR7         0x8
#define DRAM_VENDOR_MR8         0xc
#define DRAM_VENDOR_ERROR       0x10
#define DRAM_VENDOR_MASK        0xff
#define DRAM_VENDOR_SHIFT       24      /* We need to look at byte 3 */

/* DRAM Information Offsets & Masks (API v3) */
#define DRAM_DDR_INFO_MR4       0x0
#define DRAM_DDR_INFO_MR5       0x4
#define DRAM_DDR_INFO_MR6       0x8
#define DRAM_DDR_INFO_MR7       0xc
#define DRAM_DDR_INFO_MR8       0x10
#define DRAM_DDR_INFO_ERROR     0x14
#define DRAM_DDR_INFO_MASK      0xff

/* Reset register bits & masks */
#define DCPU_RESET_SHIFT        0x0
#define DCPU_RESET_MASK         0x1
#define DCPU_CLK_DISABLE_SHIFT  0x2

/* DCPU return codes */
#define DCPU_RET_ERROR_BIT      BIT(31)
#define DCPU_RET_SUCCESS        0x1
#define DCPU_RET_ERR_HEADER     (DCPU_RET_ERROR_BIT | BIT(0))
#define DCPU_RET_ERR_INVAL      (DCPU_RET_ERROR_BIT | BIT(1))
#define DCPU_RET_ERR_CHKSUM     (DCPU_RET_ERROR_BIT | BIT(2))
#define DCPU_RET_ERR_COMMAND    (DCPU_RET_ERROR_BIT | BIT(3))
/* This error code is not firmware defined and only used in the driver. */
#define DCPU_RET_ERR_TIMEDOUT   (DCPU_RET_ERROR_BIT | BIT(4))

/* Firmware magic */
#define DPFE_BE_MAGIC           0xfe1010fe
#define DPFE_LE_MAGIC           0xfe0101fe

/* Error codes */
#define ERR_INVALID_MAGIC       -1
#define ERR_INVALID_SIZE        -2
#define ERR_INVALID_CHKSUM      -3

/* Message types */
#define DPFE_MSG_TYPE_COMMAND   1
#define DPFE_MSG_TYPE_RESPONSE  2

#define DELAY_LOOP_MAX          1000

enum dpfe_msg_fields {
        MSG_HEADER,
        MSG_COMMAND,
        MSG_ARG_COUNT,
        MSG_ARG0,
        MSG_FIELD_MAX   = 16 /* Max number of arguments */
};

enum dpfe_commands {
        DPFE_CMD_GET_INFO,
        DPFE_CMD_GET_REFRESH,
        DPFE_CMD_GET_VENDOR,
        DPFE_CMD_MAX /* Last entry */
};

/*
 * Format of the binary firmware file:
 *
 *   entry
 *      0    header
 *              value:  0xfe0101fe  <== little endian
 *                      0xfe1010fe  <== big endian
 *      1    sequence:
 *              [31:16] total segments on this build
 *              [15:0]  this segment sequence.
 *      2    FW version
 *      3    IMEM byte size
 *      4    DMEM byte size
 *           IMEM
 *           DMEM
 *      last checksum ==> sum of everything
 */
struct dpfe_firmware_header {
        u32 magic;
        u32 sequence;
        u32 version;
        u32 imem_size;
        u32 dmem_size;
};

/* Things we only need during initialization. */
struct init_data {
        unsigned int dmem_len;
        unsigned int imem_len;
        unsigned int chksum;
        bool is_big_endian;
};

/* API version and corresponding commands */
struct dpfe_api {
        int version;
        const char *fw_name;
        const struct attribute_group **sysfs_attrs;
        u32 command[DPFE_CMD_MAX][MSG_FIELD_MAX];
};

/* Things we need for as long as we are active. */
struct brcmstb_dpfe_priv {
        void __iomem *regs;
        void __iomem *dmem;
        void __iomem *imem;
        struct device *dev;
        const struct dpfe_api *dpfe_api;
        struct mutex lock;
};

/*
 * Forward declaration of our sysfs attribute functions, so we can declare the
 * attribute data structures early.
 */
static ssize_t show_info(struct device *, struct device_attribute *, char *);
static ssize_t show_refresh(struct device *, struct device_attribute *, char *);
static ssize_t store_refresh(struct device *, struct device_attribute *,
                          const char *, size_t);
static ssize_t show_vendor(struct device *, struct device_attribute *, char *);
static ssize_t show_dram(struct device *, struct device_attribute *, char *);

/*
 * Declare our attributes early, so they can be referenced in the API data
 * structure. We need to do this, because the attributes depend on the API
 * version.
 */
static DEVICE_ATTR(dpfe_info, 0444, show_info, NULL);
static DEVICE_ATTR(dpfe_refresh, 0644, show_refresh, store_refresh);
static DEVICE_ATTR(dpfe_vendor, 0444, show_vendor, NULL);
static DEVICE_ATTR(dpfe_dram, 0444, show_dram, NULL);

/* API v2 sysfs attributes */
static struct attribute *dpfe_v2_attrs[] = {
        &dev_attr_dpfe_info.attr,
        &dev_attr_dpfe_refresh.attr,
        &dev_attr_dpfe_vendor.attr,
        NULL
};
ATTRIBUTE_GROUPS(dpfe_v2);

/* API v3 sysfs attributes */
static struct attribute *dpfe_v3_attrs[] = {
        &dev_attr_dpfe_info.attr,
        &dev_attr_dpfe_dram.attr,
        NULL
};
ATTRIBUTE_GROUPS(dpfe_v3);

/*
 * Old API v2 firmware commands, as defined in the rev 0.61 specification, we
 * use a version set to 1 to denote that it is not compatible with the new API
 * v2 and onwards.
 */
static const struct dpfe_api dpfe_api_old_v2 = {
        .version = 1,
        .fw_name = "dpfe.bin",
        .sysfs_attrs = dpfe_v2_groups,
        .command = {
                [DPFE_CMD_GET_INFO] = {
                        [MSG_HEADER] = DPFE_MSG_TYPE_COMMAND,
                        [MSG_COMMAND] = 1,
                        [MSG_ARG_COUNT] = 1,
                        [MSG_ARG0] = 1,
                },
                [DPFE_CMD_GET_REFRESH] = {
                        [MSG_HEADER] = DPFE_MSG_TYPE_COMMAND,
                        [MSG_COMMAND] = 2,
                        [MSG_ARG_COUNT] = 1,
                        [MSG_ARG0] = 1,
                },
                [DPFE_CMD_GET_VENDOR] = {
                        [MSG_HEADER] = DPFE_MSG_TYPE_COMMAND,
                        [MSG_COMMAND] = 2,
                        [MSG_ARG_COUNT] = 1,
                        [MSG_ARG0] = 2,
                },
        }
};

/*
 * API v2 firmware commands, as defined in the rev 0.8 specification, named new
 * v2 here
 */
static const struct dpfe_api dpfe_api_new_v2 = {
        .version = 2,
        .fw_name = NULL, /* We expect the firmware to have been downloaded! */
        .sysfs_attrs = dpfe_v2_groups,
        .command = {
                [DPFE_CMD_GET_INFO] = {
                        [MSG_HEADER] = DPFE_MSG_TYPE_COMMAND,
                        [MSG_COMMAND] = 0x101,
                },
                [DPFE_CMD_GET_REFRESH] = {
                        [MSG_HEADER] = DPFE_MSG_TYPE_COMMAND,
                        [MSG_COMMAND] = 0x201,
                },
                [DPFE_CMD_GET_VENDOR] = {
                        [MSG_HEADER] = DPFE_MSG_TYPE_COMMAND,
                        [MSG_COMMAND] = 0x202,
                },
        }
};

/* API v3 firmware commands */
static const struct dpfe_api dpfe_api_v3 = {
        .version = 3,
        .fw_name = NULL, /* We expect the firmware to have been downloaded! */
        .sysfs_attrs = dpfe_v3_groups,
        .command = {
                [DPFE_CMD_GET_INFO] = {
                        [MSG_HEADER] = DPFE_MSG_TYPE_COMMAND,
                        [MSG_COMMAND] = 0x0101,
                        [MSG_ARG_COUNT] = 1,
                        [MSG_ARG0] = 1,
                },
                [DPFE_CMD_GET_REFRESH] = {
                        [MSG_HEADER] = DPFE_MSG_TYPE_COMMAND,
                        [MSG_COMMAND] = 0x0202,
                        [MSG_ARG_COUNT] = 0,
                },
                /* There's no GET_VENDOR command in API v3. */
        },
};

static const char *get_error_text(unsigned int i)
{
        static const char * const error_text[] = {
                "Success", "Header code incorrect",
                "Unknown command or argument", "Incorrect checksum",
                "Malformed command", "Timed out", "Unknown error",
        };

        if (unlikely(i >= ARRAY_SIZE(error_text)))
                i = ARRAY_SIZE(error_text) - 1;

        return error_text[i];
}

static bool is_dcpu_enabled(struct brcmstb_dpfe_priv *priv)
{
        u32 val;

        mutex_lock(&priv->lock);
        val = readl_relaxed(priv->regs + REG_DCPU_RESET);
        mutex_unlock(&priv->lock);

        return !(val & DCPU_RESET_MASK);
}

static void __disable_dcpu(struct brcmstb_dpfe_priv *priv)
{
        u32 val;

        if (!is_dcpu_enabled(priv))
                return;

        mutex_lock(&priv->lock);

        /* Put DCPU in reset if it's running. */
        val = readl_relaxed(priv->regs + REG_DCPU_RESET);
        val |= (1 << DCPU_RESET_SHIFT);
        writel_relaxed(val, priv->regs + REG_DCPU_RESET);

        mutex_unlock(&priv->lock);
}

static void __enable_dcpu(struct brcmstb_dpfe_priv *priv)
{
        void __iomem *regs = priv->regs;
        u32 val;

        mutex_lock(&priv->lock);

        /* Clear mailbox registers. */
        writel_relaxed(0, regs + REG_TO_DCPU_MBOX);
        writel_relaxed(0, regs + REG_TO_HOST_MBOX);

        /* Disable DCPU clock gating */
        val = readl_relaxed(regs + REG_DCPU_RESET);
        val &= ~(1 << DCPU_CLK_DISABLE_SHIFT);
        writel_relaxed(val, regs + REG_DCPU_RESET);

        /* Take DCPU out of reset */
        val = readl_relaxed(regs + REG_DCPU_RESET);
        val &= ~(1 << DCPU_RESET_SHIFT);
        writel_relaxed(val, regs + REG_DCPU_RESET);

        mutex_unlock(&priv->lock);
}

static unsigned int get_msg_chksum(const u32 msg[], unsigned int max)
{
        unsigned int sum = 0;
        unsigned int i;

        /* Don't include the last field in the checksum. */
        for (i = 0; i < max; i++)
                sum += msg[i];

        return sum;
}

static void __iomem *get_msg_ptr(struct brcmstb_dpfe_priv *priv, u32 response,
                                 char *buf, ssize_t *size)
{
        unsigned int msg_type;
        unsigned int offset;
        void __iomem *ptr = NULL;

        /* There is no need to use this function for API v3 or later. */
        if (unlikely(priv->dpfe_api->version >= 3))
                return NULL;

        msg_type = (response >> DRAM_MSG_TYPE_OFFSET) & DRAM_MSG_TYPE_MASK;
        offset = (response >> DRAM_MSG_ADDR_OFFSET) & DRAM_MSG_ADDR_MASK;

        /*
         * msg_type == 1: the offset is relative to the message RAM
         * msg_type == 0: the offset is relative to the data RAM (this is the
         *                previous way of passing data)
         * msg_type is anything else: there's critical hardware problem
         */
        switch (msg_type) {
        case 1:
                ptr = priv->regs + DCPU_MSG_RAM_START + offset;
                break;
        case 0:
                ptr = priv->dmem + offset;
                break;
        default:
                dev_emerg(priv->dev, "invalid message reply from DCPU: %#x\n",
                        response);
                if (buf && size)
                        *size = sprintf(buf,
                                "FATAL: communication error with DCPU\n");
        }

        return ptr;
}

static void __finalize_command(struct brcmstb_dpfe_priv *priv)
{
        unsigned int release_mbox;

        /*
         * It depends on the API version which MBOX register we have to write to
         * to signal we are done.
         */
        release_mbox = (priv->dpfe_api->version < 2)
                        ? REG_TO_HOST_MBOX : REG_TO_DCPU_MBOX;
        writel_relaxed(0, priv->regs + release_mbox);
}

static int __send_command(struct brcmstb_dpfe_priv *priv, unsigned int cmd,
                          u32 result[])
{
        const u32 *msg = priv->dpfe_api->command[cmd];
        void __iomem *regs = priv->regs;
        unsigned int i, chksum, chksum_idx;
        int ret = 0;
        u32 resp;

        if (cmd >= DPFE_CMD_MAX)
                return -1;

        mutex_lock(&priv->lock);

        /* Wait for DCPU to become ready */
        for (i = 0; i < DELAY_LOOP_MAX; i++) {
                resp = readl_relaxed(regs + REG_TO_HOST_MBOX);
                if (resp == 0)
                        break;
                msleep(1);
        }
        if (resp != 0) {
                mutex_unlock(&priv->lock);
                return -ffs(DCPU_RET_ERR_TIMEDOUT);
        }

        /* Compute checksum over the message */
        chksum_idx = msg[MSG_ARG_COUNT] + MSG_ARG_COUNT + 1;
        chksum = get_msg_chksum(msg, chksum_idx);

        /* Write command and arguments to message area */
        for (i = 0; i < MSG_FIELD_MAX; i++) {
                if (i == chksum_idx)
                        writel_relaxed(chksum, regs + DCPU_MSG_RAM(i));
                else
                        writel_relaxed(msg[i], regs + DCPU_MSG_RAM(i));
        }

        /* Tell DCPU there is a command waiting */
        writel_relaxed(1, regs + REG_TO_DCPU_MBOX);

        /* Wait for DCPU to process the command */
        for (i = 0; i < DELAY_LOOP_MAX; i++) {
                /* Read response code */
                resp = readl_relaxed(regs + REG_TO_HOST_MBOX);
                if (resp > 0)
                        break;
                msleep(1);
        }

        if (i == DELAY_LOOP_MAX) {
                resp = (DCPU_RET_ERR_TIMEDOUT & ~DCPU_RET_ERROR_BIT);
                ret = -ffs(resp);
        } else {
                /* Read response data */
                for (i = 0; i < MSG_FIELD_MAX; i++)
                        result[i] = readl_relaxed(regs + DCPU_MSG_RAM(i));
                chksum_idx = result[MSG_ARG_COUNT] + MSG_ARG_COUNT + 1;
        }

        /* Tell DCPU we are done */
        __finalize_command(priv);

        mutex_unlock(&priv->lock);

        if (ret)
                return ret;

        /* Verify response */
        chksum = get_msg_chksum(result, chksum_idx);
        if (chksum != result[chksum_idx])
                resp = DCPU_RET_ERR_CHKSUM;

        if (resp != DCPU_RET_SUCCESS) {
                resp &= ~DCPU_RET_ERROR_BIT;
                ret = -ffs(resp);
        }

        return ret;
}

/* Ensure that the firmware file loaded meets all the requirements. */
static int __verify_firmware(struct init_data *init,
                             const struct firmware *fw)
{
        const struct dpfe_firmware_header *header = (void *)fw->data;
        unsigned int dmem_size, imem_size, total_size;
        bool is_big_endian = false;
        const u32 *chksum_ptr;

        if (header->magic == DPFE_BE_MAGIC)
                is_big_endian = true;
        else if (header->magic != DPFE_LE_MAGIC)
                return ERR_INVALID_MAGIC;

        if (is_big_endian) {
                dmem_size = be32_to_cpu(header->dmem_size);
                imem_size = be32_to_cpu(header->imem_size);
        } else {
                dmem_size = le32_to_cpu(header->dmem_size);
                imem_size = le32_to_cpu(header->imem_size);
        }

        /* Data and instruction sections are 32 bit words. */
        if ((dmem_size % sizeof(u32)) != 0 || (imem_size % sizeof(u32)) != 0)
                return ERR_INVALID_SIZE;

        /*
         * The header + the data section + the instruction section + the
         * checksum must be equal to the total firmware size.
         */
        total_size = dmem_size + imem_size + sizeof(*header) +
                sizeof(*chksum_ptr);
        if (total_size != fw->size)
                return ERR_INVALID_SIZE;

        /* The checksum comes at the very end. */
        chksum_ptr = (void *)fw->data + sizeof(*header) + dmem_size + imem_size;

        init->is_big_endian = is_big_endian;
        init->dmem_len = dmem_size;
        init->imem_len = imem_size;
        init->chksum = (is_big_endian)
                ? be32_to_cpu(*chksum_ptr) : le32_to_cpu(*chksum_ptr);

        return 0;
}

/* Verify checksum by reading back the firmware from co-processor RAM. */
static int __verify_fw_checksum(struct init_data *init,
                                struct brcmstb_dpfe_priv *priv,
                                const struct dpfe_firmware_header *header,
                                u32 checksum)
{
        u32 magic, sequence, version, sum;
        u32 __iomem *dmem = priv->dmem;
        u32 __iomem *imem = priv->imem;
        unsigned int i;

        if (init->is_big_endian) {
                magic = be32_to_cpu(header->magic);
                sequence = be32_to_cpu(header->sequence);
                version = be32_to_cpu(header->version);
        } else {
                magic = le32_to_cpu(header->magic);
                sequence = le32_to_cpu(header->sequence);
                version = le32_to_cpu(header->version);
        }

        sum = magic + sequence + version + init->dmem_len + init->imem_len;

        for (i = 0; i < init->dmem_len / sizeof(u32); i++)
                sum += readl_relaxed(dmem + i);

        for (i = 0; i < init->imem_len / sizeof(u32); i++)
                sum += readl_relaxed(imem + i);

        return (sum == checksum) ? 0 : -1;
}

static int __write_firmware(u32 __iomem *mem, const u32 *fw,
                            unsigned int size, bool is_big_endian)
{
        unsigned int i;

        /* Convert size to 32-bit words. */
        size /= sizeof(u32);

        /* It is recommended to clear the firmware area first. */
        for (i = 0; i < size; i++)
                writel_relaxed(0, mem + i);

        /* Now copy it. */
        if (is_big_endian) {
                for (i = 0; i < size; i++)
                        writel_relaxed(be32_to_cpu(fw[i]), mem + i);
        } else {
                for (i = 0; i < size; i++)
                        writel_relaxed(le32_to_cpu(fw[i]), mem + i);
        }

        return 0;
}

static int brcmstb_dpfe_download_firmware(struct brcmstb_dpfe_priv *priv)
{
        const struct dpfe_firmware_header *header;
        unsigned int dmem_size, imem_size;
        struct device *dev = priv->dev;
        bool is_big_endian = false;
        const struct firmware *fw;
        const u32 *dmem, *imem;
        struct init_data init;
        const void *fw_blob;
        int ret;

        /*
         * Skip downloading the firmware if the DCPU is already running and
         * responding to commands.
         */
        if (is_dcpu_enabled(priv)) {
                u32 response[MSG_FIELD_MAX];

                ret = __send_command(priv, DPFE_CMD_GET_INFO, response);
                if (!ret)
                        return 0;
        }

        /*
         * If the firmware filename is NULL it means the boot firmware has to
         * download the DCPU firmware for us. If that didn't work, we have to
         * bail, since downloading it ourselves wouldn't work either.
         */
        if (!priv->dpfe_api->fw_name)
                return -ENODEV;

        ret = firmware_request_nowarn(&fw, priv->dpfe_api->fw_name, dev);
        /*
         * Defer the firmware download if the firmware file couldn't be found.
         * The root file system may not be available yet.
         */
        if (ret)
                return (ret == -ENOENT) ? -EPROBE_DEFER : ret;

        ret = __verify_firmware(&init, fw);
        if (ret) {
                ret = -EFAULT;
                goto release_fw;
        }

        __disable_dcpu(priv);

        is_big_endian = init.is_big_endian;
        dmem_size = init.dmem_len;
        imem_size = init.imem_len;

        /* At the beginning of the firmware blob is a header. */
        header = (struct dpfe_firmware_header *)fw->data;
        /* Void pointer to the beginning of the actual firmware. */
        fw_blob = fw->data + sizeof(*header);
        /* IMEM comes right after the header. */
        imem = fw_blob;
        /* DMEM follows after IMEM. */
        dmem = fw_blob + imem_size;

        ret = __write_firmware(priv->dmem, dmem, dmem_size, is_big_endian);
        if (ret)
                goto release_fw;
        ret = __write_firmware(priv->imem, imem, imem_size, is_big_endian);
        if (ret)
                goto release_fw;

        ret = __verify_fw_checksum(&init, priv, header, init.chksum);
        if (ret)
                goto release_fw;

        __enable_dcpu(priv);

release_fw:
        release_firmware(fw);
        return ret;
}

static ssize_t generic_show(unsigned int command, u32 response[],
                            struct brcmstb_dpfe_priv *priv, char *buf)
{
        int ret;

        if (!priv)
                return sprintf(buf, "ERROR: driver private data not set\n");

        ret = __send_command(priv, command, response);
        if (ret < 0)
                return sprintf(buf, "ERROR: %s\n", get_error_text(-ret));

        return 0;
}

static ssize_t show_info(struct device *dev, struct device_attribute *devattr,
                         char *buf)
{
        u32 response[MSG_FIELD_MAX];
        struct brcmstb_dpfe_priv *priv;
        unsigned int info;
        ssize_t ret;

        priv = dev_get_drvdata(dev);
        ret = generic_show(DPFE_CMD_GET_INFO, response, priv, buf);
        if (ret)
                return ret;

        info = response[MSG_ARG0];

        return sprintf(buf, "%u.%u.%u.%u\n",
                       (info >> 24) & 0xff,
                       (info >> 16) & 0xff,
                       (info >> 8) & 0xff,
                       info & 0xff);
}

static ssize_t show_refresh(struct device *dev,
                            struct device_attribute *devattr, char *buf)
{
        u32 response[MSG_FIELD_MAX];
        void __iomem *info;
        struct brcmstb_dpfe_priv *priv;
        u8 refresh, sr_abort, ppre, thermal_offs, tuf;
        u32 mr4;
        ssize_t ret;

        priv = dev_get_drvdata(dev);
        ret = generic_show(DPFE_CMD_GET_REFRESH, response, priv, buf);
        if (ret)
                return ret;

        info = get_msg_ptr(priv, response[MSG_ARG0], buf, &ret);
        if (!info)
                return ret;

        mr4 = (readl_relaxed(info + DRAM_INFO_MR4) >> DRAM_INFO_MR4_SHIFT) &
               DRAM_INFO_MR4_MASK;

        refresh = (mr4 >> DRAM_MR4_REFRESH) & DRAM_MR4_REFRESH_MASK;
        sr_abort = (mr4 >> DRAM_MR4_SR_ABORT) & DRAM_MR4_SR_ABORT_MASK;
        ppre = (mr4 >> DRAM_MR4_PPRE) & DRAM_MR4_PPRE_MASK;
        thermal_offs = (mr4 >> DRAM_MR4_TH_OFFS) & DRAM_MR4_TH_OFFS_MASK;
        tuf = (mr4 >> DRAM_MR4_TUF) & DRAM_MR4_TUF_MASK;

        return sprintf(buf, "%#x %#x %#x %#x %#x %#x %#x\n",
                       readl_relaxed(info + DRAM_INFO_INTERVAL),
                       refresh, sr_abort, ppre, thermal_offs, tuf,
                       readl_relaxed(info + DRAM_INFO_ERROR));
}

static ssize_t store_refresh(struct device *dev, struct device_attribute *attr,
                          const char *buf, size_t count)
{
        u32 response[MSG_FIELD_MAX];
        struct brcmstb_dpfe_priv *priv;
        void __iomem *info;
        unsigned long val;
        int ret;

        if (kstrtoul(buf, 0, &val) < 0)
                return -EINVAL;

        priv = dev_get_drvdata(dev);
        ret = __send_command(priv, DPFE_CMD_GET_REFRESH, response);
        if (ret)
                return ret;

        info = get_msg_ptr(priv, response[MSG_ARG0], NULL, NULL);
        if (!info)
                return -EIO;

        writel_relaxed(val, info + DRAM_INFO_INTERVAL);

        return count;
}

static ssize_t show_vendor(struct device *dev, struct device_attribute *devattr,
                           char *buf)
{
        u32 response[MSG_FIELD_MAX];
        struct brcmstb_dpfe_priv *priv;
        void __iomem *info;
        ssize_t ret;
        u32 mr5, mr6, mr7, mr8, err;

        priv = dev_get_drvdata(dev);
        ret = generic_show(DPFE_CMD_GET_VENDOR, response, priv, buf);
        if (ret)
                return ret;

        info = get_msg_ptr(priv, response[MSG_ARG0], buf, &ret);
        if (!info)
                return ret;

        mr5 = (readl_relaxed(info + DRAM_VENDOR_MR5) >> DRAM_VENDOR_SHIFT) &
                DRAM_VENDOR_MASK;
        mr6 = (readl_relaxed(info + DRAM_VENDOR_MR6) >> DRAM_VENDOR_SHIFT) &
                DRAM_VENDOR_MASK;
        mr7 = (readl_relaxed(info + DRAM_VENDOR_MR7) >> DRAM_VENDOR_SHIFT) &
                DRAM_VENDOR_MASK;
        mr8 = (readl_relaxed(info + DRAM_VENDOR_MR8) >> DRAM_VENDOR_SHIFT) &
                DRAM_VENDOR_MASK;
        err = readl_relaxed(info + DRAM_VENDOR_ERROR) & DRAM_VENDOR_MASK;

        return sprintf(buf, "%#x %#x %#x %#x %#x\n", mr5, mr6, mr7, mr8, err);
}

static ssize_t show_dram(struct device *dev, struct device_attribute *devattr,
                         char *buf)
{
        u32 response[MSG_FIELD_MAX];
        struct brcmstb_dpfe_priv *priv;
        ssize_t ret;
        u32 mr4, mr5, mr6, mr7, mr8, err;

        priv = dev_get_drvdata(dev);
        ret = generic_show(DPFE_CMD_GET_REFRESH, response, priv, buf);
        if (ret)
                return ret;

        mr4 = response[MSG_ARG0 + 0] & DRAM_INFO_MR4_MASK;
        mr5 = response[MSG_ARG0 + 1] & DRAM_DDR_INFO_MASK;
        mr6 = response[MSG_ARG0 + 2] & DRAM_DDR_INFO_MASK;
        mr7 = response[MSG_ARG0 + 3] & DRAM_DDR_INFO_MASK;
        mr8 = response[MSG_ARG0 + 4] & DRAM_DDR_INFO_MASK;
        err = response[MSG_ARG0 + 5] & DRAM_DDR_INFO_MASK;

        return sprintf(buf, "%#x %#x %#x %#x %#x %#x\n", mr4, mr5, mr6, mr7,
                        mr8, err);
}

static int brcmstb_dpfe_resume(struct platform_device *pdev)
{
        struct brcmstb_dpfe_priv *priv = platform_get_drvdata(pdev);

        return brcmstb_dpfe_download_firmware(priv);
}

static int brcmstb_dpfe_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct brcmstb_dpfe_priv *priv;
        struct resource *res;
        int ret;

        priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        priv->dev = dev;

        mutex_init(&priv->lock);
        platform_set_drvdata(pdev, priv);

        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dpfe-cpu");
        priv->regs = devm_ioremap_resource(dev, res);
        if (IS_ERR(priv->regs)) {
                dev_err(dev, "couldn't map DCPU registers\n");
                return -ENODEV;
        }

        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dpfe-dmem");
        priv->dmem = devm_ioremap_resource(dev, res);
        if (IS_ERR(priv->dmem)) {
                dev_err(dev, "Couldn't map DCPU data memory\n");
                return -ENOENT;
        }

        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dpfe-imem");
        priv->imem = devm_ioremap_resource(dev, res);
        if (IS_ERR(priv->imem)) {
                dev_err(dev, "Couldn't map DCPU instruction memory\n");
                return -ENOENT;
        }

        priv->dpfe_api = of_device_get_match_data(dev);
        if (unlikely(!priv->dpfe_api)) {
                /*
                 * It should be impossible to end up here, but to be safe we
                 * check anyway.
                 */
                dev_err(dev, "Couldn't determine API\n");
                return -ENOENT;
        }

        ret = brcmstb_dpfe_download_firmware(priv);
        if (ret)
                return dev_err_probe(dev, ret, "Couldn't download firmware\n");

        ret = sysfs_create_groups(&pdev->dev.kobj, priv->dpfe_api->sysfs_attrs);
        if (!ret)
                dev_info(dev, "registered with API v%d.\n",
                         priv->dpfe_api->version);

        return ret;
}

static int brcmstb_dpfe_remove(struct platform_device *pdev)
{
        struct brcmstb_dpfe_priv *priv = dev_get_drvdata(&pdev->dev);

        sysfs_remove_groups(&pdev->dev.kobj, priv->dpfe_api->sysfs_attrs);

        return 0;
}

static const struct of_device_id brcmstb_dpfe_of_match[] = {
        /* Use legacy API v2 for a select number of chips */
        { .compatible = "brcm,bcm7268-dpfe-cpu", .data = &dpfe_api_old_v2 },
        { .compatible = "brcm,bcm7271-dpfe-cpu", .data = &dpfe_api_old_v2 },
        { .compatible = "brcm,bcm7278-dpfe-cpu", .data = &dpfe_api_old_v2 },
        { .compatible = "brcm,bcm7211-dpfe-cpu", .data = &dpfe_api_new_v2 },
        /* API v3 is the default going forward */
        { .compatible = "brcm,dpfe-cpu", .data = &dpfe_api_v3 },
        {}
};
MODULE_DEVICE_TABLE(of, brcmstb_dpfe_of_match);

static struct platform_driver brcmstb_dpfe_driver = {
        .driver = {
                .name = DRVNAME,
                .of_match_table = brcmstb_dpfe_of_match,
        },
        .probe = brcmstb_dpfe_probe,
        .remove = brcmstb_dpfe_remove,
        .resume = brcmstb_dpfe_resume,
};

module_platform_driver(brcmstb_dpfe_driver);

MODULE_AUTHOR("Markus Mayer <mmayer@broadcom.com>");
MODULE_DESCRIPTION("BRCMSTB DDR PHY Front End Driver");
MODULE_LICENSE("GPL");