// SPDX-License-Identifier: GPL-2.0
/*
 * ISH-TP client driver for ISH firmware loading
 *
 * Copyright (c) 2019, Intel Corporation.
 */

#include <linux/firmware.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/intel-ish-client-if.h>
#include <linux/property.h>
#include <asm/cacheflush.h>

/* Number of times we attempt to load the firmware before giving up */
#define MAX_LOAD_ATTEMPTS                       3

/* ISH TX/RX ring buffer pool size */
#define LOADER_CL_RX_RING_SIZE                  1
#define LOADER_CL_TX_RING_SIZE                  1

/*
 * ISH Shim firmware loader reserves 4 Kb buffer in SRAM. The buffer is
 * used to temporarily hold the data transferred from host to Shim
 * firmware loader. Reason for the odd size of 3968 bytes? Each IPC
 * transfer is 128 bytes (= 4 bytes header + 124 bytes payload). So the
 * 4 Kb buffer can hold maximum of 32 IPC transfers, which means we can
 * have a max payload of 3968 bytes (= 32 x 124 payload).
 */
#define LOADER_SHIM_IPC_BUF_SIZE                3968

/**
 * enum ish_loader_commands -   ISH loader host commands.
 * @LOADER_CMD_XFER_QUERY:      Query the Shim firmware loader for
 *                              capabilities
 * @LOADER_CMD_XFER_FRAGMENT:   Transfer one firmware image fragment at a
 *                              time. The command may be executed
 *                              multiple times until the entire firmware
 *                              image is downloaded to SRAM.
 * @LOADER_CMD_START:           Start executing the main firmware.
 */
enum ish_loader_commands {
        LOADER_CMD_XFER_QUERY = 0,
        LOADER_CMD_XFER_FRAGMENT,
        LOADER_CMD_START,
};

/* Command bit mask */
#define CMD_MASK                                GENMASK(6, 0)
#define IS_RESPONSE                             BIT(7)

/*
 * ISH firmware max delay for one transmit failure is 1 Hz,
 * and firmware will retry 2 times, so 3 Hz is used for timeout.
 */
#define ISHTP_SEND_TIMEOUT                      (3 * HZ)

/*
 * Loader transfer modes:
 *
 * LOADER_XFER_MODE_ISHTP mode uses the existing ISH-TP mechanism to
 * transfer data. This may use IPC or DMA if supported in firmware.
 * The buffer size is limited to 4 Kb by the IPC/ISH-TP protocol for
 * both IPC & DMA (legacy).
 *
 * LOADER_XFER_MODE_DIRECT_DMA - firmware loading is a bit different
 * from the sensor data streaming. Here we download a large (300+ Kb)
 * image directly to ISH SRAM memory. There is limited benefit of
 * DMA'ing 300 Kb image in 4 Kb chucks limit. Hence, we introduce
 * this "direct dma" mode, where we do not use ISH-TP for DMA, but
 * instead manage the DMA directly in kernel driver and Shim firmware
 * loader (allocate buffer, break in chucks and transfer). This allows
 * to overcome 4 Kb limit, and optimize the data flow path in firmware.
 */
#define LOADER_XFER_MODE_DIRECT_DMA             BIT(0)
#define LOADER_XFER_MODE_ISHTP                  BIT(1)

/* ISH Transport Loader client unique GUID */
static const guid_t loader_ishtp_guid =
        GUID_INIT(0xc804d06a, 0x55bd, 0x4ea7,
                  0xad, 0xed, 0x1e, 0x31, 0x22, 0x8c, 0x76, 0xdc);

#define FILENAME_SIZE                           256

/*
 * The firmware loading latency will be minimum if we can DMA the
 * entire ISH firmware image in one go. This requires that we allocate
 * a large DMA buffer in kernel, which could be problematic on some
 * platforms. So here we limit the DMA buffer size via a module_param.
 * We default to 4 pages, but a customer can set it to higher limit if
 * deemed appropriate for his platform.
 */
static int dma_buf_size_limit = 4 * PAGE_SIZE;

/**
 * struct loader_msg_hdr - Header for ISH Loader commands.
 * @command:            LOADER_CMD* commands. Bit 7 is the response.
 * @reserved:           Reserved space
 * @status:             Command response status. Non 0, is error
 *                      condition.
 *
 * This structure is used as header for every command/data sent/received
 * between Host driver and ISH Shim firmware loader.
 */
struct loader_msg_hdr {
        u8 command;
        u8 reserved[2];
        u8 status;
} __packed;

struct loader_xfer_query {
        struct loader_msg_hdr hdr;
        u32 image_size;
} __packed;

struct ish_fw_version {
        u16 major;
        u16 minor;
        u16 hotfix;
        u16 build;
} __packed;

union loader_version {
        u32 value;
        struct {
                u8 major;
                u8 minor;
                u8 hotfix;
                u8 build;
        };
} __packed;

struct loader_capability {
        u32 max_fw_image_size;
        u32 xfer_mode;
        u32 max_dma_buf_size; /* only for dma mode, multiples of cacheline */
} __packed;

struct shim_fw_info {
        struct ish_fw_version ish_fw_version;
        u32 protocol_version;
        union loader_version ldr_version;
        struct loader_capability ldr_capability;
} __packed;

struct loader_xfer_query_response {
        struct loader_msg_hdr hdr;
        struct shim_fw_info fw_info;
} __packed;

struct loader_xfer_fragment {
        struct loader_msg_hdr hdr;
        u32 xfer_mode;
        u32 offset;
        u32 size;
        u32 is_last;
} __packed;

struct loader_xfer_ipc_fragment {
        struct loader_xfer_fragment fragment;
        u8 data[] ____cacheline_aligned; /* variable length payload here */
} __packed;

struct loader_xfer_dma_fragment {
        struct loader_xfer_fragment fragment;
        u64 ddr_phys_addr;
} __packed;

struct loader_start {
        struct loader_msg_hdr hdr;
} __packed;

/**
 * struct response_info - Encapsulate firmware response related
 *                      information for passing between function
 *                      loader_cl_send() and process_recv() callback.
 * @data:               Copy the data received from firmware here.
 * @max_size:           Max size allocated for the @data buffer. If the
 *                      received data exceeds this value, we log an
 *                      error.
 * @size:               Actual size of data received from firmware.
 * @error:              Returns 0 for success, negative error code for a
 *                      failure in function process_recv().
 * @received:           Set to true on receiving a valid firmware
 *                      response to host command
 * @wait_queue:         Wait queue for Host firmware loading where the
 *                      client sends message to ISH firmware and waits
 *                      for response
 */
struct response_info {
        void *data;
        size_t max_size;
        size_t size;
        int error;
        bool received;
        wait_queue_head_t wait_queue;
};

/*
 * struct ishtp_cl_data - Encapsulate per ISH-TP Client Data.
 * @work_ishtp_reset:   Work queue for reset handling.
 * @work_fw_load:       Work queue for host firmware loading.
 * @flag_retry:         Flag for indicating host firmware loading should
 *                      be retried.
 * @retry_count:        Count the number of retries.
 *
 * This structure is used to store data per client.
 */
struct ishtp_cl_data {
        struct ishtp_cl *loader_ishtp_cl;
        struct ishtp_cl_device *cl_device;

        /*
         * Used for passing firmware response information between
         * loader_cl_send() and process_recv() callback.
         */
        struct response_info response;

        struct work_struct work_ishtp_reset;
        struct work_struct work_fw_load;

        /*
         * In certain failure scenrios, it makes sense to reset the ISH
         * subsystem and retry Host firmware loading (e.g. bad message
         * packet, ENOMEM, etc.). On the other hand, failures due to
         * protocol mismatch, etc., are not recoverable. We do not
         * retry them.
         *
         * If set, the flag indicates that we should re-try the
         * particular failure.
         */
        bool flag_retry;
        int retry_count;
};

#define IPC_FRAGMENT_DATA_PREAMBLE                              \
        offsetof(struct loader_xfer_ipc_fragment, data)

#define cl_data_to_dev(client_data) ishtp_device((client_data)->cl_device)

/**
 * get_firmware_variant() - Gets the filename of firmware image to be
 *                      loaded based on platform variant.
 * @client_data:        Client data instance.
 * @filename:           Returns firmware filename.
 *
 * Queries the firmware-name device property string.
 *
 * Return: 0 for success, negative error code for failure.
 */
static int get_firmware_variant(struct ishtp_cl_data *client_data,
                                char *filename)
{
        int rv;
        const char *val;
        struct device *devc = ishtp_get_pci_device(client_data->cl_device);

        rv = device_property_read_string(devc, "firmware-name", &val);
        if (rv < 0) {
                dev_err(devc,
                        "Error: ISH firmware-name device property required\n");
                return rv;
        }
        return snprintf(filename, FILENAME_SIZE, "intel/%s", val);
}

/**
 * loader_cl_send()     Send message from host to firmware
 * @client_data:        Client data instance
 * @out_msg:            Message buffer to be sent to firmware
 * @out_size:           Size of out going message
 * @in_msg:             Message buffer where the incoming data copied.
 *                      This buffer is allocated by calling
 * @in_size:            Max size of incoming message
 *
 * Return: Number of bytes copied in the in_msg on success, negative
 * error code on failure.
 */
static int loader_cl_send(struct ishtp_cl_data *client_data,
                          u8 *out_msg, size_t out_size,
                          u8 *in_msg, size_t in_size)
{
        int rv;
        struct loader_msg_hdr *out_hdr = (struct loader_msg_hdr *)out_msg;
        struct ishtp_cl *loader_ishtp_cl = client_data->loader_ishtp_cl;

        dev_dbg(cl_data_to_dev(client_data),
                "%s: command=%02lx is_response=%u status=%02x\n",
                __func__,
                out_hdr->command & CMD_MASK,
                out_hdr->command & IS_RESPONSE ? 1 : 0,
                out_hdr->status);

        /* Setup in coming buffer & size */
        client_data->response.data = in_msg;
        client_data->response.max_size = in_size;
        client_data->response.error = 0;
        client_data->response.received = false;

        rv = ishtp_cl_send(loader_ishtp_cl, out_msg, out_size);
        if (rv < 0) {
                dev_err(cl_data_to_dev(client_data),
                        "ishtp_cl_send error %d\n", rv);
                return rv;
        }

        wait_event_interruptible_timeout(client_data->response.wait_queue,
                                         client_data->response.received,
                                         ISHTP_SEND_TIMEOUT);
        if (!client_data->response.received) {
                dev_err(cl_data_to_dev(client_data),
                        "Timed out for response to command=%02lx",
                        out_hdr->command & CMD_MASK);
                return -ETIMEDOUT;
        }

        if (client_data->response.error < 0)
                return client_data->response.error;

        return client_data->response.size;
}

/**
 * process_recv() -     Receive and parse incoming packet
 * @loader_ishtp_cl:    Client instance to get stats
 * @rb_in_proc:         ISH received message buffer
 *
 * Parse the incoming packet. If it is a response packet then it will
 * update received and wake up the caller waiting to for the response.
 */
static void process_recv(struct ishtp_cl *loader_ishtp_cl,
                         struct ishtp_cl_rb *rb_in_proc)
{
        struct loader_msg_hdr *hdr;
        size_t data_len = rb_in_proc->buf_idx;
        struct ishtp_cl_data *client_data =
                ishtp_get_client_data(loader_ishtp_cl);

        /* Sanity check */
        if (!client_data->response.data) {
                dev_err(cl_data_to_dev(client_data),
                        "Receiving buffer is null. Should be allocated by calling function\n");
                client_data->response.error = -EINVAL;
                goto end;
        }

        if (client_data->response.received) {
                dev_err(cl_data_to_dev(client_data),
                        "Previous firmware message not yet processed\n");
                client_data->response.error = -EINVAL;
                goto end;
        }
        /*
         * All firmware messages have a header. Check buffer size
         * before accessing elements inside.
         */
        if (!rb_in_proc->buffer.data) {
                dev_warn(cl_data_to_dev(client_data),
                         "rb_in_proc->buffer.data returned null");
                client_data->response.error = -EBADMSG;
                goto end;
        }

        if (data_len < sizeof(struct loader_msg_hdr)) {
                dev_err(cl_data_to_dev(client_data),
                        "data size %zu is less than header %zu\n",
                        data_len, sizeof(struct loader_msg_hdr));
                client_data->response.error = -EMSGSIZE;
                goto end;
        }

        hdr = (struct loader_msg_hdr *)rb_in_proc->buffer.data;

        dev_dbg(cl_data_to_dev(client_data),
                "%s: command=%02lx is_response=%u status=%02x\n",
                __func__,
                hdr->command & CMD_MASK,
                hdr->command & IS_RESPONSE ? 1 : 0,
                hdr->status);

        if (((hdr->command & CMD_MASK) != LOADER_CMD_XFER_QUERY) &&
            ((hdr->command & CMD_MASK) != LOADER_CMD_XFER_FRAGMENT) &&
            ((hdr->command & CMD_MASK) != LOADER_CMD_START)) {
                dev_err(cl_data_to_dev(client_data),
                        "Invalid command=%02lx\n",
                        hdr->command & CMD_MASK);
                client_data->response.error = -EPROTO;
                goto end;
        }

        if (data_len > client_data->response.max_size) {
                dev_err(cl_data_to_dev(client_data),
                        "Received buffer size %zu is larger than allocated buffer %zu\n",
                        data_len, client_data->response.max_size);
                client_data->response.error = -EMSGSIZE;
                goto end;
        }

        /* We expect only "response" messages from firmware */
        if (!(hdr->command & IS_RESPONSE)) {
                dev_err(cl_data_to_dev(client_data),
                        "Invalid response to command\n");
                client_data->response.error = -EIO;
                goto end;
        }

        if (hdr->status) {
                dev_err(cl_data_to_dev(client_data),
                        "Loader returned status %d\n",
                        hdr->status);
                client_data->response.error = -EIO;
                goto end;
        }

        /* Update the actual received buffer size */
        client_data->response.size = data_len;

        /*
         * Copy the buffer received in firmware response for the
         * calling thread.
         */
        memcpy(client_data->response.data,
               rb_in_proc->buffer.data, data_len);

        /* Set flag before waking up the caller */
        client_data->response.received = true;

end:
        /* Free the buffer */
        ishtp_cl_io_rb_recycle(rb_in_proc);
        rb_in_proc = NULL;

        /* Wake the calling thread */
        wake_up_interruptible(&client_data->response.wait_queue);
}

/**
 * loader_cl_event_cb() - bus driver callback for incoming message
 * @cl_device:          Pointer to the ishtp client device for which this
 *                      message is targeted
 *
 * Remove the packet from the list and process the message by calling
 * process_recv
 */
static void loader_cl_event_cb(struct ishtp_cl_device *cl_device)
{
        struct ishtp_cl_rb *rb_in_proc;
        struct ishtp_cl *loader_ishtp_cl = ishtp_get_drvdata(cl_device);

        while ((rb_in_proc = ishtp_cl_rx_get_rb(loader_ishtp_cl)) != NULL) {
                /* Process the data packet from firmware */
                process_recv(loader_ishtp_cl, rb_in_proc);
        }
}

/**
 * ish_query_loader_prop() -  Query ISH Shim firmware loader
 * @client_data:        Client data instance
 * @fw:                 Pointer to firmware data struct in host memory
 * @fw_info:            Loader firmware properties
 *
 * This function queries the ISH Shim firmware loader for capabilities.
 *
 * Return: 0 for success, negative error code for failure.
 */
static int ish_query_loader_prop(struct ishtp_cl_data *client_data,
                                 const struct firmware *fw,
                                 struct shim_fw_info *fw_info)
{
        int rv;
        struct loader_xfer_query ldr_xfer_query;
        struct loader_xfer_query_response ldr_xfer_query_resp;

        memset(&ldr_xfer_query, 0, sizeof(ldr_xfer_query));
        ldr_xfer_query.hdr.command = LOADER_CMD_XFER_QUERY;
        ldr_xfer_query.image_size = fw->size;
        rv = loader_cl_send(client_data,
                            (u8 *)&ldr_xfer_query,
                            sizeof(ldr_xfer_query),
                            (u8 *)&ldr_xfer_query_resp,
                            sizeof(ldr_xfer_query_resp));
        if (rv < 0) {
                client_data->flag_retry = true;
                *fw_info = (struct shim_fw_info){};
                return rv;
        }

        /* On success, the return value is the received buffer size */
        if (rv != sizeof(struct loader_xfer_query_response)) {
                dev_err(cl_data_to_dev(client_data),
                        "data size %d is not equal to size of loader_xfer_query_response %zu\n",
                        rv, sizeof(struct loader_xfer_query_response));
                client_data->flag_retry = true;
                *fw_info = (struct shim_fw_info){};
                return -EMSGSIZE;
        }

        /* Save fw_info for use outside this function */
        *fw_info = ldr_xfer_query_resp.fw_info;

        /* Loader firmware properties */
        dev_dbg(cl_data_to_dev(client_data),
                "ish_fw_version: major=%d minor=%d hotfix=%d build=%d protocol_version=0x%x loader_version=%d\n",
                fw_info->ish_fw_version.major,
                fw_info->ish_fw_version.minor,
                fw_info->ish_fw_version.hotfix,
                fw_info->ish_fw_version.build,
                fw_info->protocol_version,
                fw_info->ldr_version.value);

        dev_dbg(cl_data_to_dev(client_data),
                "loader_capability: max_fw_image_size=0x%x xfer_mode=%d max_dma_buf_size=0x%x dma_buf_size_limit=0x%x\n",
                fw_info->ldr_capability.max_fw_image_size,
                fw_info->ldr_capability.xfer_mode,
                fw_info->ldr_capability.max_dma_buf_size,
                dma_buf_size_limit);

        /* Sanity checks */
        if (fw_info->ldr_capability.max_fw_image_size < fw->size) {
                dev_err(cl_data_to_dev(client_data),
                        "ISH firmware size %zu is greater than Shim firmware loader max supported %d\n",
                        fw->size,
                        fw_info->ldr_capability.max_fw_image_size);
                return -ENOSPC;
        }

        /* For DMA the buffer size should be multiple of cacheline size */
        if ((fw_info->ldr_capability.xfer_mode & LOADER_XFER_MODE_DIRECT_DMA) &&
            (fw_info->ldr_capability.max_dma_buf_size % L1_CACHE_BYTES)) {
                dev_err(cl_data_to_dev(client_data),
                        "Shim firmware loader buffer size %d should be multiple of cacheline\n",
                        fw_info->ldr_capability.max_dma_buf_size);
                return -EINVAL;
        }

        return 0;
}

/**
 * ish_fw_xfer_ishtp() - Loads ISH firmware using ishtp interface
 * @client_data:        Client data instance
 * @fw:                 Pointer to firmware data struct in host memory
 *
 * This function uses ISH-TP to transfer ISH firmware from host to
 * ISH SRAM. Lower layers may use IPC or DMA depending on firmware
 * support.
 *
 * Return: 0 for success, negative error code for failure.
 */
static int ish_fw_xfer_ishtp(struct ishtp_cl_data *client_data,
                             const struct firmware *fw)
{
        int rv;
        u32 fragment_offset, fragment_size, payload_max_size;
        struct loader_xfer_ipc_fragment *ldr_xfer_ipc_frag;
        struct loader_msg_hdr ldr_xfer_ipc_ack;

        payload_max_size =
                LOADER_SHIM_IPC_BUF_SIZE - IPC_FRAGMENT_DATA_PREAMBLE;

        ldr_xfer_ipc_frag = kzalloc(LOADER_SHIM_IPC_BUF_SIZE, GFP_KERNEL);
        if (!ldr_xfer_ipc_frag) {
                client_data->flag_retry = true;
                return -ENOMEM;
        }

        ldr_xfer_ipc_frag->fragment.hdr.command = LOADER_CMD_XFER_FRAGMENT;
        ldr_xfer_ipc_frag->fragment.xfer_mode = LOADER_XFER_MODE_ISHTP;

        /* Break the firmware image into fragments and send as ISH-TP payload */
        fragment_offset = 0;
        while (fragment_offset < fw->size) {
                if (fragment_offset + payload_max_size < fw->size) {
                        fragment_size = payload_max_size;
                        ldr_xfer_ipc_frag->fragment.is_last = 0;
                } else {
                        fragment_size = fw->size - fragment_offset;
                        ldr_xfer_ipc_frag->fragment.is_last = 1;
                }

                ldr_xfer_ipc_frag->fragment.offset = fragment_offset;
                ldr_xfer_ipc_frag->fragment.size = fragment_size;
                memcpy(ldr_xfer_ipc_frag->data,
                       &fw->data[fragment_offset],
                       fragment_size);

                dev_dbg(cl_data_to_dev(client_data),
                        "xfer_mode=ipc offset=0x%08x size=0x%08x is_last=%d\n",
                        ldr_xfer_ipc_frag->fragment.offset,
                        ldr_xfer_ipc_frag->fragment.size,
                        ldr_xfer_ipc_frag->fragment.is_last);

                rv = loader_cl_send(client_data,
                                    (u8 *)ldr_xfer_ipc_frag,
                                    IPC_FRAGMENT_DATA_PREAMBLE + fragment_size,
                                    (u8 *)&ldr_xfer_ipc_ack,
                                    sizeof(ldr_xfer_ipc_ack));
                if (rv < 0) {
                        client_data->flag_retry = true;
                        goto end_err_resp_buf_release;
                }

                fragment_offset += fragment_size;
        }

        kfree(ldr_xfer_ipc_frag);
        return 0;

end_err_resp_buf_release:
        /* Free ISH buffer if not done already, in error case */
        kfree(ldr_xfer_ipc_frag);
        return rv;
}

/**
 * ish_fw_xfer_direct_dma() - Loads ISH firmware using direct dma
 * @client_data:        Client data instance
 * @fw:                 Pointer to firmware data struct in host memory
 * @fw_info:            Loader firmware properties
 *
 * Host firmware load is a unique case where we need to download
 * a large firmware image (200+ Kb). This function implements
 * direct DMA transfer in kernel and ISH firmware. This allows
 * us to overcome the ISH-TP 4 Kb limit, and allows us to DMA
 * directly to ISH UMA at location of choice.
 * Function depends on corresponding support in ISH firmware.
 *
 * Return: 0 for success, negative error code for failure.
 */
static int ish_fw_xfer_direct_dma(struct ishtp_cl_data *client_data,
                                  const struct firmware *fw,
                                  const struct shim_fw_info fw_info)
{
        int rv;
        void *dma_buf;
        dma_addr_t dma_buf_phy;
        u32 fragment_offset, fragment_size, payload_max_size;
        struct loader_msg_hdr ldr_xfer_dma_frag_ack;
        struct loader_xfer_dma_fragment ldr_xfer_dma_frag;
        struct device *devc = ishtp_get_pci_device(client_data->cl_device);
        u32 shim_fw_buf_size =
                fw_info.ldr_capability.max_dma_buf_size;

        /*
         * payload_max_size should be set to minimum of
         *  (1) Size of firmware to be loaded,
         *  (2) Max DMA buffer size supported by Shim firmware,
         *  (3) DMA buffer size limit set by boot_param dma_buf_size_limit.
         */
        payload_max_size = min3(fw->size,
                                (size_t)shim_fw_buf_size,
                                (size_t)dma_buf_size_limit);

        /*
         * Buffer size should be multiple of cacheline size
         * if it's not, select the previous cacheline boundary.
         */
        payload_max_size &= ~(L1_CACHE_BYTES - 1);

        dma_buf = kmalloc(payload_max_size, GFP_KERNEL | GFP_DMA32);
        if (!dma_buf) {
                client_data->flag_retry = true;
                return -ENOMEM;
        }

        dma_buf_phy = dma_map_single(devc, dma_buf, payload_max_size,
                                     DMA_TO_DEVICE);
        if (dma_mapping_error(devc, dma_buf_phy)) {
                dev_err(cl_data_to_dev(client_data), "DMA map failed\n");
                client_data->flag_retry = true;
                rv = -ENOMEM;
                goto end_err_dma_buf_release;
        }

        ldr_xfer_dma_frag.fragment.hdr.command = LOADER_CMD_XFER_FRAGMENT;
        ldr_xfer_dma_frag.fragment.xfer_mode = LOADER_XFER_MODE_DIRECT_DMA;
        ldr_xfer_dma_frag.ddr_phys_addr = (u64)dma_buf_phy;

        /* Send the firmware image in chucks of payload_max_size */
        fragment_offset = 0;
        while (fragment_offset < fw->size) {
                if (fragment_offset + payload_max_size < fw->size) {
                        fragment_size = payload_max_size;
                        ldr_xfer_dma_frag.fragment.is_last = 0;
                } else {
                        fragment_size = fw->size - fragment_offset;
                        ldr_xfer_dma_frag.fragment.is_last = 1;
                }

                ldr_xfer_dma_frag.fragment.offset = fragment_offset;
                ldr_xfer_dma_frag.fragment.size = fragment_size;
                memcpy(dma_buf, &fw->data[fragment_offset], fragment_size);

                dma_sync_single_for_device(devc, dma_buf_phy,
                                           payload_max_size,
                                           DMA_TO_DEVICE);

                /*
                 * Flush cache here because the dma_sync_single_for_device()
                 * does not do for x86.
                 */
                clflush_cache_range(dma_buf, payload_max_size);

                dev_dbg(cl_data_to_dev(client_data),
                        "xfer_mode=dma offset=0x%08x size=0x%x is_last=%d ddr_phys_addr=0x%016llx\n",
                        ldr_xfer_dma_frag.fragment.offset,
                        ldr_xfer_dma_frag.fragment.size,
                        ldr_xfer_dma_frag.fragment.is_last,
                        ldr_xfer_dma_frag.ddr_phys_addr);

                rv = loader_cl_send(client_data,
                                    (u8 *)&ldr_xfer_dma_frag,
                                    sizeof(ldr_xfer_dma_frag),
                                    (u8 *)&ldr_xfer_dma_frag_ack,
                                    sizeof(ldr_xfer_dma_frag_ack));
                if (rv < 0) {
                        client_data->flag_retry = true;
                        goto end_err_resp_buf_release;
                }

                fragment_offset += fragment_size;
        }

        dma_unmap_single(devc, dma_buf_phy, payload_max_size, DMA_TO_DEVICE);
        kfree(dma_buf);
        return 0;

end_err_resp_buf_release:
        /* Free ISH buffer if not done already, in error case */
        dma_unmap_single(devc, dma_buf_phy, payload_max_size, DMA_TO_DEVICE);
end_err_dma_buf_release:
        kfree(dma_buf);
        return rv;
}

/**
 * ish_fw_start() -     Start executing ISH main firmware
 * @client_data:        client data instance
 *
 * This function sends message to Shim firmware loader to start
 * the execution of ISH main firmware.
 *
 * Return: 0 for success, negative error code for failure.
 */
static int ish_fw_start(struct ishtp_cl_data *client_data)
{
        struct loader_start ldr_start;
        struct loader_msg_hdr ldr_start_ack;

        memset(&ldr_start, 0, sizeof(ldr_start));
        ldr_start.hdr.command = LOADER_CMD_START;
        return loader_cl_send(client_data,
                            (u8 *)&ldr_start,
                            sizeof(ldr_start),
                            (u8 *)&ldr_start_ack,
                            sizeof(ldr_start_ack));
}

/**
 * load_fw_from_host() - Loads ISH firmware from host
 * @client_data:        Client data instance
 *
 * This function loads the ISH firmware to ISH SRAM and starts execution
 *
 * Return: 0 for success, negative error code for failure.
 */
static int load_fw_from_host(struct ishtp_cl_data *client_data)
{
        int rv;
        u32 xfer_mode;
        char *filename;
        const struct firmware *fw;
        struct shim_fw_info fw_info;
        struct ishtp_cl *loader_ishtp_cl = client_data->loader_ishtp_cl;

        client_data->flag_retry = false;

        filename = kzalloc(FILENAME_SIZE, GFP_KERNEL);
        if (!filename) {
                client_data->flag_retry = true;
                rv = -ENOMEM;
                goto end_error;
        }

        /* Get filename of the ISH firmware to be loaded */
        rv = get_firmware_variant(client_data, filename);
        if (rv < 0)
                goto end_err_filename_buf_release;

        rv = request_firmware(&fw, filename, cl_data_to_dev(client_data));
        if (rv < 0)
                goto end_err_filename_buf_release;

        /* Step 1: Query Shim firmware loader properties */

        rv = ish_query_loader_prop(client_data, fw, &fw_info);
        if (rv < 0)
                goto end_err_fw_release;

        /* Step 2: Send the main firmware image to be loaded, to ISH SRAM */

        xfer_mode = fw_info.ldr_capability.xfer_mode;
        if (xfer_mode & LOADER_XFER_MODE_DIRECT_DMA) {
                rv = ish_fw_xfer_direct_dma(client_data, fw, fw_info);
        } else if (xfer_mode & LOADER_XFER_MODE_ISHTP) {
                rv = ish_fw_xfer_ishtp(client_data, fw);
        } else {
                dev_err(cl_data_to_dev(client_data),
                        "No transfer mode selected in firmware\n");
                rv = -EINVAL;
        }
        if (rv < 0)
                goto end_err_fw_release;

        /* Step 3: Start ISH main firmware exeuction */

        rv = ish_fw_start(client_data);
        if (rv < 0)
                goto end_err_fw_release;

        release_firmware(fw);
        dev_info(cl_data_to_dev(client_data), "ISH firmware %s loaded\n",
                 filename);
        kfree(filename);
        return 0;

end_err_fw_release:
        release_firmware(fw);
end_err_filename_buf_release:
        kfree(filename);
end_error:
        /* Keep a count of retries, and give up after 3 attempts */
        if (client_data->flag_retry &&
            client_data->retry_count++ < MAX_LOAD_ATTEMPTS) {
                dev_warn(cl_data_to_dev(client_data),
                         "ISH host firmware load failed %d. Resetting ISH, and trying again..\n",
                         rv);
                ish_hw_reset(ishtp_get_ishtp_device(loader_ishtp_cl));
        } else {
                dev_err(cl_data_to_dev(client_data),
                        "ISH host firmware load failed %d\n", rv);
        }
        return rv;
}

static void load_fw_from_host_handler(struct work_struct *work)
{
        struct ishtp_cl_data *client_data;

        client_data = container_of(work, struct ishtp_cl_data,
                                   work_fw_load);
        load_fw_from_host(client_data);
}

/**
 * loader_init() -      Init function for ISH-TP client
 * @loader_ishtp_cl:    ISH-TP client instance
 * @reset:              true if called for init after reset
 *
 * Return: 0 for success, negative error code for failure
 */
static int loader_init(struct ishtp_cl *loader_ishtp_cl, int reset)
{
        int rv;
        struct ishtp_fw_client *fw_client;
        struct ishtp_cl_data *client_data =
                ishtp_get_client_data(loader_ishtp_cl);

        dev_dbg(cl_data_to_dev(client_data), "reset flag: %d\n", reset);

        rv = ishtp_cl_link(loader_ishtp_cl);
        if (rv < 0) {
                dev_err(cl_data_to_dev(client_data), "ishtp_cl_link failed\n");
                return rv;
        }

        /* Connect to firmware client */
        ishtp_set_tx_ring_size(loader_ishtp_cl, LOADER_CL_TX_RING_SIZE);
        ishtp_set_rx_ring_size(loader_ishtp_cl, LOADER_CL_RX_RING_SIZE);

        fw_client =
                ishtp_fw_cl_get_client(ishtp_get_ishtp_device(loader_ishtp_cl),
                                       &loader_ishtp_guid);
        if (!fw_client) {
                dev_err(cl_data_to_dev(client_data),
                        "ISH client uuid not found\n");
                rv = -ENOENT;
                goto err_cl_unlink;
        }

        ishtp_cl_set_fw_client_id(loader_ishtp_cl,
                                  ishtp_get_fw_client_id(fw_client));
        ishtp_set_connection_state(loader_ishtp_cl, ISHTP_CL_CONNECTING);

        rv = ishtp_cl_connect(loader_ishtp_cl);
        if (rv < 0) {
                dev_err(cl_data_to_dev(client_data), "Client connect fail\n");
                goto err_cl_unlink;
        }

        dev_dbg(cl_data_to_dev(client_data), "Client connected\n");

        ishtp_register_event_cb(client_data->cl_device, loader_cl_event_cb);

        return 0;

err_cl_unlink:
        ishtp_cl_unlink(loader_ishtp_cl);
        return rv;
}

static void loader_deinit(struct ishtp_cl *loader_ishtp_cl)
{
        ishtp_set_connection_state(loader_ishtp_cl, ISHTP_CL_DISCONNECTING);
        ishtp_cl_disconnect(loader_ishtp_cl);
        ishtp_cl_unlink(loader_ishtp_cl);
        ishtp_cl_flush_queues(loader_ishtp_cl);

        /* Disband and free all Tx and Rx client-level rings */
        ishtp_cl_free(loader_ishtp_cl);
}

static void reset_handler(struct work_struct *work)
{
        int rv;
        struct ishtp_cl_data *client_data;
        struct ishtp_cl *loader_ishtp_cl;
        struct ishtp_cl_device *cl_device;

        client_data = container_of(work, struct ishtp_cl_data,
                                   work_ishtp_reset);

        loader_ishtp_cl = client_data->loader_ishtp_cl;
        cl_device = client_data->cl_device;

        /* Unlink, flush queues & start again */
        ishtp_cl_unlink(loader_ishtp_cl);
        ishtp_cl_flush_queues(loader_ishtp_cl);
        ishtp_cl_free(loader_ishtp_cl);

        loader_ishtp_cl = ishtp_cl_allocate(cl_device);
        if (!loader_ishtp_cl)
                return;

        ishtp_set_drvdata(cl_device, loader_ishtp_cl);
        ishtp_set_client_data(loader_ishtp_cl, client_data);
        client_data->loader_ishtp_cl = loader_ishtp_cl;
        client_data->cl_device = cl_device;

        rv = loader_init(loader_ishtp_cl, 1);
        if (rv < 0) {
                dev_err(ishtp_device(cl_device), "Reset Failed\n");
                return;
        }

        /* ISH firmware loading from host */
        load_fw_from_host(client_data);
}

/**
 * loader_ishtp_cl_probe() - ISH-TP client driver probe
 * @cl_device:          ISH-TP client device instance
 *
 * This function gets called on device create on ISH-TP bus
 *
 * Return: 0 for success, negative error code for failure
 */
static int loader_ishtp_cl_probe(struct ishtp_cl_device *cl_device)
{
        struct ishtp_cl *loader_ishtp_cl;
        struct ishtp_cl_data *client_data;
        int rv;

        client_data = devm_kzalloc(ishtp_device(cl_device),
                                   sizeof(*client_data),
                                   GFP_KERNEL);
        if (!client_data)
                return -ENOMEM;

        loader_ishtp_cl = ishtp_cl_allocate(cl_device);
        if (!loader_ishtp_cl)
                return -ENOMEM;

        ishtp_set_drvdata(cl_device, loader_ishtp_cl);
        ishtp_set_client_data(loader_ishtp_cl, client_data);
        client_data->loader_ishtp_cl = loader_ishtp_cl;
        client_data->cl_device = cl_device;

        init_waitqueue_head(&client_data->response.wait_queue);

        INIT_WORK(&client_data->work_ishtp_reset,
                  reset_handler);
        INIT_WORK(&client_data->work_fw_load,
                  load_fw_from_host_handler);

        rv = loader_init(loader_ishtp_cl, 0);
        if (rv < 0) {
                ishtp_cl_free(loader_ishtp_cl);
                return rv;
        }

        ishtp_get_device(cl_device);

        client_data->retry_count = 0;

        /* ISH firmware loading from host */
        schedule_work(&client_data->work_fw_load);

        return 0;
}

/**
 * loader_ishtp_cl_remove() - ISH-TP client driver remove
 * @cl_device:          ISH-TP client device instance
 *
 * This function gets called on device remove on ISH-TP bus
 *
 * Return: 0
 */
static void loader_ishtp_cl_remove(struct ishtp_cl_device *cl_device)
{
        struct ishtp_cl_data *client_data;
        struct ishtp_cl *loader_ishtp_cl = ishtp_get_drvdata(cl_device);

        client_data = ishtp_get_client_data(loader_ishtp_cl);

        /*
         * The sequence of the following two cancel_work_sync() is
         * important. The work_fw_load can in turn schedue
         * work_ishtp_reset, so first cancel work_fw_load then
         * cancel work_ishtp_reset.
         */
        cancel_work_sync(&client_data->work_fw_load);
        cancel_work_sync(&client_data->work_ishtp_reset);
        loader_deinit(loader_ishtp_cl);
        ishtp_put_device(cl_device);
}

/**
 * loader_ishtp_cl_reset() - ISH-TP client driver reset
 * @cl_device:          ISH-TP client device instance
 *
 * This function gets called on device reset on ISH-TP bus
 *
 * Return: 0
 */
static int loader_ishtp_cl_reset(struct ishtp_cl_device *cl_device)
{
        struct ishtp_cl_data *client_data;
        struct ishtp_cl *loader_ishtp_cl = ishtp_get_drvdata(cl_device);

        client_data = ishtp_get_client_data(loader_ishtp_cl);

        schedule_work(&client_data->work_ishtp_reset);

        return 0;
}

static struct ishtp_cl_driver   loader_ishtp_cl_driver = {
        .name = "ish-loader",
        .guid = &loader_ishtp_guid,
        .probe = loader_ishtp_cl_probe,
        .remove = loader_ishtp_cl_remove,
        .reset = loader_ishtp_cl_reset,
};

static int __init ish_loader_init(void)
{
        return ishtp_cl_driver_register(&loader_ishtp_cl_driver, THIS_MODULE);
}

static void __exit ish_loader_exit(void)
{
        ishtp_cl_driver_unregister(&loader_ishtp_cl_driver);
}

late_initcall(ish_loader_init);
module_exit(ish_loader_exit);

module_param(dma_buf_size_limit, int, 0644);
MODULE_PARM_DESC(dma_buf_size_limit, "Limit the DMA buf size to this value in bytes");

MODULE_DESCRIPTION("ISH ISH-TP Host firmware Loader Client Driver");
MODULE_AUTHOR("Rushikesh S Kadam <rushikesh.s.kadam@intel.com>");

MODULE_LICENSE("GPL v2");
MODULE_ALIAS("ishtp:*");