// SPDX-License-Identifier: GPL-2.0
/*
 * NVM helpers
 *
 * Copyright (C) 2020, Intel Corporation
 * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
 */

#include <linux/idr.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>

#include "tb.h"

#define NVM_MIN_SIZE            SZ_32K
#define NVM_MAX_SIZE            SZ_1M
#define NVM_DATA_DWORDS         16

/* Intel specific NVM offsets */
#define INTEL_NVM_DEVID                 0x05
#define INTEL_NVM_VERSION               0x08
#define INTEL_NVM_CSS                   0x10
#define INTEL_NVM_FLASH_SIZE            0x45

/* ASMedia specific NVM offsets */
#define ASMEDIA_NVM_DATE                0x1c
#define ASMEDIA_NVM_VERSION             0x28

static DEFINE_IDA(nvm_ida);

/**
 * struct tb_nvm_vendor_ops - Vendor specific NVM operations
 * @read_version: Reads out NVM version from the flash
 * @validate: Validates the NVM image before update (optional)
 * @write_headers: Writes headers before the rest of the image (optional)
 */
struct tb_nvm_vendor_ops {
        int (*read_version)(struct tb_nvm *nvm);
        int (*validate)(struct tb_nvm *nvm);
        int (*write_headers)(struct tb_nvm *nvm);
};

/**
 * struct tb_nvm_vendor - Vendor to &struct tb_nvm_vendor_ops mapping
 * @vendor: Vendor ID
 * @vops: Vendor specific NVM operations
 *
 * Maps vendor ID to NVM vendor operations. If there is no mapping then
 * NVM firmware upgrade is disabled for the device.
 */
struct tb_nvm_vendor {
        u16 vendor;
        const struct tb_nvm_vendor_ops *vops;
};

static int intel_switch_nvm_version(struct tb_nvm *nvm)
{
        struct tb_switch *sw = tb_to_switch(nvm->dev);
        u32 val, nvm_size, hdr_size;
        int ret;

        /*
         * If the switch is in safe-mode the only accessible portion of
         * the NVM is the non-active one where userspace is expected to
         * write new functional NVM.
         */
        if (sw->safe_mode)
                return 0;

        ret = tb_switch_nvm_read(sw, INTEL_NVM_FLASH_SIZE, &val, sizeof(val));
        if (ret)
                return ret;

        hdr_size = sw->generation < 3 ? SZ_8K : SZ_16K;
        nvm_size = (SZ_1M << (val & 7)) / 8;
        nvm_size = (nvm_size - hdr_size) / 2;

        ret = tb_switch_nvm_read(sw, INTEL_NVM_VERSION, &val, sizeof(val));
        if (ret)
                return ret;

        nvm->major = (val >> 16) & 0xff;
        nvm->minor = (val >> 8) & 0xff;
        nvm->active_size = nvm_size;

        return 0;
}

static int intel_switch_nvm_validate(struct tb_nvm *nvm)
{
        struct tb_switch *sw = tb_to_switch(nvm->dev);
        unsigned int image_size, hdr_size;
        u16 ds_size, device_id;
        u8 *buf = nvm->buf;

        image_size = nvm->buf_data_size;

        /*
         * FARB pointer must point inside the image and must at least
         * contain parts of the digital section we will be reading here.
         */
        hdr_size = (*(u32 *)buf) & 0xffffff;
        if (hdr_size + INTEL_NVM_DEVID + 2 >= image_size)
                return -EINVAL;

        /* Digital section start should be aligned to 4k page */
        if (!IS_ALIGNED(hdr_size, SZ_4K))
                return -EINVAL;

        /*
         * Read digital section size and check that it also fits inside
         * the image.
         */
        ds_size = *(u16 *)(buf + hdr_size);
        if (ds_size >= image_size)
                return -EINVAL;

        if (sw->safe_mode)
                return 0;

        /*
         * Make sure the device ID in the image matches the one
         * we read from the switch config space.
         */
        device_id = *(u16 *)(buf + hdr_size + INTEL_NVM_DEVID);
        if (device_id != sw->config.device_id)
                return -EINVAL;

        /* Skip headers in the image */
        nvm->buf_data_start = buf + hdr_size;
        nvm->buf_data_size = image_size - hdr_size;

        return 0;
}

static int intel_switch_nvm_write_headers(struct tb_nvm *nvm)
{
        struct tb_switch *sw = tb_to_switch(nvm->dev);

        if (sw->generation < 3) {
                int ret;

                /* Write CSS headers first */
                ret = dma_port_flash_write(sw->dma_port,
                        DMA_PORT_CSS_ADDRESS, nvm->buf + INTEL_NVM_CSS,
                        DMA_PORT_CSS_MAX_SIZE);
                if (ret)
                        return ret;
        }

        return 0;
}

static const struct tb_nvm_vendor_ops intel_switch_nvm_ops = {
        .read_version = intel_switch_nvm_version,
        .validate = intel_switch_nvm_validate,
        .write_headers = intel_switch_nvm_write_headers,
};

static int asmedia_switch_nvm_version(struct tb_nvm *nvm)
{
        struct tb_switch *sw = tb_to_switch(nvm->dev);
        u32 val;
        int ret;

        ret = tb_switch_nvm_read(sw, ASMEDIA_NVM_VERSION, &val, sizeof(val));
        if (ret)
                return ret;

        nvm->major = (val << 16) & 0xff0000;
        nvm->major |= val & 0x00ff00;
        nvm->major |= (val >> 16) & 0x0000ff;

        ret = tb_switch_nvm_read(sw, ASMEDIA_NVM_DATE, &val, sizeof(val));
        if (ret)
                return ret;

        nvm->minor = (val << 16) & 0xff0000;
        nvm->minor |= val & 0x00ff00;
        nvm->minor |= (val >> 16) & 0x0000ff;

        /* ASMedia NVM size is fixed to 512k */
        nvm->active_size = SZ_512K;

        return 0;
}

static const struct tb_nvm_vendor_ops asmedia_switch_nvm_ops = {
        .read_version = asmedia_switch_nvm_version,
};

/* Router vendor NVM support table */
static const struct tb_nvm_vendor switch_nvm_vendors[] = {
        { 0x174c, &asmedia_switch_nvm_ops },
        { PCI_VENDOR_ID_INTEL, &intel_switch_nvm_ops },
        { 0x8087, &intel_switch_nvm_ops },
};

static int intel_retimer_nvm_version(struct tb_nvm *nvm)
{
        struct tb_retimer *rt = tb_to_retimer(nvm->dev);
        u32 val, nvm_size;
        int ret;

        ret = tb_retimer_nvm_read(rt, INTEL_NVM_VERSION, &val, sizeof(val));
        if (ret)
                return ret;

        nvm->major = (val >> 16) & 0xff;
        nvm->minor = (val >> 8) & 0xff;

        ret = tb_retimer_nvm_read(rt, INTEL_NVM_FLASH_SIZE, &val, sizeof(val));
        if (ret)
                return ret;

        nvm_size = (SZ_1M << (val & 7)) / 8;
        nvm_size = (nvm_size - SZ_16K) / 2;
        nvm->active_size = nvm_size;

        return 0;
}

static int intel_retimer_nvm_validate(struct tb_nvm *nvm)
{
        struct tb_retimer *rt = tb_to_retimer(nvm->dev);
        unsigned int image_size, hdr_size;
        u8 *buf = nvm->buf;
        u16 ds_size, device;

        image_size = nvm->buf_data_size;

        /*
         * FARB pointer must point inside the image and must at least
         * contain parts of the digital section we will be reading here.
         */
        hdr_size = (*(u32 *)buf) & 0xffffff;
        if (hdr_size + INTEL_NVM_DEVID + 2 >= image_size)
                return -EINVAL;

        /* Digital section start should be aligned to 4k page */
        if (!IS_ALIGNED(hdr_size, SZ_4K))
                return -EINVAL;

        /*
         * Read digital section size and check that it also fits inside
         * the image.
         */
        ds_size = *(u16 *)(buf + hdr_size);
        if (ds_size >= image_size)
                return -EINVAL;

        /*
         * Make sure the device ID in the image matches the retimer
         * hardware.
         */
        device = *(u16 *)(buf + hdr_size + INTEL_NVM_DEVID);
        if (device != rt->device)
                return -EINVAL;

        /* Skip headers in the image */
        nvm->buf_data_start = buf + hdr_size;
        nvm->buf_data_size = image_size - hdr_size;

        return 0;
}

static const struct tb_nvm_vendor_ops intel_retimer_nvm_ops = {
        .read_version = intel_retimer_nvm_version,
        .validate = intel_retimer_nvm_validate,
};

/* Retimer vendor NVM support table */
static const struct tb_nvm_vendor retimer_nvm_vendors[] = {
        { 0x8087, &intel_retimer_nvm_ops },
};

/**
 * tb_nvm_alloc() - Allocate new NVM structure
 * @dev: Device owning the NVM
 *
 * Allocates new NVM structure with unique @id and returns it.
 *
 * Return:
 * * Pointer to &struct tb_nvm - On success.
 * * %-EOPNOTSUPP - If the NVM format of the @dev is not known by the
 *   kernel.
 * * %ERR_PTR - In case of failure.
 */
struct tb_nvm *tb_nvm_alloc(struct device *dev)
{
        const struct tb_nvm_vendor_ops *vops = NULL;
        struct tb_nvm *nvm;
        int ret, i;

        if (tb_is_switch(dev)) {
                const struct tb_switch *sw = tb_to_switch(dev);

                for (i = 0; i < ARRAY_SIZE(switch_nvm_vendors); i++) {
                        const struct tb_nvm_vendor *v = &switch_nvm_vendors[i];

                        if (v->vendor == sw->config.vendor_id) {
                                vops = v->vops;
                                break;
                        }
                }

                if (!vops) {
                        tb_sw_dbg(sw, "router NVM format of vendor %#x unknown\n",
                                  sw->config.vendor_id);
                        return ERR_PTR(-EOPNOTSUPP);
                }
        } else if (tb_is_retimer(dev)) {
                const struct tb_retimer *rt = tb_to_retimer(dev);

                for (i = 0; i < ARRAY_SIZE(retimer_nvm_vendors); i++) {
                        const struct tb_nvm_vendor *v = &retimer_nvm_vendors[i];

                        if (v->vendor == rt->vendor) {
                                vops = v->vops;
                                break;
                        }
                }

                if (!vops) {
                        dev_dbg(dev, "retimer NVM format of vendor %#x unknown\n",
                                rt->vendor);
                        return ERR_PTR(-EOPNOTSUPP);
                }
        } else {
                return ERR_PTR(-EOPNOTSUPP);
        }

        nvm = kzalloc_obj(*nvm);
        if (!nvm)
                return ERR_PTR(-ENOMEM);

        ret = ida_alloc(&nvm_ida, GFP_KERNEL);
        if (ret < 0) {
                kfree(nvm);
                return ERR_PTR(ret);
        }

        nvm->id = ret;
        nvm->dev = dev;
        nvm->vops = vops;

        return nvm;
}

/**
 * tb_nvm_read_version() - Read and populate NVM version
 * @nvm: NVM structure
 *
 * Uses vendor specific means to read and fill out the existing
 * active NVM version.
 *
 * Return: %0 on success, negative errno otherwise.
 */
int tb_nvm_read_version(struct tb_nvm *nvm)
{
        const struct tb_nvm_vendor_ops *vops = nvm->vops;

        if (vops && vops->read_version)
                return vops->read_version(nvm);

        return -EOPNOTSUPP;
}

/**
 * tb_nvm_validate() - Validate new NVM image
 * @nvm: NVM structure
 *
 * Runs vendor specific validation over the new NVM image. As a
 * side effect, updates @nvm->buf_data_start and @nvm->buf_data_size
 * fields to match the actual data to be written to the NVM.
 *
 * Return: %0 on successful validation, negative errno otherwise.
 */
int tb_nvm_validate(struct tb_nvm *nvm)
{
        const struct tb_nvm_vendor_ops *vops = nvm->vops;
        unsigned int image_size;
        u8 *buf = nvm->buf;

        if (!buf)
                return -EINVAL;
        if (!vops)
                return -EOPNOTSUPP;

        /* Just do basic image size checks */
        image_size = nvm->buf_data_size;
        if (image_size < NVM_MIN_SIZE || image_size > NVM_MAX_SIZE)
                return -EINVAL;

        /*
         * Set the default data start in the buffer. The validate method
         * below can change this if needed.
         */
        nvm->buf_data_start = buf;

        return vops->validate ? vops->validate(nvm) : 0;
}

/**
 * tb_nvm_write_headers() - Write headers before the rest of the image
 * @nvm: NVM structure
 *
 * If the vendor NVM format requires writing headers before the rest of
 * the image, this function does that. Can be called even if the device
 * does not need this.
 *
 * Return: %0 on success, negative errno otherwise.
 */
int tb_nvm_write_headers(struct tb_nvm *nvm)
{
        const struct tb_nvm_vendor_ops *vops = nvm->vops;

        return vops->write_headers ? vops->write_headers(nvm) : 0;
}

/**
 * tb_nvm_add_active() - Adds active NVMem device to NVM
 * @nvm: NVM structure
 * @reg_read: Pointer to the function to read the NVM (passed directly to the
 *            NVMem device)
 *
 * Registers new active NVmem device for @nvm. The @reg_read is called
 * directly from NVMem so it must handle possible concurrent access if
 * needed. The first parameter passed to @reg_read is @nvm structure.
 *
 * Return: %0 on success, negative errno otherwise.
 */
int tb_nvm_add_active(struct tb_nvm *nvm, nvmem_reg_read_t reg_read)
{
        struct nvmem_config config;
        struct nvmem_device *nvmem;

        memset(&config, 0, sizeof(config));

        config.name = "nvm_active";
        config.reg_read = reg_read;
        config.read_only = true;
        config.id = nvm->id;
        config.stride = 4;
        config.word_size = 4;
        config.size = nvm->active_size;
        config.dev = nvm->dev;
        config.owner = THIS_MODULE;
        config.priv = nvm;

        nvmem = nvmem_register(&config);
        if (IS_ERR(nvmem))
                return PTR_ERR(nvmem);

        nvm->active = nvmem;
        return 0;
}

/**
 * tb_nvm_write_buf() - Write data to @nvm buffer
 * @nvm: NVM structure
 * @offset: Offset where to write the data
 * @val: Data buffer to write
 * @bytes: Number of bytes to write
 *
 * Helper function to cache the new NVM image before it is actually
 * written to the flash. Copies @bytes from @val to @nvm->buf starting
 * from @offset.
 *
 * Return:
 * * %0 - On success.
 * * %-ENOMEM - If buffer allocation failed.
 * * Negative errno - Another error occurred.
 */
int tb_nvm_write_buf(struct tb_nvm *nvm, unsigned int offset, void *val,
                     size_t bytes)
{
        if (!nvm->buf) {
                nvm->buf = vmalloc(NVM_MAX_SIZE);
                if (!nvm->buf)
                        return -ENOMEM;
        }

        nvm->flushed = false;
        nvm->buf_data_size = offset + bytes;
        memcpy(nvm->buf + offset, val, bytes);
        return 0;
}

/**
 * tb_nvm_add_non_active() - Adds non-active NVMem device to NVM
 * @nvm: NVM structure
 * @reg_write: Pointer to the function to write the NVM (passed directly
 *             to the NVMem device)
 *
 * Registers new non-active NVmem device for @nvm. The @reg_write is called
 * directly from NVMem so it must handle possible concurrent access if
 * needed. The first parameter passed to @reg_write is @nvm structure.
 * The size of the NVMem device is set to %NVM_MAX_SIZE.
 *
 * Return: %0 on success, negative errno otherwise.
 */
int tb_nvm_add_non_active(struct tb_nvm *nvm, nvmem_reg_write_t reg_write)
{
        struct nvmem_config config;
        struct nvmem_device *nvmem;

        memset(&config, 0, sizeof(config));

        config.name = "nvm_non_active";
        config.reg_write = reg_write;
        config.root_only = true;
        config.id = nvm->id;
        config.stride = 4;
        config.word_size = 4;
        config.size = NVM_MAX_SIZE;
        config.dev = nvm->dev;
        config.owner = THIS_MODULE;
        config.priv = nvm;

        nvmem = nvmem_register(&config);
        if (IS_ERR(nvmem))
                return PTR_ERR(nvmem);

        nvm->non_active = nvmem;
        return 0;
}

/**
 * tb_nvm_free() - Release NVM and its resources
 * @nvm: NVM structure to release
 *
 * Releases NVM and the NVMem devices if they were registered.
 */
void tb_nvm_free(struct tb_nvm *nvm)
{
        if (nvm) {
                nvmem_unregister(nvm->non_active);
                nvmem_unregister(nvm->active);
                vfree(nvm->buf);
                ida_free(&nvm_ida, nvm->id);
        }
        kfree(nvm);
}

/**
 * tb_nvm_read_data() - Read data from NVM
 * @address: Start address on the flash
 * @buf: Buffer where the read data is copied
 * @size: Size of the buffer in bytes
 * @retries: Number of retries if block read fails
 * @read_block: Function that reads block from the flash
 * @read_block_data: Data passsed to @read_block
 *
 * This is a generic function that reads data from NVM or NVM like
 * device.
 *
 * Return: %0 on success, negative errno otherwise.
 */
int tb_nvm_read_data(unsigned int address, void *buf, size_t size,
                     unsigned int retries, read_block_fn read_block,
                     void *read_block_data)
{
        do {
                unsigned int dwaddress, dwords, offset;
                u8 data[NVM_DATA_DWORDS * 4];
                size_t nbytes;
                int ret;

                offset = address & 3;
                nbytes = min_t(size_t, size + offset, NVM_DATA_DWORDS * 4);

                dwaddress = address / 4;
                dwords = ALIGN(nbytes, 4) / 4;

                ret = read_block(read_block_data, dwaddress, data, dwords);
                if (ret) {
                        if (ret != -ENODEV && retries--)
                                continue;
                        return ret;
                }

                nbytes -= offset;
                memcpy(buf, data + offset, nbytes);

                size -= nbytes;
                address += nbytes;
                buf += nbytes;
        } while (size > 0);

        return 0;
}

/**
 * tb_nvm_write_data() - Write data to NVM
 * @address: Start address on the flash
 * @buf: Buffer where the data is copied from
 * @size: Size of the buffer in bytes
 * @retries: Number of retries if the block write fails
 * @write_block: Function that writes block to the flash
 * @write_block_data: Data passed to @write_block
 *
 * This is generic function that writes data to NVM or NVM like device.
 *
 * Return: %0 on success, negative errno otherwise.
 */
int tb_nvm_write_data(unsigned int address, const void *buf, size_t size,
                      unsigned int retries, write_block_fn write_block,
                      void *write_block_data)
{
        do {
                unsigned int offset, dwaddress;
                u8 data[NVM_DATA_DWORDS * 4];
                size_t nbytes;
                int ret;

                offset = address & 3;
                nbytes = min_t(u32, size + offset, NVM_DATA_DWORDS * 4);

                memcpy(data + offset, buf, nbytes);

                dwaddress = address / 4;
                ret = write_block(write_block_data, dwaddress, data, nbytes / 4);
                if (ret) {
                        if (ret == -ETIMEDOUT) {
                                if (retries--)
                                        continue;
                                ret = -EIO;
                        }
                        return ret;
                }

                size -= nbytes;
                address += nbytes;
                buf += nbytes;
        } while (size > 0);

        return 0;
}

void tb_nvm_exit(void)
{
        ida_destroy(&nvm_ida);
}