// 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"

static DEFINE_IDA(nvm_ida);

/**
 * tb_nvm_alloc() - Allocate new NVM structure
 * @dev: Device owning the NVM
 *
 * Allocates new NVM structure with unique @id and returns it. In case
 * of error returns ERR_PTR().
 */
struct tb_nvm *tb_nvm_alloc(struct device *dev)
{
        struct tb_nvm *nvm;
        int ret;

        nvm = kzalloc(sizeof(*nvm), GFP_KERNEL);
        if (!nvm)
                return ERR_PTR(-ENOMEM);

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

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

        return nvm;
}

/**
 * tb_nvm_add_active() - Adds active NVMem device to NVM
 * @nvm: NVM structure
 * @size: Size of the active NVM in bytes
 * @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.
 * Returns %0 in success and negative errno otherwise.
 */
int tb_nvm_add_active(struct tb_nvm *nvm, size_t size, 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 = 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.
 */
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
 * @size: Size of the non-active NVM in bytes
 * @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.
 * Returns %0 in success and negative errno otherwise.
 */
int tb_nvm_add_non_active(struct tb_nvm *nvm, size_t size,
                          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 = 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) {
                if (nvm->non_active)
                        nvmem_unregister(nvm->non_active);
                if (nvm->active)
                        nvmem_unregister(nvm->active);
                vfree(nvm->buf);
                ida_simple_remove(&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.
 *
 * Returns %0 on success and 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 passwd to @write_block
 *
 * This is generic function that writes data to NVM or NVM like device.
 *
 * Returns %0 on success and 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);
}