// 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) {
		nvmem_unregister(nvm->non_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);
}