/*
 * Copyright (c) 2017 Linaro Limited
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <stdlib.h>
#include <string.h>

#include <zephyr.h>
#include <misc/printk.h>
#include <shell/shell.h>
#include <flash.h>
#include <device.h>
#include <soc.h>

#define THIS_MODULE_NAME "flash"

/*
 * When FLASH_DEV_NAME is available, we use it here. Otherwise,
 * the device can be set at runtime with the set_device command.
 */
#ifndef FLASH_DEV_NAME
#define FLASH_DEV_NAME ""
#endif

/* Command usage info. */
#define WRITE_BLOCK_SIZE_HELP \
	("Print the device's write block size. This is the smallest amount\n" \
	 "of data which may be written to the device, in bytes.")
#define READ_HELP \
	("<off> <len>\n\n" \
	 "Read <len> bytes from device offset <off>.")
#define ERASE_HELP \
	("<off> <len>\n\n" \
	 "Erase <len> bytes from device offset <off>, " \
	 "subject to hardware page limitations.")
#define WRITE_HELP \
	("<off> <byte1> [... byteN]\n\n" \
	 "Write given bytes, starting at device offset <off>.\n" \
	 "Pages must be erased before they can be written.")
#ifdef CONFIG_FLASH_PAGE_LAYOUT
#define PAGE_COUNT_HELP \
	"\n\nPrint the number of pages on the flash device."
#define PAGE_LAYOUT_HELP \
	("[start_page] [end_page]\n\n" \
	 "Print layout of flash pages in the range [start_page, end_page],\n" \
	 "which is inclusive. By default, all pages are printed.")
#define READ_PAGE_HELP \
	("<page> <len> OR <page> <off> <len>\n\n" \
	 "Read <len> bytes from given page, starting at page offset <off>,\n" \
	 "or offset 0 if not given. No checks are made that bytes read are\n" \
	 "all within the page.")
#define ERASE_PAGE_HELP \
	("<page> [num]\n\n" \
	 "Erase [num] pages (default 1), starting at page <page>.")
#define WRITE_PAGE_HELP \
	("<page> <off> <byte1> [... byteN]\n\n" \
	 "Write given bytes to given page, starting at page offset <off>.\n" \
	 "No checks are made that the bytes all fall within the page.\n" \
	 "Pages must be erased before they can be written.")
#endif
#define SET_DEVICE_HELP \
	("<device_name>\n\n" \
	 "Set flash device by name. If a flash device was not found,\n" \
	 "this command must be run first to bind a device to this module.")

/*
 * Canonicalize argc/argv.
 *
 * When run as "<command> <arguments>", i.e. after running "select
 * flash", the module name is not part of argv. When run as "flash
 * <command> <arguments>", it is. Normalize argc and argv to skip
 * "flash" regardless of the case.
 */
#define CANONICALIZE_ARGS(argc, argv) do {			\
		if (!strcmp(argv[0], THIS_MODULE_NAME)) {	\
			argc--;				\
			argv++;				\
		}						\
		/* Skip the command name as well. */		\
		argc--;					\
		argv++;					\
	} while (0)

#define ARGC_MAX 10 /* from shell.c */

static struct device *flash_device;

static int check_flash_device(void)
{
	if (flash_device == NULL) {
		printk("Flash device is unknown. Run set_device first.\n");
		return -ENODEV;
	}
	return 0;
}

static void dump_buffer(u8_t *buf, size_t size)
{
	bool newline = false;
	u8_t *p = buf;

	while (size >= 8) {
		printk("%02x %02x %02x %02x | %02x %02x %02x %02x\n",
		       p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7]);
		p += 8;
		size -= 8;
	}
	if (size > 4) {
		printk("%02x %02x %02x %02x | ",
		       p[0], p[1], p[2], p[3]);
		p += 4;
		size -= 4;
		newline = true;
	}
	while (size--) {
		printk("%02x ", *p++);
		newline = true;
	}
	if (newline) {
		printk("\n");
	}
}

static int parse_ul(const char *str, unsigned long *result)
{
	char *end;
	unsigned long val;

	val = strtoul(str, &end, 0);

	if (*str == '\0' || *end != '\0') {
		return -EINVAL;
	}

	*result = val;
	return 0;
}

static int parse_u8(const char *str, u8_t *result)
{
	unsigned long val;
	if (parse_ul(str, &val) || val > 0xff) {
		return -EINVAL;
	}
	*result = (u8_t)val;
	return 0;
}

/* Read bytes, dumping contents to console and printing on error. */
static int do_read(off_t offset, size_t len)
{
	u8_t buf[64];
	int ret;

	while (len > sizeof(buf)) {
		ret = flash_read(flash_device, offset, buf, sizeof(buf));
		if (ret) {
			goto err_read;
		}
		dump_buffer(buf, sizeof(buf));
		len -= sizeof(buf);
		offset += sizeof(buf);
	}
	ret = flash_read(flash_device, offset, buf, len);
	if (ret) {
		goto err_read;
	}
	dump_buffer(buf, len);
	return 0;

 err_read:
	printk("flash_read: %d\n", ret);
	return 0;
}

/* Erase area, handling write protection and printing on error. */
static int do_erase(off_t offset, size_t size)
{
	int ret;

	ret = flash_write_protection_set(flash_device, false);
	if (ret) {
		printk("flash_write_protection_set: %d (can't disable)\n", ret);
		return ret;
	}
	ret = flash_erase(flash_device, offset, size);
	if (ret) {
		printk("flash_erase: %d\n", ret);
		return ret;
	}
	ret = flash_write_protection_set(flash_device, true);
	if (ret) {
		printk("flash_write_protection_set: %d (can't enable)\n", ret);
	}
	return ret;
}

/* Write bytes, handling write protection and printing on error. */
static int do_write(off_t offset, u8_t *buf, size_t len, bool read_back)
{
	int ret;

	ret = flash_write_protection_set(flash_device, false);
	if (ret) {
		printk("flash_write_protection_set: %d (can't disable)\n", ret);
		return ret;
	}
	ret = flash_write(flash_device, offset, buf, len);
	if (ret) {
		printk("flash_write: %d\n", ret);
		return ret;
	}
	ret = flash_write_protection_set(flash_device, true);
	if (ret) {
		printk("flash_write_protection_set: %d (can't enable)\n", ret);
		return ret;
	}
	if (read_back) {
		printk("Reading back written bytes:\n");
		ret = do_read(offset, len);
	}
	return ret;
}

static int flash_shell_write_block_size(int argc, char *argv[])
{
	if (check_flash_device()) {
		return 0;
	}

	CANONICALIZE_ARGS(argc, argv);
	if (argc) {
		printk("No arguments expected.\n");
		return 0;
	}

	printk("%d\n", flash_get_write_block_size(flash_device));
	return 0;
}

static int flash_shell_read(int argc, char *argv[])
{
	long unsigned int offset, len;

	if (check_flash_device()) {
		return 0;
	}

	CANONICALIZE_ARGS(argc, argv);
	if (argc != 2 || parse_ul(argv[0], &offset) ||
	    parse_ul(argv[1], &len)) {
		goto bail;
	}

	do_read(offset, len);
	return 0;

 bail:
	printk("Invalid arguments.\n");
	return -EINVAL;
}

static int flash_shell_erase(int argc, char *argv[])
{
	long unsigned int offset, size;

	if (check_flash_device()) {
		return 0;
	}

	CANONICALIZE_ARGS(argc, argv);
	if (argc != 2 || parse_ul(argv[0], &offset) ||
	    parse_ul(argv[1], &size)) {
		goto bail;
	}

	do_erase((off_t)offset, (size_t)size);
	return 0;

 bail:
	printk("Invalid arguments.\n");
	return -EINVAL;
}

static int flash_shell_write(int argc, char *argv[])
{
	u8_t buf[ARGC_MAX];
	long unsigned int i, offset;

	if (check_flash_device()) {
		return 0;
	}

	CANONICALIZE_ARGS(argc, argv);
	if (argc < 2 || parse_ul(argv[0], &offset)) {
		goto bail;
	} else if (argc - 1 > sizeof(buf)) {
		/* Can only happen if Zephyr limit is increased. */
		printk("At most %lu bytes can be written.\n",
		       (unsigned long)sizeof(buf));
		return -EINVAL;
	}
	argc--;
	argv++;
	for (i = 0; i < argc; i++) {
		if (parse_u8(argv[i], &buf[i])) {
			printk("Argument %lu (%s) is not a byte.\n",
			       i + 1, argv[i]);
			goto bail;
		}
	}

	do_write(offset, buf, i, true);
	return 0;

 bail:
	printk("Invalid arguments.\n");
	return -EINVAL;
}

#ifdef CONFIG_FLASH_PAGE_LAYOUT
static int flash_shell_page_count(int argc, char *argv[])
{
	size_t page_count;

	if (check_flash_device()) {
		return 0;
	}

	CANONICALIZE_ARGS(argc, argv);
	if (argc) {
		goto bail;
	}

	page_count = flash_get_page_count(flash_device);
	printk("Flash device contains %lu pages.\n",
	       (long unsigned int)page_count);
	return 0;

 bail:
	printk("Invalid arguments.\n");
	return -EINVAL;
}

struct page_layout_data {
	long unsigned int start_page;
	long unsigned int end_page;
};

static bool page_layout_cb(const struct flash_pages_info *info, void *datav)
{
	struct page_layout_data *data = datav;
	long unsigned int sz;

	if (info->index < data->start_page) {
		return true;
	} else if (info->index > data->end_page) {
		return false;
	}

	sz = info->size;
	printk("\tPage %u: start 0x%08x, length 0x%lx (%lu, %lu KB)\n",
	       info->index, info->start_offset, sz, sz, sz / KB(1));
	return true;
}

static int flash_shell_page_layout(int argc, char *argv[])
{
	long unsigned int start_page, end_page;
	struct page_layout_data data;

	if (check_flash_device()) {
		return 0;
	}

	CANONICALIZE_ARGS(argc, argv);
	switch (argc) {
	case 0:
		start_page = 0;
		end_page = flash_get_page_count(flash_device) - 1;
		break;
	case 1:
		if (parse_ul(argv[0], &start_page)) {
			goto bail;
		}
		end_page = flash_get_page_count(flash_device) - 1;
		break;
	case 2:
		if (parse_ul(argv[0], &start_page) ||
		    parse_ul(argv[1], &end_page)) {
			goto bail;
		}
		break;
	default:
		goto bail;
	}

	data.start_page = start_page;
	data.end_page = end_page;
	flash_page_foreach(flash_device, page_layout_cb, &data);
	return 0;

 bail:
	printk("Invalid arguments.\n");
	return -EINVAL;
}

static int flash_shell_read_page(int argc, char *argv[])
{
	long unsigned int page, offset, len;
	struct flash_pages_info info;
	int ret;

	if (check_flash_device()) {
		return 0;
	}

	CANONICALIZE_ARGS(argc, argv);
	if (argc != 2 && argc != 3) {
		goto bail;
	}
	if (argc == 2) {
		if (parse_ul(argv[0], &page) || parse_ul(argv[1], &len)) {
			goto bail;
		}
		offset = 0;
	} else if (parse_ul(argv[0], &page) || parse_ul(argv[1], &offset) ||
		   parse_ul(argv[2], &len)) {
			goto bail;
	}

	ret = flash_get_page_info_by_idx(flash_device, page, &info);
	if (ret) {
		printk("flash_page_info_by_idx: %d\n", ret);
		return 0;
	}
	offset += info.start_offset;
	do_read(offset, len);
	return 0;

 bail:
	printk("Invalid arguments.\n");
	return -EINVAL;
}

static int flash_shell_erase_page(int argc, char *argv[])
{
	struct flash_pages_info info;
	long unsigned int i, page, num;
	int ret;

	if (check_flash_device()) {
		return 0;
	}

	CANONICALIZE_ARGS(argc, argv);
	if (argc < 1 || parse_ul(argv[0], &page)) {
		goto bail;
	}
	if (argc == 1) {
		num = 1;
	} else if (parse_ul(argv[1], &num)) {
		goto bail;
	}

	for (i = 0; i < num; i++) {
		ret = flash_get_page_info_by_idx(flash_device, page + i, &info);
		if (ret) {
			printk("flash_get_page_info_by_idx: %d\n", ret);
			return 0;
		}
		printk("Erasing page %u (start offset 0x%x, size 0x%x)\n",
		       info.index, info.start_offset, info.size);
		ret = do_erase(info.start_offset, info.size);
		if (ret) {
			return 0;
		}
	}

	return 0;

 bail:
	printk("Invalid arguments.\n");
	return -EINVAL;
}

static int flash_shell_write_page(int argc, char *argv[])
{
	struct flash_pages_info info;
	long unsigned int page, off;
	u8_t buf[ARGC_MAX];
	size_t i;
	int ret;

	if (check_flash_device()) {
		return 0;
	}

	CANONICALIZE_ARGS(argc, argv);
	if (argc < 2 || parse_ul(argv[0], &page) || parse_ul(argv[1], &off)) {
		goto bail;
	}
	argc -= 2;
	argv += 2;
	for (i = 0; i < argc; i++) {
		if (parse_u8(argv[i], &buf[i])) {
			printk("Argument %d (%s) is not a byte.\n",
			       i + 2, argv[i]);
			goto bail;
		}
	}

	ret = flash_get_page_info_by_idx(flash_device, page, &info);
	if (ret) {
		printk("flash_get_page_info_by_idx: %d\n", ret);
		return 0;
	}
	do_write(info.start_offset + off, buf, i, true);
	return 0;

 bail:
	printk("Invalid arguments.\n");
	return -EINVAL;
}
#endif	/* CONFIG_FLASH_PAGE_LAYOUT */

static int flash_shell_set_device(int argc, char *argv[])
{
	struct device *dev;
	const char *name;

	/* Parse arguments. */
	CANONICALIZE_ARGS(argc, argv);
	if (argc != 1) {
		goto bail;
	}
	name = argv[0];

	/* Run command. */
	dev = device_get_binding(name);
	if (!dev) {
		printk("No device named %s.\n", name);
		return -EINVAL;
	}
	if (flash_device) {
		printk("Leaving behind device %s", flash_device->config->name);
	}
	flash_device = dev;
	return 0;

 bail:
	printk("Invalid arguments.\n");
	return -EINVAL;
}

static struct shell_cmd commands[] = {
	{ "write_block_size", flash_shell_write_block_size,
	  WRITE_BLOCK_SIZE_HELP },
	{ "read", flash_shell_read, READ_HELP },
	{ "erase", flash_shell_erase, ERASE_HELP },
	{ "write", flash_shell_write, WRITE_HELP },
#ifdef CONFIG_FLASH_PAGE_LAYOUT
	{ "page_count", flash_shell_page_count, PAGE_COUNT_HELP },
	{ "page_layout", flash_shell_page_layout, PAGE_LAYOUT_HELP },
	{ "read_page", flash_shell_read_page, READ_PAGE_HELP },
	{ "erase_page", flash_shell_erase_page, ERASE_PAGE_HELP },
	{ "write_page", flash_shell_write_page, WRITE_PAGE_HELP },
#endif	/* CONFIG_FLASH_PAGE_LAYOUT */
	{ "set_device", flash_shell_set_device, SET_DEVICE_HELP },
	{ NULL, NULL, NULL },
};

void main(void)
{
	flash_device = device_get_binding(FLASH_DEV_NAME);
	if (flash_device) {
		printk("Found flash device %s.\n", FLASH_DEV_NAME);
		printk("Flash I/O commands can be run.\n");
	} else {
		printk("**No flash device found!**\n");
		printk("Run set_device <name> to specify one "
		       "before using other commands.\n");
	}

	SHELL_REGISTER(THIS_MODULE_NAME, commands);
}