/* SPDX-License-Identifier: GPL-2.0-or-later */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "imp.h"
#include <helper/binarybuffer.h>
#include <target/algorithm.h>
#include <target/armv7m.h>
#include "spi.h"

/* NOTE THAT THIS CODE REQUIRES FLASH ROUTINES in BOOTROM WITH FUNCTION TABLE PTR AT 0x00000010
   Your gdbinit should load the bootrom.elf if appropriate */

/* this is 'M' 'u', 1 (version) */
#define BOOTROM_MAGIC 0x01754d
#define BOOTROM_MAGIC_ADDR 0x00000010

/* Call a ROM function via the debug trampoline
   Up to four arguments passed in r0...r3 as per ABI
   Function address is passed in r7
   the trampoline is needed because OpenOCD "algorithm" code insists on sw breakpoints. */

#define MAKE_TAG(a, b) (((b)<<8) | a)
#define FUNC_DEBUG_TRAMPOLINE       MAKE_TAG('D', 'T')
#define FUNC_DEBUG_TRAMPOLINE_END   MAKE_TAG('D', 'E')
#define FUNC_FLASH_EXIT_XIP         MAKE_TAG('E', 'X')
#define FUNC_CONNECT_INTERNAL_FLASH MAKE_TAG('I', 'F')
#define FUNC_FLASH_RANGE_ERASE      MAKE_TAG('R', 'E')
#define FUNC_FLASH_RANGE_PROGRAM    MAKE_TAG('R', 'P')
#define FUNC_FLASH_FLUSH_CACHE      MAKE_TAG('F', 'C')
#define FUNC_FLASH_ENTER_CMD_XIP    MAKE_TAG('C', 'X')

struct rp2040_flash_bank {
	/* flag indicating successful flash probe */
	bool probed;
	/* stack used by Boot ROM calls */
	struct working_area *stack;
	/* function jump table populated by rp2040_flash_probe() */
	uint16_t jump_debug_trampoline;
	uint16_t jump_debug_trampoline_end;
	uint16_t jump_flash_exit_xip;
	uint16_t jump_connect_internal_flash;
	uint16_t jump_flash_range_erase;
	uint16_t jump_flash_range_program;
	uint16_t jump_flush_cache;
	uint16_t jump_enter_cmd_xip;
	/* detected model of SPI flash */
	const struct flash_device *dev;
};

static uint32_t rp2040_lookup_symbol(struct target *target, uint32_t tag, uint16_t *symbol)
{
	uint32_t magic;
	int err = target_read_u32(target, BOOTROM_MAGIC_ADDR, &magic);
	if (err != ERROR_OK)
		return err;

	magic &= 0xffffff; /* ignore bootrom version */
	if (magic != BOOTROM_MAGIC) {
		if (!((magic ^ BOOTROM_MAGIC)&0xffff))
			LOG_ERROR("Incorrect RP2040 BOOT ROM version");
		else
			LOG_ERROR("RP2040 BOOT ROM not found");
		return ERROR_FAIL;
	}

	/* dereference the table pointer */
	uint16_t table_entry;
	err = target_read_u16(target, BOOTROM_MAGIC_ADDR + 4, &table_entry);
	if (err != ERROR_OK)
		return err;

	uint16_t entry_tag;
	do {
		err = target_read_u16(target, table_entry, &entry_tag);
		if (err != ERROR_OK)
			return err;
		if (entry_tag == tag) {
			/* 16 bit symbol is next */
			return target_read_u16(target, table_entry + 2, symbol);
		}
		table_entry += 4;
	} while (entry_tag);
	return ERROR_FAIL;
}

static int rp2040_call_rom_func(struct target *target, struct rp2040_flash_bank *priv,
		uint16_t func_offset, uint32_t argdata[], unsigned int n_args)
{
	char *regnames[4] = { "r0", "r1", "r2", "r3" };

	assert(n_args <= ARRAY_SIZE(regnames)); /* only allow register arguments */

	if (!priv->stack) {
		LOG_ERROR("no stack for flash programming code");
		return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
	}
	target_addr_t stacktop = priv->stack->address + priv->stack->size;

	LOG_DEBUG("Calling ROM func @0x%" PRIx16 " with %d arguments", func_offset, n_args);
	LOG_DEBUG("Calling on core \"%s\"", target->cmd_name);

	struct reg_param args[ARRAY_SIZE(regnames) + 2];
	struct armv7m_algorithm alg_info;

	for (unsigned int i = 0; i < n_args; ++i) {
		init_reg_param(&args[i], regnames[i], 32, PARAM_OUT);
		buf_set_u32(args[i].value, 0, 32, argdata[i]);
	}
	/* Pass function pointer in r7 */
	init_reg_param(&args[n_args], "r7", 32, PARAM_OUT);
	buf_set_u32(args[n_args].value, 0, 32, func_offset);
	init_reg_param(&args[n_args + 1], "sp", 32, PARAM_OUT);
	buf_set_u32(args[n_args + 1].value, 0, 32, stacktop);


	for (unsigned int i = 0; i < n_args + 2; ++i)
		LOG_DEBUG("Set %s = 0x%" PRIx32, args[i].reg_name, buf_get_u32(args[i].value, 0, 32));

	/* Actually call the function */
	alg_info.common_magic = ARMV7M_COMMON_MAGIC;
	alg_info.core_mode = ARM_MODE_THREAD;
	int err = target_run_algorithm(
		target,
		0, NULL,          /* No memory arguments */
		n_args + 1, args, /* User arguments + r7 */
		priv->jump_debug_trampoline, priv->jump_debug_trampoline_end,
		3000, /* 3s timeout */
		&alg_info
	);
	for (unsigned int i = 0; i < n_args + 2; ++i)
		destroy_reg_param(&args[i]);
	if (err != ERROR_OK)
		LOG_ERROR("Failed to invoke ROM function @0x%" PRIx16 "\n", func_offset);
	return err;

}

static int stack_grab_and_prep(struct flash_bank *bank)
{
	struct rp2040_flash_bank *priv = bank->driver_priv;

	/* target_alloc_working_area always allocates multiples of 4 bytes, so no worry about alignment */
	const int STACK_SIZE = 256;
	int err = target_alloc_working_area(bank->target, STACK_SIZE, &priv->stack);
	if (err != ERROR_OK) {
		LOG_ERROR("Could not allocate stack for flash programming code");
		return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
	}

	LOG_DEBUG("Connecting internal flash");
	err = rp2040_call_rom_func(bank->target, priv, priv->jump_connect_internal_flash, NULL, 0);
	if (err != ERROR_OK) {
		LOG_ERROR("RP2040 erase: failed to connect internal flash");
		return err;
	}

	LOG_DEBUG("Kicking flash out of XIP mode");
	err = rp2040_call_rom_func(bank->target, priv, priv->jump_flash_exit_xip, NULL, 0);
	if (err != ERROR_OK) {
		LOG_ERROR("RP2040 erase: failed to exit flash XIP mode");
		return err;
	}

	return ERROR_OK;
}

static int rp2040_flash_write(struct flash_bank *bank, const uint8_t *buffer, uint32_t offset, uint32_t count)
{
	LOG_DEBUG("Writing %d bytes starting at 0x%" PRIx32, count, offset);

	struct rp2040_flash_bank *priv = bank->driver_priv;
	struct target *target = bank->target;
	struct working_area *bounce;

	int err = stack_grab_and_prep(bank);
	if (err != ERROR_OK)
		return err;

	const unsigned int chunk_size = target_get_working_area_avail(target);
	if (target_alloc_working_area(target, chunk_size, &bounce) != ERROR_OK) {
		LOG_ERROR("Could not allocate bounce buffer for flash programming. Can't continue");
		return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
	}

	LOG_DEBUG("Allocated flash bounce buffer @" TARGET_ADDR_FMT, bounce->address);

	while (count > 0) {
		uint32_t write_size = count > chunk_size ? chunk_size : count;
		LOG_DEBUG("Writing %d bytes to offset 0x%" PRIx32, write_size, offset);
		err = target_write_buffer(target, bounce->address, write_size, buffer);
		if (err != ERROR_OK) {
			LOG_ERROR("Could not load data into target bounce buffer");
			break;
		}
		uint32_t args[3] = {
			offset, /* addr */
			bounce->address, /* data */
			write_size /* count */
		};
		err = rp2040_call_rom_func(target, priv, priv->jump_flash_range_program, args, ARRAY_SIZE(args));
		if (err != ERROR_OK) {
			LOG_ERROR("Failed to invoke flash programming code on target");
			break;
		}

		buffer += write_size;
		offset += write_size;
		count -= write_size;
	}
	target_free_working_area(target, bounce);

	if (err != ERROR_OK)
		return err;

	/* Flash is successfully programmed. We can now do a bit of poking to make the flash
	   contents visible to us via memory-mapped (XIP) interface in the 0x1... memory region */
	LOG_DEBUG("Flushing flash cache after write behind");
	err = rp2040_call_rom_func(bank->target, priv, priv->jump_flush_cache, NULL, 0);
	if (err != ERROR_OK) {
		LOG_ERROR("RP2040 write: failed to flush flash cache");
		return err;
	}
	LOG_DEBUG("Configuring SSI for execute-in-place");
	err = rp2040_call_rom_func(bank->target, priv, priv->jump_enter_cmd_xip, NULL, 0);
	if (err != ERROR_OK)
		LOG_ERROR("RP2040 write: failed to flush flash cache");
	return err;
}

static int rp2040_flash_erase(struct flash_bank *bank, unsigned int first, unsigned int last)
{
	struct rp2040_flash_bank *priv = bank->driver_priv;
	uint32_t start_addr = bank->sectors[first].offset;
	uint32_t length = bank->sectors[last].offset + bank->sectors[last].size - start_addr;
	LOG_DEBUG("RP2040 erase %d bytes starting at 0x%" PRIx32, length, start_addr);

	int err = stack_grab_and_prep(bank);
	if (err != ERROR_OK)
		return err;

	LOG_DEBUG("Remote call flash_range_erase");

	uint32_t args[4] = {
		bank->sectors[first].offset, /* addr */
		bank->sectors[last].offset + bank->sectors[last].size - bank->sectors[first].offset, /* count */
		priv->dev->sectorsize, /* block_size */
		priv->dev->erase_cmd /* block_cmd */
	};

	/*
	The RP2040 Boot ROM provides a _flash_range_erase() API call documented in Section 2.8.3.1.3:
	https://datasheets.raspberrypi.org/rp2040/rp2040-datasheet.pdf
	and the particular source code for said Boot ROM function can be found here:
	https://github.com/raspberrypi/pico-bootrom/blob/master/bootrom/program_flash_generic.c

	In theory, the function algorithm provides for erasing both a smaller "sector" (4096 bytes) and
	an optional larger "block" (size and command provided in args).  OpenOCD's spi.c only uses "block" sizes.
	*/

	err = rp2040_call_rom_func(bank->target, priv, priv->jump_flash_range_erase, args, ARRAY_SIZE(args));

	return err;
}

/* -----------------------------------------------------------------------------
   Driver probing etc */

static int rp2040_ssel_active(struct target *target, bool active)
{
	const target_addr_t qspi_ctrl_addr = 0x4001800c;
	const uint32_t qspi_ctrl_outover_low  = 2UL << 8;
	const uint32_t qspi_ctrl_outover_high = 3UL << 8;
	uint32_t state = (active) ? qspi_ctrl_outover_low : qspi_ctrl_outover_high;
	uint32_t val;

	int err = target_read_u32(target, qspi_ctrl_addr, &val);
	if (err != ERROR_OK)
		return err;

	val = (val & ~qspi_ctrl_outover_high) | state;

	err = target_write_u32(target, qspi_ctrl_addr, val);
	if (err != ERROR_OK)
		return err;

	return ERROR_OK;
}

static int rp2040_flash_probe(struct flash_bank *bank)
{
	struct rp2040_flash_bank *priv = bank->driver_priv;
	struct target *target = bank->target;

	int err = rp2040_lookup_symbol(target, FUNC_DEBUG_TRAMPOLINE, &priv->jump_debug_trampoline);
	if (err != ERROR_OK) {
		LOG_ERROR("Debug trampoline not found in RP2040 ROM.");
		return err;
	}
	priv->jump_debug_trampoline &= ~1u; /* mask off thumb bit */

	err = rp2040_lookup_symbol(target, FUNC_DEBUG_TRAMPOLINE_END, &priv->jump_debug_trampoline_end);
	if (err != ERROR_OK) {
		LOG_ERROR("Debug trampoline end not found in RP2040 ROM.");
		return err;
	}
	priv->jump_debug_trampoline_end &= ~1u; /* mask off thumb bit */

	err = rp2040_lookup_symbol(target, FUNC_FLASH_EXIT_XIP, &priv->jump_flash_exit_xip);
	if (err != ERROR_OK) {
		LOG_ERROR("Function FUNC_FLASH_EXIT_XIP not found in RP2040 ROM.");
		return err;
	}

	err = rp2040_lookup_symbol(target, FUNC_CONNECT_INTERNAL_FLASH, &priv->jump_connect_internal_flash);
	if (err != ERROR_OK) {
		LOG_ERROR("Function FUNC_CONNECT_INTERNAL_FLASH not found in RP2040 ROM.");
		return err;
	}

	err = rp2040_lookup_symbol(target, FUNC_FLASH_RANGE_ERASE, &priv->jump_flash_range_erase);
	if (err != ERROR_OK) {
		LOG_ERROR("Function FUNC_FLASH_RANGE_ERASE not found in RP2040 ROM.");
		return err;
	}

	err = rp2040_lookup_symbol(target, FUNC_FLASH_RANGE_PROGRAM, &priv->jump_flash_range_program);
	if (err != ERROR_OK) {
		LOG_ERROR("Function FUNC_FLASH_RANGE_PROGRAM not found in RP2040 ROM.");
		return err;
	}

	err = rp2040_lookup_symbol(target, FUNC_FLASH_FLUSH_CACHE, &priv->jump_flush_cache);
	if (err != ERROR_OK) {
		LOG_ERROR("Function FUNC_FLASH_FLUSH_CACHE not found in RP2040 ROM.");
		return err;
	}

	err = rp2040_lookup_symbol(target, FUNC_FLASH_ENTER_CMD_XIP, &priv->jump_enter_cmd_xip);
	if (err != ERROR_OK) {
		LOG_ERROR("Function FUNC_FLASH_ENTER_CMD_XIP not found in RP2040 ROM.");
		return err;
	}

	err = stack_grab_and_prep(bank);
	if (err != ERROR_OK)
		return err;

	uint32_t device_id = 0;
	const target_addr_t ssi_dr0 = 0x18000060;

	err = rp2040_ssel_active(target, true);

	/* write RDID request into SPI peripheral's FIFO */
	for (int count = 0; (count < 4) && (err == ERROR_OK); count++)
		err = target_write_u32(target, ssi_dr0, SPIFLASH_READ_ID);

	/* by this time, there is a receive FIFO entry for every write */
	for (int count = 0; (count < 4) && (err == ERROR_OK); count++) {
		uint32_t status;
		err = target_read_u32(target, ssi_dr0, &status);

		device_id >>= 8;
		device_id |= (status & 0xFF) << 24;
	}
	device_id >>= 8;

	err = rp2040_ssel_active(target, false);
	if (err != ERROR_OK) {
		LOG_ERROR("SSEL inactive failed");
		return err;
	}

	/* search for a SPI flash Device ID match */
	priv->dev = NULL;
	for (const struct flash_device *p = flash_devices; p->name ; p++)
		if (p->device_id == device_id) {
			priv->dev = p;
			break;
		}

	if (!priv->dev) {
		LOG_ERROR("Unknown flash device (ID 0x%08" PRIx32 ")", device_id);
		return ERROR_FAIL;
	}

	LOG_INFO("Found flash device \'%s\' (ID 0x%08" PRIx32 ")",
		priv->dev->name, priv->dev->device_id);

	/* the Boot ROM flash_range_program() routine requires page alignment */
	bank->write_start_alignment = priv->dev->pagesize;
	bank->write_end_alignment = priv->dev->pagesize;

	bank->size = priv->dev->size_in_bytes;

	bank->num_sectors = bank->size / priv->dev->sectorsize;
	LOG_INFO("RP2040 B0 Flash Probe: %d bytes @" TARGET_ADDR_FMT ", in %d sectors\n",
		bank->size, bank->base, bank->num_sectors);
	bank->sectors = alloc_block_array(0, priv->dev->sectorsize, bank->num_sectors);
	if (!bank->sectors)
		return ERROR_FAIL;

	if (err == ERROR_OK)
		priv->probed = true;

	return err;
}

static int rp2040_flash_auto_probe(struct flash_bank *bank)
{
	struct rp2040_flash_bank *priv = bank->driver_priv;

	if (priv->probed)
		return ERROR_OK;

	return rp2040_flash_probe(bank);
}

static void rp2040_flash_free_driver_priv(struct flash_bank *bank)
{
	free(bank->driver_priv);
	bank->driver_priv = NULL;
}

/* -----------------------------------------------------------------------------
   Driver boilerplate */

FLASH_BANK_COMMAND_HANDLER(rp2040_flash_bank_command)
{
	struct rp2040_flash_bank *priv;
	priv = malloc(sizeof(struct rp2040_flash_bank));
	priv->probed = false;

	/* Set up driver_priv */
	bank->driver_priv = priv;

	return ERROR_OK;
}

struct flash_driver rp2040_flash = {
	.name = "rp2040_flash",
	.commands = NULL,
	.flash_bank_command = rp2040_flash_bank_command,
	.erase =  rp2040_flash_erase,
	.write = rp2040_flash_write,
	.read = default_flash_read,
	.probe = rp2040_flash_probe,
	.auto_probe = rp2040_flash_auto_probe,
	.erase_check = default_flash_blank_check,
	.free_driver_priv = rp2040_flash_free_driver_priv
};