flash/nor: flash driver for Synwit SWM050 MCUs

SWM050 is a series of MCU product by Foshan Synwit Tech, which is
available in TSSOP-8 or SSOP-16 packages.

Adds flash driver for the internal 8KiB flash of the MCU. The registers
are based on reverse engineering the J-Flash blob provided by the
vendor.

Also adds a pre-made cfg file.

Change-Id: I0b29f0c0d062883542ee743e0750a4c6b6609ebd
Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Signed-off-by: Caleb Szalacinski <contact@skiboy.net>
Reviewed-on: http://openocd.zylin.com/4927
Tested-by: jenkins
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>

3 files changed, 214 insertions, 0 deletions

diff --git a/src/flash/nor/Makefile.am b/src/flash/nor/Makefile.am
index 135128e..34f91ce 100644
--- a/src/flash/nor/Makefile.am
+++ b/src/flash/nor/Makefile.am
@@ -63,6 +63,7 @@ NOR_DRIVERS = \
 	%D%/str7x.c \
 	%D%/str9x.c \
 	%D%/str9xpec.c \
+	%D%/swm050.c \
 	%D%/tms470.c \
 	%D%/virtual.c \
 	%D%/w600.c \
diff --git a/src/flash/nor/drivers.c b/src/flash/nor/drivers.c
index 955d149..551f389 100644
--- a/src/flash/nor/drivers.c
+++ b/src/flash/nor/drivers.c
@@ -77,6 +77,7 @@ extern const struct flash_driver stmsmi_flash;
 extern const struct flash_driver str7x_flash;
 extern const struct flash_driver str9x_flash;
 extern const struct flash_driver str9xpec_flash;
+extern const struct flash_driver swm050_flash;
 extern const struct flash_driver tms470_flash;
 extern const struct flash_driver virtual_flash;
 extern const struct flash_driver w600_flash;
@@ -146,6 +147,7 @@ static const struct flash_driver * const flash_drivers[] = {
 	&str7x_flash,
 	&str9x_flash,
 	&str9xpec_flash,
+	&swm050_flash,
 	&tms470_flash,
 	&virtual_flash,
 	&xcf_flash,
diff --git a/src/flash/nor/swm050.c b/src/flash/nor/swm050.c
new file mode 100644
index 0000000..241207d
--- /dev/null
+++ b/src/flash/nor/swm050.c
@@ -0,0 +1,211 @@
+/***************************************************************************
+ *   Copyright (C) 2019 Icenowy Zheng <icenowy@aosc.io>                    *
+ *   Copyright (C) 2019 Caleb Szalacinski <contact@skiboy.net>             *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program.  If not, see <http://www.gnu.org/licenses/>. *
+ ***************************************************************************/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "imp.h"
+#include <target/image.h>
+
+#define SWM050_DELAY		100
+
+#define SWM050_FLASH_PAGE_SIZE	0x200
+#define SWM050_FLASH_PAGES	16
+
+#define SWM050_CPU_ID		0xE000ED00
+#define SWM050_CPU_ID_VAL	0x410CC200
+
+#define SWM050_FLASH_REG1	0x1F000000
+#define SWM050_FLASH_REG2	0x1F000038
+#define SWM050_FLASH_KEY	0xAAAAAAAA
+
+#define SWM050_SYSCTL_CFG_0	0x400F0000
+#define SWM050_SYSCTL_DBLF	0x400F0008
+
+static int swm050_erase(struct flash_bank *bank, int first, int last)
+{
+	struct target *target = bank->target;
+	int retval, curr_page;
+	uint32_t curr_addr;
+
+	if (target->state != TARGET_HALTED) {
+		LOG_ERROR("Target not halted");
+		return ERROR_TARGET_NOT_HALTED;
+	}
+
+	/* Perform erase */
+	retval = target_write_u32(target, SWM050_FLASH_REG1, 0x4);
+	if (retval != ERROR_OK)
+		return retval;
+
+	for (curr_page = first; curr_page <= last; curr_page++) {
+		curr_addr = bank->base + (SWM050_FLASH_PAGE_SIZE * curr_page);
+		/* Perform write */
+		retval = target_write_u32(target, curr_addr, SWM050_FLASH_KEY);
+		if (retval != ERROR_OK)
+			return retval;
+		alive_sleep(SWM050_DELAY);
+	}
+
+	/* Close flash interface */
+	retval = target_write_u32(target, SWM050_FLASH_REG1, 0x0);
+	if (retval != ERROR_OK)
+		return retval;
+
+	return ERROR_OK;
+}
+
+static int swm050_write(struct flash_bank *bank, const uint8_t *buffer, uint32_t offset, uint32_t count)
+{
+	struct target *target = bank->target;
+	int retval;
+
+	if (target->state != TARGET_HALTED) {
+		LOG_ERROR("Target not halted");
+		retval = ERROR_TARGET_NOT_HALTED;
+		return retval;
+	}
+
+	/* Perform write */
+	retval = target_write_u32(target, SWM050_FLASH_REG1, 0x1);
+	if (retval != ERROR_OK)
+		return retval;
+
+	retval = target_write_memory(target, bank->base + offset, 4, count/4, buffer);
+	if (retval != ERROR_OK)
+		return retval;
+
+	/* Close flash interface */
+	retval = target_write_u32(target, SWM050_FLASH_REG1, 0x0);
+	if (retval != ERROR_OK)
+		return retval;
+
+	return ERROR_OK;
+}
+
+static int swm050_probe(struct flash_bank *bank)
+{
+	return ERROR_OK;
+}
+
+static int swm050_mass_erase(struct flash_bank *bank)
+{
+	struct target *target = bank->target;
+	int retval;
+
+	if (target->state != TARGET_HALTED) {
+		LOG_ERROR("Target not halted");
+		return ERROR_TARGET_NOT_HALTED;
+	}
+
+	/* Perform mass erase */
+	retval = target_write_u32(target, SWM050_FLASH_REG1, 0x6);
+	if (retval != ERROR_OK)
+		return retval;
+	retval = target_write_u32(target, SWM050_FLASH_REG2, 0x1);
+	if (retval != ERROR_OK)
+		return retval;
+	retval = target_write_u32(target, 0x0, SWM050_FLASH_KEY);
+	if (retval != ERROR_OK)
+		return retval;
+
+	alive_sleep(SWM050_DELAY);
+
+	/* Close flash interface */
+	retval = target_write_u32(target, SWM050_FLASH_REG1, 0x0);
+	if (retval != ERROR_OK)
+		return retval;
+
+	return ERROR_OK;
+}
+
+COMMAND_HANDLER(swm050_handle_mass_erase_command)
+{
+	if (CMD_ARGC < 1)
+		return ERROR_COMMAND_SYNTAX_ERROR;
+
+	struct flash_bank *bank;
+	int retval = CALL_COMMAND_HANDLER(flash_command_get_bank, 0, &bank);
+	if (ERROR_OK != retval)
+		return retval;
+
+	retval = swm050_mass_erase(bank);
+	if (retval == ERROR_OK)
+		command_print(CMD, "swm050 mass erase complete");
+	else
+		command_print(CMD, "swm050 mass erase failed");
+
+	return retval;
+}
+
+FLASH_BANK_COMMAND_HANDLER(swm050_flash_bank_command)
+{
+	if (bank->sectors) {
+		free(bank->sectors);
+		bank->sectors = NULL;
+	}
+	bank->write_start_alignment = 4;
+	bank->write_end_alignment = 4;
+	bank->size = SWM050_FLASH_PAGE_SIZE * SWM050_FLASH_PAGES;
+
+	bank->num_sectors = SWM050_FLASH_PAGES;
+	bank->sectors = alloc_block_array(0, SWM050_FLASH_PAGE_SIZE, SWM050_FLASH_PAGES);
+	if (!bank->sectors)
+		return ERROR_FAIL;
+
+	for (int i = 0; i < bank->num_sectors; i++)
+		bank->sectors[i].is_protected = 0;
+
+	return ERROR_OK;
+}
+
+static const struct command_registration swm050_exec_command_handlers[] = {
+	{
+		.name = "mass_erase",
+		.handler = swm050_handle_mass_erase_command,
+		.mode = COMMAND_EXEC,
+		.usage = "bank_id",
+		.help = "Erase entire flash device.",
+	},
+	COMMAND_REGISTRATION_DONE
+};
+
+static const struct command_registration swm050_command_handlers[] = {
+	{
+		.name = "swm050",
+		.mode = COMMAND_ANY,
+		.help = "swm050 flash command group",
+		.usage = "",
+		.chain = swm050_exec_command_handlers,
+	},
+	COMMAND_REGISTRATION_DONE
+};
+
+struct flash_driver swm050_flash = {
+	.name = "swm050",
+	.commands = swm050_command_handlers,
+	.flash_bank_command = swm050_flash_bank_command,
+	.erase = swm050_erase,
+	.write = swm050_write,
+	.read = default_flash_read,
+	.probe = swm050_probe,
+	.auto_probe = swm050_probe,
+	.erase_check = default_flash_blank_check,
+	.free_driver_priv = default_flash_free_driver_priv,
+};