feat(plat/st): add STM32CubeProgrammer support on UART

Add a file to support the STMicroelectronics tool STM32CubeProgrammer
over UART in BL2 for STM32MP15x platform.

This tools is based on protocol defined in AN5275,
"USB DFU/USART protocols used in STM32MP1 Series bootloaders"
based on STM32 MCU protocols (AN3155, "USART protocol used
in the STM32 bootloader").

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Change-Id: I956c95d8de0a94d1eb8e61f043651dae7b838170

plat/st/common/include/stm32cubeprogrammer.h

@@ -24,4 +24,6 @@ int stm32cubeprog_usb_load(struct usb_handle *usb_core_handle,
 			   uintptr_t ssbl_base,
 			   size_t ssbl_len);
 
+int stm32cubeprog_uart_load(uintptr_t instance, uintptr_t base, size_t len);
+
 #endif /* STM32CUBEPROGRAMMER_H */

plat/st/common/stm32cubeprogrammer_uart.c

@@ -0,0 +1,521 @@
+/*
+ * Copyright (c) 2021, STMicroelectronics - All Rights Reserved
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <endian.h>
+#include <errno.h>
+#include <string.h>
+
+#include <arch_helpers.h>
+#include <common/debug.h>
+#include <drivers/delay_timer.h>
+#include <drivers/st/stm32_iwdg.h>
+#include <drivers/st/stm32_uart.h>
+#include <drivers/st/stm32_uart_regs.h>
+#include <lib/mmio.h>
+#include <tools_share/firmware_image_package.h>
+
+#include <platform_def.h>
+#include <stm32cubeprogrammer.h>
+
+/* USART bootloader protocol version V4.0 */
+#define USART_BL_VERSION	0x40U
+
+/* Command definition */
+#define GET_CMD_COMMAND		0x00U
+#define GET_VER_COMMAND		0x01U
+#define GET_ID_COMMAND		0x02U
+#define PHASE_COMMAND		0x03U
+#define READ_PART_COMMAND	0x12U
+#define START_COMMAND		0x21U
+#define DOWNLOAD_COMMAND	0x31U
+
+/* Answer defines */
+#define INIT_BYTE		0x7FU
+#define ACK_BYTE		0x79U
+#define NACK_BYTE		0x1FU
+#define ABORT			0x5FU
+
+#define UNDEFINED_DOWN_ADDR	U(0xFFFFFFFF)
+#define PROGRAMMER_TIMEOUT_US	20000U
+
+static const uint8_t command_tab[] = {
+	GET_CMD_COMMAND,
+	GET_VER_COMMAND,
+	GET_ID_COMMAND,
+	PHASE_COMMAND,
+	START_COMMAND,
+	DOWNLOAD_COMMAND
+};
+
+/* STM32CubeProgrammer over UART handle */
+struct stm32prog_uart_handle_s {
+	struct stm32_uart_handle_s uart;
+	uint32_t packet;
+	uint8_t *addr;
+	uint32_t len;
+	uint8_t phase;
+	/* Error msg buffer: max 255 in UART protocol, reduced in TF-A */
+	uint8_t error[64];
+} handle;
+
+/* Trace and handle unrecoverable UART protocol error */
+#define STM32PROG_ERROR(...) \
+	{ \
+		ERROR(__VA_ARGS__); \
+		if (handle.phase != PHASE_RESET) { \
+			snprintf((char *)&handle.error, sizeof(handle.error), __VA_ARGS__); \
+			handle.phase = PHASE_RESET; \
+			handle.addr = (uint8_t *)UNDEFINED_DOWN_ADDR; \
+			handle.len = 0U; \
+			handle.packet = 0U; \
+		} \
+	}
+
+static int uart_write(const uint8_t *addr, uint16_t size)
+{
+	while (size != 0U) {
+		if (stm32_uart_putc(&handle.uart, *addr) != 0) {
+			return -EIO;
+		}
+		size--;
+		addr++;
+	}
+
+	return 0;
+}
+
+static int uart_write_8(uint8_t byte)
+{
+	return stm32_uart_putc(&handle.uart, byte);
+}
+
+static int uart_write_32(uint32_t value)
+{
+	return uart_write((uint8_t *)&value, 4U);
+}
+
+static int uart_read_8(uint8_t *byte)
+{
+	int ret;
+	uint64_t timeout_ref = timeout_init_us(PROGRAMMER_TIMEOUT_US);
+
+	do {
+		ret = stm32_uart_getc(&handle.uart);
+		if (ret == -EAGAIN) {
+			if (timeout_elapsed(timeout_ref)) {
+				return -ETIMEDOUT;
+			}
+		} else if (ret < 0) {
+			return ret;
+		}
+	} while (ret == -EAGAIN);
+
+	*byte = (uint8_t)ret;
+
+	return 0;
+}
+
+static int uart_send_result(uint8_t byte)
+{
+	int ret;
+
+	/* Always flush fifo before to send result = read all pending data */
+	do {
+		ret = stm32_uart_getc(&handle.uart);
+	} while (ret >= 0);
+
+	return uart_write_8(byte);
+}
+
+static bool is_valid_header(fip_toc_header_t *header)
+{
+	return (header->name == TOC_HEADER_NAME) &&
+	       (header->serial_number != 0U);
+}
+
+static int uart_receive_command(uint8_t *command)
+{
+	uint8_t byte = 0U;
+	uint8_t xor = 0U;
+	unsigned int count;
+	bool found = false;
+	int ret;
+
+	/* Repeat read until something is received */
+	do {
+		stm32_iwdg_refresh();
+		ret = uart_read_8(&byte);
+	} while (ret == -ETIMEDOUT);
+
+	if (ret != 0) {
+		return ret;
+	}
+
+	/* Handle reconnection request */
+	if (byte == INIT_BYTE) {
+		*command = byte;
+		return 0;
+	}
+
+	for (count = 0U; count < ARRAY_SIZE(command_tab); count++) {
+		if (command_tab[count] == byte) {
+			found = true;
+			break;
+		}
+	}
+	if (!found) {
+		VERBOSE("UART: Command unknown (byte=0x%x)\n", byte);
+		return -EPROTO;
+	}
+
+	ret = uart_read_8(&xor);
+	if (ret != 0) {
+		return ret;
+	}
+	if ((byte ^ xor) != 0xFF) {
+		VERBOSE("UART: Command XOR check fail (byte=0x%x, xor=0x%x)\n",
+			byte, xor);
+		return -EPROTO;
+	}
+
+	*command = byte;
+
+	return 0;
+}
+
+static int get_cmd_command(void)
+{
+	const uint8_t msg[2] = {
+		sizeof(command_tab), /* Length of data - 1 */
+		USART_BL_VERSION
+	};
+	int ret;
+
+	ret = uart_write(msg, sizeof(msg));
+	if (ret != 0) {
+		return ret;
+	}
+
+	return uart_write(command_tab, sizeof(command_tab));
+}
+
+static int get_version_command(void)
+{
+	return uart_write_8(STM32_TF_VERSION);
+}
+
+static int get_id_command(void)
+{
+	uint8_t msg[3] = {
+		sizeof(msg) - 1 /* Length of data - 1 */
+	};
+	uint32_t chip_id = stm32mp_get_chip_dev_id();
+
+	be16enc(&msg[1], chip_id);
+
+	return uart_write(msg, sizeof(msg));
+}
+
+static int uart_send_phase(uint32_t address)
+{
+	int ret;
+	uint8_t msg_size = 5U; /* Length of data - 1 */
+	uint8_t error_size = 0U;
+
+	/* Additional information only for RESET phase */
+	if (handle.phase == PHASE_RESET) {
+		error_size = strnlen((char *)&handle.error, sizeof(handle.error));
+	}
+	ret = uart_write_8(msg_size + error_size);
+	if (ret != 0) {
+		return ret;
+	}
+
+	/* Send the ID of next partition */
+	ret = uart_write_8(handle.phase);
+	if (ret != 0) {
+		return ret;
+	}
+
+	/* Destination address */
+	ret = uart_write_32(address);
+	if (ret != 0) {
+		return ret;
+	}
+
+	ret = uart_write_8(error_size);
+	if (ret != 0) {
+		return ret;
+	}
+
+	/* Additional information: message error */
+	if (error_size > 0U) {
+		ret = uart_write(handle.error, error_size);
+	}
+
+	return ret;
+}
+
+static int uart_download_part(void)
+{
+	uint8_t operation = 0U;
+	uint8_t xor;
+	uint8_t byte = 0U;
+	uint32_t packet_number = 0U;
+	uint32_t packet_size = 0U;
+	uint32_t i = 0U;
+	int ret;
+
+	/* Get operation number */
+	ret = uart_read_8(&operation);
+	if (ret != 0) {
+		return ret;
+	}
+
+	xor = operation;
+
+	/* Get packet number */
+	for (i = 3U; i != 0U; i--) {
+		ret = uart_read_8(&byte);
+		if (ret != 0) {
+			return ret;
+		}
+
+		xor ^= byte;
+		packet_number = (packet_number << 8) | byte;
+	}
+
+	if (packet_number != handle.packet) {
+		WARN("UART: Bad packet number receive: %u, expected %u\n",
+		     packet_number, handle.packet);
+		return -EPROTO;
+	}
+
+	/* Checksum */
+	ret = uart_read_8(&byte);
+	if (ret != 0) {
+		return ret;
+	}
+	if (xor != byte) {
+		VERBOSE("UART: Download Command checksum xor: %x, received %x\n",
+			xor, byte);
+		return -EPROTO;
+	}
+
+	ret = uart_send_result(ACK_BYTE);
+	if (ret != 0) {
+		return ret;
+	}
+
+	ret = uart_read_8(&byte);
+	if (ret != 0) {
+		return ret;
+	}
+	xor = byte;
+	packet_size = byte + 1U;
+	if (handle.len < packet_size) {
+		STM32PROG_ERROR("Download overflow at %p\n", handle.addr + packet_size);
+		return 0;
+	}
+
+	for (i = 0U; i < packet_size; i++) {
+		ret = uart_read_8(&byte);
+		if (ret != 0) {
+			return ret;
+		}
+
+		*(handle.addr + i) = byte;
+		xor ^= byte;
+	}
+
+	/* Checksum */
+	ret = uart_read_8(&byte) != 0;
+	if (ret != 0) {
+		return ret;
+	}
+	if (xor != byte) {
+		VERBOSE("UART: Download Data checksum xor: %x, received %x\n",
+			xor, byte);
+		return -EPROTO;
+	}
+
+	/* Packet treated */
+	handle.packet++;
+	handle.addr += packet_size;
+	handle.len -= packet_size;
+
+	return 0;
+}
+
+static int uart_start_cmd(uintptr_t buffer)
+{
+	uint8_t byte = 0U;
+	uint8_t xor = 0U;
+	uint32_t i;
+	uint32_t start_address = 0U;
+	int ret;
+
+	/* Get address */
+	for (i = 4U; i != 0U; i--) {
+		ret = uart_read_8(&byte);
+		if (ret != 0U) {
+			return ret;
+		}
+
+		xor ^= byte;
+		start_address = (start_address << 8) | byte;
+	}
+
+	/* Checksum */
+	ret = uart_read_8(&byte);
+	if (ret != 0) {
+		return ret;
+	}
+
+	if (xor != byte) {
+		VERBOSE("UART: Start Command checksum xor: %x, received %x\n",
+			xor, byte);
+		return -EPROTO;
+	}
+
+	if (start_address != UNDEFINED_DOWN_ADDR) {
+		STM32PROG_ERROR("Invalid start at %x, for phase %u\n",
+				start_address, handle.phase);
+		return 0;
+	}
+
+	if (!is_valid_header((fip_toc_header_t *)buffer)) {
+		STM32PROG_ERROR("FIP Header check failed %lx, for phase %u\n",
+				buffer, handle.phase);
+		return -EIO;
+	}
+	VERBOSE("FIP header looks OK.\n");
+
+	return 0;
+}
+
+static int uart_read(uint8_t id, uintptr_t buffer, size_t length)
+{
+	bool start_done = false;
+	int ret;
+	uint8_t command = 0U;
+
+	handle.phase = id;
+	handle.packet = 0U;
+	handle.addr = (uint8_t *)buffer;
+	handle.len = length;
+
+	INFO("UART: read phase %u at 0x%lx size 0x%x\n",
+	     id, buffer, length);
+	while (!start_done) {
+		ret = uart_receive_command(&command);
+		if (ret != 0) {
+			/* Delay to wait STM32CubeProgrammer end of transmission */
+			mdelay(3);
+
+			ret = uart_send_result(NACK_BYTE);
+			if (ret != 0U) {
+				return ret;
+			}
+
+			continue;
+		}
+
+		uart_send_result(ACK_BYTE);
+
+		switch (command) {
+		case INIT_BYTE:
+			INFO("UART: Connected\n");
+			/* Nothing to do */
+			continue;
+
+		case GET_CMD_COMMAND:
+			ret = get_cmd_command();
+			break;
+
+		case GET_VER_COMMAND:
+			ret = get_version_command();
+			break;
+
+		case GET_ID_COMMAND:
+			ret = get_id_command();
+			break;
+
+		case PHASE_COMMAND:
+			ret = uart_send_phase((uint32_t)buffer);
+			if ((ret == 0) && (handle.phase == PHASE_RESET)) {
+				start_done = true;
+				INFO("UART: Reset\n");
+			}
+			break;
+
+		case DOWNLOAD_COMMAND:
+			ret = uart_download_part();
+			break;
+
+		case START_COMMAND:
+			ret = uart_start_cmd(buffer);
+			if ((ret == 0) && (handle.phase == id)) {
+				INFO("UART: Start phase %u\n", handle.phase);
+				start_done = true;
+			}
+			break;
+
+		default:
+			WARN("UART: Unknown command\n");
+			ret = -EINVAL;
+			break;
+		}
+
+		if (ret == 0) {
+			ret = uart_send_result(ACK_BYTE);
+		} else {
+			ret = uart_send_result(NACK_BYTE);
+		}
+		if (ret != 0) {
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+/* Init UART: 115200, 8bit 1stop parity even and enable FIFO mode */
+const struct stm32_uart_init_s init = {
+	.baud_rate = U(115200),
+	.word_length = STM32_UART_WORDLENGTH_9B,
+	.stop_bits = STM32_UART_STOPBITS_1,
+	.parity = STM32_UART_PARITY_EVEN,
+	.hw_flow_control = STM32_UART_HWCONTROL_NONE,
+	.mode = STM32_UART_MODE_TX_RX,
+	.over_sampling = STM32_UART_OVERSAMPLING_16,
+	.fifo_mode = STM32_UART_FIFOMODE_EN,
+};
+
+int stm32cubeprog_uart_load(uintptr_t instance, uintptr_t base, size_t len)
+{
+	int ret;
+
+	if (stm32_uart_init(&handle.uart, instance, &init) != 0) {
+		return -EIO;
+	}
+
+	/*
+	 * The following NACK_BYTE is written because STM32CubeProgrammer has
+	 * already sent its command before TF-A has reached this point, and
+	 * because FIFO was not configured by BootROM.
+	 * The byte in the UART_RX register is then the checksum and not the
+	 * command. NACK_BYTE has to be written, so that the programmer will
+	 * re-send the good command.
+	 */
+	ret = uart_send_result(NACK_BYTE);
+	if (ret != 0) {
+		return ret;
+	}
+
+	return uart_read(PHASE_SSBL, base, len);
+}