Add support for STLINK V3 debugger/programmer via its SPI bridge

Change-Id: Icffab87ac8f2c570187ed753ec70f054541873a4
Signed-off-by: Miklós Márton <martonmiklosqdev@gmail.com>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/34661
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>

6 files changed, 590 insertions, 0 deletions

diff --git a/Makefile b/Makefile
index 518d41b44..7242b0913 100644
--- a/Makefile
+++ b/Makefile
@@ -190,6 +190,11 @@ UNSUPPORTED_FEATURES += CONFIG_CH341A_SPI=yes
 else
 override CONFIG_CH341A_SPI = no
 endif
+ifeq ($(CONFIG_STLINKV3_SPI), yes)
+UNSUPPORTED_FEATURES += CONFIG_STLINKV3_SPI=yes
+else
+override CONFIG_STLINKV3_SPI = no
+endif
 # libjaylink is also not available for DOS
 ifeq ($(CONFIG_JLINK_SPI), yes)
 UNSUPPORTED_FEATURES += CONFIG_JLINK_SPI=yes
@@ -366,6 +371,11 @@ UNSUPPORTED_FEATURES += CONFIG_PICKIT2_SPI=yes
 else
 override CONFIG_PICKIT2_SPI = no
 endif
+ifeq ($(CONFIG_STLINKV3_SPI), yes)
+UNSUPPORTED_FEATURES += CONFIG_STLINKV3_SPI=yes
+else
+override CONFIG_STLINKV3_SPI = no
+endif
 ifeq ($(CONFIG_CH341A_SPI), yes)
 UNSUPPORTED_FEATURES += CONFIG_CH341A_SPI=yes
 else
@@ -631,6 +641,9 @@ CONFIG_MSTARDDC_SPI ?= no
 # Always enable PICkit2 SPI dongles for now.
 CONFIG_PICKIT2_SPI ?= yes
 
+# Always enable STLink V3
+CONFIG_STLINKV3_SPI ?= yes
+
 # Always enable dummy tracing for now.
 CONFIG_DUMMY ?= yes
 
@@ -709,6 +722,7 @@ override CONFIG_DEDIPROG = no
 override CONFIG_DIGILENT_SPI = no
 override CONFIG_DEVELOPERBOX_SPI = no
 override CONFIG_PICKIT2_SPI = no
+override CONFIG_STLINKV3_SPI = no
 endif
 ifeq ($(CONFIG_ENABLE_LIBPCI_PROGRAMMERS), no)
 override CONFIG_INTERNAL = no
@@ -876,6 +890,12 @@ PROGRAMMER_OBJS += pickit2_spi.o
 NEED_LIBUSB1 += CONFIG_PICKIT2_SPI
 endif
 
+ifeq ($(CONFIG_STLINKV3_SPI), yes)
+FEATURE_CFLAGS += -D'CONFIG_STLINKV3_SPI=1'
+PROGRAMMER_OBJS += stlinkv3_spi.o
+NEED_LIBUSB1 += CONFIG_STLINKV3_SPI
+endif
+
 ifneq ($(NEED_LIBFTDI), )
 FTDILIBS := $(call debug_shell,[ -n "$(PKG_CONFIG_LIBDIR)" ] && export PKG_CONFIG_LIBDIR="$(PKG_CONFIG_LIBDIR)" ; $(PKG_CONFIG) --libs libftdi1 || $(PKG_CONFIG) --libs libftdi || printf "%s" "-lftdi -lusb")
 FEATURE_CFLAGS += $(call debug_shell,grep -q "FT232H := yes" .features && printf "%s" "-D'HAVE_FT232H=1'")
diff --git a/flashrom.8.tmpl b/flashrom.8.tmpl
index 8ef2cbf01..aa5bcd457 100644
--- a/flashrom.8.tmpl
+++ b/flashrom.8.tmpl
@@ -343,6 +343,8 @@ bitbanging adapter)
 .sp
 .BR "* ni845x_spi" " (for SPI flash ROMs attached to National Instruments USB-8451 or USB-8452)"
 .sp
+.BR "* stlinkv3_spi" " (for SPI flash ROMs attached to STMicroelectronics STLINK V3 devices)"
+.sp
 Some programmers have optional or mandatory parameters which are described
 in detail in the
 .B PROGRAMMER-SPECIFIC INFORMATION
@@ -1260,6 +1262,31 @@ The SPI speed can be selected by using the
 syntax where \fBfrequency\fP is the SPI clock frequency in kHz.
 The maximum speed depends on the device in use.
 .SS
+.BR "stlinkv3_spi " programmer
+.IP
+This module supports SPI flash programming through the STMicroelectronics
+STLINK V3 programmer/debugger's SPI bridge interface
+.sp
+.B "  flashrom \-p stlinkv3_spi"
+.sp
+If there is more than one compatible device connected, you can select which one
+should be used by specifying its serial number with the
+.sp
+.B "  flashrom \-p stlinkv3_spi:serial=number"
+.sp
+syntax where
+.B number
+is the serial number of the device (which can be found for example in the
+output of lsusb -v).
+.sp
+The SPI speed can be selected by using the
+.sp
+.B "  flashrom \-p stlinkv3_spi:spispeed=frequency"
+.sp
+syntax where \fBfrequency\fP is the SPI clock frequency in kHz.
+If the passed frequency is not supported by the adapter the nearest lower
+supported frequency will be used.
+.SS
 
 .SH EXAMPLES
 To back up and update your BIOS, run
diff --git a/flashrom.c b/flashrom.c
index 2534e4a7a..e540027ca 100644
--- a/flashrom.c
+++ b/flashrom.c
@@ -460,6 +460,19 @@ const struct programmer_entry programmer_table[] = {
 		.delay			= internal_delay,
 	},
 #endif
+
+#if CONFIG_STLINKV3_SPI == 1
+	{
+		.name			= "stlinkv3_spi",
+		.type			= USB,
+		.devs.dev		= devs_stlinkv3_spi,
+		.init			= stlinkv3_spi_init,
+		.map_flash_region	= fallback_map,
+		.unmap_flash_region	= fallback_unmap,
+		.delay			= internal_delay,
+	},
+#endif
+
 	{0}, /* This entry corresponds to PROGRAMMER_INVALID. */
 };
 
diff --git a/meson.build b/meson.build
index b63875e23..375089c30 100644
--- a/meson.build
+++ b/meson.build
@@ -61,6 +61,7 @@ config_satamv = get_option('config_satamv')
 config_satasii = get_option('config_satasii')
 config_serprog = get_option('config_serprog')
 config_usbblaster_spi = get_option('config_usbblaster_spi')
+config_stlinkv3_spi = get_option('config_stlinkv3_spi')
 
 cargs = []
 deps = []
@@ -271,6 +272,10 @@ if config_usbblaster_spi
   srcs += 'usbblaster_spi.c'
   cargs += '-DCONFIG_USBBLASTER_SPI=1'
 endif
+if config_stlinkv3_spi
+  srcs += 'stlinkv3_spi.c'
+  cargs += '-DCONFIG_STLINKV3_SPI=1'
+endif
 
 # bitbanging SPI infrastructure
 if config_bitbang_spi
diff --git a/programmer.h b/programmer.h
index 5a21b2e2f..3cf53b94b 100644
--- a/programmer.h
+++ b/programmer.h
@@ -124,6 +124,9 @@ enum programmer {
 #if CONFIG_NI845X_SPI == 1
 	PROGRAMMER_NI845X_SPI,
 #endif
+#if CONFIG_STLINKV3_SPI == 1
+	PROGRAMMER_STLINKV3_SPI,
+#endif
 	PROGRAMMER_INVALID /* This must always be the last entry. */
 };
 
@@ -501,6 +504,12 @@ int pickit2_spi_init(void);
 extern const struct dev_entry devs_pickit2_spi[];
 #endif
 
+/* stlinkv3_spi.c */
+#if CONFIG_STLINKV3_SPI == 1
+int stlinkv3_spi_init(void);
+extern const struct dev_entry devs_stlinkv3_spi[];
+#endif
+
 /* rayer_spi.c */
 #if CONFIG_RAYER_SPI == 1
 int rayer_spi_init(void);
diff --git a/stlinkv3_spi.c b/stlinkv3_spi.c
new file mode 100644
index 000000000..02e87bc76
--- /dev/null
+++ b/stlinkv3_spi.c
@@ -0,0 +1,516 @@
+/*
+ * This file is part of the flashrom project.
+ *
+ * Copyright (C) 2019 Miklós Márton martonmiklosqdev@gmail.com
+ *
+ * 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.
+ *
+ */
+
+/*
+ * Driver for programming SPI flash chips using the SPI port
+ * of the STMicroelectronics's STLINK-V3 programmer/debugger.
+ *
+ * The implementation is inspired by the ST's STLINK-V3-BRIDGE C++ API:
+ * https://www.st.com/en/development-tools/stlink-v3-bridge.html
+ */
+
+#include "flash.h"
+#include "programmer.h"
+#include "spi.h"
+
+#include <libusb.h>
+#include <limits.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+enum fw_version_check_result {
+	FW_VERSION_OK,
+	FW_VERSION_OLD,
+};
+
+enum spi_prescaler {
+	SPI_BAUDRATEPRESCALER_2 = 0,
+	SPI_BAUDRATEPRESCALER_4 = 1,
+	SPI_BAUDRATEPRESCALER_8 = 2,
+	SPI_BAUDRATEPRESCALER_16 = 3,
+	SPI_BAUDRATEPRESCALER_32 = 4,
+	SPI_BAUDRATEPRESCALER_64 = 5,
+	SPI_BAUDRATEPRESCALER_128 = 6,
+	SPI_BAUDRATEPRESCALER_256 = 7
+};
+
+enum spi_dir {
+	SPI_DIRECTION_2LINES_FULLDUPLEX = 0,
+	SPI_DIRECTION_2LINES_RXONLY = 1,
+	SPI_DIRECTION_1LINE_RX = 2,
+	SPI_DIRECTION_1LINE_TX = 3
+};
+
+enum spi_mode {
+	SPI_MODE_SLAVE = 0,
+	SPI_MODE_MASTER = 1
+};
+
+enum spi_datasize {
+	SPI_DATASIZE_16B = 0,
+	SPI_DATASIZE_8B = 1
+};
+
+enum spi_cpol {
+	SPI_CPOL_LOW = 0,
+	SPI_CPOL_HIGH = 1
+};
+
+enum spi_cpha {
+	SPI_CPHA_1EDGE = 0,
+	SPI_CPHA_2EDGE = 1
+};
+
+enum spi_firstbit {
+	SPI_FIRSTBIT_LSB = 0,
+	SPI_FIRSTBIT_MSB = 1
+};
+
+// ST calls the Chip select (CS) NSS == Negated Slave Select
+enum spi_nss {
+	SPI_NSS_SOFT = 0,
+	SPI_NSS_HARD = 1
+};
+
+enum spi_nss_level {
+	SPI_NSS_LOW = 0,
+	SPI_NSS_HIGH = 1
+};
+
+#define ST_GETVERSION_EXT					0xFB
+
+#define STLINK_BRIDGE_COMMAND					0xFC
+#define STLINK_BRIDGE_CLOSE					0x01
+#define STLINK_BRIDGE_GET_RWCMD_STATUS				0x02
+#define STLINK_BRIDGE_GET_CLOCK					0x03
+#define STLINK_BRIDGE_INIT_SPI					0x20
+#define STLINK_BRIDGE_WRITE_SPI					0x21
+#define STLINK_BRIDGE_READ_SPI					0x22
+#define STLINK_BRIDGE_CS_SPI					0x23
+
+#define STLINK_BRIDGE_SPI_ERROR					0x02
+
+#define STLINK_SPI_COM						0x02
+
+#define STLINK_EP_OUT						0x06
+#define STLINK_EP_IN						0x86
+
+#define FIRST_COMPATIBLE_BRIDGE_FW_VERSION			3
+
+#define USB_TIMEOUT_IN_MS					5000
+
+const struct dev_entry devs_stlinkv3_spi[] = {
+	{0x0483, 0x374F, OK, "STMicroelectronics", "STLINK-V3"},
+	{0}
+};
+
+static struct libusb_context *usb_ctx;
+static libusb_device_handle *stlinkv3_handle;
+
+static int stlinkv3_command(uint8_t *command, size_t command_length,
+		     uint8_t *answer, size_t answer_length, const char *command_name)
+{
+	int actual_length = 0;
+	int rc = libusb_bulk_transfer(stlinkv3_handle, STLINK_EP_OUT,
+				  command, command_length,
+				  &actual_length, USB_TIMEOUT_IN_MS);
+	if (rc != LIBUSB_TRANSFER_COMPLETED || (size_t)actual_length != command_length) {
+		msg_perr("Failed to issue the %s command: '%s'\n",
+			 command_name,
+			 libusb_error_name(rc));
+		return -1;
+	}
+
+	rc = libusb_bulk_transfer(stlinkv3_handle, STLINK_EP_IN,
+				  answer, answer_length,
+				  &actual_length, USB_TIMEOUT_IN_MS);
+	if (rc != LIBUSB_TRANSFER_COMPLETED || (size_t)actual_length != answer_length) {
+		msg_perr("Failed to get %s answer: '%s'\n",
+			 command_name,
+			 libusb_error_name(rc));
+		return -1;
+	}
+	return 0;
+}
+
+/**
+ * @param[out] bridge_input_clk Current input frequency in kHz of the given com.
+ */
+static int stlinkv3_get_clk(uint32_t *bridge_input_clk)
+{
+	uint8_t command[16];
+	uint8_t answer[12];
+
+	if (bridge_input_clk == NULL)
+		return -1;
+
+	memset(command, 0, sizeof(command));
+
+	command[0] = STLINK_BRIDGE_COMMAND;
+	command[1] = STLINK_BRIDGE_GET_CLOCK;
+	command[2] = STLINK_SPI_COM;
+
+	if (stlinkv3_command(command, sizeof(command), answer, sizeof(answer), "STLINK_BRIDGE_GET_CLOCK") != 0)
+		return -1;
+
+	*bridge_input_clk = (uint32_t)answer[4]
+			  | (uint32_t)answer[5]<<8
+			  | (uint32_t)answer[6]<<16
+			  | (uint32_t)answer[7]<<24;
+	return 0;
+
+}
+
+static int stlinkv3_spi_calc_prescaler(uint16_t reqested_freq_in_kHz,
+				       enum spi_prescaler *prescaler,
+				       uint16_t *calculated_freq_in_kHz)
+{
+	uint32_t bridge_clk_in_kHz;
+	uint32_t calculated_prescaler = 1;
+	uint16_t prescaler_value;
+
+	if (stlinkv3_get_clk(&bridge_clk_in_kHz))
+		return -1;
+
+	calculated_prescaler  = bridge_clk_in_kHz/reqested_freq_in_kHz;
+	// Apply a smaller frequency if not exact
+	if (calculated_prescaler  <= 2) {
+		*prescaler = SPI_BAUDRATEPRESCALER_2;
+		prescaler_value = 2;
+	} else if (calculated_prescaler  <= 4) {
+		*prescaler = SPI_BAUDRATEPRESCALER_4;
+		prescaler_value = 4;
+	} else if (calculated_prescaler  <= 8) {
+		*prescaler = SPI_BAUDRATEPRESCALER_8;
+		prescaler_value = 8;
+	} else if (calculated_prescaler  <= 16) {
+		*prescaler = SPI_BAUDRATEPRESCALER_16;
+		prescaler_value = 16;
+	} else if (calculated_prescaler  <= 32) {
+		*prescaler = SPI_BAUDRATEPRESCALER_32;
+		prescaler_value = 32;
+	} else if (calculated_prescaler  <= 64) {
+		*prescaler = SPI_BAUDRATEPRESCALER_64;
+		prescaler_value = 64;
+	} else if (calculated_prescaler  <= 128) {
+		*prescaler = SPI_BAUDRATEPRESCALER_128;
+		prescaler_value = 128;
+	} else if (calculated_prescaler  <= 256) {
+		*prescaler = SPI_BAUDRATEPRESCALER_256;
+		prescaler_value = 256;
+	} else {
+		// smaller frequency not possible
+		*prescaler = SPI_BAUDRATEPRESCALER_256;
+		prescaler_value = 256;
+	}
+
+	*calculated_freq_in_kHz = bridge_clk_in_kHz / prescaler_value;
+
+	return 0;
+}
+
+static int stlinkv3_check_version(enum fw_version_check_result *result)
+{
+	uint8_t answer[12];
+	uint8_t command[16];
+
+	memset(command, 0, sizeof(command));
+
+	command[0] = ST_GETVERSION_EXT;
+	command[1] = 0x80;
+
+	if (stlinkv3_command(command, sizeof(command), answer, sizeof(answer), "ST_GETVERSION_EXT") != 0)
+		return -1;
+
+	msg_pinfo("Connected to STLink V3 with bridge FW version: %d\n", answer[4]);
+	*result = answer[4] >= FIRST_COMPATIBLE_BRIDGE_FW_VERSION
+			? FW_VERSION_OK
+			: FW_VERSION_OLD;
+	return 0;
+}
+
+static int stlinkv3_spi_open(uint16_t reqested_freq_in_kHz)
+{
+	uint8_t command[16];
+	uint8_t answer[2];
+	uint16_t SCK_freq_in_kHz;
+	enum spi_prescaler prescaler;
+	enum fw_version_check_result fw_check_result;
+
+	if (stlinkv3_check_version(&fw_check_result)) {
+		msg_perr("Failed to query FW version");
+		return -1;
+	}
+
+	if (fw_check_result != FW_VERSION_OK) {
+		msg_pinfo("Your STLink V3 has too old version of the bridge interface\n"
+			  "Please update the firmware with the STSW-LINK007 which can be downloaded from here:\n"
+			  "https://www.st.com/en/development-tools/stsw-link007.html");
+		return -1;
+	}
+
+	if (stlinkv3_spi_calc_prescaler(reqested_freq_in_kHz,
+					&prescaler,
+					&SCK_freq_in_kHz)) {
+		msg_perr("Failed to calculate SPI clock prescaler");
+		return -1;
+	}
+	msg_pinfo("SCK frequency set to %d kHz\n", SCK_freq_in_kHz);
+
+	memset(command, 0, sizeof(command));
+
+	command[0] = STLINK_BRIDGE_COMMAND;
+	command[1] = STLINK_BRIDGE_INIT_SPI;
+	command[2] = SPI_DIRECTION_2LINES_FULLDUPLEX;
+	command[3] = (SPI_MODE_MASTER
+		      | (SPI_CPHA_1EDGE << 1)
+		      | (SPI_CPOL_LOW << 2)
+		      | (SPI_FIRSTBIT_MSB << 3));
+	command[4] = SPI_DATASIZE_8B;
+	command[5] = SPI_NSS_SOFT;
+	command[6] = (uint8_t)prescaler;
+
+	return stlinkv3_command(command, sizeof(command), answer, sizeof(answer), "STLINK_BRIDGE_INIT_SPI");
+}
+
+static int stlinkv3_get_last_readwrite_status(uint32_t *status)
+{
+	uint8_t command[16];
+	uint16_t answer[4];
+
+	memset(command, 0, sizeof(command));
+
+	command[0] = STLINK_BRIDGE_COMMAND;
+	command[1] = STLINK_BRIDGE_GET_RWCMD_STATUS;
+
+	if (stlinkv3_command(command, sizeof(command),
+			     (uint8_t *)answer, sizeof(answer),
+			     "STLINK_BRIDGE_GET_RWCMD_STATUS") != 0)
+		return -1;
+
+	*status = (uint32_t)answer[2] | (uint32_t)answer[3]<<16;
+	return 0;
+}
+
+static int stlinkv3_spi_set_SPI_NSS(enum spi_nss_level nss_level)
+{
+	uint8_t command[16];
+	uint8_t answer[2];
+
+	memset(command, 0, sizeof(command));
+
+	command[0] = STLINK_BRIDGE_COMMAND;
+	command[1] = STLINK_BRIDGE_CS_SPI;
+	command[2] = (uint8_t) (nss_level);
+
+	if (stlinkv3_command(command, sizeof(command), answer, sizeof(answer), "STLINK_BRIDGE_CS_SPI") != 0)
+		return -1;
+	return 0;
+}
+
+static int stlinkv3_spi_transmit(struct flashctx *flash,
+				 unsigned int write_cnt,
+				 unsigned int read_cnt,
+				 const unsigned char *write_arr,
+				 unsigned char *read_arr)
+{
+	uint8_t command[16];
+	int rc = 0;
+	int actual_length = 0;
+	uint32_t rw_status = 0;
+
+	if (stlinkv3_spi_set_SPI_NSS(SPI_NSS_LOW)) {
+		msg_perr("Failed to set the NSS pin to low\n");
+		return -1;
+	}
+
+	memset(command, 0, sizeof(command));
+
+	command[0] = STLINK_BRIDGE_COMMAND;
+	command[1] = STLINK_BRIDGE_WRITE_SPI;
+	command[2] = (uint8_t)write_cnt;
+	command[3] = (uint8_t)(write_cnt >> 8);
+
+	for (unsigned int i = 0; (i < 8) && (i < write_cnt); i++)
+		command[4+i] = write_arr[i];
+
+	rc = libusb_bulk_transfer(stlinkv3_handle, STLINK_EP_OUT,
+				  command, sizeof(command),
+				  &actual_length, USB_TIMEOUT_IN_MS);
+	if (rc != LIBUSB_TRANSFER_COMPLETED || actual_length != sizeof(command)) {
+		msg_perr("Failed to issue the STLINK_BRIDGE_WRITE_SPI command: '%s'\n",
+			 libusb_error_name(rc));
+		goto transmit_err;
+	}
+
+	if (write_cnt > 8) {
+		rc = libusb_bulk_transfer(stlinkv3_handle,
+					  STLINK_EP_OUT,
+					  (unsigned char *)&write_arr[8],
+					  (unsigned int)(write_cnt - 8),
+					  &actual_length,
+					  USB_TIMEOUT_IN_MS);
+		if (rc != LIBUSB_TRANSFER_COMPLETED || (unsigned int)actual_length != (write_cnt - 8)) {
+			msg_perr("Failed to send the  data after the  STLINK_BRIDGE_WRITE_SPI command: '%s'\n",
+				 libusb_error_name(rc));
+			goto transmit_err;
+		}
+	}
+
+	if (stlinkv3_get_last_readwrite_status(&rw_status))
+		return -1;
+
+	if (rw_status != 0) {
+		msg_perr("SPI read/write failure: %d\n", rw_status);
+		goto transmit_err;
+	}
+
+	if (read_cnt) {
+		command[1] = STLINK_BRIDGE_READ_SPI;
+		command[2] = (uint8_t)read_cnt;
+		command[3] = (uint8_t)(read_cnt >> 8);
+
+		rc = libusb_bulk_transfer(stlinkv3_handle, STLINK_EP_OUT,
+					  command, sizeof(command),
+					  &actual_length, USB_TIMEOUT_IN_MS);
+		if (rc != LIBUSB_TRANSFER_COMPLETED || (unsigned int)actual_length != sizeof(command)) {
+			msg_perr("Failed to issue the STLINK_BRIDGE_READ_SPI command: '%s'\n",
+				 libusb_error_name(rc));
+			goto transmit_err;
+		}
+
+		rc = libusb_bulk_transfer(stlinkv3_handle,
+					  STLINK_EP_IN,
+					  (unsigned char *)read_arr,
+					  (int)read_cnt,
+					  &actual_length,
+					  USB_TIMEOUT_IN_MS);
+		if (rc != LIBUSB_TRANSFER_COMPLETED || (unsigned int)actual_length != read_cnt) {
+			msg_perr("Failed to retrive the STLINK_BRIDGE_READ_SPI answer: '%s'\n",
+				 libusb_error_name(rc));
+			goto transmit_err;
+		}
+	}
+
+	if (stlinkv3_get_last_readwrite_status(&rw_status))
+		goto transmit_err;
+
+	if (rw_status != 0) {
+		msg_perr("SPI read/write failure: %d\n", rw_status);
+		goto transmit_err;
+	}
+
+	if (stlinkv3_spi_set_SPI_NSS(SPI_NSS_HIGH)) {
+		msg_perr("Failed to set the NSS pin to high\n");
+		return -1;
+	}
+	return 0;
+
+transmit_err:
+	if (stlinkv3_spi_set_SPI_NSS(SPI_NSS_HIGH))
+		msg_perr("Failed to set the NSS pin to high\n");
+	return -1;
+}
+
+static int stlinkv3_spi_shutdown(void *data)
+{
+	uint8_t command[16];
+	uint8_t answer[2];
+
+	memset(command, 0, sizeof(command));
+
+	command[0] = STLINK_BRIDGE_COMMAND;
+	command[1] = STLINK_BRIDGE_CLOSE;
+	command[2] = STLINK_SPI_COM;
+
+	stlinkv3_command(command, sizeof(command), answer, sizeof(answer), "STLINK_BRIDGE_CLOSE");
+
+	libusb_close(stlinkv3_handle);
+	libusb_exit(usb_ctx);
+
+	return 0;
+}
+
+static const struct spi_master spi_programmer_stlinkv3 = {
+	.max_data_read = UINT16_MAX,
+	.max_data_write = UINT16_MAX,
+	.command = stlinkv3_spi_transmit,
+	.multicommand = default_spi_send_multicommand,
+	.read = default_spi_read,
+	.write_256 = default_spi_write_256,
+	.write_aai = default_spi_write_aai,
+};
+
+int stlinkv3_spi_init(void)
+{
+	uint16_t sck_freq_kHz = 1000;	// selecting 1 MHz SCK is a good bet
+	char *speed_str = NULL;
+	char *serialno = NULL;
+	char *endptr = NULL;
+
+	libusb_init(&usb_ctx);
+	if (!usb_ctx) {
+		msg_perr("Could not initialize libusb!\n");
+		return 1;
+	}
+
+	serialno = extract_programmer_param("serial");
+	if (serialno)
+		msg_pdbg("Opening STLINK-V3 with serial: %s\n", serialno);
+	stlinkv3_handle = usb_dev_get_by_vid_pid_serial(usb_ctx,
+							devs_stlinkv3_spi[0].vendor_id,
+							devs_stlinkv3_spi[0].device_id,
+							serialno);
+
+	if (!stlinkv3_handle) {
+		if (serialno)
+			msg_perr("No STLINK-V3 seems to be connected with serial %s\n", serialno);
+		else
+			msg_perr("Could not find any connected STLINK-V3\n");
+		free(serialno);
+		goto err_exit;
+	}
+	free(serialno);
+
+	speed_str = extract_programmer_param("spispeed");
+	if (speed_str) {
+		sck_freq_kHz = strtoul(speed_str, &endptr, 0);
+		if (*endptr) {
+			msg_perr("The spispeed parameter passed with invalid format: %s\n",
+				 speed_str);
+			msg_perr("Please pass the parameter with a simple number in kHz\n");
+			return -1;
+		}
+		free(speed_str);
+	}
+
+	if (stlinkv3_spi_open(sck_freq_kHz))
+		goto err_exit;
+
+	if (register_shutdown(stlinkv3_spi_shutdown, NULL))
+		goto err_exit;
+
+	if (register_spi_master(&spi_programmer_stlinkv3))
+		goto err_exit;
+
+	return 0;
+
+err_exit:
+	libusb_exit(usb_ctx);
+	return 1;
+}