From 528bd32a7b4bf9b1d28c0cdbbae5458623453e34 Mon Sep 17 00:00:00 2001
From: Alexandre Boeglin <alex@boeglin.org>
Date: Tue, 29 Apr 2014 21:35:26 +0200
Subject: [PATCH] Add programmer for the MSTAR I2C ISP protocol

Signed-off-by: Alexandre Boeglin <alex@boeglin.org>
---
 Makefile        |  13 ++++
 flashrom.8.tmpl |  53 +++++++++++++
 flashrom.c      |  12 +++
 mstarddc_spi.c  | 234 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 programmer.h    |  11 +++
 5 files changed, 323 insertions(+)
 create mode 100644 mstarddc_spi.c

diff --git a/Makefile b/Makefile
index 98230a5..6c5fcb9 100644
--- a/Makefile
+++ b/Makefile
@@ -300,6 +300,11 @@ UNSUPPORTED_FEATURES += CONFIG_LINUX_SPI=yes
 else
 override CONFIG_LINUX_SPI = no
 endif
+ifeq ($(CONFIG_MSTARDDC_SPI), yes)
+UNSUPPORTED_FEATURES += CONFIG_MSTARDDC_SPI=yes
+else
+override CONFIG_MSTARDDC_SPI = no
+endif
 endif
 
 ###############################################################################
@@ -413,6 +418,9 @@ CONFIG_FT2232_SPI ?= yes
 # Always enable Altera USB-Blaster dongles for now.
 CONFIG_USBBLASTER_SPI ?= yes
 
+# Always enable MSTAR DDC for now.
+CONFIG_MSTARDDC_SPI ?= yes
+
 # Always enable dummy tracing for now.
 CONFIG_DUMMY ?= yes
 
@@ -591,6 +599,11 @@ NEED_FTDI := yes
 PROGRAMMER_OBJS += usbblaster_spi.o
 endif
 
+ifeq ($(CONFIG_MSTARDDC_SPI), yes)
+FEATURE_CFLAGS += -D'CONFIG_MSTARDDC_SPI=1'
+PROGRAMMER_OBJS += mstarddc_spi.o
+endif
+
 ifeq ($(NEED_FTDI), yes)
 FTDILIBS := $(shell pkg-config --libs libftdi 2>/dev/null || printf "%s" "-lftdi -lusb")
 FEATURE_CFLAGS += $(shell LC_ALL=C grep -q "FT232H := yes" .features && printf "%s" "-D'HAVE_FT232H=1'")
diff --git a/flashrom.8.tmpl b/flashrom.8.tmpl
index 81eceaa..e1004d4 100644
--- a/flashrom.8.tmpl
+++ b/flashrom.8.tmpl
@@ -227,6 +227,8 @@ bitbanging adapter)
 .sp
 .BR "* nicintel_eeprom" " (for SPI EEPROMs on Intel Gigabit network cards)"
 .sp
+.BR "* mstarddc_spi" " (for SPI flash ROMs accessible through DDC in MSTAR-equipped displays)"
+.sp
 Some programmers have optional or mandatory parameters which are described
 in detail in the
 .B PROGRAMMER-SPECIFIC INFORMATION
@@ -889,6 +891,57 @@ Example that sets the frequency to 8 MHz:
 .B "  flashrom \-p linux_spi:dev=/dev/spidevX.Y,spispeed=8000"
 .sp
 Please note that the linux_spi driver only works on Linux.
+.SS
+.BR "mstarddc_spi " programmer
+The Display Data Channel (DDC) is an I2C bus present on VGA and DVI
+connectors, that allows exchanging informations between a computer and its
+attached displays. Its most common uses are getting display capabilities
+through EDID (at I2C address 0x50) and sending commands to the display using
+the DDC/CI protocol (at address 0x37). On displays driven by MSTAR SoCs, it is
+also possible to access the SoC firmware flash (connected to the Soc through
+another SPI bus) using an In-System Programming (ISP) port, usually at address
+0x49.
+.sp
+.B IMPORTANT:
+Before using this programmer, the display
+.B MUST
+be in standby mode, and only connected to the computer that will run flashrom
+using a VGA cable, to an inactive VGA output. It absolutely
+.B MUST NOT
+be used as a display during the procedure!
+.sp
+You have to specify the DDC/I2C controller and I2C address to use with the
+.sp
+.B "  flashrom \-p mstarddc_spi:dev=/dev/i2c-X:YY"
+.sp
+syntax where
+.B /dev/i2c-X
+is the Linux device node for your I2C controller conected to the display's DDC
+channel, and
+.B YY
+is the (hexadecimal) address of the MSTAR ISP port (address 0x49 is usually
+used).
+Example that uses I2C controller /dev/i2c-1 and address 0x49:
+.sp
+.B "  flashrom \-p mstarddc_spi:dev=/dev/i2c-1:49
+.sp
+It is also possible to inhibit the reset command that is normally sent to the
+display once the flashrom operation is completed using the optional
+.B noreset
+parameter. A value of 1 prevents flashrom from sending the reset command.
+Example that does not reset the display at the end of the operation:
+.sp
+.B "  flashrom \-p mstarddc_spi:dev=/dev/i2c-1:49,noreset=1
+.sp
+Please note that sending the reset command is also inhibited in the event an
+error occured during the operation. To send the reset command afterwards, you
+can simply run flashrom once more, in chip probe mode (not specifying an
+operation), without the
+.B noreset
+parameter, once the flash read/write operation you intended to perform has
+completed successfully.
+.sp
+Please also note that the mstarddc_spi driver only works on Linux.
 .SH EXAMPLES
 To back up and update your BIOS, run
 .sp
diff --git a/flashrom.c b/flashrom.c
index 93b292b..184e181 100644
--- a/flashrom.c
+++ b/flashrom.c
@@ -354,6 +354,18 @@ const struct programmer_entry programmer_table[] = {
 	},
 #endif
 
+#if CONFIG_MSTARDDC_SPI == 1
+	{
+		.name			= "mstarddc_spi",
+		.type			= OTHER,
+		.devs.note		= "Device files /dev/i2c-*\n",
+		.init			= mstarddc_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/mstarddc_spi.c b/mstarddc_spi.c
new file mode 100644
index 0000000..a2c91bd
--- /dev/null
+++ b/mstarddc_spi.c
@@ -0,0 +1,234 @@
+/*
+ * This file is part of the flashrom project.
+ *
+ * Copyright (C) 2014 Alexandre Boeglin <alex@boeglin.org>
+ *
+ * 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; version 2 of the License.
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+
+#if CONFIG_MSTARDDC_SPI == 1
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/ioctl.h>
+#include <linux/i2c-dev.h>
+#include <linux/i2c.h>
+#include "flash.h"
+#include "programmer.h"
+#include "spi.h"
+
+static const struct spi_master spi_master_mstarddc;
+
+static int mstarddc_fd;
+static int mstarddc_addr;
+static int mstarddc_doreset = 1;
+
+// MSTAR DDC Commands
+#define MSTARDDC_SPI_WRITE	0x10
+#define MSTARDDC_SPI_READ	0x11
+#define MSTARDDC_SPI_END	0x12
+#define MSTARDDC_SPI_RESET	0x24
+
+/* Returns 0 upon success, a negative number upon errors. */
+static int mstarddc_spi_shutdown(void *data)
+{
+	// Reset, disables ISP mode
+	if (mstarddc_doreset == 1) {
+		uint8_t cmd = MSTARDDC_SPI_RESET;
+		if (write(mstarddc_fd, &cmd, 1) < 0) {
+			msg_perr("Error sending reset command: errno %d.\n",
+				 errno);
+			return -1;
+		}
+	} else {
+		msg_pinfo("Info: Reset command was not sent. "
+			  "Either the noreset=1 option was used, "
+			  "or an error occured.\n");
+	}
+
+	if (close(mstarddc_fd) < 0) {
+		msg_perr("Error closing device: errno %d.\n", errno);
+		return -1;
+	}
+	return 0;
+}
+
+/* Returns 0 upon success, a negative number upon errors. */
+int mstarddc_spi_init(void)
+{
+	char *i2c_device;
+	char *i2c_address;
+	char *noreset;
+
+	// Get device, address from command-line
+	i2c_device = extract_programmer_param("dev");
+	if (i2c_device && strlen(i2c_device)) {
+		if ((i2c_address = strchr(i2c_device, ':'))) {
+			*i2c_address = '\0';
+			i2c_address++;
+		}
+		if (!i2c_address || !strlen(i2c_address)) {
+			msg_perr("Error: no address specified.\n"
+				 "Use flashrom -p mstarddc_spi:dev=/dev/device:address.\n");
+			return -1;
+		}
+		mstarddc_addr = strtol(i2c_address, NULL, 16);
+	} else {
+		msg_perr("Error: no device specified.\n"
+			 "Use flashrom -p mstarddc_spi:dev=/dev/device:address.\n");
+		return -1;
+	}
+	msg_pinfo("Info: Will try to use device %s and address 0x%02x.\n",
+		  i2c_device, mstarddc_addr);
+
+	// Get noreset=1 option from command-line
+	if ((noreset = extract_programmer_param("noreset"))
+	    && noreset[0] == '1')
+		mstarddc_doreset = 0;
+	msg_pinfo("Info: WILL %sreset the device at the end.\n",
+		  mstarddc_doreset ? "" : "NOT ");
+	// Open device
+	if ((mstarddc_fd = open(i2c_device, O_RDWR)) < 0) {
+		switch (errno) {
+		case EACCES:
+			msg_perr("Error opening %s: Permission denied.\n"
+				 "Please use sudo or run as root.\n",
+				 i2c_device);
+			break;
+		case ENOENT:
+			msg_perr("Error opening %s: No such file.\n"
+				 "Please check you specified the correct device.\n",
+				 i2c_device);
+			break;
+		default:
+			msg_perr("Error opening %s: errno %d.\n",
+				 i2c_device, errno);
+		}
+		return -1;
+	}
+	// Set slave address
+	if (ioctl(mstarddc_fd, I2C_SLAVE, mstarddc_addr) < 0) {
+		msg_perr("Error setting slave address 0x%02x: errno %d.\n",
+			 mstarddc_addr, errno);
+		return -1;
+	}
+	// Enable ISP mode
+	uint8_t cmd[5] = { 'M', 'S', 'T', 'A', 'R' };
+	if (write(mstarddc_fd, cmd, 5) < 0) {
+		int enable_err = errno;
+		char end_cmd = MSTARDDC_SPI_END;
+
+		// Assume device is already in ISP mode, try to send END command
+		if (write(mstarddc_fd, &end_cmd, 1) < 0) {
+			msg_perr("Error enabling ISP mode: errno %d & %d.\n"
+				 "Please check that device (%s) and address (0x%02x) are correct.\n",
+				 enable_err, errno, i2c_device, mstarddc_addr);
+			return -1;
+		}
+	}
+	// Register shutdown function
+	register_shutdown(mstarddc_spi_shutdown, NULL);
+
+	// Register master
+	register_spi_master(&spi_master_mstarddc);
+	return 0;
+}
+
+/* Returns 0 upon success, a negative number upon errors. */
+static int mstarddc_spi_send_command(struct flashctx *flash,
+				     unsigned int writecnt,
+				     unsigned int readcnt,
+				     const unsigned char *writearr,
+				     unsigned char *readarr)
+{
+	int ret = 0;
+	uint8_t *cmd;
+
+	if ((cmd = malloc((writecnt + 1) * sizeof(uint8_t))) < 0) {
+		msg_perr("Error allocating memory: errno %d.\n", errno);
+		ret = -1;
+	}
+
+	if (!ret && writecnt) {
+		cmd[0] = MSTARDDC_SPI_WRITE;
+		memcpy(cmd + 1, writearr, writecnt);
+		if (write(mstarddc_fd, cmd, writecnt + 1) < 0) {
+			msg_perr("Error sending write command: errno %d.\n",
+				 errno);
+			ret = -1;
+		}
+	}
+
+	if (!ret && readcnt) {
+		struct i2c_rdwr_ioctl_data i2c_data;
+		struct i2c_msg msg[2];
+
+		cmd[0] = MSTARDDC_SPI_READ;
+		i2c_data.nmsgs = 2;
+		i2c_data.msgs = msg;
+		i2c_data.msgs[0].addr = mstarddc_addr;
+		i2c_data.msgs[0].len = 1;
+		i2c_data.msgs[0].flags = 0;
+		i2c_data.msgs[0].buf = cmd;
+		i2c_data.msgs[1].addr = mstarddc_addr;
+		i2c_data.msgs[1].len = readcnt;
+		i2c_data.msgs[1].flags = I2C_M_RD;
+		i2c_data.msgs[1].buf = readarr;
+
+		if (ioctl(mstarddc_fd, I2C_RDWR, &i2c_data) < 0) {
+			msg_perr("Error sending read command: errno %d.\n",
+				 errno);
+			ret = -1;
+		}
+	}
+
+	if (!ret && (writecnt || readcnt)) {
+		cmd[0] = MSTARDDC_SPI_END;
+		if (write(mstarddc_fd, cmd, 1) < 0) {
+			msg_perr("Error sending end command: errno %d.\n",
+				 errno);
+			ret = -1;
+		}
+	}
+
+	/* Do not reset if something went wrong, as it might prevent from
+	 * retrying flashing. */
+	if (ret != 0)
+		mstarddc_doreset = 0;
+
+	if (cmd)
+		free(cmd);
+
+	return ret;
+}
+
+static const struct spi_master spi_master_mstarddc = {
+	.type = SPI_CONTROLLER_MSTARDDC,
+	.max_data_read = 256,
+	.max_data_write = 256,
+	.command = mstarddc_spi_send_command,
+	.multicommand = default_spi_send_multicommand,
+	.read = default_spi_read,
+	.write_256 = default_spi_write_256,
+	.write_aai = default_spi_write_aai,
+};
+
+#endif
diff --git a/programmer.h b/programmer.h
index 09b6087..d6e06cb 100644
--- a/programmer.h
+++ b/programmer.h
@@ -99,6 +99,9 @@ enum programmer {
 #if CONFIG_USBBLASTER_SPI == 1
 	PROGRAMMER_USBBLASTER_SPI,
 #endif
+#if CONFIG_MSTARDDC_SPI == 1
+	PROGRAMMER_MSTARDDC_SPI,
+#endif
 	PROGRAMMER_INVALID /* This must always be the last entry. */
 };
 
@@ -474,6 +477,11 @@ int usbblaster_spi_init(void);
 extern const struct dev_entry devs_usbblasterspi[];
 #endif
 
+/* mstarddc_spi.c */
+#if CONFIG_MSTARDDC_SPI == 1
+int mstarddc_spi_init(void);
+#endif
+
 /* rayer_spi.c */
 #if CONFIG_RAYER_SPI == 1
 int rayer_spi_init(void);
@@ -555,6 +563,9 @@ enum spi_controller {
 #if CONFIG_USBBLASTER_SPI == 1
 	SPI_CONTROLLER_USBBLASTER,
 #endif
+#if CONFIG_MSTARDDC_SPI == 1
+	SPI_CONTROLLER_MSTARDDC,
+#endif
 };
 
 #define MAX_DATA_UNSPECIFIED 0
-- 
2.1.0

