Add support for the MSTAR I2C ISP protocol

Basically, among other chips, MSTAR manufactures SoCs that equip TV sets
and computer screens, and it seems that all of their products use the
same in-system programming protocol. Basically, they use the DDC channel
of VGA or DVI connectors, which is actually an I2C bus, to encapsulate
SPI frames (the flash chip is connected to the SoC through an SPI bus).

I wrote this patch since the screen I bought had a software bug, and the
manufacturer only released a new firmware binary, but no tool or
instructions on flashing it.

More details can be found here:
http://boeglin.org/blog/index.php?entry=Flashing-a-BenQ-Z-series-for-free(dom)

I only read code from Linux kernel archives published by Acer to figure
out the protocol (for a touchscreen controller and an NFC chip, both by
MSTAR, that share the same ISP protocol), so I don't think there are
any legal problems with it.

Compilation is currently disabled by default in the Makefile.
If in doubt, additional Makefile bugs were added by Stefan.

Corresponding to flashrom svn r1860.

Signed-off-by: Alexandre Boeglin <alex@boeglin.org>
Signed-off-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>

1 files changed, 234 insertions, 0 deletions

diff --git a/mstarddc_spi.c b/mstarddc_spi.c
new file mode 100644
index 0000000..0b41a1b
--- /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;
+		uint8_t 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 programmer
+	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