Add support for the ENE Embedded Debug Interface EDI and KB9012 EC

The ENE Embedded Debug Interface (EDI) is a SPI-based interface for
accessing the memory of ENE embedded controllers.

The ENE KB9012 EC is an embedded controller found on various laptops
such as the Lenovo G505s. It features a 8051 microcontroller and
has 128 KiB of internal storage for program data.

EDI can be accessed on the KB9012 through pins 59-62 (CS-CLK-MOSI-MISO)
when flash direct access is not in use. Some firmwares disable EDI at runtime
so it might be necessary to ground pin 42 to reset the 8051 microcontroller
before accessing the KB9012 via EDI.

The example of flashing KB9012 at Lenovo G505S laptop could be found here:
http://dangerousprototypes.com/docs/Flashing_KB9012_with_Bus_Pirate

Change-Id: Ib8b2eb2feeef5c337d725d15ebf994a299897854
Signed-off-by: Mike Banon <mikebdp2@gmail.com>
Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
Reviewed-on: https://review.coreboot.org/23259
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>

1 files changed, 497 insertions, 0 deletions

diff --git a/edi.c b/edi.c
new file mode 100644
index 000000000..0ca170428
--- /dev/null
+++ b/edi.c
@@ -0,0 +1,497 @@
+/*
+ * This file is part of the flashrom project.
+ *
+ * Copyright (C) 2015 Paul Kocialkowski <contact@paulk.fr>
+ *
+ * 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.
+ */
+
+#include <string.h>
+#include "flash.h"
+#include "ene.h"
+#include "edi.h"
+
+static unsigned int edi_read_buffer_length = EDI_READ_BUFFER_LENGTH_DEFAULT;
+
+static const struct ene_chip ene_kb9012 = {
+	.hwversion = ENE_KB9012_HWVERSION,
+	.ediid = ENE_KB9012_EDIID,
+};
+
+static void edi_write_cmd(unsigned char *cmd, unsigned short address, unsigned char data)
+{
+	cmd[0] = EDI_WRITE; /* EDI write command. */
+	cmd[1] = 0x00; /* Address is only 2 bytes. */
+	cmd[2] = (address >> 8) & 0xff; /* Address higher byte. */
+	cmd[3] = (address >> 0) & 0xff; /* Address lower byte. */
+	cmd[4] = data; /* Write data. */
+}
+
+static void edi_read_cmd(unsigned char *cmd, unsigned short address)
+{
+	cmd[0] = EDI_READ; /* EDI read command. */
+	cmd[1] = 0x00; /* Address is only 2 bytes. */
+	cmd[2] = (address >> 8) & 0xff; /* Address higher byte. */
+	cmd[3] = (address >> 0) & 0xff; /* Address lower byte. */
+}
+
+static int edi_write(struct flashctx *flash, unsigned short address, unsigned char data)
+{
+	unsigned char cmd[5];
+	int rc;
+
+	edi_write_cmd(cmd, address, data);
+
+	rc = spi_send_command(flash, sizeof(cmd), 0, cmd, NULL);
+	if (rc)
+		return -1;
+
+	return 0;
+}
+
+static int edi_read_byte(struct flashctx *flash, unsigned short address, unsigned char *data)
+{
+	unsigned char cmd[4];
+	unsigned char buffer[edi_read_buffer_length];
+	unsigned int index;
+	unsigned int i;
+	int rc;
+
+	edi_read_cmd(cmd, address);
+
+	rc = spi_send_command(flash, sizeof(cmd), sizeof(buffer), cmd, buffer);
+	if (rc)
+		return -1;
+
+	index = 0;
+
+	for (i = 0; i < sizeof(buffer); i++) {
+		index = i;
+
+		if (buffer[i] == EDI_NOT_READY)
+			continue;
+
+		if (buffer[i] == EDI_READY) {
+			if (i == (sizeof(buffer) - 1)) {
+				/*
+				 * Buffer size was too small for receiving the value.
+				 * This is as good as getting only EDI_NOT_READY.
+				 */
+
+				buffer[i] = EDI_NOT_READY;
+				break;
+			}
+
+			*data = buffer[i + 1];
+			return 0;
+		}
+	}
+
+	if (buffer[index] == EDI_NOT_READY)
+		return -EDI_NOT_READY;
+
+	return -1;
+}
+
+static int edi_read(struct flashctx *flash, unsigned short address, unsigned char *data)
+{
+	int rc;
+
+	do {
+		rc = edi_read_byte(flash, address, data);
+		if (rc == -EDI_NOT_READY) {
+			/*
+			 * Buffer size is increased, one step at a time,
+			 * to hold more data if we only catch EDI_NOT_READY.
+			 * Once CS is deasserted, no more data will be sent by the EC,
+			 * so we cannot keep reading afterwards and have to start a new
+			 * transaction with a longer buffer, to be safe.
+			 */
+
+			if (edi_read_buffer_length < EDI_READ_BUFFER_LENGTH_MAX) {
+				msg_pwarn("%s: Retrying read with greater buffer length!\n", __func__);
+				edi_read_buffer_length++;
+			} else {
+				msg_perr("%s: Maximum buffer length reached and data still not ready!\n", __func__);
+				return -1;
+			}
+		} else if (rc < 0) {
+			return -1;
+		}
+	} while (rc == -EDI_NOT_READY);
+
+	return 0;
+}
+
+static int edi_disable(struct flashctx *flash)
+{
+	unsigned char cmd = EDI_DISABLE;
+	int rc;
+
+	rc = spi_send_command(flash, sizeof(cmd), 0, &cmd, NULL);
+	if (rc)
+		return -1;
+
+	return 0;
+}
+
+static int edi_chip_probe(struct flashctx *flash, const struct ene_chip *chip)
+{
+	unsigned char hwversion;
+	unsigned char ediid;
+	int rc;
+
+	rc = edi_read(flash, ENE_EC_HWVERSION, &hwversion);
+	if (rc < 0)
+		return 0;
+
+	rc = edi_read(flash, ENE_EC_EDIID, &ediid);
+	if (rc < 0)
+		return 0;
+
+	if (chip->hwversion == hwversion && chip->ediid == ediid)
+		return 1;
+
+	return 0;
+}
+
+static int edi_spi_enable(struct flashctx *flash)
+{
+	unsigned char buffer;
+	int rc;
+
+	rc = edi_read(flash, ENE_XBI_EFCFG, &buffer);
+	if (rc < 0)
+		return -1;
+
+	buffer |= ENE_XBI_EFCFG_CMD_WE;
+
+	rc = edi_write(flash, ENE_XBI_EFCFG, buffer);
+	if (rc < 0)
+		return -1;
+
+	return 0;
+}
+
+static int edi_spi_disable(struct flashctx *flash)
+{
+	unsigned char buffer;
+	int rc;
+
+	rc = edi_read(flash, ENE_XBI_EFCFG, &buffer);
+	if (rc < 0)
+		return -1;
+
+	buffer &= ~ENE_XBI_EFCFG_CMD_WE;
+
+	rc = edi_write(flash, ENE_XBI_EFCFG, buffer);
+	if (rc < 0)
+		return -1;
+
+	return 0;
+}
+
+static int edi_spi_busy(struct flashctx *flash)
+{
+	unsigned char buffer;
+	int rc;
+
+	rc = edi_read(flash, ENE_XBI_EFCFG, &buffer);
+	if (rc < 0)
+		return -1;
+
+	return !!(buffer & ENE_XBI_EFCFG_BUSY);
+}
+
+static int edi_spi_address(struct flashctx *flash, unsigned int start, unsigned int address)
+{
+	int rc;
+
+	if ((address == start) || (((address - 1) & 0xff) != (address & 0xff))) {
+		rc = edi_write(flash, ENE_XBI_EFA0, ((address & 0xff) >> 0));
+		if (rc < 0)
+			return -1;
+	}
+
+	if ((address == start) || (((address - 1) & 0xff00) != (address & 0xff00))) {
+		rc = edi_write(flash, ENE_XBI_EFA1, ((address & 0xff00) >> 8));
+		if (rc < 0)
+			return -1;
+	}
+
+	if ((address == start) || (((address - 1) & 0xff0000) != (address & 0xff0000))) {
+		rc = edi_write(flash, ENE_XBI_EFA2, ((address & 0xff0000) >> 16));
+		if (rc < 0)
+			return -1;
+	}
+
+	return 0;
+}
+
+static int edi_8051_reset(struct flashctx *flash)
+{
+	unsigned char buffer;
+	int rc;
+
+	rc = edi_read(flash, ENE_EC_PXCFG, &buffer);
+	if (rc < 0)
+		return -1;
+
+	buffer |= ENE_EC_PXCFG_8051_RESET;
+
+	rc = edi_write(flash, ENE_EC_PXCFG, buffer);
+	if (rc < 0)
+		return -1;
+
+	return 0;
+}
+
+static int edi_8051_execute(struct flashctx *flash)
+{
+	unsigned char buffer;
+	int rc;
+
+	rc = edi_read(flash, ENE_EC_PXCFG, &buffer);
+	if (rc < 0)
+		return -1;
+
+	buffer &= ~ENE_EC_PXCFG_8051_RESET;
+
+	rc = edi_write(flash, ENE_EC_PXCFG, buffer);
+	if (rc < 0)
+		return -1;
+
+	return 0;
+}
+
+int edi_chip_block_erase(struct flashctx *flash, unsigned int page, unsigned int size)
+{
+	unsigned int timeout = 64;
+	int rc;
+
+	if (size != flash->chip->page_size) {
+		msg_perr("%s: Block erase size is not page size!\n", __func__);
+		return -1;
+	}
+
+	rc = edi_spi_enable(flash);
+	if (rc < 0) {
+		msg_perr("%s: Unable to enable SPI!\n", __func__);
+		return -1;
+	}
+
+	rc = edi_spi_address(flash, page, page);
+	if (rc < 0)
+		return -1;
+
+	rc = edi_write(flash, ENE_XBI_EFCMD, ENE_XBI_EFCMD_ERASE);
+	if (rc < 0)
+		return -1;
+
+	while (edi_spi_busy(flash) == 1 && timeout) {
+		programmer_delay(10);
+		timeout--;
+	}
+
+	if (!timeout) {
+		msg_perr("%s: Timed out waiting for SPI not busy!\n", __func__);
+		return -1;
+	}
+
+	rc = edi_spi_disable(flash);
+	if (rc < 0) {
+		msg_perr("%s: Unable to disable SPI!\n", __func__);
+		return -1;
+	}
+
+	return 0;
+}
+
+int edi_chip_write(struct flashctx *flash, const uint8_t *buf, unsigned int start, unsigned int len)
+{
+	unsigned int address = start;
+	unsigned int pages;
+	unsigned int timeout;
+	unsigned int i, j;
+	int rc;
+
+	if ((start % flash->chip->page_size) != 0) {
+		msg_perr("%s: Start address is not page-aligned!\n", __func__);
+		return -1;
+	}
+
+	if ((len % flash->chip->page_size) != 0) {
+		msg_perr("%s: Length is not page-aligned!\n", __func__);
+		return -1;
+	}
+
+	pages = len / flash->chip->page_size;
+
+	rc = edi_spi_enable(flash);
+	if (rc < 0) {
+		msg_perr("%s: Unable to enable SPI!\n", __func__);
+		return -1;
+	}
+
+	for (i = 0; i < pages; i++) {
+		timeout = 64;
+
+		/* Clear page buffer. */
+		rc = edi_write(flash, ENE_XBI_EFCMD, ENE_XBI_EFCMD_HVPL_CLEAR);
+		if (rc < 0)
+			return -1;
+
+		for (j = 0; j < flash->chip->page_size; j++) {
+			rc = edi_spi_address(flash, start, address);
+			if (rc < 0)
+				return -1;
+
+			rc = edi_write(flash, ENE_XBI_EFDAT, *buf);
+			if (rc < 0)
+				return -1;
+
+			rc = edi_write(flash, ENE_XBI_EFCMD, ENE_XBI_EFCMD_HVPL_LATCH);
+			if (rc < 0)
+				return -1;
+
+			buf++;
+			address++;
+		}
+
+		/* Program page buffer to flash. */
+		rc = edi_write(flash, ENE_XBI_EFCMD, ENE_XBI_EFCMD_PROGRAM);
+		if (rc < 0)
+			return -1;
+
+		while (edi_spi_busy(flash) == 1 && timeout) {
+			programmer_delay(10);
+			timeout--;
+		}
+
+		if (!timeout) {
+			msg_perr("%s: Timed out waiting for SPI not busy!\n", __func__);
+			return -1;
+		}
+	}
+
+	rc = edi_spi_disable(flash);
+	if (rc < 0) {
+		msg_perr("%s: Unable to disable SPI!\n", __func__);
+		return -1;
+	}
+
+	return 0;
+}
+
+int edi_chip_read(struct flashctx *flash, uint8_t *buf, unsigned int start, unsigned int len)
+{
+	unsigned int address = start;
+	unsigned int i;
+	unsigned int timeout;
+	int rc;
+
+	rc = edi_spi_enable(flash);
+	if (rc < 0) {
+		msg_perr("%s: Unable to enable SPI!\n", __func__);
+		return -1;
+	}
+
+	/*
+	 * EDI brings such a drastic overhead that there is about no need to
+	 * have any delay in between calls. The EDI protocol will handle wait
+	 * I/O times on its own anyway.
+	 */
+
+	for (i = 0; i < len; i++) {
+		timeout = 64;
+
+		rc = edi_spi_address(flash, start, address);
+		if (rc < 0)
+			return -1;
+
+		rc = edi_write(flash, ENE_XBI_EFCMD, ENE_XBI_EFCMD_READ);
+		if (rc < 0)
+			return -1;
+
+		do {
+			rc = edi_read(flash, ENE_XBI_EFDAT, buf);
+			if (rc == 0)
+				break;
+
+			/* Just in case. */
+			while (edi_spi_busy(flash) == 1 && timeout) {
+				programmer_delay(10);
+				timeout--;
+			}
+
+			if (!timeout) {
+				msg_perr("%s: Timed out waiting for SPI not busy!\n", __func__);
+				return -1;
+			}
+		} while (1);
+
+		buf++;
+		address++;
+	}
+
+	rc = edi_spi_disable(flash);
+	if (rc < 0) {
+		msg_perr("%s: Unable to disable SPI!\n", __func__);
+		return -1;
+	}
+
+	return 0;
+}
+
+int edi_shutdown(void *data)
+{
+	struct flashctx *flash;
+	int rc;
+
+	if (data == NULL)
+		return -1;
+
+	flash = (struct flashctx *)data;
+
+	rc = edi_8051_execute(flash);
+	if (rc < 0) {
+		msg_perr("%s: Unable to execute 8051!\n", __func__);
+		return -1;
+	}
+
+	rc = edi_disable(flash);
+	if (rc < 0) {
+		msg_perr("%s: Unable to disable EDI!\n", __func__);
+		return -1;
+	}
+
+	return 0;
+}
+
+int edi_probe_kb9012(struct flashctx *flash)
+{
+	int probe;
+	int rc;
+
+	probe = edi_chip_probe(flash, &ene_kb9012);
+	if (!probe)
+		return 0;
+
+	rc = edi_8051_reset(flash);
+	if (rc < 0) {
+		msg_perr("%s: Unable to reset 8051!\n", __func__);
+		return 0;
+	}
+
+	register_shutdown(edi_shutdown, (void *)flash);
+
+	return 1;
+}