util/e6400-flash-unlock: Rename to dell-flash-unlock

This more accurately describes the scope of the utility.

Signed-off-by: Nicholas Chin <nic.c3.14@gmail.com>

1 files changed, 217 insertions, 0 deletions

diff --git a/util/dell-flash-unlock/dell_flash_unlock.c b/util/dell-flash-unlock/dell_flash_unlock.c
new file mode 100644
index 00000000..174a1c92
--- /dev/null
+++ b/util/dell-flash-unlock/dell_flash_unlock.c
@@ -0,0 +1,217 @@
+/* SPDX-License-Identifier: MIT */
+/* SPDX-FileCopyrightText: 2023 Nicholas Chin */
+
+#include <sys/mman.h>
+
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "accessors.h"
+
+int get_fdo_status(void);
+int check_lpc_decode(void);
+void ec_set_fdo();
+void write_ec_reg(uint8_t index, uint8_t data);
+void send_ec_cmd(uint8_t cmd);
+int wait_ec(void);
+int check_bios_write_en(void);
+int set_gbl_smi_en(int enable);
+int get_gbl_smi_en(void);
+
+#define EC_INDEX 0x910
+#define EC_DATA 0x911
+#define EC_ENABLE_FDO 2
+
+#define LPC_DEV PCI_DEV(0, 0x1f, 0)
+
+#define RCBA_MMIO_LEN 0x4000
+
+/* Register offsets */
+#define SPIBAR 0x3800
+#define HSFS_REG  0x04
+#define SMI_EN_REG 0x30
+
+volatile uint8_t *rcba_mmio;
+uint16_t pmbase;
+
+int
+main(int argc, char *argv[])
+{
+	int devmemfd;
+	(void)argc;
+	(void)argv;
+
+	if (sys_iopl(3) == -1)
+		err(errno, "Could not access IO ports");
+	if ((devmemfd = open("/dev/mem", O_RDONLY)) == -1)
+		err(errno, "/dev/mem");
+
+	/* Read RCBA and PMBASE from the LPC config registers */
+	long int rcba = pci_read_32(LPC_DEV, 0xf0) & 0xffffc000;
+	pmbase = pci_read_32(LPC_DEV, 0x40) & 0xff80;
+
+	/* FDO pin-strap status bit is in RCBA mmio space */
+	rcba_mmio = mmap(0, RCBA_MMIO_LEN, PROT_READ, MAP_SHARED, devmemfd,
+			rcba);
+	if (rcba_mmio == MAP_FAILED)
+		err(errno, "Could not map RCBA");
+
+	if (get_fdo_status() == 1) { /* Descriptor not overridden */
+		if (check_lpc_decode() == -1)
+			err(errno = ECANCELED, "Can't forward I/O to LPC");
+
+		printf("Sending FDO override command to EC:\n");
+		ec_set_fdo();
+		printf("Flash Descriptor Override enabled.\n"
+			"Shut down (don't reboot) now.\n\n"
+			"The EC may auto-boot on some systems; if not then "
+			"manually power on.\n When the system boots rerun "
+			"this utility to finish unlocking.\n");
+	} else if (check_bios_write_en() == 0) {
+		/* SMI locks in place, try disabling SMIs to bypass them */
+		if (set_gbl_smi_en(0)) {
+			printf("SMIs disabled. Internal flashing should work "
+				"now.\n After flashing, re-run this utility "
+				"to enable SMIs.\n (shutdown is buggy when "
+				"SMIs are disabled)\n");
+		} else {
+			err(errno = ECANCELED, "Could not disable SMIs!");
+		}
+	} else { /* SMI locks not in place or bypassed */
+		if (get_gbl_smi_en()) {
+			/* SMIs are still enabled, assume this is an Exx10
+			 * or newer which don't need the SMM bypass */
+			printf("Flash is unlocked.\n"
+				"Internal flashing should work.\n");
+		} else {
+			/* SMIs disabled, assume this is an Exx00 after
+			 * unlocking and flashing */
+			set_gbl_smi_en(1);
+			printf("SMIs enabled.\n"
+				"You can now shutdown the system.\n");
+		}
+	}
+	return errno;
+}
+
+int
+get_fdo_status(void)
+{
+	return (*(uint16_t*)(rcba_mmio + SPIBAR + HSFS_REG) >> 13) & 1;
+}
+
+int
+check_lpc_decode(void)
+{
+	/* Check that at a Generic Decode Range Register is set up to
+	 * forward I/O ports 0x910 and 0x911 over LPC for the EC */
+	int i = 0;
+	int gen_dec_free = -1;
+	for (; i < 4; i++) {
+		uint32_t reg_val = pci_read_32(LPC_DEV, 0x84 + 4*i);
+		uint16_t base_addr = reg_val & 0xfffc;
+		uint16_t mask = ((reg_val >> 16) & 0xfffc) | 0x3;
+
+		/* Bit 0 is the enable for each decode range. If disabled, note
+		 * this register as available to add our own range decode */
+		if ((reg_val & 1) == 0)
+			gen_dec_free = i;
+
+		/* Check if the current range register matches port 0x910.
+		 * 0x911 doesn't need to be checked as the LPC bridge only
+		 * decodes at the dword level, and thus a check is redundant */
+		if ((0x910 & ~mask) == base_addr) {
+			return 0;
+		}
+	}
+
+	/* No matching range found, try setting a range in a free register */
+	if (gen_dec_free != -1) {
+		/* Set up an I/O decode range from 0x910-0x913 */
+		pci_write_32(LPC_DEV, 0x84 + 4 * gen_dec_free, 0x911);
+		return 0;
+	} else {
+		return -1;
+	}
+}
+
+void
+ec_set_fdo()
+{
+	/* EC FDO command arguments for reference:
+	 * 0 = Query EC FDO status
+	 * 2 = Enable FDO for next boot
+	 * 3 = Disable FDO for next boot */
+	write_ec_reg(0x12, EC_ENABLE_FDO);
+	send_ec_cmd(0xb8);
+}
+
+void
+write_ec_reg(uint8_t index, uint8_t data)
+{
+	sys_outb(EC_INDEX, index);
+	sys_outb(EC_DATA, data);
+}
+
+void
+send_ec_cmd(uint8_t cmd)
+{
+	sys_outb(EC_INDEX, 0);
+	sys_outb(EC_DATA, cmd);
+	if (wait_ec() == -1)
+		err(errno = ECANCELED, "Timeout while waiting for EC!");
+}
+
+int
+wait_ec(void)
+{
+	uint8_t busy;
+	int timeout = 1000;
+	do {
+		sys_outb(EC_INDEX, 0);
+		busy = sys_inb(EC_DATA);
+		timeout--;
+		usleep(1000);
+	} while (busy && timeout > 0);
+	return timeout > 0 ? 0 : -1;
+}
+
+int
+check_bios_write_en(void)
+{
+	uint8_t bios_cntl = pci_read_32(LPC_DEV, 0xdc) & 0xff;
+	/* Bit 5 = SMM BIOS Write Protect Disable (SMM_BWP)
+	 * Bit 1 = BIOS Lock Enable (BLE)
+	 * If both are 0, then there's no write protection */
+	if ((bios_cntl & 0x22) == 0)
+		return 1;
+
+	/* SMM protection is enabled, but try enabling writes
+	 * anyway in case the vendor SMM code doesn't reset it */
+	pci_write_32(LPC_DEV, 0xdc, bios_cntl | 0x1);
+	return pci_read_32(LPC_DEV, 0xdc) & 0x1;
+}
+
+int
+set_gbl_smi_en(int enable)
+{
+	uint32_t smi_en = sys_inl(pmbase + SMI_EN_REG);
+	if (enable) {
+		smi_en |= 1;
+	} else {
+		smi_en &= ~1;
+	}
+	sys_outl(pmbase + SMI_EN_REG, smi_en);
+	return (get_gbl_smi_en() == enable);
+}
+
+int
+get_gbl_smi_en(void)
+{
+	return sys_inl(pmbase + SMI_EN_REG) & 1;
+}