Add E6400 flash unlock utility

Adding it to lbmk for now as it is not yet in coreboot. If it is merged
into coreboot we can just reference the one there. The original README
will be incorporated into a new page on lbwww, so README.md just points
to a placeholder URL that should match the new page.

util/e6400-flash-unlock/COPYING

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+Copyright (c) 2023 Nicholas Chin
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

util/e6400-flash-unlock/Makefile

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+# Copyright (c) 2023 Nicholas Chin
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+CC=cc
+CFLAGS=-Wall -Wextra -Werror -O2 -pedantic
+
+all: e6400_flash_unlock.c
+	$(CC) $(CFLAGS) e6400_flash_unlock.c -o e6400_flash_unlock
+
+clean:
+	rm -f e6400_flash_unlock

util/e6400-flash-unlock/README.md

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+
+This documentation has become part of lbwww. See:
+
+<https://libreboot.org/docs/install/e6400_flash_unlock.html>

util/e6400-flash-unlock/e6400_flash_unlock.c

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+/*
+ * Copyright (c) 2023 Nicholas Chin
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <sys/io.h>
+#include <sys/mman.h>
+
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+enum
+EC_FDO_CMD {
+	QUERY = 0,
+	SET_OVERRIDE = 2,
+	UNSET_OVERRIDE = 3
+};
+
+int get_fdo_status(void);
+uint8_t ec_fdo_command(enum EC_FDO_CMD arg);
+void write_ec_reg(uint8_t index, uint8_t data);
+void send_ec_cmd(uint8_t cmd);
+void wait_ec(void);
+int get_gbl_smi_en(void);
+int set_gbl_smi_en(int enable);
+/* uint8_t read_ec_reg(uint8_t index); */
+
+#define EC_INDEX 0x910
+#define EC_DATA 0x911
+#define PMBASE 0x1000
+#define SMI_EN_REG (PMBASE + 0x30)
+
+/* Assume this is the same on all vendor BIOS versions */
+#define RCBA 0xfed18000
+
+#define RCBA_MMIO_LEN 0x4000
+#define SPIBAR 0x3800
+#define HSFS_REG  0x04
+
+volatile uint8_t *rcba_mmio;
+
+int
+main(int argc, char *argv[])
+{
+	int devmemfd;
+	(void)argc;
+	(void)argv;
+
+	if ((ioperm(EC_INDEX, 2, 1) == -1) || (ioperm(SMI_EN_REG, 4, 1) == -1))
+		err(errno, "Could not access IO ports");
+	if ((devmemfd = open("/dev/mem", O_RDONLY)) == -1)
+		err(errno, "/dev/mem");
+
+	/* 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) {
+		ec_fdo_command(SET_OVERRIDE);
+		printf("Flash Descriptor Override enabled. Shut down now. The "
+			"EC will auto-boot the system and set the override.\n"
+			"Upon boot, re-run this utility to unlock flash.\n");
+	} else if (get_gbl_smi_en()){
+		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 {
+		set_gbl_smi_en(1);
+		printf("SMIs enabled, you can now shutdown the system.\n");
+	}
+	return errno;
+}
+
+int
+get_fdo_status(void)
+{
+	return (*(uint16_t*)(rcba_mmio + SPIBAR + HSFS_REG) >> 13) & 1;
+}
+
+/*
+ * arg:
+ * 0 = Query EC FDO status - TODO
+ * 2 = Enable FDO for next boot
+ * 3 = Disable FDO for next boot - TODO
+ */
+uint8_t
+ec_fdo_command(enum EC_FDO_CMD arg)
+{
+	write_ec_reg(0x12, arg);
+	send_ec_cmd(0xb8);
+	return 1;
+}
+
+void
+write_ec_reg(uint8_t index, uint8_t data)
+{
+	outb(index, EC_INDEX);
+	outb(data, EC_DATA);
+}
+
+void
+send_ec_cmd(uint8_t cmd)
+{
+	outb(0, EC_INDEX);
+	outb(cmd, EC_DATA);
+	wait_ec();
+}
+
+void
+wait_ec(void)
+{
+	uint8_t busy;
+	do {
+		outb(0, EC_INDEX);
+		busy = inb(EC_DATA);
+	} while (busy); 
+}
+
+int
+get_gbl_smi_en(void)
+{
+	return inl(SMI_EN_REG) & 1;
+}
+
+int
+set_gbl_smi_en(int enable)
+{
+	uint32_t smi_en = inl(SMI_EN_REG);	
+	if (enable) {
+		smi_en |= 1;
+	} else {
+		smi_en &= ~1;
+	}
+	outl(smi_en, SMI_EN_REG);
+	return (get_gbl_smi_en() == enable);
+}
+
+/*
+uint8_t
+read_ec_reg(uint8_t index)
+{
+	outb(index, EC_INDEX);
+	return inb(EC_DATA);
+}
+*/