x86: ifdtool: Add support for early microcode access

Some Intel CPUs use an 'FSP' binary blob which provides an inflexible
means of starting up the CPU. One result is that microcode updates can only
be done before RAM is available and therefore parsing of the device tree
is impracticle.

Worse, the addess of the microcode update must be stored in ROM since a
pointer to its start address and size is passed to the 'FSP' blob. It is
not possible to perform any calculations to obtain the address and size.

To work around this, ifdtool is enhanced to work out the address and size of
the first microcode update it finds in the supplied device tree. It then
writes these into the correct place in the ROM. U-Boot can then start up
the FSP correctly.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

2 files changed, 103 insertions, 8 deletions

diff --git a/tools/Makefile b/tools/Makefile
index a4216a1de7..e549f8e63c 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -126,6 +126,7 @@ hostprogs-$(CONFIG_EXYNOS5250) += mkexynosspl
 hostprogs-$(CONFIG_EXYNOS5420) += mkexynosspl
 HOSTCFLAGS_mkexynosspl.o := -pedantic
 
+ifdtool-objs := $(LIBFDT_OBJS) ifdtool.o
 hostprogs-$(CONFIG_X86) += ifdtool
 
 hostprogs-$(CONFIG_MX23) += mxsboot
diff --git a/tools/ifdtool.c b/tools/ifdtool.c
index 4077ba8b2e..fe8366ba4f 100644
--- a/tools/ifdtool.c
+++ b/tools/ifdtool.c
@@ -18,6 +18,7 @@
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <libfdt.h>
 #include "ifdtool.h"
 
 #undef DEBUG
@@ -34,6 +35,8 @@
 
 enum input_file_type_t {
 	IF_normal,
+	IF_fdt,
+	IF_uboot,
 };
 
 struct input_file {
@@ -703,7 +706,7 @@ int inject_region(char *image, int size, int region_type, char *region_fname)
  *			0xffffffff so use an address relative to that. For an
  *			8MB ROM the start address is 0xfff80000.
  * @write_fname:	Filename to add to the image
- * @return 0 if OK, -ve on error
+ * @return number of bytes written if OK, -ve on error
  */
 static int write_data(char *image, int size, unsigned int addr,
 		      const char *write_fname)
@@ -715,7 +718,7 @@ static int write_data(char *image, int size, unsigned int addr,
 	if (write_fd < 0)
 		return write_fd;
 
-	offset = addr + size;
+	offset = (uint32_t)(addr + size);
 	debug("Writing %s to offset %#x\n", write_fname, offset);
 
 	if (offset < 0 || offset + write_size > size) {
@@ -731,6 +734,68 @@ static int write_data(char *image, int size, unsigned int addr,
 
 	close(write_fd);
 
+	return write_size;
+}
+
+/**
+ * write_uboot() - Write U-Boot, device tree and microcode pointer
+ *
+ * This writes U-Boot into a place in the flash, followed by its device tree.
+ * The microcode pointer is written so that U-Boot can find the microcode in
+ * the device tree very early in boot.
+ *
+ * @image:	Pointer to image
+ * @size:	Size of image in bytes
+ * @uboot:	Input file information for u-boot.bin
+ * @fdt:	Input file information for u-boot.dtb
+ * @ucode_ptr:	Address in U-Boot where the microcode pointer should be placed
+ * @return 0 if OK, -ve on error
+ */
+static int write_uboot(char *image, int size, struct input_file *uboot,
+		       struct input_file *fdt, unsigned int ucode_ptr)
+{
+	const void *blob;
+	const char *data;
+	int uboot_size;
+	uint32_t *ptr;
+	int data_size;
+	int offset;
+	int node;
+	int ret;
+
+	uboot_size = write_data(image, size, uboot->addr, uboot->fname);
+	if (uboot_size < 0)
+		return uboot_size;
+	fdt->addr = uboot->addr + uboot_size;
+	debug("U-Boot size %#x, FDT at %#x\n", uboot_size, fdt->addr);
+	ret = write_data(image, size, fdt->addr, fdt->fname);
+	if (ret < 0)
+		return ret;
+
+	if (ucode_ptr) {
+		blob = (void *)image + (uint32_t)(fdt->addr + size);
+		debug("DTB at %lx\n", (char *)blob - image);
+		node = fdt_node_offset_by_compatible(blob, 0,
+						     "intel,microcode");
+		if (node < 0) {
+			debug("No microcode found in FDT: %s\n",
+			      fdt_strerror(node));
+			return -ENOENT;
+		}
+		data = fdt_getprop(blob, node, "data", &data_size);
+		if (!data) {
+			debug("No microcode data found in FDT: %s\n",
+			      fdt_strerror(data_size));
+			return -ENOENT;
+		}
+		offset = ucode_ptr - uboot->addr;
+		ptr = (void *)image + offset;
+		ptr[0] = uboot->addr + (data - image);
+		ptr[1] = data_size;
+		debug("Wrote microcode pointer at %x: addr=%x, size=%x\n",
+		      ucode_ptr, ptr[0], ptr[1]);
+	}
+
 	return 0;
 }
 
@@ -800,7 +865,7 @@ int main(int argc, char *argv[])
 	char *desc_fname = NULL, *addr_str = NULL;
 	int region_type = -1, inputfreq = 0;
 	enum spi_frequency spifreq = SPI_FREQUENCY_20MHZ;
-	struct input_file input_file[WRITE_MAX], *ifile;
+	struct input_file input_file[WRITE_MAX], *ifile, *fdt = NULL;
 	unsigned char wr_idx, wr_num = 0;
 	int rom_size = -1;
 	bool write_it;
@@ -808,6 +873,8 @@ int main(int argc, char *argv[])
 	char *outfile = NULL;
 	struct stat buf;
 	int size = 0;
+	unsigned int ucode_ptr = 0;
+	bool have_uboot = false;
 	int bios_fd;
 	char *image;
 	int ret;
@@ -817,18 +884,21 @@ int main(int argc, char *argv[])
 		{"descriptor", 1, NULL, 'D'},
 		{"em100", 0, NULL, 'e'},
 		{"extract", 0, NULL, 'x'},
+		{"fdt", 1, NULL, 'f'},
 		{"inject", 1, NULL, 'i'},
 		{"lock", 0, NULL, 'l'},
+		{"microcode", 1, NULL, 'm'},
 		{"romsize", 1, NULL, 'r'},
 		{"spifreq", 1, NULL, 's'},
 		{"unlock", 0, NULL, 'u'},
+		{"uboot", 1, NULL, 'U'},
 		{"write", 1, NULL, 'w'},
 		{"version", 0, NULL, 'v'},
 		{"help", 0, NULL, 'h'},
 		{0, 0, 0, 0}
 	};
 
-	while ((opt = getopt_long(argc, argv, "cdD:ehi:lr:s:uvw:x?",
+	while ((opt = getopt_long(argc, argv, "cdD:ef:hi:lm:r:s:uU:vw:x?",
 				  long_options, &option_index)) != EOF) {
 		switch (opt) {
 		case 'c':
@@ -871,6 +941,9 @@ int main(int argc, char *argv[])
 		case 'l':
 			mode_locked = 1;
 			break;
+		case 'm':
+			ucode_ptr = strtoul(optarg, NULL, 0);
+			break;
 		case 'r':
 			rom_size = strtol(optarg, NULL, 0);
 			debug("ROM size %d\n", rom_size);
@@ -904,6 +977,8 @@ int main(int argc, char *argv[])
 			exit(EXIT_SUCCESS);
 			break;
 		case 'w':
+		case 'U':
+		case 'f':
 			ifile = &input_file[wr_num];
 			mode_write = 1;
 			if (wr_num < WRITE_MAX) {
@@ -913,7 +988,12 @@ int main(int argc, char *argv[])
 					exit(EXIT_FAILURE);
 				}
 				ifile->addr = strtol(optarg, NULL, 0);
-				ifile->type = IF_normal;
+				ifile->type = opt == 'f' ? IF_fdt :
+					opt == 'U' ? IF_uboot : IF_normal;
+				if (ifile->type == IF_fdt)
+					fdt = ifile;
+				else if (ifile->type == IF_uboot)
+					have_uboot = true;
 				wr_num++;
 			} else {
 				fprintf(stderr,
@@ -970,6 +1050,13 @@ int main(int argc, char *argv[])
 		exit(EXIT_FAILURE);
 	}
 
+	if (have_uboot && !fdt) {
+		fprintf(stderr,
+			"You must supply a device tree file for U-Boot\n\n");
+		print_usage(argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
 	filename = argv[optind];
 	if (optind + 2 != argc)
 		outfile = argv[optind + 1];
@@ -1034,9 +1121,16 @@ int main(int argc, char *argv[])
 	if (mode_write) {
 		for (wr_idx = 0; wr_idx < wr_num; wr_idx++) {
 			ifile = &input_file[wr_idx];
-			ret = write_data(image, size, ifile->addr,
+			if (ifile->type == IF_fdt) {
+				continue;
+			} else if (ifile->type == IF_uboot) {
+				ret = write_uboot(image, size, ifile, fdt,
+						  ucode_ptr);
+			} else {
+				ret = write_data(image, size, ifile->addr,
 					 ifile->fname);
-			if (ret)
+			}
+			if (ret < 0)
 				break;
 		}
 	}
@@ -1071,5 +1165,5 @@ int main(int argc, char *argv[])
 	free(image);
 	close(bios_fd);
 
-	return ret ? 1 : 0;
+	return ret < 0 ? 1 : 0;
 }