spl: Add an option to load a FIT containing U-Boot

This provides a way to load a FIT containing U-Boot and a selection of device
tree files. The board can select the correct device tree by probing the
hardware. Then U-Boot is started with the selected device tree.

Signed-off-by: Simon Glass <sjg@chromium.org>

Kconfig

@@ -273,6 +273,17 @@ config SYS_TEXT_BASE
 	help
 	  TODO: Move CONFIG_SYS_TEXT_BASE for all the architecture
 
+config SPL_LOAD_FIT
+	bool "Enable SPL loading U-Boot as a FIT"
+	depends on FIT
+	help
+	  Normally with the SPL framework a legacy image is generated as part
+	  of the build. This contains U-Boot along with information as to
+	  where it should be loaded. This option instead enables generation
+	  of a FIT (Flat Image Tree) which provides more flexibility. In
+	  particular it can handle selecting from multiple device tree
+	  and passing the correct one to U-Boot.
+
 config SYS_CLK_FREQ
 	depends on ARC || ARCH_SUNXI
 	int "CPU clock frequency"

common/spl/Makefile

@@ -10,6 +10,7 @@
 
 ifdef CONFIG_SPL_BUILD
 obj-$(CONFIG_SPL_FRAMEWORK) += spl.o
+obj-$(CONFIG_SPL_LOAD_FIT) += spl_fit.o
 obj-$(CONFIG_SPL_NOR_SUPPORT) += spl_nor.o
 obj-$(CONFIG_SPL_YMODEM_SUPPORT) += spl_ymodem.o
 obj-$(CONFIG_SPL_NAND_SUPPORT) += spl_nand.o

common/spl/spl_fit.c

@@ -0,0 +1,194 @@
+/*
+ * Copyright (C) 2016 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+
+#include <common.h>
+#include <errno.h>
+#include <image.h>
+#include <libfdt.h>
+#include <spl.h>
+
+static ulong fdt_getprop_u32(const void *fdt, int node, const char *prop)
+{
+	const u32 *cell;
+	int len;
+
+	cell = fdt_getprop(fdt, node, prop, &len);
+	if (len != sizeof(*cell))
+		return -1U;
+	return fdt32_to_cpu(*cell);
+}
+
+static int spl_fit_select_fdt(const void *fdt, int images, int *fdt_offsetp)
+{
+	const char *name, *fdt_name;
+	int conf, node, fdt_node;
+	int len;
+
+	*fdt_offsetp = 0;
+	conf = fdt_path_offset(fdt, FIT_CONFS_PATH);
+	if (conf < 0) {
+		debug("%s: Cannot find /configurations node: %d\n", __func__,
+		      conf);
+		return -EINVAL;
+	}
+	for (node = fdt_first_subnode(fdt, conf);
+	     node >= 0;
+	     node = fdt_next_subnode(fdt, node)) {
+		name = fdt_getprop(fdt, node, "description", &len);
+		if (!name)
+			return -EINVAL;
+		if (board_fit_config_name_match(name))
+			continue;
+
+		debug("Selecting config '%s'", name);
+		fdt_name = fdt_getprop(fdt, node, FIT_FDT_PROP, &len);
+		if (!fdt_name) {
+			debug("%s: Cannot find fdt name property: %d\n",
+			      __func__, len);
+			return -EINVAL;
+		}
+
+		debug(", fdt '%s'\n", fdt_name);
+		fdt_node = fdt_subnode_offset(fdt, images, fdt_name);
+		if (fdt_node < 0) {
+			debug("%s: Cannot find fdt node '%s': %d\n",
+			      __func__, fdt_name, fdt_node);
+			return -EINVAL;
+		}
+
+		*fdt_offsetp = fdt_getprop_u32(fdt, fdt_node, "data-offset");
+		len = fdt_getprop_u32(fdt, fdt_node, "data-size");
+#ifdef CONFIG_SPL_LIBCOMMON_SUPPORT
+		printf("FIT: Selected '%s'\n", name);
+#endif
+
+		return len;
+	}
+
+#ifdef CONFIG_SPL_LIBCOMMON_SUPPORT
+	printf("No matching DT out of these options:\n");
+	for (node = fdt_first_subnode(fdt, conf);
+	     node >= 0;
+	     node = fdt_next_subnode(fdt, node)) {
+		name = fdt_getprop(fdt, node, "name", &len);
+		printf("   %s\n", name);
+	}
+#endif
+
+	return -ENOENT;
+}
+
+int spl_load_simple_fit(struct spl_load_info *info, ulong sector, void *fit)
+{
+	int sectors;
+	ulong size, load;
+	unsigned long count;
+	int node, images;
+	void *load_ptr;
+	int fdt_offset, fdt_len;
+	int data_offset, data_size;
+	int base_offset;
+	int src_sector;
+	void *dst;
+
+	/*
+	 * Figure out where the external images start. This is the base for the
+	 * data-offset properties in each image.
+	 */
+	size = fdt_totalsize(fit);
+	size = (size + 3) & ~3;
+	base_offset = (size + 3) & ~3;
+
+	/*
+	 * So far we only have one block of data from the FIT. Read the entire
+	 * thing, including that first block, placing it so it finishes before
+	 * where we will load the image.
+	 *
+	 * Note that we will load the image such that its first byte will be
+	 * at the load address. Since that byte may be part-way through a
+	 * block, we may load the image up to one block before the load
+	 * address. So take account of that here by subtracting an addition
+	 * block length from the FIT start position.
+	 *
+	 * In fact the FIT has its own load address, but we assume it cannot
+	 * be before CONFIG_SYS_TEXT_BASE.
+	 */
+	fit = (void *)(CONFIG_SYS_TEXT_BASE - size - info->bl_len);
+	sectors = (size + info->bl_len - 1) / info->bl_len;
+	count = info->read(info, sector, sectors, fit);
+	debug("fit read sector %lx, sectors=%d, dst=%p, count=%lu\n",
+	      sector, sectors, fit, count);
+	if (count == 0)
+		return -EIO;
+
+	/* find the firmware image to load */
+	images = fdt_path_offset(fit, FIT_IMAGES_PATH);
+	if (images < 0) {
+		debug("%s: Cannot find /images node: %d\n", __func__, images);
+		return -1;
+	}
+	node = fdt_first_subnode(fit, images);
+	if (node < 0) {
+		debug("%s: Cannot find first image node: %d\n", __func__, node);
+		return -1;
+	}
+
+	/* Get its information and set up the spl_image structure */
+	data_offset = fdt_getprop_u32(fit, node, "data-offset");
+	data_size = fdt_getprop_u32(fit, node, "data-size");
+	load = fdt_getprop_u32(fit, node, "load");
+	debug("data_offset=%x, data_size=%x\n", data_offset, data_size);
+	spl_image.load_addr = load;
+	spl_image.entry_point = load;
+	spl_image.os = IH_OS_U_BOOT;
+
+	/*
+	 * Work out where to place the image. We read it so that the first
+	 * byte will be at 'load'. This may mean we need to load it starting
+	 * before then, since we can only read whole blocks.
+	 */
+	sectors = (data_size + info->bl_len - 1) / info->bl_len;
+	data_offset += base_offset;
+	load_ptr = (void *)load;
+	debug("U-Boot size %x, data %p\n", data_size, load_ptr);
+	dst = load_ptr - (data_offset % info->bl_len);
+
+	/* Read the image */
+	src_sector = sector + data_offset / info->bl_len;
+	debug("image: data_offset=%x, dst=%p, src_sector=%x, sectors=%x\n",
+	      data_offset, dst, src_sector, sectors);
+	count = info->read(info, src_sector, sectors, dst);
+	if (count != sectors)
+		return -EIO;
+
+	/* Figure out which device tree the board wants to use */
+	fdt_len = spl_fit_select_fdt(fit, images, &fdt_offset);
+	if (fdt_len < 0)
+		return fdt_len;
+
+	/*
+	 * Read the device tree and place it after the image. There may be
+	 * some extra data before it since we can only read entire blocks.
+	 */
+	dst = load_ptr + data_size;
+	fdt_offset += base_offset;
+	count = info->read(info, sector + fdt_offset / info->bl_len, sectors,
+			   dst);
+	debug("fit read %x sectors to %x, dst %p, data_offset %x\n",
+	      sectors, spl_image.load_addr, dst, fdt_offset);
+	if (count != sectors)
+		return -EIO;
+
+	/*
+	 * Copy the device tree so that it starts immediately after the image.
+	 * After this we will have the U-Boot image and its device tree ready
+	 * for us to start.
+	 */
+	memcpy(dst, dst + fdt_offset % info->bl_len, fdt_len);
+
+	return 0;
+}

include/image.h

@@ -780,7 +780,6 @@ int bootz_setup(ulong image, ulong *start, ulong *end);
 /*******************************************************************/
 /* New uImage format specific code (prefixed with fit_) */
 /*******************************************************************/
-#if IMAGE_ENABLE_FIT
 
 #define FIT_IMAGES_PATH		"/images"
 #define FIT_CONFS_PATH		"/configurations"
@@ -813,6 +812,7 @@ int bootz_setup(ulong image, ulong *start, ulong *end);
 
 #define FIT_MAX_HASH_LEN	HASH_MAX_DIGEST_SIZE
 
+#if IMAGE_ENABLE_FIT
 /* cmdline argument format parsing */
 int fit_parse_conf(const char *spec, ulong addr_curr,
 		ulong *addr, const char **conf_name);

include/spl.h

@@ -29,6 +29,24 @@ struct spl_image_info {
 	u32 flags;
 };
 
+/*
+ * Information required to load data from a device
+ *
+ * @dev: Pointer to the device, e.g. struct mmc *
+ * @priv: Private data for the device
+ * @bl_len: Block length for reading in bytes
+ * @read: Function to call to read from the device
+ */
+struct spl_load_info {
+	void *dev;
+	void *priv;
+	int bl_len;
+	ulong (*read)(struct spl_load_info *load, ulong sector, ulong count,
+		      void *buf);
+};
+
+int spl_load_simple_fit(struct spl_load_info *info, ulong sector, void *fdt);
+
 #define SPL_COPY_PAYLOAD_ONLY	1
 
 extern struct spl_image_info spl_image;