fel: Add FIT image parsing and loading

So far sunxi-fel expects a legacy U-Boot image after the SPL, when
called with the "uboot" command.
This only works for (current) 32-bit builds, which only need one image
to load (U-Boot proper).

64-bit builds also include at least a Trusted Firmware binary, and also
might contain a firmware image for the ARISC management processor. So
we use the more capable FIT image, which can contain multiple images
to load.

Introduce support for that, by adding code to parse a FIT image, find
the image files included, and load them to their respective load
addresses. On the way we keep track of the entry point, that only one of
those images provides, and also note the architecture of this image
(ARMv7 or AArch64).
On top of that we detect which of the images is the actual U-Boot proper
image, and append the chosen DTB to the end of it.

This all mimics the code U-Boot's SPL uses to achieve the same goal when
running from MMC or SPI flash, compare the implementation of
spl_load_simple_fit() in U-Boot's common/spl/spl_fit.c:
https://gitlab.denx.de/u-boot/u-boot/-/blob/master/common/spl/spl_fit.c

This requires the libfdt library for parsing the FIT image (which is in
fact a devicetree blob).

Signed-off-by: Andre Przywara <osp@andrep.de>

1 files changed, 282 insertions, 0 deletions

diff --git a/fit_image.c b/fit_image.c
new file mode 100644
index 0000000..899e868
--- /dev/null
+++ b/fit_image.c
@@ -0,0 +1,282 @@
+/*
+ * Copyright (C) 2018-2020  Andre Przywara <osp@andrep.de>
+ *
+ * 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; under version 2 of the License.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <libfdt.h>
+
+#include "common.h"
+#include "fel_lib.h"
+#include "fit_image.h"
+
+/* defined in fel.c */
+extern bool verbose;
+
+#define IH_ARCH_INVALID			0
+#define IH_ARCH_ARM			2
+#define IH_ARCH_ARM64			22
+
+#define IH_OS_INVALID			0
+#define IH_OS_LINUX			5
+#define IH_OS_U_BOOT			17
+#define IH_OS_ARM_TRUSTED_FIRMWARE	25
+#define IH_OS_EFI			28
+
+struct fit_image_info {
+	const char *description;
+	const char *data;
+	uint32_t data_size;
+	uint32_t load_addr;
+	uint32_t entry_point;
+	uint8_t os;
+	uint8_t arch;
+};
+
+static int fit_parse_os(const char *value)
+{
+	if (!value || !*value)
+		return IH_OS_INVALID;
+
+	if (!strcmp(value, "u-boot"))
+		return IH_OS_U_BOOT;
+	if (!strcmp(value, "linux"))
+		return IH_OS_LINUX;
+	if (!strcmp(value, "arm-trusted-firmware"))
+		return IH_OS_ARM_TRUSTED_FIRMWARE;
+	if (!strcmp(value, "efi"))
+		return IH_OS_EFI;
+
+	return IH_OS_INVALID;
+}
+
+static int fit_parse_arch(const char *value)
+{
+	if (!value || !*value)
+		return IH_ARCH_INVALID;
+
+	if (!strcmp(value, "arm"))
+		return IH_ARCH_ARM;
+	if (!strcmp(value, "arm64"))
+		return IH_ARCH_ARM64;
+
+	return IH_ARCH_INVALID;
+}
+
+static uint32_t fdt_getprop_u32(const void *fdt, int node, const char *name)
+{
+	const struct fdt_property *prop;
+
+	prop = fdt_get_property(fdt, node, name, NULL);
+	if (!prop)
+		return ~0U;
+
+	return be32toh(*(uint32_t *)prop->data);
+}
+
+static const char *fdt_getprop_str(const void *fdt, int node, const char *name)
+{
+	const struct fdt_property *prop;
+
+	prop = fdt_get_property(fdt, node, name, NULL);
+	if (!prop)
+		return NULL;
+
+	return prop->data;
+}
+
+/*
+ * Find the image with the given name under the /images node, and parse
+ * its information into the fit_image_info struct.
+ * Returns 0 on success, and a negative error value otherwise.
+ */
+static int fit_get_image_info(const void *fit, const char *name,
+			      struct fit_image_info *info)
+{
+	int node;
+	const char *str;
+	uint32_t data_offset;
+
+	node = fdt_path_offset(fit, "/images");
+	if (node < 0)
+		return -1;
+	node = fdt_subnode_offset(fit, node, name);
+	if (node < 0)
+		return -1;
+
+	info->load_addr = fdt_getprop_u32(fit, node, "load");
+	info->entry_point = fdt_getprop_u32(fit, node, "entry");
+	info->description = fdt_getprop_str(fit, node, "description");
+	/* properties used for FIT images with external data */
+	info->data_size = fdt_getprop_u32(fit, node, "data-size");
+	data_offset = fdt_getprop_u32(fit, node, "data-offset");
+
+	/* check for embedded data (when invalid external data properties) */
+	if (info->data_size == ~0U || data_offset == ~0U) {
+		const struct fdt_property *prop;
+		int len;
+
+		prop = fdt_get_property(fit, node, "data", &len);
+		info->data_size = len;
+		info->data = prop->data;
+	} else {
+		/* external data is appended at the end of the FIT DTB blob */
+		info->data = (const char *)fit + ((fdt_totalsize(fit) + 3) & ~3U);
+		info->data += data_offset;
+	}
+
+	info->os = fit_parse_os(fdt_getprop_str(fit, node, "os"));
+	info->arch = fit_parse_arch(fdt_getprop_str(fit, node, "arch"));
+
+	str = fdt_getprop_str(fit, node, "compression");
+	/* The current SPL does not support compression either. */
+	if (str && strcmp(str, "none")) {
+		printf("compression \"%s\" not supported for image \"%s\"\n",
+		       str, info->description);
+		return -2;
+	}
+
+	return 0;
+}
+
+static int entry_arch;
+static uint32_t dtb_addr;
+
+/*
+ * Upload the image described by its fit_image_info struct to the board.
+ * Detect if an image contains an entry point and return that.
+ * Set entry_arch to arm or arm64 on the way. Also detect the image
+ * containing U-Boot and record its end address, so that the DTB can be
+ * appended later on.
+ * Returns the entry point if any is specified, or 0 otherwise.
+ */
+static uint32_t fit_load_image(feldev_handle *dev, struct fit_image_info *img)
+{
+	uint32_t ret = 0;
+
+	if (verbose)
+		printf("loading image \"%s\" (%d bytes) to 0x%x\n",
+		       img->description, img->data_size, img->load_addr);
+	aw_fel_write_buffer(dev, img->data,
+			    img->load_addr, img->data_size, true);
+
+	if (img->entry_point != ~0U) {
+		ret = img->entry_point;
+		entry_arch = img->arch;
+	}
+	/* either explicitly marked as U-Boot, or the first invalid one */
+	if (img->os == IH_OS_U_BOOT ||
+	    (!dtb_addr && img->os == IH_OS_INVALID))
+		dtb_addr = img->load_addr + img->data_size;
+
+	return ret;
+}
+
+uint32_t load_fit_images(feldev_handle *dev, const void *fit,
+			 const char *dt_name, bool *use_aarch64)
+{
+	const struct fdt_property *prop;
+	struct fit_image_info img;
+	const char *str;
+	int node, len;
+	uint32_t entry_point = 0;
+
+	node = fdt_path_offset(fit, "/configurations");
+	if (node < 0) {
+		pr_error("invalid FIT image, no /configurations node\n");
+		return 0;
+	}
+
+	/*
+	 * Find the right configuration node, either by using the provided
+	 * DT name as an identifier, falling back to the node titled "default",
+	 * or by using just the first node.
+	 */
+	if (dt_name) {
+		for (node = fdt_first_subnode(fit, node);
+		     node >= 0;
+		     node = fdt_next_subnode(fit, node)) {
+			prop = fdt_get_property(fit, node, "description", NULL);
+			if (prop && !strcmp(prop->data, dt_name))
+				break;
+		}
+		if (node < 0) {
+			pr_error("no matching FIT configuration node for \"%s\"\n",
+			       dt_name);
+			return 0;
+		}
+	} else {
+		prop = fdt_get_property(fit, node, "default", NULL);
+		if (!prop)
+			node = fdt_first_subnode(fit, node);
+		else
+			node = fdt_subnode_offset(fit, node, prop->data);
+		if (node < 0) {
+			pr_error("no default FIT configuration node\n");
+			return 0;
+		}
+	}
+
+	entry_arch = IH_ARCH_INVALID;
+	dtb_addr = 0;
+
+	/* Load the image described as "firmware". */
+	str = fdt_getprop_str(fit, node, "firmware");
+	if (str && !fit_get_image_info(fit, str, &img)) {
+		uint32_t addr = fit_load_image(dev, &img);
+
+		if (addr != 0)
+			entry_point = addr;
+	} else {
+		printf("WARNING: no valid \"firmware\" image entry in FIT\n");
+	}
+
+	/* load all loadables, at their respective load addresses */
+	prop = fdt_get_property(fit, node, "loadables", &len);
+	for (str = prop ? prop->data : NULL;
+	     prop && (str - prop->data) < len && *str;
+	     str += strlen(str) + 1) {
+		uint32_t addr;
+
+		if (fit_get_image_info(fit, str, &img)) {
+			printf("Can't load loadable \"%s\", skipping.\n", str);
+			continue;
+		}
+		addr = fit_load_image(dev, &img);
+		if (addr != 0)
+			entry_point = addr;
+	}
+
+	if (use_aarch64)
+		*use_aarch64 = (entry_arch == IH_ARCH_ARM64);
+
+	if (!dtb_addr) {
+		printf("Warning: no U-Boot image found, not loading DTB\n");
+		return entry_point;
+	}
+
+	/* load .dtb right after the U-Boot image (appended DTB) */
+	str = fdt_getprop_str(fit, node, "fdt");
+	if (!str || fit_get_image_info(fit, str, &img)) {
+		printf("Warning: no FDT found in FIT image\n");
+		return entry_point;
+	}
+	if (verbose)
+		printf("loading DTB \"%s\" (%d bytes)\n", img.description,
+		       img.data_size);
+	aw_fel_write_buffer(dev, img.data, dtb_addr, img.data_size, false);
+
+	return entry_point;
+}