common: Add support for Android DT image

Android documentation recommends new image format for storing DTB/DTBO
files: [1]. To support that format, this patch adds helper functions for
Android DTB/DTBO format. In image-android-dt.* files you can find helper
functions to work with Android DT image format, such us routines for:
    - printing the dump of image structure
    - getting the address and size of desired dtb/dtbo file

This patch uses dt_table.h file, that was added in commit 643cefa4d8
("Import Android's dt_table.h for DT image format") by Alex Deymo.

[1] https://source.android.com/devices/architecture/dto/partitions

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Tom Rini <trini@konsulko.com>

common/image-android-dt.c

@@ -0,0 +1,156 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2018 Linaro Ltd.
+ * Sam Protsenko <semen.protsenko@linaro.org>
+ */
+
+#include <image-android-dt.h>
+#include <dt_table.h>
+#include <common.h>
+#include <linux/libfdt.h>
+#include <mapmem.h>
+
+/**
+ * Check if image header is correct.
+ *
+ * @param hdr_addr Start address of DT image
+ * @return true if header is correct or false if header is incorrect
+ */
+bool android_dt_check_header(ulong hdr_addr)
+{
+	const struct dt_table_header *hdr;
+	u32 magic;
+
+	hdr = map_sysmem(hdr_addr, sizeof(*hdr));
+	magic = fdt32_to_cpu(hdr->magic);
+	unmap_sysmem(hdr);
+
+	return magic == DT_TABLE_MAGIC;
+}
+
+/**
+ * Get the address of FDT (dtb or dtbo) in memory by its index in image.
+ *
+ * @param hdr_addr Start address of DT image
+ * @param index Index of desired FDT in image (starting from 0)
+ * @param[out] addr If not NULL, will contain address to specified FDT
+ * @param[out] size If not NULL, will contain size of specified FDT
+ *
+ * @return true on success or false on error
+ */
+bool android_dt_get_fdt_by_index(ulong hdr_addr, u32 index, ulong *addr,
+				 u32 *size)
+{
+	const struct dt_table_header *hdr;
+	const struct dt_table_entry *e;
+	u32 entry_count, entries_offset, entry_size;
+	ulong e_addr;
+	u32 dt_offset, dt_size;
+
+	hdr = map_sysmem(hdr_addr, sizeof(*hdr));
+	entry_count = fdt32_to_cpu(hdr->dt_entry_count);
+	entries_offset = fdt32_to_cpu(hdr->dt_entries_offset);
+	entry_size = fdt32_to_cpu(hdr->dt_entry_size);
+	unmap_sysmem(hdr);
+
+	if (index > entry_count) {
+		printf("Error: index > dt_entry_count (%u > %u)\n", index,
+		       entry_count);
+		return false;
+	}
+
+	e_addr = hdr_addr + entries_offset + index * entry_size;
+	e = map_sysmem(e_addr, sizeof(*e));
+	dt_offset = fdt32_to_cpu(e->dt_offset);
+	dt_size = fdt32_to_cpu(e->dt_size);
+	unmap_sysmem(e);
+
+	if (addr)
+		*addr = hdr_addr + dt_offset;
+	if (size)
+		*size = dt_size;
+
+	return true;
+}
+
+#if !defined(CONFIG_SPL_BUILD)
+static void android_dt_print_fdt_info(const struct fdt_header *fdt)
+{
+	u32 fdt_size;
+	int root_node_off;
+	const char *compatible = NULL;
+
+	fdt_size = fdt_totalsize(fdt);
+	root_node_off = fdt_path_offset(fdt, "/");
+	if (root_node_off < 0) {
+		printf("Error: Root node not found\n");
+	} else {
+		compatible = fdt_getprop(fdt, root_node_off, "compatible",
+					 NULL);
+	}
+
+	printf("           (FDT)size = %d\n", fdt_size);
+	printf("     (FDT)compatible = %s\n",
+	       compatible ? compatible : "(unknown)");
+}
+
+/**
+ * Print information about DT image structure.
+ *
+ * @param hdr_addr Start address of DT image
+ */
+void android_dt_print_contents(ulong hdr_addr)
+{
+	const struct dt_table_header *hdr;
+	u32 entry_count, entries_offset, entry_size;
+	u32 i;
+
+	hdr = map_sysmem(hdr_addr, sizeof(*hdr));
+	entry_count = fdt32_to_cpu(hdr->dt_entry_count);
+	entries_offset = fdt32_to_cpu(hdr->dt_entries_offset);
+	entry_size = fdt32_to_cpu(hdr->dt_entry_size);
+
+	/* Print image header info */
+	printf("dt_table_header:\n");
+	printf("               magic = %08x\n", fdt32_to_cpu(hdr->magic));
+	printf("          total_size = %d\n", fdt32_to_cpu(hdr->total_size));
+	printf("         header_size = %d\n", fdt32_to_cpu(hdr->header_size));
+	printf("       dt_entry_size = %d\n", entry_size);
+	printf("      dt_entry_count = %d\n", entry_count);
+	printf("   dt_entries_offset = %d\n", entries_offset);
+	printf("           page_size = %d\n", fdt32_to_cpu(hdr->page_size));
+	printf("             version = %d\n", fdt32_to_cpu(hdr->version));
+
+	unmap_sysmem(hdr);
+
+	/* Print image entries info */
+	for (i = 0; i < entry_count; ++i) {
+		const ulong e_addr = hdr_addr + entries_offset + i * entry_size;
+		const struct dt_table_entry *e;
+		const struct fdt_header *fdt;
+		u32 dt_offset, dt_size;
+		u32 j;
+
+		e = map_sysmem(e_addr, sizeof(*e));
+		dt_offset = fdt32_to_cpu(e->dt_offset);
+		dt_size = fdt32_to_cpu(e->dt_size);
+
+		printf("dt_table_entry[%d]:\n", i);
+		printf("             dt_size = %d\n", dt_size);
+		printf("           dt_offset = %d\n", dt_offset);
+		printf("                  id = %08x\n", fdt32_to_cpu(e->id));
+		printf("                 rev = %08x\n", fdt32_to_cpu(e->rev));
+		for (j = 0; j < 4; ++j) {
+			printf("           custom[%d] = %08x\n", j,
+			       fdt32_to_cpu(e->custom[j]));
+		}
+
+		unmap_sysmem(e);
+
+		/* Print FDT info for this entry */
+		fdt = map_sysmem(hdr_addr + dt_offset, sizeof(*fdt));
+		android_dt_print_fdt_info(fdt);
+		unmap_sysmem(fdt);
+	}
+}
+#endif

include/image-android-dt.h

@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * (C) Copyright 2018 Linaro Ltd.
+ * Sam Protsenko <semen.protsenko@linaro.org>
+ */
+
+#ifndef IMAGE_ANDROID_DT_H
+#define IMAGE_ANDROID_DT_H
+
+#include <linux/types.h>
+
+bool android_dt_check_header(ulong hdr_addr);
+bool android_dt_get_fdt_by_index(ulong hdr_addr, u32 index, ulong *addr,
+				 u32 *size);
+
+#if !defined(CONFIG_SPL_BUILD)
+void android_dt_print_contents(ulong hdr_addr);
+#endif
+
+#endif /* IMAGE_ANDROID_DT_H */