cmd: Add a SEAMA image load command

Add a command to load SEAMA (Seattle Image), a NAND flash
on-flash storage format.

This type of flash image is found in some D-Link routers such
as DIR-645, DIR-842, DIR-859, DIR-860L, DIR-885L, DIR890L and
DCH-M225, as well as in WD and NEC routers on the ath79
(MIPS), Broadcom BCM53xx, and RAMIPS platforms.

This U-Boot command will read and decode a SEAMA image from
raw NAND flash on any platform. As it is always using big endian
format for the data decoding is always necessary on platforms
such as ARM.

The command is needed to read a SEAMA-encoded boot image on the
D-Link DIR-890L router for boot from NAND flash in an upcoming
port of U-Boot to the Broadcom Northstar (BCM4709, BCM53xx)
architecture.

A basic test and documentation is added as well. The test must
be run on a target with NAND flash support and at least one
resident SEAMA image in flash.

Cc: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

3 files changed, 165 insertions, 0 deletions

diff --git a/cmd/Kconfig b/cmd/Kconfig
index dc0446e02e..b50e14f70a 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -337,6 +337,12 @@ config BOOTM_RTEMS
 	help
 	  Support booting RTEMS images via the bootm command.
 
+config CMD_SEAMA
+	bool "Support read SEAMA NAND images"
+	depends on MTD_RAW_NAND
+	help
+	  Support reading NAND Seattle Image (SEAMA) images.
+
 config CMD_VBE
 	bool "vbe - Verified Boot for Embedded"
 	depends on BOOTMETH_VBE
diff --git a/cmd/Makefile b/cmd/Makefile
index 7b6ff73186..b03d68d5f9 100644
--- a/cmd/Makefile
+++ b/cmd/Makefile
@@ -156,6 +156,7 @@ obj-$(CONFIG_SANDBOX) += sb.o
 obj-$(CONFIG_CMD_SF) += sf.o
 obj-$(CONFIG_CMD_SCSI) += scsi.o disk.o
 obj-$(CONFIG_CMD_SHA1SUM) += sha1sum.o
+obj-$(CONFIG_CMD_SEAMA) += seama.o
 obj-$(CONFIG_CMD_SETEXPR) += setexpr.o
 obj-$(CONFIG_CMD_SETEXPR_FMT) += printf.o
 obj-$(CONFIG_CMD_SPI) += spi.o
diff --git a/cmd/seama.c b/cmd/seama.c
new file mode 100644
index 0000000000..3aafb43c48
--- /dev/null
+++ b/cmd/seama.c
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2023 Linus Walleij <linus.walleij@linaro.org>
+ * Support for the "SEAttle iMAge" SEAMA NAND image format
+ */
+
+#include <common.h>
+#include <command.h>
+#include <nand.h>
+
+/*
+ * All SEAMA data is stored in the flash in "network endianness"
+ * i.e. big endian, which means that it needs to be byte-swapped
+ * on all little endian platforms.
+ *
+ * structure for a SEAMA entity in NAND flash:
+ *
+ * 32 bit SEAMA magic 0x5EA3A417
+ * 16 bit reserved
+ * 16 bit metadata size (following the header)
+ * 32 bit image size
+ * 16 bytes MD5 digest of the image
+ * meta data
+ * ... image data ...
+ *
+ * Then if a new SEAMA magic follows, that is the next image.
+ */
+
+#define SEAMA_MAGIC		0x5EA3A417
+#define SEAMA_HDR_NO_META_SZ	28
+#define SEAMA_MAX_META_SZ	(1024 - SEAMA_HDR_NO_META_SZ)
+
+struct seama_header {
+	u32 magic;
+	u32 meta_size;
+	u32 image_size;
+	u8 md5[16];
+	u8 metadata[SEAMA_MAX_META_SZ];
+};
+
+static struct seama_header shdr;
+
+static int env_set_val(const char *varname, ulong val)
+{
+	int ret;
+
+	ret = env_set_hex(varname, val);
+	if (ret)
+		printf("Failed to %s env var\n", varname);
+
+	return ret;
+}
+
+static int do_seama_load_image(struct cmd_tbl *cmdtp, int flag, int argc,
+			       char *const argv[])
+{
+	struct mtd_info *mtd;
+	uintptr_t load_addr;
+	unsigned long image_index;
+	u32 len;
+	size_t readsz;
+	int ret;
+	u32 *start;
+	u32 *offset;
+	u32 *end;
+	u32 tmp;
+
+	if (argc < 2 || argc > 3)
+		return CMD_RET_USAGE;
+
+	load_addr = hextoul(argv[1], NULL);
+	if (!load_addr) {
+		printf("Invalid load address\n");
+		return CMD_RET_USAGE;
+	}
+
+	/* Can be 0 for first image */
+	image_index = hextoul(argv[2], NULL);
+
+	/* We only support one NAND, the first one */
+	nand_curr_device = 0;
+	mtd = get_nand_dev_by_index(0);
+	if (!mtd) {
+		printf("NAND Device 0 not available\n");
+		return CMD_RET_FAILURE;
+	}
+
+#ifdef CONFIG_SYS_NAND_SELECT_DEVICE
+	board_nand_select_device(mtd_to_nand(mtd), 0);
+#endif
+
+	printf("Loading SEAMA image %lu from %s\n", image_index, mtd->name);
+
+	readsz = sizeof(shdr);
+	offset = 0;
+	ret = nand_read_skip_bad(mtd, 0, &readsz, NULL, mtd->size,
+				 (u_char *)&shdr);
+	if (ret) {
+		printf("Read error reading SEAMA header\n");
+		return CMD_RET_FAILURE;
+	}
+
+	if (shdr.magic != SEAMA_MAGIC) {
+		printf("Invalid SEAMA image magic: 0x%08x\n", shdr.magic);
+		return CMD_RET_FAILURE;
+	}
+
+	/* Only the lower 16 bits are valid */
+	shdr.meta_size &= 0xFFFF;
+
+	if (env_set_val("seama_image_size", 0))
+		return CMD_RET_FAILURE;
+
+	printf("SEMA IMAGE:\n");
+	printf("  metadata size %d\n", shdr.meta_size);
+	printf("  image size %d\n", shdr.image_size);
+	printf("  checksum %02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x\n",
+	       shdr.md5[0], shdr.md5[1], shdr.md5[2], shdr.md5[3],
+	       shdr.md5[4], shdr.md5[5], shdr.md5[6], shdr.md5[7],
+	       shdr.md5[8], shdr.md5[9], shdr.md5[10], shdr.md5[11],
+	       shdr.md5[12], shdr.md5[13], shdr.md5[14], shdr.md5[15]);
+
+	/* TODO: handle metadata if needed */
+
+	len = shdr.image_size;
+	if (env_set_val("seama_image_size", len))
+		return CMD_RET_FAILURE;
+
+	/* We need to include the header (read full pages) */
+	readsz = shdr.image_size + SEAMA_HDR_NO_META_SZ + shdr.meta_size;
+	ret = nand_read_skip_bad(mtd, 0, &readsz, NULL, mtd->size,
+				 (u_char *)load_addr);
+	if (ret) {
+		printf("Read error reading SEAMA main image\n");
+		return CMD_RET_FAILURE;
+	}
+
+	/* We use a temporary variable tmp to avoid to hairy casts */
+	start = (u32 *)load_addr;
+	tmp = (u32)start;
+	tmp += SEAMA_HDR_NO_META_SZ + shdr.meta_size;
+	offset = (u32 *)tmp;
+	tmp += shdr.image_size;
+	end = (u32 *)tmp;
+
+	printf("Decoding SEAMA image 0x%08x..0x%08x to 0x%08x\n",
+	       (u32)offset, (u32)end, (u32)start);
+	for (; start < end; start++, offset++)
+		*start = be32_to_cpu(*offset);
+
+	return CMD_RET_SUCCESS;
+}
+
+U_BOOT_CMD
+	(seama, 3, 1, do_seama_load_image,
+	 "Load the SEAMA image and sets envs",
+	 "seama <addr> <imageindex>\n"
+);