common/armflash: Support for ARM flash images

The ARM reference designs all use a special flash image format
that stores a footer (two versions exist) at the end of the last
erase block of the image in flash memory.

Version one of the footer is indicated by the magic number
0xA0FFFF9F at 12 bytes before the end of the flash block and
version two is indicated by the magic number 0x464F4F54 0x464C5348
(ASCII for "FLSHFOOT") in the very last 8 bytes of the erase block.

This command driver implements support for both versions of the
AFS images (the name comes from the Linux driver in drivers/mtd/afs.c)
and makes it possible to list images and load an image by name into
the memory with these commands:

afs - lists flash contents
afs load <image> - loads image to address indicated in the image
afs load <image> <addres> - loads image to a specified address

This image scheme is used on the ARM Integrator family, ARM
Versatile family, ARM RealView family (not yet supported in U-Boot)
and ARM Versatile Express family up to and including the new
Juno board for 64 bit development.

Reviewed-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

common/Kconfig

@@ -193,6 +193,12 @@ config CMD_FLASH
 	    erase - FLASH memory
 	    protect - enable or disable FLASH write protection
 
+config CMD_ARMFLASH
+	depends on FLASH_CFI_DRIVER
+	bool "armflash"
+	help
+	  ARM Ltd reference designs flash partition access
+
 config CMD_NAND
 	bool "nand"
 	help

common/Makefile

@@ -60,6 +60,7 @@ obj-$(CONFIG_ENV_IS_NOWHERE) += env_nowhere.o
 # command
 obj-$(CONFIG_CMD_AES) += cmd_aes.o
 obj-$(CONFIG_CMD_AMBAPP) += cmd_ambapp.o
+obj-$(CONFIG_CMD_ARMFLASH) += cmd_armflash.o
 obj-$(CONFIG_SOURCE) += cmd_source.o
 obj-$(CONFIG_CMD_SOURCE) += cmd_source.o
 obj-$(CONFIG_CMD_BDI) += cmd_bdinfo.o

common/cmd_armflash.c

@@ -0,0 +1,278 @@
+/*
+ * (C) Copyright 2015
+ * Linus Walleij, Linaro
+ *
+ * Support for ARM Flash Partitions
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+#include <common.h>
+#include <command.h>
+#include <asm/io.h>
+
+#define MAX_REGIONS 4
+#define MAX_IMAGES 32
+
+struct afs_region {
+	u32 load_address;
+	u32 size;
+	u32 offset;
+};
+
+struct afs_image {
+	flash_info_t *flinfo;
+	const char *name;
+	u32 version;
+	u32 entrypoint;
+	u32 attributes;
+	u32 region_count;
+	struct afs_region regions[MAX_REGIONS];
+	ulong flash_mem_start;
+	ulong flash_mem_end;
+};
+
+static struct afs_image afs_images[MAX_IMAGES];
+static int num_afs_images;
+
+static u32 compute_crc(ulong start, u32 len)
+{
+	u32 sum = 0;
+	int i;
+
+	if (len % 4 != 0) {
+		printf("bad checksumming\n");
+		return 0;
+	}
+
+	for (i = 0; i < len; i += 4) {
+		u32 val;
+
+		val = readl((void *)start + i);
+		if (val > ~sum)
+			sum++;
+		sum += val;
+	}
+	return ~sum;
+}
+
+static void parse_bank(ulong bank)
+{
+	int i;
+	ulong flstart, flend;
+	flash_info_t *info;
+
+	info = &flash_info[bank];
+	if (info->flash_id != FLASH_MAN_CFI) {
+		printf("Bank %lu: missing or unknown FLASH type\n", bank);
+		return;
+	}
+	if (!info->sector_count) {
+		printf("Bank %lu: no FLASH sectors\n", bank);
+		return;
+	}
+
+	flstart = info->start[0];
+	flend = flstart + info->size;
+
+	for (i = 0; i < info->sector_count; ++i) {
+		ulong secend;
+		u32 foot1, foot2;
+
+		if (ctrlc())
+			break;
+
+		if (i == info->sector_count-1)
+			secend = flend;
+		else
+			secend = info->start[i+1];
+
+		/* Check for v1 header */
+		foot1 = readl((void *)secend - 0x0c);
+		if (foot1 == 0xA0FFFF9FU) {
+			struct afs_image *afi = &afs_images[num_afs_images];
+			ulong imginfo;
+
+			afi->flinfo = info;
+			afi->version = 1;
+			afi->flash_mem_start = readl((void *)secend - 0x10);
+			afi->flash_mem_end = readl((void *)secend - 0x14);
+			afi->attributes = readl((void *)secend - 0x08);
+			/* Adjust to even address */
+			imginfo = afi->flash_mem_end + afi->flash_mem_end % 4;
+			/* Record as a single region */
+			afi->region_count = 1;
+			afi->regions[0].offset = readl((void *)imginfo + 0x04);
+			afi->regions[0].load_address =
+				readl((void *)imginfo + 0x08);
+			afi->regions[0].size = readl((void *)imginfo + 0x0C);
+			afi->entrypoint = readl((void *)imginfo + 0x10);
+			afi->name = (const char *)imginfo + 0x14;
+			num_afs_images++;
+		}
+
+		/* Check for v2 header */
+		foot1 = readl((void *)secend - 0x04);
+		foot2 = readl((void *)secend - 0x08);
+		/* This makes up the string "HSLFTOOF" flash footer */
+		if (foot1 == 0x464F4F54U && foot2 == 0x464C5348U) {
+			struct afs_image *afi = &afs_images[num_afs_images];
+			ulong imginfo;
+			u32 block_start, block_end;
+			int j;
+
+			afi->flinfo = info;
+			afi->version = readl((void *)secend - 0x0c);
+			imginfo = secend - 0x30 - readl((void *)secend - 0x10);
+			afi->name = (const char *)secend - 0x30;
+
+			afi->entrypoint = readl((void *)imginfo+0x08);
+			afi->attributes = readl((void *)imginfo+0x0c);
+			afi->region_count = readl((void *)imginfo+0x10);
+			block_start = readl((void *)imginfo+0x54);
+			block_end = readl((void *)imginfo+0x58);
+			afi->flash_mem_start = afi->flinfo->start[block_start];
+			afi->flash_mem_end = afi->flinfo->start[block_end];
+
+			/*
+			 * Check footer CRC, the algorithm saves the inverse
+			 * checksum as part of the summed words, and thus
+			 * the result should be zero.
+			 */
+			if (compute_crc(imginfo + 8, 0x88) != 0) {
+				printf("BAD CRC on ARM image info\n");
+				printf("(continuing anyway)\n");
+			}
+
+			/* Parse regions */
+			for (j = 0; j < afi->region_count; j++) {
+				afi->regions[j].load_address =
+					readl((void *)imginfo+0x14 + j*0x10);
+				afi->regions[j].size =
+					readl((void *)imginfo+0x18 + j*0x10);
+				afi->regions[j].offset =
+					readl((void *)imginfo+0x1c + j*0x10);
+				/*
+				 * At offset 0x20 + j*0x10 there is a region
+				 * checksum which seems to be the running
+				 * sum + 3, however since we anyway checksum
+				 * the entire footer this is skipped over for
+				 * checking here.
+				 */
+			}
+			num_afs_images++;
+		}
+	}
+}
+
+static void parse_flash(void)
+{
+	ulong bank;
+
+	/* We have already parsed the images in flash */
+	if (num_afs_images > 0)
+		return;
+	for (bank = 0; bank < CONFIG_SYS_MAX_FLASH_BANKS; ++bank)
+		parse_bank(bank);
+}
+
+static void load_image(const char * const name, const ulong address)
+{
+	struct afs_image *afi = NULL;
+	int i;
+
+	parse_flash();
+	for (i = 0; i < num_afs_images; i++) {
+		struct afs_image *tmp = &afs_images[i];
+
+		if (!strcmp(tmp->name, name)) {
+			afi = tmp;
+			break;
+		}
+	}
+	if (!afi) {
+		printf("image \"%s\" not found in flash\n", name);
+		return;
+	}
+
+	for (i = 0; i < afi->region_count; i++) {
+		ulong from, to;
+
+		from = afi->flash_mem_start + afi->regions[i].offset;
+		if (address) {
+			to = address;
+		} else if (afi->regions[i].load_address) {
+			to = afi->regions[i].load_address;
+		} else {
+			printf("no valid load address\n");
+			return;
+		}
+
+		memcpy((void *)to, (void *)from, afi->regions[i].size);
+
+		printf("loaded region %d from %08lX to %08lX, %08X bytes\n",
+		       i,
+		       from,
+		       to,
+		       afi->regions[i].size);
+	}
+}
+
+static void print_images(void)
+{
+	int i;
+
+	parse_flash();
+	for (i = 0; i < num_afs_images; i++) {
+		struct afs_image *afi = &afs_images[i];
+		int j;
+
+		printf("Image: \"%s\" (v%d):\n", afi->name, afi->version);
+		printf("    Entry point: 0x%08X\n", afi->entrypoint);
+		printf("    Attributes: 0x%08X: ", afi->attributes);
+		if (afi->attributes == 0x01)
+			printf("ARM executable");
+		if (afi->attributes == 0x08)
+			printf("ARM backup");
+		printf("\n");
+		printf("    Flash mem start: 0x%08lX\n",
+		       afi->flash_mem_start);
+		printf("    Flash mem end: 0x%08lX\n",
+		       afi->flash_mem_end);
+		for (j = 0; j < afi->region_count; j++) {
+			printf("    region %d\n"
+			       "        load address: %08X\n"
+			       "        size: %08X\n"
+			       "        offset: %08X\n",
+			       j,
+			       afi->regions[j].load_address,
+			       afi->regions[j].size,
+			       afi->regions[j].offset);
+		}
+	}
+}
+
+static int do_afs(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	if (argc == 1) {
+		print_images();
+	} else if (argc == 3 && !strcmp(argv[1], "load")) {
+		load_image(argv[2], 0x0);
+	} else if (argc == 4 && !strcmp(argv[1], "load")) {
+		ulong load_addr;
+
+		load_addr = simple_strtoul(argv[3], NULL, 16);
+		load_image(argv[2], load_addr);
+	} else {
+		return CMD_RET_USAGE;
+	}
+
+	return 0;
+}
+
+U_BOOT_CMD(afs, 4, 0, do_afs, "show AFS partitions",
+	   "no arguments\n"
+	   "    - list images in flash\n"
+	   "load <image>\n"
+	   "    - load an image to the location indicated in the header\n"
+	   "load <image> 0x<address>\n"
+	   "    - load an image to the location specified\n");