sandbox: block driver using host file/device as backing store

Provide a way to use any host file or device as a block device in U-Boot.
This can be used to provide filesystem access within U-Boot to an ext2
image file on the host, for example.

The support is plumbed into the filesystem and partition interfaces.

We don't want to print a message in the driver every time we find a missing
device. Pass the information back to the caller where a message can be printed
if desired.

Signed-off-by: Henrik Nordström <henrik@henriknordstrom.net>
Signed-off-by: Simon Glass <sjg@chromium.org>
- Removed change to part.c get_device_and_partition()

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

common/cmd_sandbox.c

@@ -6,6 +6,9 @@
 
 #include <common.h>
 #include <fs.h>
+#include <part.h>
+#include <sandboxblockdev.h>
+#include <asm/errno.h>
 
 static int do_sandbox_load(cmd_tbl_t *cmdtp, int flag, int argc,
 			   char * const argv[])
@@ -25,10 +28,69 @@ static int do_sandbox_save(cmd_tbl_t *cmdtp, int flag, int argc,
 	return do_save(cmdtp, flag, argc, argv, FS_TYPE_SANDBOX);
 }
 
+static int do_sandbox_bind(cmd_tbl_t *cmdtp, int flag, int argc,
+			   char * const argv[])
+{
+	if (argc < 2 || argc > 3)
+		return CMD_RET_USAGE;
+	char *ep;
+	char *dev_str = argv[1];
+	char *file = argc >= 3 ? argv[2] : NULL;
+	int dev = simple_strtoul(dev_str, &ep, 16);
+	if (*ep) {
+		printf("** Bad device specification %s **\n", dev_str);
+		return CMD_RET_USAGE;
+	}
+	return host_dev_bind(dev, file);
+}
+
+static int do_sandbox_info(cmd_tbl_t *cmdtp, int flag, int argc,
+			   char * const argv[])
+{
+	if (argc < 1 || argc > 2)
+		return CMD_RET_USAGE;
+	int min_dev = 0;
+	int max_dev = CONFIG_HOST_MAX_DEVICES - 1;
+	if (argc >= 2) {
+		char *ep;
+		char *dev_str = argv[1];
+		int dev = simple_strtoul(dev_str, &ep, 16);
+		if (*ep) {
+			printf("** Bad device specification %s **\n", dev_str);
+			return CMD_RET_USAGE;
+		}
+		min_dev = dev;
+		max_dev = dev;
+	}
+	int dev;
+	printf("%3s %12s %s\n", "dev", "blocks", "path");
+	for (dev = min_dev; dev <= max_dev; dev++) {
+		block_dev_desc_t *blk_dev;
+		int ret;
+
+		printf("%3d ", dev);
+		ret = host_get_dev_err(dev, &blk_dev);
+		if (ret) {
+			if (ret == -ENOENT)
+				puts("Not bound to a backing file\n");
+			else if (ret == -ENODEV)
+				puts("Invalid host device number\n");
+
+			continue;
+		}
+		struct host_block_dev *host_dev = blk_dev->priv;
+		printf("%12lu %s\n", (unsigned long)blk_dev->lba,
+		       host_dev->filename);
+	}
+	return 0;
+}
+
 static cmd_tbl_t cmd_sandbox_sub[] = {
 	U_BOOT_CMD_MKENT(load, 7, 0, do_sandbox_load, "", ""),
 	U_BOOT_CMD_MKENT(ls, 3, 0, do_sandbox_ls, "", ""),
 	U_BOOT_CMD_MKENT(save, 6, 0, do_sandbox_save, "", ""),
+	U_BOOT_CMD_MKENT(bind, 3, 0, do_sandbox_bind, "", ""),
+	U_BOOT_CMD_MKENT(info, 3, 0, do_sandbox_info, "", ""),
 };
 
 static int do_sandbox(cmd_tbl_t *cmdtp, int flag, int argc,
@@ -57,4 +119,6 @@ U_BOOT_CMD(
 	"sb ls host <filename>                      - list files on host\n"
 	"sb save host <dev> <filename> <addr> <bytes> [<offset>] - "
 		"save a file to host\n"
+	"sb bind <dev> [<filename>] - bind \"host\" device to file\n"
+	"sb info [<dev>]            - show device binding & info"
 );

disk/part.c

@@ -42,6 +42,9 @@ static const struct block_drvr block_drvr[] = {
 #endif
 #if defined(CONFIG_SYSTEMACE)
 	{ .name = "ace", .get_dev = systemace_get_dev, },
+#endif
+#if defined(CONFIG_SANDBOX)
+	{ .name = "host", .get_dev = host_get_dev, },
 #endif
 	{ },
 };
@@ -286,6 +289,9 @@ static void print_part_header (const char *type, block_dev_desc_t * dev_desc)
 	case IF_TYPE_MMC:
 		puts ("MMC");
 		break;
+	case IF_TYPE_HOST:
+		puts("HOST");
+		break;
 	default:
 		puts ("UNKNOWN");
 		break;

drivers/block/Makefile

@@ -18,5 +18,6 @@ obj-$(CONFIG_SATA_DWC) += sata_dwc.o
 obj-$(CONFIG_SATA_SIL3114) += sata_sil3114.o
 obj-$(CONFIG_SATA_SIL) += sata_sil.o
 obj-$(CONFIG_IDE_SIL680) += sil680.o
+obj-$(CONFIG_SANDBOX) += sandbox.o
 obj-$(CONFIG_SCSI_SYM53C8XX) += sym53c8xx.o
 obj-$(CONFIG_SYSTEMACE) += systemace.o

drivers/block/sandbox.c

@@ -0,0 +1,124 @@
+/*
+ * Copyright (C) 2013 Henrik Nordstrom <henrik@henriknordstrom.net>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <config.h>
+#include <common.h>
+#include <part.h>
+#include <os.h>
+#include <malloc.h>
+#include <sandboxblockdev.h>
+#include <asm/errno.h>
+
+static struct host_block_dev host_devices[CONFIG_HOST_MAX_DEVICES];
+
+static struct host_block_dev *find_host_device(int dev)
+{
+	if (dev >= 0 && dev < CONFIG_HOST_MAX_DEVICES)
+		return &host_devices[dev];
+
+	return NULL;
+}
+
+static unsigned long host_block_read(int dev, unsigned long start,
+				     lbaint_t blkcnt, void *buffer)
+{
+	struct host_block_dev *host_dev = find_host_device(dev);
+
+	if (!host_dev)
+		return -1;
+	if (os_lseek(host_dev->fd,
+		     start * host_dev->blk_dev.blksz,
+		     OS_SEEK_SET) == -1) {
+		printf("ERROR: Invalid position\n");
+		return -1;
+	}
+	ssize_t len = os_read(host_dev->fd, buffer,
+			      blkcnt * host_dev->blk_dev.blksz);
+	if (len >= 0)
+		return len / host_dev->blk_dev.blksz;
+	return -1;
+}
+
+static unsigned long host_block_write(int dev, unsigned long start,
+				      lbaint_t blkcnt, const void *buffer)
+{
+	struct host_block_dev *host_dev = find_host_device(dev);
+	if (os_lseek(host_dev->fd,
+		     start * host_dev->blk_dev.blksz,
+		     OS_SEEK_SET) == -1) {
+		printf("ERROR: Invalid position\n");
+		return -1;
+	}
+	ssize_t len = os_write(host_dev->fd, buffer, blkcnt *
+			       host_dev->blk_dev.blksz);
+	if (len >= 0)
+		return len / host_dev->blk_dev.blksz;
+	return -1;
+}
+
+int host_dev_bind(int dev, char *filename)
+{
+	struct host_block_dev *host_dev = find_host_device(dev);
+
+	if (!host_dev)
+		return -1;
+	if (host_dev->blk_dev.priv) {
+		os_close(host_dev->fd);
+		host_dev->blk_dev.priv = NULL;
+	}
+	if (host_dev->filename)
+		free(host_dev->filename);
+	if (filename && *filename) {
+		host_dev->filename = strdup(filename);
+	} else {
+		host_dev->filename = NULL;
+		return 0;
+	}
+
+	host_dev->fd = os_open(host_dev->filename, OS_O_RDWR);
+	if (host_dev->fd == -1) {
+		printf("Failed to access host backing file '%s'\n",
+		       host_dev->filename);
+		return 1;
+	}
+
+	block_dev_desc_t *blk_dev = &host_dev->blk_dev;
+	blk_dev->if_type = IF_TYPE_HOST;
+	blk_dev->priv = host_dev;
+	blk_dev->blksz = 512;
+	blk_dev->lba = os_lseek(host_dev->fd, 0, OS_SEEK_END) / blk_dev->blksz;
+	blk_dev->block_read = host_block_read;
+	blk_dev->block_write = host_block_write;
+	blk_dev->dev = dev;
+	blk_dev->part_type = PART_TYPE_UNKNOWN;
+	init_part(blk_dev);
+
+	return 0;
+}
+
+int host_get_dev_err(int dev, block_dev_desc_t **blk_devp)
+{
+	struct host_block_dev *host_dev = find_host_device(dev);
+
+	if (!host_dev)
+		return -ENODEV;
+
+	if (!host_dev->blk_dev.priv)
+		return -ENOENT;
+
+	*blk_devp = &host_dev->blk_dev;
+	return 0;
+}
+
+block_dev_desc_t *host_get_dev(int dev)
+{
+	block_dev_desc_t *blk_dev;
+
+	if (host_get_dev_err(dev, &blk_dev))
+		return NULL;
+
+	return blk_dev;
+}

include/config_fallbacks.h

@@ -50,7 +50,8 @@
 	defined(CONFIG_CMD_PART) || \
 	defined(CONFIG_CMD_GPT) || \
 	defined(CONFIG_MMC) || \
-	defined(CONFIG_SYSTEMACE)
+	defined(CONFIG_SYSTEMACE) || \
+	defined(CONFIG_SANDBOX)
 #define HAVE_BLOCK_DEVICE
 #endif
 

include/configs/sandbox.h

@@ -39,6 +39,9 @@
 #define CONFIG_CMD_FAT
 #define CONFIG_CMD_EXT4
 #define CONFIG_CMD_EXT4_WRITE
+#define CONFIG_CMD_PART
+#define CONFIG_DOS_PARTITION
+#define CONFIG_HOST_MAX_DEVICES 4
 
 #define CONFIG_SYS_VSNPRINTF
 

include/part.h

@@ -58,6 +58,8 @@ typedef struct block_dev_desc {
 #define IF_TYPE_MMC		6
 #define IF_TYPE_SD		7
 #define IF_TYPE_SATA		8
+#define IF_TYPE_HOST		9
+#define IF_TYPE_MAX		10	/* Max number of IF_TYPE_* supported */
 
 /* Part types */
 #define PART_TYPE_UNKNOWN	0x00
@@ -102,6 +104,8 @@ block_dev_desc_t* usb_stor_get_dev(int dev);
 block_dev_desc_t* mmc_get_dev(int dev);
 block_dev_desc_t* systemace_get_dev(int dev);
 block_dev_desc_t* mg_disk_get_dev(int dev);
+block_dev_desc_t *host_get_dev(int dev);
+int host_get_dev_err(int dev, block_dev_desc_t **blk_devp);
 
 /* disk/part.c */
 int get_partition_info (block_dev_desc_t * dev_desc, int part, disk_partition_t *info);
@@ -123,6 +127,7 @@ static inline block_dev_desc_t* usb_stor_get_dev(int dev) { return NULL; }
 static inline block_dev_desc_t* mmc_get_dev(int dev) { return NULL; }
 static inline block_dev_desc_t* systemace_get_dev(int dev) { return NULL; }
 static inline block_dev_desc_t* mg_disk_get_dev(int dev) { return NULL; }
+static inline block_dev_desc_t *host_get_dev(int dev) { return NULL; }
 
 static inline int get_partition_info (block_dev_desc_t * dev_desc, int part,
 	disk_partition_t *info) { return -1; }

include/sandboxblockdev.h

@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2013, Henrik Nordstrom <henrik@henriknordstrom.net>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef __SANDBOX_BLOCK_DEV__
+#define __SANDBOX_BLOCK_DEV__
+
+struct host_block_dev {
+	block_dev_desc_t blk_dev;
+	char *filename;
+	int fd;
+};
+
+int host_dev_bind(int dev, char *filename);
+
+#endif