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>

2 files changed, 125 insertions, 0 deletions

diff --git a/drivers/block/Makefile b/drivers/block/Makefile
index 4e94378..8697da4 100644
--- a/drivers/block/Makefile
+++ b/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
diff --git a/drivers/block/sandbox.c b/drivers/block/sandbox.c
new file mode 100644
index 0000000..73f4c4a
--- /dev/null
+++ b/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;
+}