Re: [RFC 07/22] dm: blk: add UCLASS_PARTITION

[Heinrich Schuchardt <xypron.glpk@gmx.de>]

On 10/1/21 07:01, AKASHI Takahiro wrote:
> UCLASS_PARTITION device will be created as a child node of
> UCLASS_BLK device.
>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> ---
>   drivers/block/blk-uclass.c | 111 +++++++++++++++++++++++++++++++++++++
>   include/blk.h              |   9 +++
>   include/dm/uclass-id.h     |   1 +
>   3 files changed, 121 insertions(+)
>
> diff --git a/drivers/block/blk-uclass.c b/drivers/block/blk-uclass.c
> index 83682dcc181a..dd7f3c0fe31e 100644
> --- a/drivers/block/blk-uclass.c
> +++ b/drivers/block/blk-uclass.c
> @@ -12,6 +12,7 @@
>   #include <log.h>
>   #include <malloc.h>
>   #include <part.h>
> +#include <string.h>
>   #include <dm/device-internal.h>
>   #include <dm/lists.h>
>   #include <dm/uclass-internal.h>
> @@ -695,6 +696,44 @@ int blk_unbind_all(int if_type)
>   	return 0;
>   }
>
> +int blk_create_partitions(struct udevice *parent)
> +{
> +	int part, count;
> +	struct blk_desc *desc = dev_get_uclass_plat(parent);
> +	struct disk_partition info;
> +	struct disk_part *part_data;
> +	char devname[32];
> +	struct udevice *dev;
> +	int ret;
> +
> +	if (!CONFIG_IS_ENABLED(PARTITIONS) ||
> +	    !CONFIG_IS_ENABLED(HAVE_BLOCK_DEVICE))
> +		return 0;
> +
> +	/* Add devices for each partition */
> +	for (count = 0, part = 1; part <= MAX_SEARCH_PARTITIONS; part++) {
> +		if (part_get_info(desc, part, &info))
> +			continue;
> +		snprintf(devname, sizeof(devname), "%s:%d", parent->name,
> +			 part);
> +
> +		ret = device_bind_driver(parent, "blk_partition",
> +					 strdup(devname), &dev);
> +		if (ret)
> +			return ret;
> +
> +		part_data = dev_get_uclass_plat(dev);
> +		part_data->partnum = part;
> +		part_data->gpt_part_info = info;
> +		count++;
> +
> +		device_probe(dev);
> +	}
> +	debug("%s: %d partitions found in %s\n", __func__, count, parent->name);
> +
> +	return 0;
> +}
> +
>   static int blk_post_probe(struct udevice *dev)
>   {
>   	if (IS_ENABLED(CONFIG_PARTITIONS) &&
> @@ -713,3 +752,75 @@ UCLASS_DRIVER(blk) = {
>   	.post_probe	= blk_post_probe,
>   	.per_device_plat_auto	= sizeof(struct blk_desc),
>   };
> +
> +static ulong blk_part_read(struct udevice *dev, lbaint_t start,
> +			   lbaint_t blkcnt, void *buffer)
> +{
> +	struct udevice *parent;
> +	struct disk_part *part;
> +	const struct blk_ops *ops;
> +
> +	parent = dev_get_parent(dev);

What device type will the parent have if it is a eMMC hardware partition?

> +	ops = blk_get_ops(parent);
> +	if (!ops->read)
> +		return -ENOSYS;
> +
> +	part = dev_get_uclass_plat(dev);

You should check that we do not access the block device past the
partition end:

struct blk_desc *desc = dev_get_uclass_plat(parent);
if ((start + blkcnt) * desc->blksz < part->gpt_part_info.blksz)
	return -EFAULT.

> +	start += part->gpt_part_info.start;
> +
> +	return ops->read(parent, start, blkcnt, buffer);
> +}
> +
> +static ulong blk_part_write(struct udevice *dev, lbaint_t start,
> +			    lbaint_t blkcnt, const void *buffer)
> +{
> +	struct udevice *parent;
> +	struct disk_part *part;
> +	const struct blk_ops *ops;
> +
> +	parent = dev_get_parent(dev);
> +	ops = blk_get_ops(parent);
> +	if (!ops->write)
> +		return -ENOSYS;
> +
> +	part = dev_get_uclass_plat(dev);
> +	start += part->gpt_part_info.start;

here too

> +
> +	return ops->write(parent, start, blkcnt, buffer);
> +}
> +
> +static ulong blk_part_erase(struct udevice *dev, lbaint_t start,
> +			    lbaint_t blkcnt)
> +{
> +	struct udevice *parent;
> +	struct disk_part *part;
> +	const struct blk_ops *ops;
> +
> +	parent = dev_get_parent(dev);
> +	ops = blk_get_ops(parent);
> +	if (!ops->erase)
> +		return -ENOSYS;
> +
> +	part = dev_get_uclass_plat(dev);
> +	start += part->gpt_part_info.start;

here too

Best regards

Heinrich

> +
> +	return ops->erase(parent, start, blkcnt);
> +}
> +
> +static const struct blk_ops blk_part_ops = {
> +	.read	= blk_part_read,
> +	.write	= blk_part_write,
> +	.erase	= blk_part_erase,
> +};
> +
> +U_BOOT_DRIVER(blk_partition) = {
> +	.name		= "blk_partition",
> +	.id		= UCLASS_PARTITION,
> +	.ops		= &blk_part_ops,
> +};
> +
> +UCLASS_DRIVER(partition) = {
> +	.id		= UCLASS_PARTITION,
> +	.per_device_plat_auto	= sizeof(struct disk_part),
> +	.name		= "partition",
> +};
> diff --git a/include/blk.h b/include/blk.h
> index 19bab081c2cd..3d883eb1db64 100644
> --- a/include/blk.h
> +++ b/include/blk.h
> @@ -366,6 +366,15 @@ int blk_create_devicef(struct udevice *parent, const char *drv_name,
>   		       const char *name, int if_type, int devnum, int blksz,
>   		       lbaint_t lba, struct udevice **devp);
>
> +/**
> + * blk_create_partitions - Create block devices for disk partitions
> + *
> + * Create UCLASS_PARTITION udevices for each of disk partitions in @parent
> + *
> + * @parent:	Whole disk device
> + */
> +int blk_create_partitions(struct udevice *parent);
> +
>   /**
>    * blk_unbind_all() - Unbind all device of the given interface type
>    *
> diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
> index e7edd409f307..30892d01ce13 100644
> --- a/include/dm/uclass-id.h
> +++ b/include/dm/uclass-id.h
> @@ -80,6 +80,7 @@ enum uclass_id {
>   	UCLASS_P2SB,		/* (x86) Primary-to-Sideband Bus */
>   	UCLASS_PANEL,		/* Display panel, such as an LCD */
>   	UCLASS_PANEL_BACKLIGHT,	/* Backlight controller for panel */
> +	UCLASS_PARTITION,	/* Logical disk partition device */
>   	UCLASS_PCH,		/* x86 platform controller hub */
>   	UCLASS_PCI,		/* PCI bus */
>   	UCLASS_PCI_EP,		/* PCI endpoint device */
>