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

[AKASHI Takahiro <takahiro.akashi@linaro.org>]

On Mon, Oct 04, 2021 at 12:27:59PM +0900, AKASHI Takahiro wrote:
> On Fri, Oct 01, 2021 at 11:30:37AM +0200, Heinrich Schuchardt wrote:
> > 
> > 
> > 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:
> 
> Yes, I will fix all of checks.
> 
> > 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;

A better solution is:
        if (start >= part->gpt_part_info.size)
                return 0;

        if ((start + blkcnt) > part->gpt_part_info.size)
                blkcnt = part->gpt_part_info.size - start;
        start += part->gpt_part_info.start;
instead of returning -EFAULT.
(note that start and blkcnt are in "block".)

-Takahiro Akashi

> > > +
> > > +	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 */
> > >