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From: Randy Dunlap on 19 May 2010 15:50
On Wed, 19 May 2010 10:08:15 +0200 Ulf Hansson wrote:

> This adds an option to pass in block device partitions from the
> kernel cmdline.
>
> The rationale is that in embedded systems we sometimes have no
> standard partition table available: often due to the fact that raw
> binary data is read out from the first sectors of the device by
> ROM code in ASICs. We have for a long time supplied custom partition
> information to embedded flash memories through the MTDparts interface
> which has similar semantics, and with the advent of embedded MMC
> block devices this now comes to standard block devices.
>
> Acked-by: Linus Walleij <linus.walleij(a)stericsson.com>
> Signed-off-by: Ulf Hansson <ulf.hansson(a)stericsson.com>
> ---
> fs/partitions/Kconfig | 19 ++++++
> fs/partitions/Makefile | 1 +
> fs/partitions/blkdev_parts.c | 127 ++++++++++++++++++++++++++++++++++++++++++
> fs/partitions/blkdev_parts.h | 14 +++++
> fs/partitions/check.c | 4 +
> 5 files changed, 165 insertions(+), 0 deletions(-)
> create mode 100755 fs/partitions/blkdev_parts.c
> create mode 100755 fs/partitions/blkdev_parts.h
>
> diff --git a/fs/partitions/Kconfig b/fs/partitions/Kconfig
> index cb5f0a3..097be19 100644
> --- a/fs/partitions/Kconfig
> +++ b/fs/partitions/Kconfig
> @@ -68,6 +68,25 @@ config ACORN_PARTITION_RISCIX
> of machines called RISCiX. If you say 'Y' here, Linux will be able
> to read disks partitioned under RISCiX.
>
> +config BLKDEV_PARTITION
> + bool "Blockdev commandline partition support" if PARTITION_ADVANCED

command line

> + default n
> + help
> + Say Y if you like to setup partitions for block devices by reading
> + from the kernel command line (kernel boot arguments).
> +
> + The format of the partitions on the command line:
> + blkdevparts=<blkdev-def>[;<blkdev-def>]
> + <blkdev-def> := <blkdev-id>:<partdef>[,<partdef>]
> + <partdef> := <size>[@<offset>]
> +
> + <blkdev-id> := unique id used to map driver to blockdev name
> + <size> := size in numbers of sectors
> + <offset> := offset in sectors for partition to start at

Are MMC sectors always a known, fixed size? 512 bytes or 4096 bytes?


> +
> + Example:
> + blkdevparts=mmc0:1024@0,524288(a)1024;mmc1:8192@0,8192(a)8192
> +
> config OSF_PARTITION
> bool "Alpha OSF partition support" if PARTITION_ADVANCED
> default y if ALPHA

> diff --git a/fs/partitions/blkdev_parts.c b/fs/partitions/blkdev_parts.c
> new file mode 100755
> index 0000000..48f4136
> --- /dev/null
> +++ b/fs/partitions/blkdev_parts.c
> @@ -0,0 +1,127 @@
> +/*
> + *
> + * Copyright (C) ST-Ericsson SA 2010
> + *
> + * Author: Ulf Hansson <ulf.hansson(a)stericsson.com> for ST-Ericsson
> + * License terms: GNU General Public License (GPL) version 2
> + *
> + * Create partitions for block devices by reading from the kernel
> + * command line (kernel boot arguments).
> + *
> + */
> +
> +#include "check.h"
> +#include "blkdev_parts.h"
> +
> +static char *cmdline;

> +int blkdev_partition(struct parsed_partitions *state, struct block_device *bdev)
> +{
> + char blkdev_name[BDEVNAME_SIZE];
> +
> + /* Check if there are any partitions to handle */
> + if (cmdline == NULL)
> + return 0;
> +
> + /* Get the name of the blockdevice we are operating upon */
> + if (bdevname(bdev, blkdev_name) == NULL) {
> + printk(KERN_WARNING "Could not get a blkdev name\n");

Needs some message source id; maybe:
printk(KERN_WARNING "blkdevparts: Could not get a blkdev name\n");

> + return 0;
> + }
> +
> + /* Parse for partitions and add them to the state */
> + return parse_blkdev_parts(blkdev_name, state);
> +}


---
~Randy
*** Remember to use Documentation/SubmitChecklist when testing your code ***
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From: Ulf HANSSON on 20 May 2010 05:20

> On Wed, 19 May 2010 10:08:15 +0200 Ulf Hansson wrote:
>
> > This adds an option to pass in block device partitions from
> the kernel
> > cmdline.
> >
> > The rationale is that in embedded systems we sometimes have no
> > standard partition table available: often due to the fact that raw
> > binary data is read out from the first sectors of the device by ROM
> > code in ASICs. We have for a long time supplied custom partition
> > information to embedded flash memories through the MTDparts
> interface
> > which has similar semantics, and with the advent of
> embedded MMC block
> > devices this now comes to standard block devices.
> >
> > Acked-by: Linus Walleij <linus.walleij(a)stericsson.com>
> > Signed-off-by: Ulf Hansson <ulf.hansson(a)stericsson.com>
> > ---
> > fs/partitions/Kconfig | 19 ++++++
> > fs/partitions/Makefile | 1 +
> > fs/partitions/blkdev_parts.c | 127
> ++++++++++++++++++++++++++++++++++++++++++
> > fs/partitions/blkdev_parts.h | 14 +++++
> > fs/partitions/check.c | 4 +
> > 5 files changed, 165 insertions(+), 0 deletions(-) create mode
> > 100755 fs/partitions/blkdev_parts.c create mode 100755
> > fs/partitions/blkdev_parts.h
> >
> > diff --git a/fs/partitions/Kconfig b/fs/partitions/Kconfig index
> > cb5f0a3..097be19 100644
> > --- a/fs/partitions/Kconfig
> > +++ b/fs/partitions/Kconfig
> > @@ -68,6 +68,25 @@ config ACORN_PARTITION_RISCIX
> > of machines called RISCiX. If you say 'Y' here,
> Linux will be able
> > to read disks partitioned under RISCiX.
> >
> > +config BLKDEV_PARTITION
> > + bool "Blockdev commandline partition support" if
> PARTITION_ADVANCED
>
> command line
>
> > + default n
> > + help
> > + Say Y if you like to setup partitions for block
> devices by reading
> > + from the kernel command line (kernel boot arguments).
> > +
> > + The format of the partitions on the command line:
> > + blkdevparts=<blkdev-def>[;<blkdev-def>]
> > + <blkdev-def> := <blkdev-id>:<partdef>[,<partdef>]
> > + <partdef> := <size>[@<offset>]
> > +
> > + <blkdev-id> := unique id used to map driver to blockdev name
> > + <size> := size in numbers of sectors
> > + <offset> := offset in sectors for partition to start at
>
> Are MMC sectors always a known, fixed size? 512 bytes or 4096 bytes?

Yes, 512 bytes are always supported for MMC devices.

>
>
> > +
> > + Example:
> > + blkdevparts=mmc0:1024@0,524288(a)1024;mmc1:8192@0,8192(a)8192
> > +
> > config OSF_PARTITION
> > bool "Alpha OSF partition support" if PARTITION_ADVANCED
> > default y if ALPHA
>
> > diff --git a/fs/partitions/blkdev_parts.c
> > b/fs/partitions/blkdev_parts.c new file mode 100755 index
> > 0000000..48f4136
> > --- /dev/null
> > +++ b/fs/partitions/blkdev_parts.c
> > @@ -0,0 +1,127 @@
> > +/*
> > + *
> > + * Copyright (C) ST-Ericsson SA 2010
> > + *
> > + * Author: Ulf Hansson <ulf.hansson(a)stericsson.com> for ST-Ericsson
> > + * License terms: GNU General Public License (GPL) version 2
> > + *
> > + * Create partitions for block devices by reading from the kernel
> > + * command line (kernel boot arguments).
> > + *
> > + */
> > +
> > +#include "check.h"
> > +#include "blkdev_parts.h"
> > +
> > +static char *cmdline;
>
> > +int blkdev_partition(struct parsed_partitions *state, struct
> > +block_device *bdev) {
> > + char blkdev_name[BDEVNAME_SIZE];
> > +
> > + /* Check if there are any partitions to handle */
> > + if (cmdline == NULL)
> > + return 0;
> > +
> > + /* Get the name of the blockdevice we are operating upon */
> > + if (bdevname(bdev, blkdev_name) == NULL) {
> > + printk(KERN_WARNING "Could not get a blkdev name\n");
>
> Needs some message source id; maybe:
> printk(KERN_WARNING "blkdevparts: Could not get
> a blkdev name\n");

Good point! :-)

>
> > + return 0;
> > + }
> > +
> > + /* Parse for partitions and add them to the state */
> > + return parse_blkdev_parts(blkdev_name, state); }
>
>
> ---
> ~Randy
> *** Remember to use Documentation/SubmitChecklist when
> testing your code ***
>
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