Re: [RFC PATCH 0/2] Add UIO device supporting dynamic memoryallocation

From: Hans J. Koch
Date: Wed Sep 12 2012 - 18:11:18 EST

On Wed, Sep 12, 2012 at 02:29:43PM +0900, Damian Hobson-Garcia wrote:
> Reposting: I realized that this series should have gone out to a broader list.

You forgot GregKH, I added him.

> My apologies to those who those who will recieve a duplicate post.
> Hello all,
> I've been using this UIO driver for allocation/deallocation
> of memory regions through an IOMMU via the dma-mapping API, but
> it seems that it would be more generally useful for userspace drivers
> to access CMA memory regions. I don't know if it's useful to try to add
> this functionality into the core uio driver or not, so for now I've kept
> all dynamic memory handling in the specific device driver.
> The number and size of the dynamically allocatable regions is defined
> statically in the device platform data, and the actually memory is
> allocated and deallocated when the device is opened/closed.
> Details of the dynamically allocated regions are available from sysfs in
> exactly the same was as for static regions. The total number of
> dynamic and static regions combined cannot exceed MAX_UIO_MAPS.
> Any comments, especially with regard to exposing the dma-mapping API to
> userspace in this way, would be greatly appreciated.
> Damian Hobson-Garcia (2):
> Add new uio device for dynamic memory allocation
> ARM: shmobile: sh7372: Change VPU UIO to uio_dmem_genirq
> arch/arm/mach-shmobile/setup-sh7372.c | 19 +-
> drivers/uio/Kconfig | 16 ++
> drivers/uio/Makefile | 1 +
> drivers/uio/uio_dmem_genirq.c | 356 +++++++++++++++++++++++++
> include/linux/platform_data/uio_dmem_genirq.h | 26 ++
> 5 files changed, 413 insertions(+), 5 deletions(-)
> create mode 100644 drivers/uio/uio_dmem_genirq.c
> create mode 100644 include/linux/platform_data/uio_dmem_genirq.h

Please add a third patch with a few words for Documentation/DocBook/uio-howto.tmpl
since this driver could be useful for other people, too.

Otherwise, looks good to me.

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