On Tue, Sep 09, 2014 at 03:26:55PM +0530, Ankit Jindal wrote:
> Currently, three types of mem regions are supported: UIO_MEM_PHYS,
> UIO_MEM_LOGICAL and UIO_MEM_VIRTUAL. Among these UIO_MEM_PHYS helps
> UIO driver export physcial memory to user space as non-cacheable
> user memory. Typcially memory-mapped registers of a device are exported
> to user space as UIO_MEM_PHYS type mem region. The UIO_MEM_PHYS type
> is not useful if dma-capable devices are capable of maintaining coherency
> with CPU caches becasue we can allow cacheable access to memory shared
> between such devices and user space.
>
> This patch adds new type UIO_MEM_PHYS_CACHE for mem regions to enable
> cacheable access to physical memory from user space.
>
> Signed-off-by: Ankit Jindal <ankit.jin...@linaro.org>
> Signed-off-by: Tushar Jagad <tushar.ja...@linaro.org>
> ---
> drivers/uio/uio.c | 22 +++++++++++++---------
> include/linux/uio_driver.h | 7 ++++---
> 2 files changed, 17 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
> index a673e5b..ff5b6c0 100644
> --- a/drivers/uio/uio.c
> +++ b/drivers/uio/uio.c
> @@ -644,7 +644,7 @@ static const struct vm_operations_struct
> uio_physical_vm_ops = {
> #endif
> };
>
> -static int uio_mmap_physical(struct vm_area_struct *vma)
> +static int uio_mmap_physical(struct vm_area_struct *vma, bool cacheable)
> {
> struct uio_device *idev = vma->vm_private_data;
> int mi = uio_find_mem_index(vma);
> @@ -659,7 +659,9 @@ static int uio_mmap_physical(struct vm_area_struct *vma)
> return -EINVAL;
>
> vma->vm_ops = &uio_physical_vm_ops;
> - vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
> +
> + if (!cacheable)
> + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
>
> /*
> * We cannot use the vm_iomap_memory() helper here,
> @@ -706,13 +708,15 @@ static int uio_mmap(struct file *filep, struct
> vm_area_struct *vma)
> }
>
> switch (idev->info->mem[mi].memtype) {
> - case UIO_MEM_PHYS:
> - return uio_mmap_physical(vma);
> - case UIO_MEM_LOGICAL:
> - case UIO_MEM_VIRTUAL:
> - return uio_mmap_logical(vma);
> - default:
> - return -EINVAL;
> + case UIO_MEM_PHYS:
> + return uio_mmap_physical(vma, false);
> + case UIO_MEM_LOGICAL:
> + case UIO_MEM_VIRTUAL:
> + return uio_mmap_logical(vma);
> + case UIO_MEM_PHYS_CACHE:
> + return uio_mmap_physical(vma, true);
> + default:
> + return -EINVAL;
Please don't do code style cleanups in the same patch you are adding new
functionality. I can't take this because of this, sorry.
greg k-h
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
