| Message ID | 1416220572-13381-3-git-send-email-ankit.jindal@linaro.org |
|---|---|
| State | New |
| Headers | show |
On 27 November 2014 at 05:31, Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > On Mon, Nov 17, 2014 at 04:06:08PM +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 efficient if dma-capable devices are capable of maintaining coherency >> with CPU caches. > > Not efficient in what way? Sorry, I will rephrase this. > >> 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.jindal@linaro.org> >> Signed-off-by: Tushar Jagad <tushar.jagad@linaro.org> >> --- >> drivers/uio/uio.c | 11 ++++++++--- >> include/linux/uio_driver.h | 1 + >> 2 files changed, 9 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c >> index 97e6444..120a84b 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) > > I despise "bool" flags in a function, as they don't give any idea of > what is going on when you see the function being called. Please create > a new function that does this properly, with a correct name, if it's > needed. Sure, will take care of this in next revision. > > thanks, > > greg k-h Thanks, Ankit -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c index 97e6444..120a84b 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, @@ -707,10 +709,13 @@ 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); + 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; } diff --git a/include/linux/uio_driver.h b/include/linux/uio_driver.h index 1ad4724..40ca3f3 100644 --- a/include/linux/uio_driver.h +++ b/include/linux/uio_driver.h @@ -118,6 +118,7 @@ extern void uio_event_notify(struct uio_info *info); #define UIO_MEM_PHYS 1 #define UIO_MEM_LOGICAL 2 #define UIO_MEM_VIRTUAL 3 +#define UIO_MEM_PHYS_CACHE 4 /* defines for uio_port->porttype */ #define UIO_PORT_NONE 0