[PATCH RESEND v2 3/8] uio: Add new UIO_MEM_PHYS_CACHE type for mem regions
From: Anup Patel <hidden>
Date: 2016-08-08 05:53:29
Also in:
linux-devicetree, lkml
Subsystem:
the rest, userspace i/o (uio) · Maintainers:
Linus Torvalds, Greg Kroah-Hartman
From: Ankit Jindal <redacted> 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. 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 <redacted> Signed-off-by: Anup Patel <redacted> --- drivers/uio/uio.c | 16 +++++++++++++--- include/linux/uio_driver.h | 9 +++++---- 2 files changed, 18 insertions(+), 7 deletions(-)
diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index f2729b7..0e53076 100644
--- a/drivers/uio/uio.c
+++ b/drivers/uio/uio.c@@ -641,7 +641,7 @@ 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, int memtype) { struct uio_device *idev = vma->vm_private_data; int mi = uio_find_mem_index(vma);
@@ -656,7 +656,16 @@ 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); + switch (memtype) { + case UIO_MEM_PHYS: + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); + break; + case UIO_MEM_PHYS_CACHE: + /* Do nothing. */ + break; + default: + return -EINVAL; + } /* * We cannot use the vm_iomap_memory() helper here,
@@ -704,7 +713,8 @@ 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_PHYS_CACHE: + return uio_mmap_physical(vma, idev->info->mem[mi].memtype); case UIO_MEM_LOGICAL: case UIO_MEM_VIRTUAL: return uio_mmap_logical(vma);
diff --git a/include/linux/uio_driver.h b/include/linux/uio_driver.h
index 32c0e83..31359aee 100644
--- a/include/linux/uio_driver.h
+++ b/include/linux/uio_driver.h@@ -124,10 +124,11 @@ extern void uio_event_notify(struct uio_info *info); #define UIO_IRQ_NONE 0 /* defines for uio_mem->memtype */ -#define UIO_MEM_NONE 0 -#define UIO_MEM_PHYS 1 -#define UIO_MEM_LOGICAL 2 -#define UIO_MEM_VIRTUAL 3 +#define UIO_MEM_NONE 0 +#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
--
1.9.1