From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932487AbcGOJHE (ORCPT ); Fri, 15 Jul 2016 05:07:04 -0400 Received: from mail-pa0-f49.google.com ([209.85.220.49]:35193 "EHLO mail-pa0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932259AbcGOJEb (ORCPT ); Fri, 15 Jul 2016 05:04:31 -0400 From: Anup Patel To: "Hans J. Koch" , Greg Kroah-Hartman , Jonathan Corbet Cc: Ankit Jindal , Jan Viktorin , Rob Herring , Ray Jui , Scott Branden , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, bcm-kernel-feedback-list@broadcom.com, Anup Patel Subject: [PATCH 2/8] uio: Add new UIO_MEM_PHYS_CACHE type for mem regions Date: Fri, 15 Jul 2016 14:33:57 +0530 Message-Id: <1468573443-4670-3-git-send-email-anup.patel@broadcom.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1468573443-4670-1-git-send-email-anup.patel@broadcom.com> References: <1468573443-4670-1-git-send-email-anup.patel@broadcom.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ankit Jindal 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 Signed-off-by: Anup Patel --- 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