Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754398AbaJUF60 (ORCPT ); Tue, 21 Oct 2014 01:58:26 -0400 Received: from mail-pd0-f173.google.com ([209.85.192.173]:62209 "EHLO mail-pd0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754300AbaJUF6W (ORCPT ); Tue, 21 Oct 2014 01:58:22 -0400 From: Ankit Jindal To: linux-kernel@vger.kernel.org Cc: "Hans J. Koch" , Greg Kroah-Hartman , patches@apm.com, linux-arm-kernel@lists.infradead.org, Rob Herring , Tushar Jagad , Russell King - ARM Linux , devicetree@vger.kernel.org, Guenter Roeck , Varka Bhadram , Ankit Jindal Subject: [PATCH v3 2/6] uio: Add new UIO_MEM_PHYS_CACHE type for mem regions Date: Tue, 21 Oct 2014 11:26:46 +0530 Message-Id: <1413871011-4101-3-git-send-email-ankit.jindal@linaro.org> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1413871011-4101-1-git-send-email-ankit.jindal@linaro.org> References: <1413871011-4101-1-git-send-email-ankit.jindal@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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: Tushar Jagad --- 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) { 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 -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/