Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757494AbXJXK6W (ORCPT ); Wed, 24 Oct 2007 06:58:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753662AbXJXK6D (ORCPT ); Wed, 24 Oct 2007 06:58:03 -0400 Received: from mo11.iij4u.or.jp ([210.138.174.79]:38545 "EHLO mo11.iij4u.or.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753023AbXJXK6A (ORCPT ); Wed, 24 Oct 2007 06:58:00 -0400 Date: Wed, 24 Oct 2007 19:48:01 +0900 To: akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, James.Bottomley@SteelEye.com, jens.axboe@oracle.com, greg@kroah.com, jeff@garzik.org, fujita.tomonori@lab.ntt.co.jp Subject: [PATCH -mm 01/11] add device_dma_parameters structure From: FUJITA Tomonori In-Reply-To: <67bb10d9f4e9473ddc84d9839114602c1966f19f.tomof@acm.org> References: <67bb10d9f4e9473ddc84d9839114602c1966f19f.tomof@acm.org> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-Id: <20071024174021G.tomof@acm.org> X-Dispatcher: imput version 20050308(IM148) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3047 Lines: 84 iommu code merges scatter/gather segments without considering a low level driver's restrictions. The problem is that iommu code can't access to the limitations because they are in request_queue. This patch adds a new structure, device_dma_parameters, including dma information. A pointer to device_dma_parameters is added to struct device. - there are only max_segment_size and segment_boundary_mask there but we'll move more dma stuff in struct device (like dma_mask) to struct device_dma_parameters later. segment_boundary_mask is not supported yet. - new accessors for the dma parameters are added. So we can easily change where to place struct device_dma_parameters in the future. - dma_get_max_seg_size returns 64K if dma_parms in struct device isn't set up properly. 64K is the default max_segment_size in the block layer. Signed-off-by: FUJITA Tomonori --- include/linux/device.h | 11 +++++++++++ include/linux/dma-mapping.h | 15 +++++++++++++++ 2 files changed, 26 insertions(+), 0 deletions(-) diff --git a/include/linux/device.h b/include/linux/device.h index 2e15822..9eb883f 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -397,6 +397,15 @@ extern int devres_release_group(struct device *dev, void *id); extern void *devm_kzalloc(struct device *dev, size_t size, gfp_t gfp); extern void devm_kfree(struct device *dev, void *p); +struct device_dma_parameters { + /* + * a low level driver may set these to teach IOMMU code about + * sg limitations. + */ + unsigned int max_segment_size; + unsigned long segment_boundary_mask; +}; + struct device { struct klist klist_children; struct klist_node knode_parent; /* node in sibling list */ @@ -432,6 +441,8 @@ struct device { 64 bit addresses for consistent allocations such descriptors. */ + struct device_dma_parameters *dma_parms; + struct list_head dma_pools; /* dma pools (if dma'ble) */ struct dma_coherent_mem *dma_mem; /* internal for coherent mem diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index 101a2d4..71972ca 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -60,6 +60,21 @@ static inline int is_device_dma_capable(struct device *dev) extern u64 dma_get_required_mask(struct device *dev); +static inline unsigned int dma_get_max_seg_size(struct device *dev) +{ + return dev->dma_parms ? dev->dma_parms->max_segment_size : 65536; +} + +static inline unsigned int dma_set_max_seg_size(struct device *dev, + unsigned int size) +{ + if (dev->dma_parms) { + dev->dma_parms->max_segment_size = size; + return 0; + } else + return -EIO; +} + /* flags for the coherent memory api */ #define DMA_MEMORY_MAP 0x01 #define DMA_MEMORY_IO 0x02 -- 1.5.2.4 - 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/