From patchwork Wed Jan 21 04:16:46 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sumit Semwal X-Patchwork-Id: 27957 Received: from mail.tu-berlin.de ([130.149.7.33]) by www.linuxtv.org with esmtp (Exim 4.72) (envelope-from ) id 1YDmk3-0001Y2-Uz; Wed, 21 Jan 2015 05:18:07 +0100 X-tubIT-Incoming-IP: 209.132.180.67 Received: from vger.kernel.org ([209.132.180.67]) by mail.tu-berlin.de (exim-4.72/mailfrontend-7) with esmtp id 1YDmk2-00033a-05; Wed, 21 Jan 2015 05:18:07 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754062AbbAUERd (ORCPT + 1 other); Tue, 20 Jan 2015 23:17:33 -0500 Received: from mail-pa0-f53.google.com ([209.85.220.53]:40210 "EHLO mail-pa0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754037AbbAUER3 (ORCPT ); Tue, 20 Jan 2015 23:17:29 -0500 Received: by mail-pa0-f53.google.com with SMTP id kx10so5877467pab.12 for ; Tue, 20 Jan 2015 20:17:29 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=9Qrto0rMMol223HrGx/UIXvb5utCGfrAU8XfyOiO9A4=; b=LOqNGZCqK11dceu/ejamXsquUUIbIE3KJdS/CURpfFsb2lyfzAkK7uGdiMaBc/z/BH dTT5fKuGIfOT7gwC+9BaLzPWXPqSNgn01xIPsyBpliZ74V2N0ELb7jYA0JBTg0uCZIra vLWUIWT6ZsghhyqoRujjKIzt4MTl1Fz6pRYm6SS6Ljc3NPoALlcgrDS46bfLE9UUW8MV xwMZlvIfWBwFPSGnRrAL4MYrUbbSEbhUmCJzGxuJYktpv/Nrux3l1b6VOLVuwUReba8I NiSEkjPdbpiaFhmUK2Um890GNjFvbnLGK5mDPtQKwkTdwdwbuu7UqjuX+1R1wSfyd+Av PKnA== X-Gm-Message-State: ALoCoQkobcvZDqalv77yNhfY5EFnwPyqOG3S3cTOV7QHsyWlU8enUcBW3UsbvD3pAKFEKDRpnbdN X-Received: by 10.70.128.15 with SMTP id nk15mr57810923pdb.121.1421813849452; Tue, 20 Jan 2015 20:17:29 -0800 (PST) Received: from ss-ubuntu.lan ([106.51.225.38]) by mx.google.com with ESMTPSA id hx9sm4684773pad.38.2015.01.20.20.17.25 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 20 Jan 2015 20:17:28 -0800 (PST) From: Sumit Semwal To: linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org Cc: linaro-kernel@lists.linaro.org, robdclark@gmail.com, daniel@ffwll.ch, m.szyprowski@samsung.com, t.stanislaws@samsung.com, Sumit Semwal Subject: [RFCv2 1/2] device: add dma_params->max_segment_count Date: Wed, 21 Jan 2015 09:46:46 +0530 Message-Id: <1421813807-9178-2-git-send-email-sumit.semwal@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1421813807-9178-1-git-send-email-sumit.semwal@linaro.org> References: <1421813807-9178-1-git-send-email-sumit.semwal@linaro.org> Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-PMX-Version: 6.0.0.2142326, Antispam-Engine: 2.7.2.2107409, Antispam-Data: 2015.1.21.40921 X-PMX-Spam: Gauge=IIIIIIII, Probability=8%, Report=' MULTIPLE_RCPTS 0.1, HTML_00_01 0.05, HTML_00_10 0.05, BODYTEXTP_SIZE_3000_LESS 0, BODY_SIZE_2000_2999 0, BODY_SIZE_5000_LESS 0, BODY_SIZE_7000_LESS 0, REFERENCES 0, URI_ENDS_IN_HTML 0, __ANY_URI 0, __CP_URI_IN_BODY 0, __FRAUD_BODY_WEBMAIL 0, __FRAUD_WEBMAIL 0, __HAS_FROM 0, __HAS_MSGID 0, __HAS_X_MAILER 0, __HAS_X_MAILING_LIST 0, __IN_REP_TO 0, __MIME_TEXT_ONLY 0, __MULTIPLE_RCPTS_CC_X2 0, __MULTIPLE_RCPTS_TO_X5 0, __REFERENCES 0, __SANE_MSGID 0, __TO_MALFORMED_2 0, __TO_NO_NAME 0, __URI_NO_WWW 0, __URI_NS , __YOUTUBE_RCVD 0' From: Rob Clark For devices which have constraints about maximum number of segments in an sglist. For example, a device which could only deal with contiguous buffers would set max_segment_count to 1. The initial motivation is for devices sharing buffers via dma-buf, to allow the buffer exporter to know the constraints of other devices which have attached to the buffer. The dma_mask and fields in 'struct device_dma_parameters' tell the exporter everything else that is needed, except whether the importer has constraints about maximum number of segments. Signed-off-by: Rob Clark [sumits: Minor updates wrt comments on the first version] Signed-off-by: Sumit Semwal --- include/linux/device.h | 1 + include/linux/dma-mapping.h | 19 +++++++++++++++++++ 2 files changed, 20 insertions(+) diff --git a/include/linux/device.h b/include/linux/device.h index fb50673..a32f9b6 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -647,6 +647,7 @@ struct device_dma_parameters { * sg limitations. */ unsigned int max_segment_size; + unsigned int max_segment_count; /* INT_MAX for unlimited */ unsigned long segment_boundary_mask; }; diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index c3007cb..38e2835 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -154,6 +154,25 @@ static inline unsigned int dma_set_max_seg_size(struct device *dev, return -EIO; } +#define DMA_SEGMENTS_MAX_SEG_COUNT ((unsigned int) INT_MAX) + +static inline unsigned int dma_get_max_seg_count(struct device *dev) +{ + return dev->dma_parms ? + dev->dma_parms->max_segment_count : + DMA_SEGMENTS_MAX_SEG_COUNT; +} + +static inline int dma_set_max_seg_count(struct device *dev, + unsigned int count) +{ + if (dev->dma_parms) { + dev->dma_parms->max_segment_count = count; + return 0; + } else + return -EIO; +} + static inline unsigned long dma_get_seg_boundary(struct device *dev) { return dev->dma_parms ?