From patchwork Fri Jul 12 21:48:11 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Santosh Shilimkar X-Patchwork-Id: 2827079 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 41D4AC0AB2 for ; Fri, 12 Jul 2013 21:51:52 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 6660C2013B for ; Fri, 12 Jul 2013 21:51:51 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 161EE2013A for ; Fri, 12 Jul 2013 21:51:50 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1UxlDx-00041S-8M; Fri, 12 Jul 2013 21:49:57 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1UxlDf-00005D-Vw; Fri, 12 Jul 2013 21:49:40 +0000 Received: from arroyo.ext.ti.com ([192.94.94.40]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1UxlDN-0008Ta-Uh for linux-arm-kernel@lists.infradead.org; Fri, 12 Jul 2013 21:49:24 +0000 Received: from dlelxv90.itg.ti.com ([172.17.2.17]) by arroyo.ext.ti.com (8.13.7/8.13.7) with ESMTP id r6CLmnMW004698; Fri, 12 Jul 2013 16:48:49 -0500 Received: from DFLE73.ent.ti.com (dfle73.ent.ti.com [128.247.5.110]) by dlelxv90.itg.ti.com (8.14.3/8.13.8) with ESMTP id r6CLmnxg014799; Fri, 12 Jul 2013 16:48:49 -0500 Received: from dlelxv22.itg.ti.com (172.17.1.197) by DFLE73.ent.ti.com (128.247.5.110) with Microsoft SMTP Server id 14.2.342.3; Fri, 12 Jul 2013 16:48:49 -0500 Received: from ula0393909.am.dhcp.ti.com (ula0393909.am.dhcp.ti.com [158.218.103.117]) by dlelxv22.itg.ti.com (8.13.8/8.13.8) with ESMTP id r6CLmkXM016005; Fri, 12 Jul 2013 16:48:49 -0500 From: Santosh Shilimkar To: , Subject: [RFC/RFT PATCH 2/5] mm: dma-mapping: Add dma_max_pfn(dev) helper function Date: Fri, 12 Jul 2013 17:48:11 -0400 Message-ID: <1373665694-7580-3-git-send-email-santosh.shilimkar@ti.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1373665694-7580-1-git-send-email-santosh.shilimkar@ti.com> References: <1373665694-7580-1-git-send-email-santosh.shilimkar@ti.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130712_174922_361242_02CE66CD X-CRM114-Status: GOOD ( 11.89 ) X-Spam-Score: -7.2 (-------) Cc: Jens Axboe , Santosh Shilimkar , Russell King X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.5 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Most of the kernel assumes that PFN0 is the start of the physical memory (RAM). This assumptions is not true on most of the ARM SOCs and hence and if one try to update the ARM port to follow the assumptions, we end of breaking the dma bounce limit for few block layer drivers. One such example is trying to unify the meaning of max*_pfn on ARM as the bootmem layer expects, breaks few block layer driver dma bounce limit. To fix this problem, we introduce dma_max_pfn(dev) generic helper with a possibility of override from the architecture code. The helper converts a DMA bitmask of bits to a block PFN number. In all the generic cases, it is just "dev->dma_mask >> PAGE_SHIFT" and hence default behavior is maintained as is. Subsequent patches will make use of the helper. No functional change. Cc: Russell King Cc: Jens Axboe Signed-off-by: Santosh Shilimkar --- include/linux/dma-mapping.h | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index 94af418..68a7863 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -129,6 +129,13 @@ static inline int dma_set_seg_boundary(struct device *dev, unsigned long mask) return -EIO; } +#ifndef dma_max_pfn +static inline unsigned long dma_max_pfn(struct device *dev) +{ + return *dev->dma_mask >> PAGE_SHIFT; +} +#endif + static inline void *dma_zalloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t flag) {