From patchwork Wed Oct 31 15:57:38 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tony Lindgren X-Patchwork-Id: 10662867 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0461214BD for ; Wed, 31 Oct 2018 15:57:48 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E9E752AC96 for ; Wed, 31 Oct 2018 15:57:47 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id DD7392ACA6; Wed, 31 Oct 2018 15:57:47 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4329A2AC96 for ; Wed, 31 Oct 2018 15:57:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729699AbeKAA4U (ORCPT ); Wed, 31 Oct 2018 20:56:20 -0400 Received: from muru.com ([72.249.23.125]:53074 "EHLO muru.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729613AbeKAA4U (ORCPT ); Wed, 31 Oct 2018 20:56:20 -0400 Received: from hillo.muru.com (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTP id E9B2A8080; Wed, 31 Oct 2018 15:57:43 +0000 (UTC) From: Tony Lindgren To: Ulf Hansson Cc: linux-mmc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-omap@vger.kernel.org, Kishon Vijay Abraham I , Peter Ujfalusi , Russell King Subject: [PATCH] mmc: core: Lower max_seg_size if too high for DMA Date: Wed, 31 Oct 2018 08:57:38 -0700 Message-Id: <20181031155738.18367-1-tony@atomide.com> X-Mailer: git-send-email 2.19.1 MIME-Version: 1.0 Sender: linux-mmc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mmc@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP With CONFIG_DMA_API_DEBUG_SG a device may produce the following warning: "DMA-API: mapping sg segment longer than device claims to support" We default to 64KiB if a DMA engine driver does not initialize dma_parms and call dma_set_max_seg_size(). This may be lower that what many MMC drivers do with mmc->max_seg_size = mmc->max_blk_size * mmc->max_blk_count. Let's do a sanity check for max_seg_size being higher than what DMA supports in mmc_add_host() and lower it as needed. Cc: Kishon Vijay Abraham I Cc: Peter Ujfalusi Cc: Russell King Reported-by: Russell King Signed-off-by: Tony Lindgren Reviewed-by: Peter Ujfalusi --- drivers/mmc/core/host.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c --- a/drivers/mmc/core/host.c +++ b/drivers/mmc/core/host.c @@ -13,6 +13,7 @@ */ #include +#include #include #include #include @@ -415,6 +416,19 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev) EXPORT_SYMBOL(mmc_alloc_host); +static void mmc_check_max_seg_size(struct mmc_host *host) +{ + unsigned int max_seg_size = dma_get_max_seg_size(mmc_dev(host)); + + if (host->max_seg_size <= max_seg_size) + return; + + dev_info(mmc_dev(host), "Lowering max_seg_size for DMA: %u vs %u\n", + host->max_seg_size, max_seg_size); + + host->max_seg_size = max_seg_size; +} + /** * mmc_add_host - initialise host hardware * @host: mmc host @@ -430,6 +444,8 @@ int mmc_add_host(struct mmc_host *host) WARN_ON((host->caps & MMC_CAP_SDIO_IRQ) && !host->ops->enable_sdio_irq); + mmc_check_max_seg_size(host); + err = device_add(&host->class_dev); if (err) return err;