From patchwork Fri Sep 16 11:39:51 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vincent Whitchurch X-Patchwork-Id: 12978453 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BC856C6FA93 for ; Fri, 16 Sep 2022 11:40:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231239AbiIPLkB (ORCPT ); Fri, 16 Sep 2022 07:40:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47010 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231139AbiIPLkA (ORCPT ); Fri, 16 Sep 2022 07:40:00 -0400 Received: from smtp1.axis.com (smtp1.axis.com [195.60.68.17]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2EC972CC97; Fri, 16 Sep 2022 04:39:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=axis.com; q=dns/txt; s=axis-central1; t=1663328398; x=1694864398; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=522Kxf6U1q7s2dtT3SsExSNapFPwyU8RLSswskWzai8=; b=TfneD9eTL6XivhGCtWAcEhjTVLROmOQBXNFGkByRRWKCXS3gojsIEUJ+ +JstlQrYh/ONRk/RdkJ2sTBYkK2XxQkGADU6p/JBWRyZYKzTRcy/41EVV PzT1Za44VbqDsB1hZ/9dw73sXN3QQXbGA1by870v6dFWy1slk+X8iwKd5 TzA5KHPkZaJ+oex1F9lv5NhcEUBej9sG6S8PIb6d+/y55RUAnpoqJ0UM6 zlibkTW1SJhHbuzBYexO3UY5Tw5ZQgCSVl3VYjZTLlzxbHAFEIi06pdcP p+od6pD8W4RMrnmkRq+Hq0tszA+IWEe+NrKGuaU3RQc8PuRSI/iPL3YDn A==; From: Vincent Whitchurch To: , , CC: , Vincent Whitchurch , , , , , Subject: [PATCH 4/4] spi: s3c64xx: Fix large transfers with DMA Date: Fri, 16 Sep 2022 13:39:51 +0200 Message-ID: <20220916113951.228398-5-vincent.whitchurch@axis.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220916113951.228398-1-vincent.whitchurch@axis.com> References: <20220916113951.228398-1-vincent.whitchurch@axis.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org The COUNT_VALUE in the PACKET_CNT register is 16-bit so the maximum value is 65535. Asking the driver to transfer a larger size currently leads to the DMA transfer timing out. Fix this by splitting the transfer as needed. With this, the len>64 KiB tests in spi-loopback-test pass. (Note that len==64 KiB tests work even without this patch for some reason. The driver programs 0 to the COUNT_VALUE field in that case, but it's unclear if it's by design, since the hardware documentation doesn't say anything about the behaviour when COUNT_VALUE == 0, so play it safe and split at 65535.) Fixes: 230d42d422e7b69 ("spi: Add s3c64xx SPI Controller driver") Signed-off-by: Vincent Whitchurch Acked-by: Krzysztof Kozlowski --- drivers/spi/spi-s3c64xx.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c index 7f346866614a..85e1d1f90109 100644 --- a/drivers/spi/spi-s3c64xx.c +++ b/drivers/spi/spi-s3c64xx.c @@ -701,6 +701,16 @@ static int s3c64xx_spi_prepare_message(struct spi_master *master, struct spi_device *spi = msg->spi; struct s3c64xx_spi_csinfo *cs = spi->controller_data; + if (master->can_dma) { + int ret; + + /* Limited by size of PACKET_CNT.COUNT_VALUE. */ + ret = spi_split_transfers_maxsize(master, msg, 65535, + GFP_KERNEL | GFP_DMA); + if (ret) + return ret; + } + /* Configure feedback delay */ if (!cs) /* No delay if not defined */