From patchwork Fri Oct 21 16:37:56 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sinan Kaya X-Patchwork-Id: 9389643 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 5898460780 for ; Fri, 21 Oct 2016 16:39:34 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4AD342A173 for ; Fri, 21 Oct 2016 16:39:34 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3F0782A1F2; Fri, 21 Oct 2016 16:39:34 +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=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID 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 26DEF2A173 for ; Fri, 21 Oct 2016 16:39:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935371AbcJUQiU (ORCPT ); Fri, 21 Oct 2016 12:38:20 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:39050 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753520AbcJUQiS (ORCPT ); Fri, 21 Oct 2016 12:38:18 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 8AB9661D4C; Fri, 21 Oct 2016 16:38:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1477067897; bh=nPZwo6fLGVZJppuItmYYT6epXgVSK/4J4oRpNC4uX+o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ohrJ5dTHWSG9F2eCv84hs0zclBXrpgPZByMMK7Nb9i26s/tJMxfqZY1PNMybkMT0d +gh45kJaiD05220mxDt9bhiCVTWuzZBQgnNQtlv59AHrjhhqdQSNnxan69hV93PBWO gcdiwE8y91ETWT6WlArnoiDNp8zleKeEAAOmIgKw= Received: from drakthul.qualcomm.com (global_nat1_iad_fw.qualcomm.com [129.46.232.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: okaya@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id 6A520617BF; Fri, 21 Oct 2016 16:38:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1477067896; bh=nPZwo6fLGVZJppuItmYYT6epXgVSK/4J4oRpNC4uX+o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=k1/k7b2ddhbY8gloWWX5GzE05DNOO+GqMcml1kiObSbjQsWnzZH/QXmVKDwXuK4OI NJC+GXPptFeaHAgLr6oCXO/0TdnHWFQA7UQK6vF62yjE0hSDE+ihN0+mYbKdXblNQ2 dGkOw/CMN/T3xI2d0/2Egx5zXfkSBk4jH+ksXtSY= DMARC-Filter: OpenDMARC Filter v1.3.1 smtp.codeaurora.org 6A520617BF Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=pass smtp.mailfrom=okaya@codeaurora.org From: Sinan Kaya To: dmaengine@vger.kernel.org, timur@codeaurora.org, devicetree@vger.kernel.org, cov@codeaurora.org, vinod.koul@intel.com, jcm@redhat.com Cc: agross@codeaurora.org, arnd@arndb.de, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Sinan Kaya , Dan Williams , Andy Shevchenko , linux-kernel@vger.kernel.org Subject: [PATCH V7 1/4] dmaengine: qcom_hidma: make pending_tre_count atomic Date: Fri, 21 Oct 2016 12:37:56 -0400 Message-Id: <1477067879-23750-2-git-send-email-okaya@codeaurora.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1477067879-23750-1-git-send-email-okaya@codeaurora.org> References: <1477067879-23750-1-git-send-email-okaya@codeaurora.org> Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Getting ready for the MSI interrupts. The pending_tre_count is used in the interrupt handler to make sure all outstanding requests are serviced. The driver will allocate 11 MSI interrupts. Each MSI interrupt can be assigned to a different CPU. Then, we have a race condition for common variables as they share the same interrupt handler with a different cause bit and they can potentially be executed in parallel. Making this variable atomic so that it can be updated from multiple processor contexts. Signed-off-by: Sinan Kaya --- drivers/dma/qcom/hidma.h | 2 +- drivers/dma/qcom/hidma_dbg.c | 3 ++- drivers/dma/qcom/hidma_ll.c | 13 ++++++------- 3 files changed, 9 insertions(+), 9 deletions(-) diff --git a/drivers/dma/qcom/hidma.h b/drivers/dma/qcom/hidma.h index de61764..181f7e0 100644 --- a/drivers/dma/qcom/hidma.h +++ b/drivers/dma/qcom/hidma.h @@ -59,7 +59,7 @@ struct hidma_lldev { void __iomem *evca; /* Event Channel address */ struct hidma_tre **pending_tre_list; /* Pointers to pending TREs */ - s32 pending_tre_count; /* Number of TREs pending */ + atomic_t pending_tre_count; /* Number of TREs pending */ void *tre_ring; /* TRE ring */ dma_addr_t tre_dma; /* TRE ring to be shared with HW */ diff --git a/drivers/dma/qcom/hidma_dbg.c b/drivers/dma/qcom/hidma_dbg.c index 3d83b99..3bdcb80 100644 --- a/drivers/dma/qcom/hidma_dbg.c +++ b/drivers/dma/qcom/hidma_dbg.c @@ -74,7 +74,8 @@ static void hidma_ll_devstats(struct seq_file *s, void *llhndl) seq_printf(s, "tre_ring_handle=%pap\n", &lldev->tre_dma); seq_printf(s, "tre_ring_size = 0x%x\n", lldev->tre_ring_size); seq_printf(s, "tre_processed_off = 0x%x\n", lldev->tre_processed_off); - seq_printf(s, "pending_tre_count=%d\n", lldev->pending_tre_count); + seq_printf(s, "pending_tre_count=%d\n", + atomic_read(&lldev->pending_tre_count)); seq_printf(s, "evca=%p\n", lldev->evca); seq_printf(s, "evre_ring=%p\n", lldev->evre_ring); seq_printf(s, "evre_ring_handle=%pap\n", &lldev->evre_dma); diff --git a/drivers/dma/qcom/hidma_ll.c b/drivers/dma/qcom/hidma_ll.c index e605c90..114409e 100644 --- a/drivers/dma/qcom/hidma_ll.c +++ b/drivers/dma/qcom/hidma_ll.c @@ -218,10 +218,9 @@ static int hidma_post_completed(struct hidma_lldev *lldev, int tre_iterator, * Keep track of pending TREs that SW is expecting to receive * from HW. We got one now. Decrement our counter. */ - lldev->pending_tre_count--; - if (lldev->pending_tre_count < 0) { + if (atomic_dec_return(&lldev->pending_tre_count) < 0) { dev_warn(lldev->dev, "tre count mismatch on completion"); - lldev->pending_tre_count = 0; + atomic_set(&lldev->pending_tre_count, 0); } spin_unlock_irqrestore(&lldev->lock, flags); @@ -328,7 +327,7 @@ void hidma_cleanup_pending_tre(struct hidma_lldev *lldev, u8 err_info, u32 tre_read_off; tre_iterator = lldev->tre_processed_off; - while (lldev->pending_tre_count) { + while (atomic_read(&lldev->pending_tre_count)) { if (hidma_post_completed(lldev, tre_iterator, err_info, err_code)) break; @@ -555,7 +554,7 @@ void hidma_ll_queue_request(struct hidma_lldev *lldev, u32 tre_ch) tre->err_code = 0; tre->err_info = 0; tre->queued = 1; - lldev->pending_tre_count++; + atomic_inc(&lldev->pending_tre_count); lldev->tre_write_offset = (lldev->tre_write_offset + HIDMA_TRE_SIZE) % lldev->tre_ring_size; spin_unlock_irqrestore(&lldev->lock, flags); @@ -650,7 +649,7 @@ int hidma_ll_setup(struct hidma_lldev *lldev) u32 val; u32 nr_tres = lldev->nr_tres; - lldev->pending_tre_count = 0; + atomic_set(&lldev->pending_tre_count, 0); lldev->tre_processed_off = 0; lldev->evre_processed_off = 0; lldev->tre_write_offset = 0; @@ -831,7 +830,7 @@ int hidma_ll_uninit(struct hidma_lldev *lldev) tasklet_kill(&lldev->task); memset(lldev->trepool, 0, required_bytes); lldev->trepool = NULL; - lldev->pending_tre_count = 0; + atomic_set(&lldev->pending_tre_count, 0); lldev->tre_write_offset = 0; rc = hidma_ll_reset(lldev);