From patchwork Mon Jan 7 11:21:56 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fabio Baltieri X-Patchwork-Id: 1940821 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork1.kernel.org (Postfix) with ESMTP id 581B83FE37 for ; Mon, 7 Jan 2013 11:34:07 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1TsAti-0003Wb-1I; Mon, 07 Jan 2013 11:29:44 +0000 Received: from mail-wg0-f49.google.com ([74.125.82.49]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1TsApb-0001Bv-V9 for linux-arm-kernel@lists.infradead.org; Mon, 07 Jan 2013 11:25:31 +0000 Received: by mail-wg0-f49.google.com with SMTP id 15so9272830wgd.4 for ; Mon, 07 Jan 2013 03:25:26 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=x-received:from:to:cc:subject:date:message-id:x-mailer:in-reply-to :references:x-gm-message-state; bh=/Uvy37mo2Le7WAuhEWrKKibZXmGNTGjP91Qmcxid1IQ=; b=ZJavh33zcDZfKLVCT3KuKm1BMrnCyJh0L5GdXB1y/3GJ8dOMjpi3ZSOyJWL7kbQISI ut60irKSo1ibMmZ1mq1CP3bKUwdssfdwtJ8LSb/Bcq9rl7d6kYLRMCVjUyfuyoVkX9LC 0J4i9Rnb9/IOKkb/tvX5z021D3Wn0c+CweD+gl3hPZH5sywuXSeWvQ0GCbdnbF/n0n81 8Qw7TcZrUJIaj1yDbn5FkqTGMbDg2jDNZwiyGmXj/Rffi8k5QnNzgz16XNhfLFsBKAiS 2QutjlEFwEtJJc9WKkhtSmgHeeUDdG4NcOT+ijMJWngiCIozI8tBH3By6wlE53YSwa6N 0dcw== X-Received: by 10.194.174.196 with SMTP id bu4mr94867756wjc.35.1357557926345; Mon, 07 Jan 2013 03:25:26 -0800 (PST) Received: from localhost ([2a01:2029:1:11e3:8e70:5aff:feac:ad8]) by mx.google.com with ESMTPS id s16sm12140892wii.0.2013.01.07.03.25.20 (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Mon, 07 Jan 2013 03:25:25 -0800 (PST) From: Fabio Baltieri To: Vinod Koul Subject: [PATCH 14/16] dmaengine: ste_dma40: add software lli support Date: Mon, 7 Jan 2013 12:21:56 +0100 Message-Id: <1357557718-15676-15-git-send-email-fabio.baltieri@linaro.org> X-Mailer: git-send-email 1.7.12.1 In-Reply-To: <1357557718-15676-1-git-send-email-fabio.baltieri@linaro.org> References: <1357557718-15676-1-git-send-email-fabio.baltieri@linaro.org> X-Gm-Message-State: ALoCoQl2H9X+YH1OJvCzpDruRrVGhqt+ttc8cNx1Y2wBKBncZY+RwGoBvcBdh0/JcdClrcINKUKv X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130107_062529_961492_AC038FA2 X-CRM114-Status: GOOD ( 19.71 ) X-Spam-Score: -2.6 (--) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-2.6 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [74.125.82.49 listed in list.dnswl.org] -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: Srinidhi Kasagar , Fabio Baltieri , Linus Walleij , linux-kernel@vger.kernel.org, Dan Williams , linux-arm-kernel@lists.infradead.org, Shreshtha Kumar Sahu X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org This patch add support to manage LLI by SW for select phy channels. There is a HW issue in certain controllers due to which on certain occassions HW LLI cannot be used on some physical channels. To avoid the HW issue on a specific phy channel, the phy channel number can be added to the list of soft_lli_channels and there after all the transfers on that channel will use software LLI, for peripheral to memory transfers. SoftLLI introduces relink overhead, that could impact performace for certain use cases. This is based on a previous patch of Narayanan Gopalakrishnan. Cc: Shreshtha Kumar Sahu Acked-by: Linus Walleij Signed-off-by: Fabio Baltieri --- drivers/dma/ste_dma40.c | 20 +++++++++++++++++++- include/linux/platform_data/dma-ste-dma40.h | 8 ++++++++ 2 files changed, 27 insertions(+), 1 deletion(-) diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c index e317deb..2ecefb7 100644 --- a/drivers/dma/ste_dma40.c +++ b/drivers/dma/ste_dma40.c @@ -355,6 +355,7 @@ struct d40_lcla_pool { * @allocated_dst: Same as for src but is dst. * allocated_dst and allocated_src uses the D40_ALLOC* defines as well as * event line number. + * @use_soft_lli: To mark if the linked lists of channel are managed by SW. */ struct d40_phy_res { spinlock_t lock; @@ -362,6 +363,7 @@ struct d40_phy_res { int num; u32 allocated_src; u32 allocated_dst; + bool use_soft_lli; }; struct d40_base; @@ -783,7 +785,16 @@ static void d40_log_lli_to_lcxa(struct d40_chan *chan, struct d40_desc *desc) * can't link back to the one in LCPA space */ if (linkback || (lli_len - lli_current > 1)) { - curr_lcla = d40_lcla_alloc_one(chan, desc); + /* + * If the channel is expected to use only soft_lli don't + * allocate a lcla. This is to avoid a HW issue that exists + * in some controller during a peripheral to memory transfer + * that uses linked lists. + */ + if (!(chan->phy_chan->use_soft_lli && + chan->dma_cfg.dir == STEDMA40_PERIPH_TO_MEM)) + curr_lcla = d40_lcla_alloc_one(chan, desc); + first_lcla = curr_lcla; } @@ -3063,6 +3074,13 @@ static int __init d40_phy_res_init(struct d40_base *base) num_phy_chans_avail--; } + /* Mark soft_lli channels */ + for (i = 0; i < base->plat_data->num_of_soft_lli_chans; i++) { + int chan = base->plat_data->soft_lli_chans[i]; + + base->phy_res[chan].use_soft_lli = true; + } + dev_info(base->dev, "%d of %d physical DMA channels available\n", num_phy_chans_avail, base->num_phy_chans); diff --git a/include/linux/platform_data/dma-ste-dma40.h b/include/linux/platform_data/dma-ste-dma40.h index b99024b..4b78101 100644 --- a/include/linux/platform_data/dma-ste-dma40.h +++ b/include/linux/platform_data/dma-ste-dma40.h @@ -147,6 +147,12 @@ struct stedma40_chan_cfg { * @memcpy_conf_log: default configuration of logical channel memcpy * @disabled_channels: A vector, ending with -1, that marks physical channels * that are for different reasons not available for the driver. + * @soft_lli_chans: A vector, that marks physical channels will use LLI by SW + * which avoids HW bug that exists in some versions of the controller. + * SoftLLI introduces relink overhead that could impact performace for + * certain use cases. + * @num_of_soft_lli_chans: The number of channels that needs to be configured + * to use SoftLLI. * @use_esram_lcla: flag for mapping the lcla into esram region * @num_of_phy_chans: The number of physical channels implemented in HW. * 0 means reading the number of channels from DMA HW but this is only valid @@ -161,6 +167,8 @@ struct stedma40_platform_data { struct stedma40_chan_cfg *memcpy_conf_phy; struct stedma40_chan_cfg *memcpy_conf_log; int disabled_channels[STEDMA40_MAX_PHYS]; + int *soft_lli_chans; + int num_of_soft_lli_chans; bool use_esram_lcla; int num_of_phy_chans; };