From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D9F4FC433ED for ; Thu, 23 Jul 2020 00:59:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BFA2820825 for ; Thu, 23 Jul 2020 00:59:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387535AbgGWA7G (ORCPT ); Wed, 22 Jul 2020 20:59:06 -0400 Received: from mail.baikalelectronics.com ([87.245.175.226]:32770 "EHLO mail.baikalelectronics.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387492AbgGWA7C (ORCPT ); Wed, 22 Jul 2020 20:59:02 -0400 Received: from localhost (unknown [127.0.0.1]) by mail.baikalelectronics.ru (Postfix) with ESMTP id C23A28040A6C; Thu, 23 Jul 2020 00:58:57 +0000 (UTC) X-Virus-Scanned: amavisd-new at baikalelectronics.ru Received: from mail.baikalelectronics.ru ([127.0.0.1]) by localhost (mail.baikalelectronics.ru [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id v200v0VsdfLp; Thu, 23 Jul 2020 03:58:57 +0300 (MSK) From: Serge Semin To: Vinod Koul , Viresh Kumar , Andy Shevchenko , Dan Williams CC: Serge Semin , Serge Semin , Alexey Malahov , Pavel Parkhomenko , Peter Ujfalusi , Andy Shevchenko , Rob Herring , , , Subject: [PATCH v8 09/10] dmaengine: dw: Introduce max burst length hw config Date: Thu, 23 Jul 2020 03:58:47 +0300 Message-ID: <20200723005848.31907-10-Sergey.Semin@baikalelectronics.ru> In-Reply-To: <20200723005848.31907-1-Sergey.Semin@baikalelectronics.ru> References: <20200723005848.31907-1-Sergey.Semin@baikalelectronics.ru> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-ClientProxiedBy: MAIL.baikal.int (192.168.51.25) To mail (192.168.51.25) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org IP core of the DW DMA controller may be synthesized with different max burst length of the transfers per each channel. According to Synopsis having the fixed maximum burst transactions length may provide some performance gain. At the same time setting up the source and destination multi size exceeding the max burst length limitation may cause a serious problems. In our case the DMA transaction just hangs up. In order to fix this lets introduce the max burst length platform config of the DW DMA controller device and don't let the DMA channels configuration code exceed the burst length hardware limitation. Note the maximum burst length parameter can be detected either in runtime from the DWC parameter registers or from the dedicated DT property. Depending on the IP core configuration the maximum value can vary from channel to channel so by overriding the channel slave max_burst capability we make sure a DMA consumer will get the channel-specific max burst length. Signed-off-by: Serge Semin Reviewed-by: Andy Shevchenko --- Changelog v2: - Rearrange SoBs. - Discard dwc_get_maxburst() accessor. It's enough to have a clamping guard against exceeding the hardware max burst limitation. Changelog v3: - Override the slave channel max_burst capability instead of calculating the minimum value of max burst lengths and setting the DMA-device generic capability. Changelog v5: - Clamp the dst and src burst lengths in the generic dwc_config() method instead of doing that in the encode_maxburst() callback. - Define max_burst with u32 type in struct dw_dma_platform_data. - Perform of_property_read_u32_array() directly into the platform data max_burst member. Changelog v6: - Move DW_DMA_MAX_BURST macro definition to the previous patch. Changelog v8: - Meld the patch "dmaengine: dw: Add dummy device_caps callback" into this one. --- drivers/dma/dw/core.c | 16 ++++++++++++++++ drivers/dma/dw/of.c | 5 +++++ drivers/dma/dw/regs.h | 2 ++ include/linux/platform_data/dma-dw.h | 3 +++ 4 files changed, 26 insertions(+) diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c index afe5a2e465af..588b9bae827c 100644 --- a/drivers/dma/dw/core.c +++ b/drivers/dma/dw/core.c @@ -791,6 +791,11 @@ static int dwc_config(struct dma_chan *chan, struct dma_slave_config *sconfig) memcpy(&dwc->dma_sconfig, sconfig, sizeof(*sconfig)); + dwc->dma_sconfig.src_maxburst = + clamp(dwc->dma_sconfig.src_maxburst, 0U, dwc->max_burst); + dwc->dma_sconfig.dst_maxburst = + clamp(dwc->dma_sconfig.dst_maxburst, 0U, dwc->max_burst); + dw->encode_maxburst(dwc, &dwc->dma_sconfig.src_maxburst); dw->encode_maxburst(dwc, &dwc->dma_sconfig.dst_maxburst); @@ -1049,6 +1054,13 @@ static void dwc_free_chan_resources(struct dma_chan *chan) dev_vdbg(chan2dev(chan), "%s: done\n", __func__); } +static void dwc_caps(struct dma_chan *chan, struct dma_slave_caps *caps) +{ + struct dw_dma_chan *dwc = to_dw_dma_chan(chan); + + caps->max_burst = dwc->max_burst; +} + int do_dma_probe(struct dw_dma_chip *chip) { struct dw_dma *dw = chip->dw; @@ -1189,9 +1201,12 @@ int do_dma_probe(struct dw_dma_chip *chip) dwc->nollp = (dwc_params >> DWC_PARAMS_MBLK_EN & 0x1) == 0 || (dwc_params >> DWC_PARAMS_HC_LLP & 0x1) == 1; + dwc->max_burst = + (0x4 << (dwc_params >> DWC_PARAMS_MSIZE & 0x7)); } else { dwc->block_size = pdata->block_size; dwc->nollp = !pdata->multi_block[i]; + dwc->max_burst = pdata->max_burst[i] ?: DW_DMA_MAX_BURST; } } @@ -1214,6 +1229,7 @@ int do_dma_probe(struct dw_dma_chip *chip) dw->dma.device_prep_dma_memcpy = dwc_prep_dma_memcpy; dw->dma.device_prep_slave_sg = dwc_prep_slave_sg; + dw->dma.device_caps = dwc_caps; dw->dma.device_config = dwc_config; dw->dma.device_pause = dwc_pause; dw->dma.device_resume = dwc_resume; diff --git a/drivers/dma/dw/of.c b/drivers/dma/dw/of.c index 9e27831dee32..1474b3817ef4 100644 --- a/drivers/dma/dw/of.c +++ b/drivers/dma/dw/of.c @@ -98,6 +98,11 @@ struct dw_dma_platform_data *dw_dma_parse_dt(struct platform_device *pdev) pdata->multi_block[tmp] = 1; } + if (of_property_read_u32_array(np, "snps,max-burst-len", pdata->max_burst, + nr_channels)) { + memset32(pdata->max_burst, DW_DMA_MAX_BURST, nr_channels); + } + if (!of_property_read_u32(np, "snps,dma-protection-control", &tmp)) { if (tmp > CHAN_PROTCTL_MASK) return NULL; diff --git a/drivers/dma/dw/regs.h b/drivers/dma/dw/regs.h index 1ab840b06e79..76654bd13c1a 100644 --- a/drivers/dma/dw/regs.h +++ b/drivers/dma/dw/regs.h @@ -126,6 +126,7 @@ struct dw_dma_regs { /* Bitfields in DWC_PARAMS */ #define DWC_PARAMS_MBLK_EN 11 /* multi block transfer */ #define DWC_PARAMS_HC_LLP 13 /* set LLP register to zero */ +#define DWC_PARAMS_MSIZE 16 /* max group transaction size */ /* bursts size */ enum dw_dma_msize { @@ -284,6 +285,7 @@ struct dw_dma_chan { /* hardware configuration */ unsigned int block_size; bool nollp; + u32 max_burst; /* custom slave configuration */ struct dw_dma_slave dws; diff --git a/include/linux/platform_data/dma-dw.h b/include/linux/platform_data/dma-dw.h index 369e41e9dcc9..4f681df85c27 100644 --- a/include/linux/platform_data/dma-dw.h +++ b/include/linux/platform_data/dma-dw.h @@ -44,6 +44,8 @@ struct dw_dma_slave { * @data_width: Maximum data width supported by hardware per AHB master * (in bytes, power of 2) * @multi_block: Multi block transfers supported by hardware per channel. + * @max_burst: Maximum value of burst transaction size supported by hardware + * per channel (in units of CTL.SRC_TR_WIDTH/CTL.DST_TR_WIDTH). * @protctl: Protection control signals setting per channel. */ struct dw_dma_platform_data { @@ -58,6 +60,7 @@ struct dw_dma_platform_data { unsigned char nr_masters; unsigned char data_width[DW_DMA_MAX_NR_MASTERS]; unsigned char multi_block[DW_DMA_MAX_NR_CHANNELS]; + u32 max_burst[DW_DMA_MAX_NR_CHANNELS]; #define CHAN_PROTCTL_PRIVILEGED BIT(0) #define CHAN_PROTCTL_BUFFERABLE BIT(1) #define CHAN_PROTCTL_CACHEABLE BIT(2) -- 2.26.2