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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CC7CAC43217 for ; Mon, 23 May 2022 18:42:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229713AbiEWSmY (ORCPT ); Mon, 23 May 2022 14:42:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38994 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244445AbiEWSll (ORCPT ); Mon, 23 May 2022 14:41:41 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 41482187D9F; Mon, 23 May 2022 11:22:35 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id B4CA0B81202; Mon, 23 May 2022 18:22:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F1002C385AA; Mon, 23 May 2022 18:22:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1653330142; bh=Jq4X9tEfkNqa2aO7nyQNSqyYMNMwtkA/v3xJPFMy80s=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=EUWkaGd/YDszCDrA/9222yzmSZ/zKiRUTFiXHgb9X7P5vBMsHt8q2GMtSh2AuLA7W N84phJhAaVkS/j2O38R/ZFFvTrYzjc2tm1HoaOR0TgV0ZDswAufzqyNLC/5QF4ARlB pQSr/7c8lY7n3EeV7WMoEIFdWgrrbeXAiQwToPxCSkZeMdqRtCyhSY3DYpmbGbK/zg HN95ajOwOU+5SOTQjbBgosnCk07ZjUTnnZfJzOg9wjs9UJXa/i2qho4uTf3A7AyhP0 s4ECX/of6+nfx4EokEyvywtSj7zqpF68V91f6449FigTpiaJyQ/TLpp6Yp1zEF+ouP w6gUGHnk9ChNA== Date: Mon, 23 May 2022 13:22:19 -0500 From: Bjorn Helgaas To: Frank Li Cc: gustavo.pimentel@synopsys.com, hongxing.zhu@nxp.com, l.stach@pengutronix.de, linux-imx@nxp.com, linux-pci@vger.kernel.org, dmaengine@vger.kernel.org, fancer.lancer@gmail.com, lznuaa@gmail.com, kishon@ti.com, vkoul@kernel.org, lorenzo.pieralisi@arm.com, robh@kernel.org, kw@linux.com, bhelgaas@google.com, manivannan.sadhasivam@linaro.org, Sergey.Semin@baikalelectronics.ru Subject: Re: [PATCH v11 8/8] PCI: endpoint: Enable DMA tests for endpoints with DMA capabilities Message-ID: <20220523182219.GA168626@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220517151915.2212838-9-Frank.Li@nxp.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Tue, May 17, 2022 at 10:19:15AM -0500, Frank Li wrote: > Some PCI Endpoints controllers integrate an eDMA (embedded DMA). > eDMA only sends once a bus read/write command to complete once > data transfer. eDMA can bypass the outbound memory address translation > unit to access all RC memory space. s/Endpoints/Endpoint/ I'm not sure what "only sends once a command to complete once transfer" means or why it is revelant here. I guess it just means "the eDMA controller issues a single bus command per data transfer"? > Add DMA support for pci-epf-test. It looks like pci-epf-test.c already *has* DMA support, but you're adding support for separate RX and TX DMA channels. > EPF test can use, depending on HW availability, eDMA or general system > DMA controllers to perform DMA. The test probes the EPF DMA channel > capabilities. > > Separate dma_chan to dma_chan_tx and dma_chan_rx. eDMA channels have > higher priority than general DMA channels. I think the "priority" you refer to is merely that the *test* uses eDMA channels if present, not that there's any actual hardware priority involved here, right? > If general memory to memory > DMA hannels are used, dma_chan_rx = dma_chan_tx. s/hannels/channels/ > Add dma_addr_t dma_remote in function pci_epf_test_data_transfer() > because eDMA using remote RC physical address directly s/function pci_epf_test_data_transfer()/pci_epf_test_data_transfer()/ s/eDMA using/eDMA uses/ s/directly/directly./ (No need to specify "function" since the parens make it obvious that pci_epf_test_data_transfer() is a function. Same thing below.) > Add enum dma_transfer_direction dir in function pci_epf_test_data_transfer() > because eDMA chooses the correct RX/TX channel by dir. > > The overall steps are > > 1. Execute dma_request_channel() and filter function to find correct eDMA > RX and TX Channel. If a channel does not exist, fallback to try to allocate > general memory to memory DMA channel. s/exist, /exist, / remove extra space s/memory DMA /memory DMA / remove extra space again > 2. Execute dmaengine_slave_config() to configure remote side physical address. Rewrap to fit in 75 columns. > 3. Execute dmaengine_prep_slave_single() to create transfer descriptor. > 4. Execute tx_submit(). > 5. Execute dma_async_issue_pending() > > Signed-off-by: Frank Li > Acked-by: Manivannan Sadhasivam > --- > Change from v10 to v11: > - rewrite commit message > Change from v9 to v10: > - rewrite commit message > Change from v4 to v9: > - none > Change from v3 to v4: > - reverse Xmas tree order > - local -> dma_local > - change error message > - IS_ERR -> IS_ERR_OR_NULL > - check return value of dmaengine_slave_config() > Change from v1 to v2: > - none > > drivers/pci/endpoint/functions/pci-epf-test.c | 108 ++++++++++++++++-- > 1 file changed, 98 insertions(+), 10 deletions(-) > > diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c > index 90d84d3bc868f..f26afd02f3a86 100644 > --- a/drivers/pci/endpoint/functions/pci-epf-test.c > +++ b/drivers/pci/endpoint/functions/pci-epf-test.c > @@ -52,9 +52,11 @@ struct pci_epf_test { > enum pci_barno test_reg_bar; > size_t msix_table_offset; > struct delayed_work cmd_handler; > - struct dma_chan *dma_chan; > + struct dma_chan *dma_chan_tx; > + struct dma_chan *dma_chan_rx; > struct completion transfer_complete; > bool dma_supported; > + bool dma_private; > const struct pci_epc_features *epc_features; > }; > > @@ -105,12 +107,15 @@ static void pci_epf_test_dma_callback(void *param) > */ > static int pci_epf_test_data_transfer(struct pci_epf_test *epf_test, > dma_addr_t dma_dst, dma_addr_t dma_src, > - size_t len) > + size_t len, dma_addr_t dma_remote, > + enum dma_transfer_direction dir) Please update the kernel-doc for these two new parameters. You can use: $ make W=1 drivers/pci/endpoint/functions/ to find errors like this. > { > + struct dma_chan *chan = (dir == DMA_DEV_TO_MEM) ? epf_test->dma_chan_tx : epf_test->dma_chan_rx; > + dma_addr_t dma_local = (dir == DMA_MEM_TO_DEV) ? dma_src : dma_dst; > enum dma_ctrl_flags flags = DMA_CTRL_ACK | DMA_PREP_INTERRUPT; > - struct dma_chan *chan = epf_test->dma_chan; > struct pci_epf *epf = epf_test->epf; > struct dma_async_tx_descriptor *tx; > + struct dma_slave_config sconf = {}; > struct device *dev = &epf->dev; > dma_cookie_t cookie; > int ret; > @@ -120,7 +125,22 @@ static int pci_epf_test_data_transfer(struct pci_epf_test *epf_test, > return -EINVAL; > } > > - tx = dmaengine_prep_dma_memcpy(chan, dma_dst, dma_src, len, flags); > + if (epf_test->dma_private) { > + sconf.direction = dir; > + if (dir == DMA_MEM_TO_DEV) > + sconf.dst_addr = dma_remote; > + else > + sconf.src_addr = dma_remote; > + > + if (dmaengine_slave_config(chan, &sconf)) { > + dev_err(dev, "DMA slave config fail\n"); > + return -EIO; > + } > + tx = dmaengine_prep_slave_single(chan, dma_local, len, dir, flags); > + } else { > + tx = dmaengine_prep_dma_memcpy(chan, dma_dst, dma_src, len, flags); > + } > + > if (!tx) { > dev_err(dev, "Failed to prepare DMA memcpy\n"); > return -EIO; > @@ -148,6 +168,23 @@ static int pci_epf_test_data_transfer(struct pci_epf_test *epf_test, > return 0; > } > > +struct epf_dma_filter { > + struct device *dev; > + u32 dma_mask; > +}; > + > +static bool epf_dma_filter_fn(struct dma_chan *chan, void *node) > +{ > + struct epf_dma_filter *filter = node; > + struct dma_slave_caps caps; > + > + memset(&caps, 0, sizeof(caps)); > + dma_get_slave_caps(chan, &caps); > + > + return chan->device->dev == filter->dev > + && (filter->dma_mask & caps.directions); > +} > + > /** > * pci_epf_test_init_dma_chan() - Function to initialize EPF test DMA channel > * @epf_test: the EPF test device that performs data transfer operation > @@ -158,10 +195,44 @@ static int pci_epf_test_init_dma_chan(struct pci_epf_test *epf_test) > { > struct pci_epf *epf = epf_test->epf; > struct device *dev = &epf->dev; > + struct epf_dma_filter filter; > struct dma_chan *dma_chan; > dma_cap_mask_t mask; > int ret; > > + filter.dev = epf->epc->dev.parent; > + filter.dma_mask = BIT(DMA_DEV_TO_MEM); > + > + dma_cap_zero(mask); > + dma_cap_set(DMA_SLAVE, mask); > + dma_chan = dma_request_channel(mask, epf_dma_filter_fn, &filter); > + if (IS_ERR_OR_NULL(dma_chan)) { > + dev_info(dev, "Failed to get private DMA channel. Falling back to generic one\n"); > + goto fail_back_tx; > + } > + > + epf_test->dma_chan_rx = dma_chan; > + > + filter.dma_mask = BIT(DMA_MEM_TO_DEV); > + dma_chan = dma_request_channel(mask, epf_dma_filter_fn, &filter); > + > + if (IS_ERR(dma_chan)) { > + dev_info(dev, "Failed to get private DMA channel. Falling back to generic one\n"); These messages should indicate whether the failure was for the DEV_TO_MEM channel or the MEM_TO_DEV channel. Otherwise the failure looks the same to the user. > + goto fail_back_rx; > + } > + > + epf_test->dma_chan_tx = dma_chan; > + epf_test->dma_private = true; > + > + init_completion(&epf_test->transfer_complete); > + > + return 0; > + > +fail_back_rx: > + dma_release_channel(epf_test->dma_chan_rx); > + epf_test->dma_chan_tx = NULL; > + > +fail_back_tx: > dma_cap_zero(mask); > dma_cap_set(DMA_MEMCPY, mask); > > @@ -174,7 +245,7 @@ static int pci_epf_test_init_dma_chan(struct pci_epf_test *epf_test) > } > init_completion(&epf_test->transfer_complete); > > - epf_test->dma_chan = dma_chan; > + epf_test->dma_chan_tx = epf_test->dma_chan_rx = dma_chan; > > return 0; > } > @@ -190,8 +261,17 @@ static void pci_epf_test_clean_dma_chan(struct pci_epf_test *epf_test) > if (!epf_test->dma_supported) > return; > > - dma_release_channel(epf_test->dma_chan); > - epf_test->dma_chan = NULL; > + dma_release_channel(epf_test->dma_chan_tx); > + if (epf_test->dma_chan_tx == epf_test->dma_chan_rx) { > + epf_test->dma_chan_tx = NULL; > + epf_test->dma_chan_rx = NULL; > + return; > + } > + > + dma_release_channel(epf_test->dma_chan_rx); > + epf_test->dma_chan_rx = NULL; > + > + return; > } > > static void pci_epf_test_print_rate(const char *ops, u64 size, > @@ -280,8 +360,14 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test) > goto err_map_addr; > } > > + if (epf_test->dma_private) { > + dev_err(dev, "Cannot transfer data using DMA\n"); > + ret = -EINVAL; > + goto err_map_addr; > + } > + > ret = pci_epf_test_data_transfer(epf_test, dst_phys_addr, > - src_phys_addr, reg->size); > + src_phys_addr, reg->size, 0, DMA_MEM_TO_MEM); > if (ret) > dev_err(dev, "Data transfer failed\n"); > } else { > @@ -363,7 +449,8 @@ static int pci_epf_test_read(struct pci_epf_test *epf_test) > > ktime_get_ts64(&start); > ret = pci_epf_test_data_transfer(epf_test, dst_phys_addr, > - phys_addr, reg->size); > + phys_addr, reg->size, > + reg->src_addr, DMA_DEV_TO_MEM); > if (ret) > dev_err(dev, "Data transfer failed\n"); > ktime_get_ts64(&end); > @@ -453,8 +540,9 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test) > } > > ktime_get_ts64(&start); > + > ret = pci_epf_test_data_transfer(epf_test, phys_addr, > - src_phys_addr, reg->size); > + src_phys_addr, reg->size, reg->dst_addr, DMA_MEM_TO_DEV); Wrap to fit in 80 columns, like the rest of the file. There are a couple other cases above (the dev_info() cases are fine since we don't want to split info/error message strings). > if (ret) > dev_err(dev, "Data transfer failed\n"); > ktime_get_ts64(&end); > -- > 2.35.1 >