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 C6F6CC433EF for ; Wed, 11 May 2022 19:12:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346464AbiEKTMx (ORCPT ); Wed, 11 May 2022 15:12:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58288 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345686AbiEKTMw (ORCPT ); Wed, 11 May 2022 15:12:52 -0400 Received: from mail-ed1-x52d.google.com (mail-ed1-x52d.google.com [IPv6:2a00:1450:4864:20::52d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 830BF737A5; Wed, 11 May 2022 12:12:50 -0700 (PDT) Received: by mail-ed1-x52d.google.com with SMTP id t5so3630990edw.11; Wed, 11 May 2022 12:12:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=3uzK29iYJTvDTVRda9NakAnnspLjzcAKbKtofwnI2fc=; b=BiAxVjAh3uR8nOts58m9jbAlcY4G9EPccU1iBeSe+uRn9TAofdH7t0Uo7yVDRz9zDE jcOzu7vNqRitUI0DFAyawKPrCdgbTOEDNayhYbC1311JLUDTPnWU39b0VIQRWqQ9kR7l A3Zg+ePAvjBw5Nrd+8/7CA99gU8d4JvgdbIFGu5tLjpUreeT4c0mZFbo1hOXn62UUPR6 i9uCki/j2Bc6KfeBUxagBPoGWdyrBVbV7E/0/gGwJt7Ndscops/ySGLzplpQT16nQ5lT u1TLP6hOp3iQ0UgOS2LhtsipYjaY2sRaTrrn9680Oe0sVIPlLo0WPRam09La9GMAyjmi FrIQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=3uzK29iYJTvDTVRda9NakAnnspLjzcAKbKtofwnI2fc=; b=E3irInswqeD00hOIX0wNkMvBeh6OW9lMfRfv/Rs9/sF0qdq6sIKruzBARqy+pFgWIi eyGx9gb3eIrWyv5mINvDIVrVGW/TIWz9uwWmTumulLD7dmz2l3zw7GnkchVourpsi+pC ZKw/qOUxAXTtpZbskODsE9sGEV+A2VrOD092ptKpkyAunfUuOk5t/sUQRfWjPac1ed9N yySaMy3SuXG7de8VjwOQPzxacX9Ae+GRuW2WxbHhXXxRQkZ20xjgGXaesusc8/jiWqlo mPOOqljicmVx853P2Erfl89Zor5MPNpa4u7MWChqAj/1XdZWF1S/Pyu3uAfdAfJ6lQrQ 6Cmw== X-Gm-Message-State: AOAM533AnHI2TqbN8w3cEztr91GCVrZHwBsTapSc4qUgPTR8AavUSZyO B/jKF5FMe39jeSoLH7m/hkGNTfPgnADlpsyKNFxlI9wg0Ty9ygn3 X-Google-Smtp-Source: ABdhPJzs9OPPzNGK0vPRxWROYexho4rTaKFZGTBwfzmoBvGkIF8wvUZLYs7ksYtr9eI/w6NOKK8bS4tPyf307dNEhaI= X-Received: by 2002:a50:cd08:0:b0:426:1d9b:4b13 with SMTP id z8-20020a50cd08000000b004261d9b4b13mr30790039edi.360.1652296368767; Wed, 11 May 2022 12:12:48 -0700 (PDT) MIME-Version: 1.0 References: <20220503005801.1714345-1-Frank.Li@nxp.com> <20220503005801.1714345-10-Frank.Li@nxp.com> In-Reply-To: From: Zhi Li Date: Wed, 11 May 2022 14:12:37 -0500 Message-ID: Subject: Re: [PATCH v10 9/9] PCI: endpoint: Enable DMA controller tests for endpoints with DMA capabilities To: Lorenzo Pieralisi Cc: Frank Li , Gustavo Pimentel , hongxing.zhu@nxp.com, Lucas Stach , dl-linux-imx , linux-pci@vger.kernel.org, dmaengine@vger.kernel.org, Serge Semin , Bjorn Helgaas , Vinod Koul , Rob Herring , =?UTF-8?Q?Krzysztof_Wilczy=C5=84ski?= , Bjorn Helgaas , Manivannan Sadhasivam , Serge Semin , Kishon Vijay Abraham I Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org On Wed, May 11, 2022 at 12:30 PM Lorenzo Pieralisi wrote: > > On Wed, May 11, 2022 at 11:18:20AM -0500, Zhi Li wrote: > > On Wed, May 11, 2022 at 4:28 AM Lorenzo Pieralisi > > wrote: > > > > > > [+Kishon] > > > > > > On Mon, May 02, 2022 at 07:58:01PM -0500, Frank Li wrote: > > > > Some Endpoints controllers have DMA capabilities. This DMA controller has > > > > more efficiency then a general external DMA controller. And this DMA > > > > controller can bypass outbound memory address translation unit. > > > > > > I am sorry to be pedantic but which DMA controller ? > > > > > > Do you mean "DMA controllers embedded in Endpoint controllers" ? > > > > Yes. > > > > > > > > This is a bit vague and overall you are patching pci-epf-test.c, > > > that's the change that has to be explained. > > > > > > If Kishon can have a look that would be greatly appreciated too. > > > > > > When we agree on a proper commit log I can ACK the patch, the whole > > > series can then go via the DMA engine tree. > > > > How about the below commit message? Is it clear? > > It is better but I have some suggestions below. > > > PCI: endpoint: Enable DMA controller tests for endpoints with DMA > > capabilities > > "PCI: endpoint: Enable DMA tests for endpoints with DMA capabilities" > > > Some PCI Endpoints controllers integrate an eDMA (embedded DMA). > > eDMA has more efficiency than a general DMA controller. > > What does "has more efficiency" means ? You mean it can bypass the > memory translation unit ? Generally Memory to memory DMA work as - DMA read from DDR into DMA controller FIFO, AXI Read - DMA write to PCI space from DMA controller FIFO, AXI write - PCI EP controller converts AXI write to PCI TLP into PCI bus. EP eDMA works as - eDMA read from DDR, - Convert PCI TLP into PCI bus. a AXI write operator saved. so I think efficiency is higher than general DMA. > > > And eDMA can bypass > > Don't start a sentence with "And". > > > outbound memory address translation unit to access all RC memory space. > > > > This patch added eDMA support for pci-epf-test. > > "Add eDMA support for pci-epf-test". > > This patch is doing more than this though, doesn't it ? > > I would write (always use imperative statements): > > "Add DMA support for pci-epf-test. > > EPF endpoints can use, depending on HW availability, eDMA or general > system DMA controllers to perform DMA. > > The test probes the EPF DMA channel capabilities." > > Then you can add the description below. > > > - Separate DMA channel to TX and RX. eDMA channels have higher priority than > > general DMA channels. If general memory to memory DMA channels are used, > > RX and TX channels are equal. > > What does "are equal" mean ? By the way, please remove double spaces RX = TX. > after a period. If you need to start a new paragraph add a new line. > > > - Add dma_addr_t dma_remote in in function > > pci_epf_test_data_transfer() because > > eDMA using remote RC physical address directly > > - 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. Using dma_request_channel() and filter function to find correct > > s/Using/Execute > > > eDMA RX and TX Channel. if channel not exist, fallback to try allocate > > "If a channel does not exist" > > > general memory to memory DMA channel. > > 2. Using dmaengine_slave_config() config remote side physical address. > > s/Using/Execute - "to configure remote" > > > 3. Using dmaengine_prep_slave_single() create transfer descriptor. > > s/Using/Execute - "to create" > > > > 4. tx_submit(); > > Execute tx_submit() > > > 5. dma_async_issue_pending(); > > Execute dma_async_issue_pending() > > Overall, all you need to do describe is what the patch does, hopefully > the comments above can help. Updated commit message: PCI: endpoint: Enable DMA tests for endpoints with DMA capabilities 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. Add DMA support for pci-epf-test. 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. If general memory to memory DMA hannels are used, dma_chan_rx = dma_chan_tx. Add dma_addr_t dma_remote in in function pci_epf_test_data_transfer() because eDMA using remote RC physical address directly 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. 2. Execute dmaengine_slave_config() to configure remote side physical address. 3. Execute dmaengine_prep_slave_single() to create transfer descriptor. 4. Execute tx_submit(). 5. Execute dma_async_issue_pending() > > Thanks, > Lorenzo > > > > Thanks, > > > Lorenzo > > > > > > > > > > > The whole flow use standard DMA usage module > > > > > > > > 1. Using dma_request_channel() and filter function to find correct > > > > RX and TX Channel. if not exist, fallback to try allocate > > > > general DMA controller channel. > > > > 2. dmaengine_slave_config() config remote side physcial address. > > > > 3. using dmaengine_prep_slave_single() create transfer descriptor. > > > > 4. tx_submit(); > > > > 5. dma_async_issue_pending(); > > > > > > > > Signed-off-by: Frank Li > > > > Acked-by: Manivannan Sadhasivam > > > > --- > > > > 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) > > > > { > > > > + 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"); > > > > + 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); > > > > if (ret) > > > > dev_err(dev, "Data transfer failed\n"); > > > > ktime_get_ts64(&end); > > > > -- > > > > 2.35.1 > > > >