{"id":2175217,"url":"http://patchwork.ozlabs.org/api/1.0/patches/2175217/?format=json","project":{"id":28,"url":"http://patchwork.ozlabs.org/api/1.0/projects/28/?format=json","name":"Linux PCI development","link_name":"linux-pci","list_id":"linux-pci.vger.kernel.org","list_email":"linux-pci@vger.kernel.org","web_url":null,"scm_url":null,"webscm_url":null},"msgid":"<20251217151609.3162665-21-den@valinux.co.jp>","date":"2025-12-17T15:15:54","name":"[RFC,v3,20/35] dmaengine: dw-edma: Add notify-only channels support","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"aea03251ed0f5d4b4798b7fe9b15aac721f89fc0","submitter":{"id":91573,"url":"http://patchwork.ozlabs.org/api/1.0/people/91573/?format=json","name":"Koichiro Den","email":"den@valinux.co.jp"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/linux-pci/patch/20251217151609.3162665-21-den@valinux.co.jp/mbox/","series":[{"id":485709,"url":"http://patchwork.ozlabs.org/api/1.0/series/485709/?format=json","date":"2025-12-17T15:15:53","name":"NTB transport backed by endpoint DW eDMA","version":3,"mbox":"http://patchwork.ozlabs.org/series/485709/mbox/"}],"check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2175217/checks/","tags":{},"headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-pci@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=valinux.co.jp header.i=@valinux.co.jp\n header.a=rsa-sha256 header.s=selector1 header.b=U6lkX6n3;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n 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bh=lBHhV8flWb08jkfgSrsYDEjcKE4stA0DKcw1IQNChX8=;\n b=U6lkX6n3xMtDG1BIz4td3w98KjelghQqPwv/zKoXJcwETn5DHcxnF1zOawyjojTOqfaX+1rfdMgo9FupxtVfi846/jFTo9OaLWrEh369dSf7P4pkood9YeSwS3q8cTLX75lSwQRht2CuoL54KAIYuo377ie6TQbxfI+5tjmDlJk=","From":"Koichiro Den ","To":"Frank.Li@nxp.com,\n\tdave.jiang@intel.com,\n\tntb@lists.linux.dev,\n\tlinux-pci@vger.kernel.org,\n\tdmaengine@vger.kernel.org,\n\tlinux-renesas-soc@vger.kernel.org,\n\tnetdev@vger.kernel.org,\n\tlinux-kernel@vger.kernel.org","Cc":"mani@kernel.org,\n\tkwilczynski@kernel.org,\n\tkishon@kernel.org,\n\tbhelgaas@google.com,\n\tcorbet@lwn.net,\n\tgeert+renesas@glider.be,\n\tmagnus.damm@gmail.com,\n\trobh@kernel.org,\n\tkrzk+dt@kernel.org,\n\tconor+dt@kernel.org,\n\tvkoul@kernel.org,\n\tjoro@8bytes.org,\n\twill@kernel.org,\n\trobin.murphy@arm.com,\n\tjdmason@kudzu.us,\n\tallenbh@gmail.com,\n\tandrew+netdev@lunn.ch,\n\tdavem@davemloft.net,\n\tedumazet@google.com,\n\tkuba@kernel.org,\n\tpabeni@redhat.com,\n\tBasavaraj.Natikar@amd.com,\n\tShyam-sundar.S-k@amd.com,\n\tkurt.schwemmer@microsemi.com,\n\tlogang@deltatee.com,\n\tjingoohan1@gmail.com,\n\tlpieralisi@kernel.org,\n\tutkarsh02t@gmail.com,\n\tjbrunet@baylibre.com,\n\tdlemoal@kernel.org,\n\tarnd@arndb.de,\n\telfring@users.sourceforge.net,\n\tden@valinux.co.jp","Subject":"[RFC PATCH v3 20/35] dmaengine: dw-edma: Add notify-only channels\n support","Date":"Thu, 18 Dec 2025 00:15:54 +0900","Message-ID":"<20251217151609.3162665-21-den@valinux.co.jp>","X-Mailer":"git-send-email 2.51.0","In-Reply-To":"<20251217151609.3162665-1-den@valinux.co.jp>","References":"<20251217151609.3162665-1-den@valinux.co.jp>","Content-Transfer-Encoding":"8bit","Content-Type":"text/plain","X-ClientProxiedBy":"TYCPR01CA0119.jpnprd01.prod.outlook.com\n (2603:1096:405:4::35) To TYWP286MB2697.JPNP286.PROD.OUTLOOK.COM\n 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0b848c19-2894-4397-792c-08de3d7f4249","X-MS-Exchange-CrossTenant-AuthSource":"TYWP286MB2697.JPNP286.PROD.OUTLOOK.COM","X-MS-Exchange-CrossTenant-AuthAs":"Internal","X-MS-Exchange-CrossTenant-OriginalArrivalTime":"17 Dec 2025 15:16:31.6140\n (UTC)","X-MS-Exchange-CrossTenant-FromEntityHeader":"Hosted","X-MS-Exchange-CrossTenant-Id":"7a57bee8-f73d-4c5f-a4f7-d72c91c8c111","X-MS-Exchange-CrossTenant-MailboxType":"HOSTED","X-MS-Exchange-CrossTenant-UserPrincipalName":"\n 2cgrHeotYXTbPDtpiFU54i+YqoA87nMT3B45UosmgeROQ9vzpbLXvLKEuShFuhyh3nlh9aI+nfHyXF0yQU3xnQ==","X-MS-Exchange-Transport-CrossTenantHeadersStamped":"TYCP286MB2863"},"content":"Remote eDMA users may want to prepare descriptors on the remote side while\nthe local side only needs completion notifications (no cookie-based\naccounting).\n\nProvide a lightweight per-channel notification callback infrastructure.\n\nSigned-off-by: Koichiro Den \n---\n drivers/dma/dw-edma/dw-edma-core.c | 32 ++++++++++++++++++++++++++++++\n drivers/dma/dw-edma/dw-edma-core.h | 4 ++++\n include/linux/dma/edma.h | 22 ++++++++++++++++++++\n 3 files changed, 58 insertions(+)","diff":"diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c\nindex 09b10ad1f38a..8e262f61f02d 100644\n--- a/drivers/dma/dw-edma/dw-edma-core.c\n+++ b/drivers/dma/dw-edma/dw-edma-core.c\n@@ -608,6 +608,13 @@ static void dw_edma_done_interrupt(struct dw_edma_chan *chan)\n \tstruct virt_dma_desc *vd;\n \tunsigned long flags;\n \n+\tif (chan->notify_only) {\n+\t\tif (chan->notify_cb)\n+\t\t\tchan->notify_cb(&chan->vc.chan, chan->notify_cb_param);\n+\t\t/* no cookie on this side, just return */\n+\t\treturn;\n+\t}\n+\n \tspin_lock_irqsave(&chan->vc.lock, flags);\n \tvd = vchan_next_desc(&chan->vc);\n \tif (vd) {\n@@ -811,6 +818,9 @@ static int dw_edma_channel_setup(struct dw_edma *dw, u32 wr_alloc, u32 rd_alloc)\n \t\tchan->request = EDMA_REQ_NONE;\n \t\tchan->status = EDMA_ST_IDLE;\n \t\tchan->irq_mode = DW_EDMA_CH_IRQ_DEFAULT;\n+\t\tchan->notify_cb = NULL;\n+\t\tchan->notify_cb_param = NULL;\n+\t\tchan->notify_only = false;\n \n \t\tif (chan->dir == EDMA_DIR_WRITE)\n \t\t\tchan->ll_max = (chip->ll_region_wr[chan->id].sz / EDMA_LL_SZ);\n@@ -1171,6 +1181,28 @@ bool dw_edma_chan_ignore_irq(struct dma_chan *dchan)\n }\n EXPORT_SYMBOL_GPL(dw_edma_chan_ignore_irq);\n \n+int dw_edma_chan_register_notify(struct dma_chan *dchan,\n+\t\t\t\t void (*cb)(struct dma_chan *chan, void *user),\n+\t\t\t\t void *user)\n+{\n+\tstruct dw_edma_chan *chan;\n+\n+\tif (!dchan || !dchan->device ||\n+\t dchan->device->device_prep_slave_sg_config != dw_edma_device_prep_slave_sg_config)\n+\t\treturn -ENODEV;\n+\n+\tchan = dchan2dw_edma_chan(dchan);\n+\tif (!chan)\n+\t\treturn -ENODEV;\n+\n+\tchan->notify_cb = cb;\n+\tchan->notify_cb_param = user;\n+\tchan->notify_only = !!cb;\n+\n+\treturn dw_edma_chan_irq_config(dchan, DW_EDMA_CH_IRQ_LOCAL);\n+}\n+EXPORT_SYMBOL_GPL(dw_edma_chan_register_notify);\n+\n MODULE_LICENSE(\"GPL v2\");\n MODULE_DESCRIPTION(\"Synopsys DesignWare eDMA controller core driver\");\n MODULE_AUTHOR(\"Gustavo Pimentel \");\ndiff --git a/drivers/dma/dw-edma/dw-edma-core.h b/drivers/dma/dw-edma/dw-edma-core.h\nindex 11fe4532f0bf..f652d2e38843 100644\n--- a/drivers/dma/dw-edma/dw-edma-core.h\n+++ b/drivers/dma/dw-edma/dw-edma-core.h\n@@ -84,6 +84,10 @@ struct dw_edma_chan {\n \n \tenum dw_edma_ch_irq_mode\tirq_mode;\n \n+\tvoid (*notify_cb)(struct dma_chan *chan, void *user);\n+\tvoid *notify_cb_param;\n+\tbool notify_only;\n+\n \tstruct delayed_work\t\tpoll_work;\n \tspinlock_t\t\t\tpoll_lock;\n \ndiff --git a/include/linux/dma/edma.h b/include/linux/dma/edma.h\nindex 8c1b1d25fa44..4caf5cc5c368 100644\n--- a/include/linux/dma/edma.h\n+++ b/include/linux/dma/edma.h\n@@ -95,6 +95,21 @@ int dw_edma_chan_irq_config(struct dma_chan *chan,\n */\n bool dw_edma_chan_ignore_irq(struct dma_chan *chan);\n \n+/**\n+ * dw_edma_chan_register_notify - register local completion callback for a\n+ * notification-only channel\n+ * @chan: DMA channel obtained from dma_request_channel()\n+ * @cb: callback invoked in hardirq context when LIE interrupt is raised\n+ * @user: opaque pointer passed back to @cb\n+ *\n+ * Intended for channels where descriptors are prepared on the remote side and\n+ * the local side only wants completion notifications. This forces LOCAL mode\n+ * so that the local side receives LIE interrupts.\n+ */\n+int dw_edma_chan_register_notify(struct dma_chan *chan,\n+\t\t\t\t void (*cb)(struct dma_chan *chan, void *user),\n+\t\t\t\t void *user);\n+\n #if IS_REACHABLE(CONFIG_PCIE_DW)\n /**\n * dw_edma_get_reg_window - get eDMA register base and size\n@@ -185,6 +200,13 @@ static inline bool dw_edma_chan_ignore_irq(struct dma_chan *chan)\n {\n \treturn false;\n }\n+static inline int dw_edma_chan_register_notify(struct dma_chan *chan,\n+\t\t\t\t\t void (*cb)(struct dma_chan *chan,\n+\t\t\t\t\t\t\t void *user),\n+\t\t\t\t\t void *user)\n+{\n+\treturn -ENODEV;\n+}\n #endif\n \n #endif /* _DW_EDMA_H */\n","prefixes":["RFC","v3","20/35"]}