From patchwork Wed Jun 17 23:40:23 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Serge Semin X-Patchwork-Id: 11610961 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8A0B390 for ; Wed, 17 Jun 2020 23:41:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7C8EB2166E for ; Wed, 17 Jun 2020 23:41:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727053AbgFQXkr (ORCPT ); Wed, 17 Jun 2020 19:40:47 -0400 Received: from mail.baikalelectronics.com ([87.245.175.226]:57816 "EHLO mail.baikalelectronics.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726867AbgFQXkq (ORCPT ); Wed, 17 Jun 2020 19:40:46 -0400 Received: from localhost (unknown [127.0.0.1]) by mail.baikalelectronics.ru (Postfix) with ESMTP id 570AF803202B; Wed, 17 Jun 2020 23:40:42 +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 WumHxgepebhi; Thu, 18 Jun 2020 02:40:41 +0300 (MSK) From: Serge Semin To: Vinod Koul , Viresh Kumar , Dan Williams CC: Serge Semin , Serge Semin , Andy Shevchenko , Alexey Malahov , Thomas Bogendoerfer , Arnd Bergmann , Rob Herring , , , , Subject: [PATCH v6 4/9] dmaengine: Introduce DMA-device device_caps callback Date: Thu, 18 Jun 2020 02:40:23 +0300 Message-ID: <20200617234028.25808-5-Sergey.Semin@baikalelectronics.ru> In-Reply-To: <20200617234028.25808-1-Sergey.Semin@baikalelectronics.ru> References: <20200617234028.25808-1-Sergey.Semin@baikalelectronics.ru> MIME-Version: 1.0 X-ClientProxiedBy: MAIL.baikal.int (192.168.51.25) To mail (192.168.51.25) Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org There are DMA devices (like ours version of Synopsys DW DMAC) which have DMA capabilities non-uniformly redistributed between the device channels. In order to provide a way of exposing the channel-specific parameters to the DMA engine consumers, we introduce a new DMA-device callback. In case if provided it gets called from the dma_get_slave_caps() method and is able to override the generic DMA-device capabilities. Signed-off-by: Serge Semin Reviewed-by: Andy Shevchenko Cc: Alexey Malahov Cc: Thomas Bogendoerfer Cc: Arnd Bergmann Cc: Andy Shevchenko Cc: Rob Herring Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org --- Changelog v3: - This is a new patch created as a result of the discussion with Vinod and Andy in the framework of DW DMA burst and LLP capabilities. Changelog v5: - Add in-line comment at the point of the device_caps callback invocation. - Add doc-comment for the device_caps member of struct dma_device. --- drivers/dma/dmaengine.c | 10 ++++++++++ include/linux/dmaengine.h | 4 ++++ 2 files changed, 14 insertions(+) diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index b332ffe52780..7d6ac0ca2af5 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -598,6 +598,16 @@ int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps) caps->cmd_resume = !!device->device_resume; caps->cmd_terminate = !!device->device_terminate_all; + /* + * DMA engine device might be configured with non-uniformly + * distributed slave capabilities per device channels. In this + * case the corresponding driver may provide the device_caps + * callback to override the generic capabilities with + * channel-specific ones. + */ + if (device->device_caps) + device->device_caps(chan, caps); + return 0; } EXPORT_SYMBOL_GPL(dma_get_slave_caps); diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index 0c7403b27133..7ae0daafda82 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -792,6 +792,8 @@ struct dma_filter { * be called after period_len bytes have been transferred. * @device_prep_interleaved_dma: Transfer expression in a generic way. * @device_prep_dma_imm_data: DMA's 8 byte immediate data to the dst address + * @device_caps: May be used to override the generic DMA slave capabilities + * with per-channel specific ones * @device_config: Pushes a new configuration to a channel, return 0 or an error * code * @device_pause: Pauses any transfer happening on a channel. Returns @@ -891,6 +893,8 @@ struct dma_device { struct dma_chan *chan, dma_addr_t dst, u64 data, unsigned long flags); + void (*device_caps)(struct dma_chan *chan, + struct dma_slave_caps *caps); int (*device_config)(struct dma_chan *chan, struct dma_slave_config *config); int (*device_pause)(struct dma_chan *chan);