From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933281Ab3GOPwa (ORCPT ); Mon, 15 Jul 2013 11:52:30 -0400 Received: from smtp-out-191.synserver.de ([212.40.185.191]:1034 "EHLO smtp-out-191.synserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933210Ab3GOPw2 (ORCPT ); Mon, 15 Jul 2013 11:52:28 -0400 X-SynServer-TrustedSrc: 1 X-SynServer-AuthUser: lars@metafoo.de X-SynServer-PPID: 3256 From: Lars-Peter Clausen To: Vinod Koul Cc: Dan Williams , Jassi Brar , linux-kernel@vger.kernel.org, Lars-Peter Clausen Subject: [PATCH] dma: pl330: Implement device_slave_caps Date: Mon, 15 Jul 2013 17:53:08 +0200 Message-Id: <1373903588-19358-1-git-send-email-lars@metafoo.de> X-Mailer: git-send-email 1.8.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Implemnt the device_slave_caps() callback for the pl330 driver. This allows dmaengine users like the generic ALSA dmaengine PCM driver to query the capabilities of the driver. The PL330 supports all buswidths and both mem-to-dev as well as dev-to-mem transfers. In theory there is no limit on the number of segments that can be transferred (in practice you'll run out of memory eventually) and the number of bytes per segment is limited by the size of the PL330 program buffer. Due to the nature of the PL330 the maximum number of bytes per segment depends on the burstsize, the driver sets it to the value for a 1-byte burstsize, since it is the smallest. Signed-off-by: Lars-Peter Clausen --- drivers/dma/pl330.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c index 593827b..2bf578c 100644 --- a/drivers/dma/pl330.c +++ b/drivers/dma/pl330.c @@ -2855,6 +2855,32 @@ static irqreturn_t pl330_irq_handler(int irq, void *data) return IRQ_NONE; } +#define PL330_DMA_BUSWIDTHS \ + BIT(DMA_SLAVE_BUSWIDTH_UNDEFINED) | \ + BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \ + BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \ + BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) | \ + BIT(DMA_SLAVE_BUSWIDTH_8_BYTES) + +static int pl330_dma_device_slave_caps(struct dma_chan *dchan, + struct dma_slave_caps *caps) +{ + caps->src_addr_widths = PL330_DMA_BUSWIDTHS; + caps->dstn_addr_widths = PL330_DMA_BUSWIDTHS; + caps->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV); + caps->cmd_pause = false; + caps->cmd_terminate = true; + + /* + * This is the limit for transfers with a buswidth of 1, larger buswidths + * will have larger limits. + */ + caps->max_sg_len = 1900800; + caps->max_sg_nr = 0; + + return 0; +} + static int pl330_probe(struct amba_device *adev, const struct amba_id *id) { @@ -2959,6 +2985,7 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id) pd->device_prep_slave_sg = pl330_prep_slave_sg; pd->device_control = pl330_control; pd->device_issue_pending = pl330_issue_pending; + pd->device_slave_caps = pl330_dma_device_slave_caps; ret = dma_async_device_register(pd); if (ret) { -- 1.8.0