From e6fe5767961dbdcabbdfcc570993a91eebca4586 Mon Sep 17 00:00:00 2001 From: Serge Semin Date: Thu, 23 Jul 2020 03:58:45 +0300 Subject: [PATCH] dmaengine: dw: Set DMA device max segment size parameter Maximum block size DW DMAC configuration corresponds to the max segment size DMA parameter in the DMA core subsystem notation. Lets set it with a value specific to the probed DW DMA controller. It shall help the DMA clients to create size-optimized SG-list items for the controller. This in turn will cause less dw_desc allocations, less LLP reinitializations, better DMA device performance. Signed-off-by: Serge Semin Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20200723005848.31907-8-Sergey.Semin@baikalelectronics.ru Signed-off-by: Vinod Koul --- drivers/dma/dw/core.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c index 33e99d9..fb95920 100644 --- a/drivers/dma/dw/core.c +++ b/drivers/dma/dw/core.c @@ -1229,6 +1229,13 @@ int do_dma_probe(struct dw_dma_chip *chip) BIT(DMA_MEM_TO_MEM); dw->dma.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST; + /* + * For now there is no hardware with non uniform maximum block size + * across all of the device channels, so we set the maximum segment + * size as the block size found for the very first channel. + */ + dma_set_max_seg_size(dw->dma.dev, dw->chan[0].block_size); + err = dma_async_device_register(&dw->dma); if (err) goto err_dma_register; -- 2.7.4