Commit e6fe5767 authored Jul 23, 2020 by Serge Semin Committed by Vinod Koul Jul 27, 2020

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 <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200723005848.31907-8-Sergey.Semin@baikalelectronics.ru

Signed-off-by: Vinod Koul <vkoul@kernel.org>

parent ef3e515a

drivers/dma/dw/core.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -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;