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dmaengine: dw: Initialize min and max burst DMA device capability

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According to the DW APB DMAC data book the minimum burst transaction
length is 1 and it's true for any version of the controller since
isn't parametrised in the coreAssembler so can't be changed at the
IP-core synthesis stage. The maximum burst transaction can vary from
channel to channel and from controller to controller depending on a
IP-core parameter the system engineer activated during the IP-core
synthesis. Let's initialise both min_burst and max_burst members of the
DMA controller descriptor with extreme values so the DMA clients could
use them to properly optimize the DMA requests. The channels and
controller-specific max_burst length initialization will be introduced
by the follow-up patches.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200723005848.31907-9-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Serge Semin
2020-07-23 03:58:46 +03:00
committed by Vinod Koul
parent e6fe576796
commit 585d35451e
2 changed files with 4 additions and 0 deletions
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2
include/linux/platform_data/dma-dw.h
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@@ -12,6 +12,8 @@
#define DW_DMA_MAX_NR_MASTERS 4
#define DW_DMA_MAX_NR_CHANNELS 8
#define DW_DMA_MIN_BURST 1
#define DW_DMA_MAX_BURST 256
/**
* struct dw_dma_slave - Controller-specific information about a slave