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| author | Serge Semin <Sergey.Semin@baikalelectronics.ru> | 2020-07-23 03:58:46 +0300 |
|---|---|---|
| committer | Vinod Koul <vkoul@kernel.org> | 2020-07-27 14:30:55 +0530 |
| commit | 585d35451e94b2e1b0bf59ef55d3b4a1c8ab3d77 (patch) | |
| tree | 930cedb9ff20c5a2edc286c0dab36197aa05a9c4 | |
| parent | e6fe5767961dbdcabbdfcc570993a91eebca4586 (diff) | |
| download | linux-585d35451e94b2e1b0bf59ef55d3b4a1c8ab3d77.tar.gz linux-585d35451e94b2e1b0bf59ef55d3b4a1c8ab3d77.tar.bz2 linux-585d35451e94b2e1b0bf59ef55d3b4a1c8ab3d77.zip | |
dmaengine: dw: Initialize min and max burst DMA device capability
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>
| -rw-r--r-- | drivers/dma/dw/core.c | 2 | ||||
| -rw-r--r-- | include/linux/platform_data/dma-dw.h | 2 |
2 files changed, 4 insertions, 0 deletions
diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c index fb95920c429e..afe5a2e465af 100644 --- a/drivers/dma/dw/core.c +++ b/drivers/dma/dw/core.c @@ -1223,6 +1223,8 @@ int do_dma_probe(struct dw_dma_chip *chip) dw->dma.device_issue_pending = dwc_issue_pending; /* DMA capabilities */ + dw->dma.min_burst = DW_DMA_MIN_BURST; + dw->dma.max_burst = DW_DMA_MAX_BURST; dw->dma.src_addr_widths = DW_DMA_BUSWIDTHS; dw->dma.dst_addr_widths = DW_DMA_BUSWIDTHS; dw->dma.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV) | diff --git a/include/linux/platform_data/dma-dw.h b/include/linux/platform_data/dma-dw.h index f3eaf9ec00a1..369e41e9dcc9 100644 --- a/include/linux/platform_data/dma-dw.h +++ b/include/linux/platform_data/dma-dw.h @@ -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 |