Messages in this thread Patch in this message | | | From | Andy Shevchenko <> | Subject | [PATCH v1 2/2] spi: pxa2xx: Update DMA mapping and using logic in the documentation | Date | Fri, 8 Dec 2023 00:13:40 +0200 |
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Update DMA mapping and using logic in the documentation to follow what the code does.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> --- Documentation/spi/pxa2xx.rst | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-)
diff --git a/Documentation/spi/pxa2xx.rst b/Documentation/spi/pxa2xx.rst index b66702724ccf..61c7b9dd833b 100644 --- a/Documentation/spi/pxa2xx.rst +++ b/Documentation/spi/pxa2xx.rst @@ -193,17 +193,14 @@ mode supports both coherent and stream based DMA mappings. The following logic is used to determine the type of I/O to be used on a per "spi_transfer" basis:: - if !enable_dma then - always use PIO transfers + if spi_message.len > 65536 then + if spi_message.is_dma_mapped or rx_dma_buf != 0 or tx_dma_buf != 0 then + reject premapped transfers - if spi_message.len > 8191 then print "rate limited" warning use PIO transfers - if spi_message.is_dma_mapped and rx_dma_buf != 0 and tx_dma_buf != 0 then - use coherent DMA mode - - if rx_buf and tx_buf are aligned on 8 byte boundary then + if enable_dma and the size is in the range [DMA burst size..65536] then use streaming DMA mode otherwise -- 2.43.0.rc1.1.gbec44491f096
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