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Subject[PATCH v1 2/2] spi: pxa2xx: Update DMA mapping and using logic in the documentation
Date
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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