[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20231207221426.3259806-3-andriy.shevchenko@linux.intel.com>
Date: Fri, 8 Dec 2023 00:13:40 +0200
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
linux-spi@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: Mark Brown <broonie@...nel.org>
Subject: [PATCH v1 2/2] spi: pxa2xx: Update DMA mapping and using logic in the documentation
Update DMA mapping and using logic in the documentation to follow what
the code does.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.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
Powered by blists - more mailing lists