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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Mark Brown <broonie@kernel.org>
Subject: [PATCH v2 2/2] spi: pxa2xx: Update DMA mapping and using logic in the documentation
Date: Fri,  8 Dec 2023 19:02:55 +0200	[thread overview]
Message-ID: <20231208170436.3309648-3-andriy.shevchenko@linux.intel.com> (raw)
In-Reply-To: <20231208170436.3309648-1-andriy.shevchenko@linux.intel.com>

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 143f1df83f79..19479b801826 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


  parent reply	other threads:[~2023-12-08 17:04 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-12-08 17:02 [PATCH v2 0/2] spi: pxa2xx: Update documentation Andy Shevchenko
2023-12-08 17:02 ` [PATCH v2 1/2] spi: pxa2xx: Use inclusive language Andy Shevchenko
2023-12-08 17:02 ` Andy Shevchenko [this message]
2023-12-09 17:52 ` [PATCH v2 0/2] spi: pxa2xx: Update documentation Mark Brown

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