diff options
| author | Joy Chakraborty <joychakr@google.com> | 2023-05-12 13:47:45 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-07-19 17:21:05 +0300 |
| commit | 34d04d70194d19ba9847400c12fcdeae6826630c (patch) | |
| tree | 2531cc2a4ef43512de7163ebb96614099f3edb76 /drivers/spi | |
| parent | c6a9fc82fe188f0f1c07839c2ca4b40a2b14621f (diff) | |
| download | linux-34d04d70194d19ba9847400c12fcdeae6826630c.tar.xz | |
spi: dw: Round of n_bytes to power of 2
[ Upstream commit 9f34baf67e4d08908fd94ff29c825bb673295336 ]
n_bytes variable in the driver represents the number of bytes per word
that needs to be sent/copied to fifo. Bits/word can be between 8 and 32
bits from the client but in memory they are a power of 2, same is mentioned
in spi.h header:
"
* @bits_per_word: Data transfers involve one or more words; word sizes
* like eight or 12 bits are common. In-memory wordsizes are
* powers of two bytes (e.g. 20 bit samples use 32 bits).
* This may be changed by the device's driver, or left at the
* default (0) indicating protocol words are eight bit bytes.
* The spi_transfer.bits_per_word can override this for each transfer.
"
Hence, round of n_bytes to a power of 2 to avoid values like 3 which
would generate unalligned/odd accesses to memory/fifo.
* tested on Baikal-T1 based system with DW SPI-looped back interface
transferring a chunk of data with DFS:8,12,16.
Fixes: a51acc2400d4 ("spi: dw: Add support for 32-bits max xfer size")
Suggested-by: Andy Shevchenko <andriy.shevchenko@intel.com
Signed-off-by: Joy Chakraborty <joychakr@google.com
Reviewed-by: Serge Semin <fancer.lancer@gmail.com
Tested-by: Serge Semin <fancer.lancer@gmail.com
Link: https://lore.kernel.org/r/20230512104746.1797865-4-joychakr@google.com
Signed-off-by: Mark Brown <broonie@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/spi-dw-core.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c index c3bfb6c84cab..4976e3b8923e 100644 --- a/drivers/spi/spi-dw-core.c +++ b/drivers/spi/spi-dw-core.c @@ -426,7 +426,10 @@ static int dw_spi_transfer_one(struct spi_controller *master, int ret; dws->dma_mapped = 0; - dws->n_bytes = DIV_ROUND_UP(transfer->bits_per_word, BITS_PER_BYTE); + dws->n_bytes = + roundup_pow_of_two(DIV_ROUND_UP(transfer->bits_per_word, + BITS_PER_BYTE)); + dws->tx = (void *)transfer->tx_buf; dws->tx_len = transfer->len / dws->n_bytes; dws->rx = transfer->rx_buf; |