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| author | Martin Sperl <kernel@martin.sperl.org> | 2019-03-30 09:31:00 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-09-10 10:29:50 +0100 |
| commit | e187a57fc653cfc3016875b80f53f78af4eac172 (patch) | |
| tree | ab1d8301c09a1aab99f7a6bfb881909991d654bc /arch | |
| parent | b2f16660fc8687febdc133f9b5082482f2a280fc (diff) | |
spi: bcm2835aux: fix corruptions for longer spi transfers
[ Upstream commit 73b114ee7db1750c0b535199fae383b109bd61d0 ]
On long running tests with a mcp2517fd can controller it showed that
on rare occations the data read shows corruptions for longer spi transfers.
Example of a 22 byte transfer:
expected (as captured on logic analyzer):
FF FF 78 00 00 00 08 06 00 00 91 20 77 56 84 85 86 87 88 89 8a 8b
read by the driver:
FF FF 78 00 00 00 08 06 00 00 91 20 77 56 84 88 89 8a 00 00 8b 9b
To fix this use BCM2835_AUX_SPI_STAT_RX_LVL to determine when we may
read data from the fifo reliably without any corruption.
Surprisingly the only values ever empirically read in
BCM2835_AUX_SPI_STAT_RX_LVL are 0x00, 0x10, 0x20 and 0x30.
So whenever the mask is not 0 we can read from the fifo in a safe manner.
The patch has now been tested intensively and we are no longer
able to reproduce the "RX" issue any longer.
Fixes: 1ea29b39f4c812ec ("spi: bcm2835aux: add bcm2835 auxiliary spi device...")
Reported-by: Hubert Denkmair <h.denkmair@intence.de>
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Acked-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch')
0 files changed, 0 insertions, 0 deletions