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| author | Christian Loehle <christian.loehle@arm.com> | 2024-12-06 19:50:55 +0000 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2024-12-09 13:06:23 +0000 |
| commit | 0bb394067a792e7119abc9e0b7158ef19381f456 (patch) | |
| tree | dc1fd97377e051ff3efb7d9f8e24a790f77915bd /drivers/spi | |
| parent | c84dda3751e945a67d71cbe3af4474aad24a5794 (diff) | |
| download | lwn-0bb394067a792e7119abc9e0b7158ef19381f456.tar.gz lwn-0bb394067a792e7119abc9e0b7158ef19381f456.zip | |
spi: rockchip: Fix PM runtime count on no-op cs
The early bail out that caused an out-of-bounds write was removed with
commit 5c018e378f91 ("spi: spi-rockchip: Fix out of bounds array
access")
Unfortunately that caused the PM runtime count to be unbalanced and
underflowed on the first call. To fix that reintroduce a no-op check
by reading the register directly.
Cc: stable@vger.kernel.org
Fixes: 5c018e378f91 ("spi: spi-rockchip: Fix out of bounds array access")
Signed-off-by: Christian Loehle <christian.loehle@arm.com>
Link: https://patch.msgid.link/1f2b3af4-2b7a-4ac8-ab95-c80120ebf44c@arm.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/spi-rockchip.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c index 864e58167417..1bc012fce7cb 100644 --- a/drivers/spi/spi-rockchip.c +++ b/drivers/spi/spi-rockchip.c @@ -241,6 +241,20 @@ static void rockchip_spi_set_cs(struct spi_device *spi, bool enable) struct spi_controller *ctlr = spi->controller; struct rockchip_spi *rs = spi_controller_get_devdata(ctlr); bool cs_asserted = spi->mode & SPI_CS_HIGH ? enable : !enable; + bool cs_actual; + + /* + * SPI subsystem tries to avoid no-op calls that would break the PM + * refcount below. It can't however for the first time it is used. + * To detect this case we read it here and bail out early for no-ops. + */ + if (spi_get_csgpiod(spi, 0)) + cs_actual = !!(readl_relaxed(rs->regs + ROCKCHIP_SPI_SER) & 1); + else + cs_actual = !!(readl_relaxed(rs->regs + ROCKCHIP_SPI_SER) & + BIT(spi_get_chipselect(spi, 0))); + if (unlikely(cs_actual == cs_asserted)) + return; if (cs_asserted) { /* Keep things powered as long as CS is asserted */ |