[PATCH 5.12 220/296] spi: take the SPI IO-mutex in the spi_set_cs_timing method

Greg Kroah-Hartman
2021-05-31T16:40:50Z

From: Leilk Liu <leilk.liu@mediatek.com>

[ Upstream commit dc5fa590273890a8541ce6e999d606bfb2d73797 ]

this patch takes the io_mutex to prevent an unprotected HW
register modification in the set_cs_timing callback.

Fixes: 4cea6b8cc34e ("spi: add power control when set_cs_timing")
Signed-off-by: Leilk Liu <leilk.liu@mediatek.com>
Link: https://lore.kernel.org/r/20210508060214.1485-1-leilk.liu@mediatek.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/spi/spi.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 8da4fe475b84..5495138c257e 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -3463,9 +3463,12 @@ int spi_set_cs_timing(struct spi_device *spi, struct spi_delay *setup,

if (spi->controller->set_cs_timing &&
!(spi->cs_gpiod || gpio_is_valid(spi->cs_gpio))) {
+ mutex_lock(&spi->controller->io_mutex);
+
if (spi->controller->auto_runtime_pm) {
status = pm_runtime_get_sync(parent);
if (status < 0) {
+ mutex_unlock(&spi->controller->io_mutex);
pm_runtime_put_noidle(parent);
dev_err(&spi->controller->dev, "Failed to power device: %d\n",
status);
@@ -3476,11 +3479,13 @@ int spi_set_cs_timing(struct spi_device *spi, struct spi_delay *setup,
hold, inactive);
pm_runtime_mark_last_busy(parent);
pm_runtime_put_autosuspend(parent);
- return status;
} else {
- return spi->controller->set_cs_timing(spi, setup, hold,
+ status = spi->controller->set_cs_timing(spi, setup, hold,
inactive);
}
+
+ mutex_unlock(&spi->controller->io_mutex);
+ return status;
}

if ((setup && setup->unit == SPI_DELAY_UNIT_SCK) ||
--
2.30.2