Unverified Commit 0bb39406 authored by Christian Loehle's avatar Christian Loehle Committed by Mark Brown
Browse files

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 5c018e37 ("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: 5c018e37 ("spi: spi-rockchip: Fix out of bounds array access")
Signed-off-by: default avatarChristian Loehle <christian.loehle@arm.com>
Link: https://patch.msgid.link/1f2b3af4-2b7a-4ac8-ab95-c80120ebf44c@arm.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent c84dda37

drivers/spi/spi-rockchip.c

+14 −0
Original line number Diff line number Diff line
@@ -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 */