Commit 45c2fdde authored Mar 07, 2017 by Thomas Petazzoni Committed by Herbert Xu Mar 08, 2017

hwrng: omap - write registers after enabling the clock



Commit 38321242 ("hwrng: omap - Add device variant for SafeXcel
IP-76 found in Armada 8K") added support for the SafeXcel IP-76 variant
of the IP. This modification included getting a reference and enabling a
clock. Unfortunately, this was done *after* writing to the
RNG_INTMASK_REG register. This generally works fine when the driver is
built-in because the clock might have been left enabled by the
bootloader, but fails short when the driver is built as a module: it
causes a system hang because a register is being accessed while the
clock is not enabled.

This commit fixes that by making the register access *after* enabling
the clock.

This issue was found by the kernelci.org testing effort.

Fixes: 38321242 ("hwrng: omap - Add device variant for SafeXcel IP-76 found in Armada 8K")
Cc: <stable@vger.kernel.org>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

parent 07de4bc8

drivers/char/hw_random/omap-rng.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -397,7 +397,6 @@ static int of_get_omap_rng_device_details(struct omap_rng_dev *priv,
		irq, err);
		return err;
		}
		omap_rng_write(priv, RNG_INTMASK_REG, RNG_SHUTDOWN_OFLO_MASK);

		priv->clk = of_clk_get(pdev->dev.of_node, 0);
		if (IS_ERR(priv->clk) && PTR_ERR(priv->clk) == -EPROBE_DEFER)
		@@ -408,6 +407,8 @@ static int of_get_omap_rng_device_details(struct omap_rng_dev *priv,
		dev_err(&pdev->dev, "unable to enable the clk, "
		"err = %d\n", err);
		}

		omap_rng_write(priv, RNG_INTMASK_REG, RNG_SHUTDOWN_OFLO_MASK);
		}
		return 0;
		}