| From 45c2fdde01299b02a6e3225e848598a3c1e55539 Mon Sep 17 00:00:00 2001 |
| From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> |
| Date: Tue, 7 Mar 2017 15:14:46 +0100 |
| Subject: hwrng: omap - write registers after enabling the clock |
| |
| From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> |
| |
| commit 45c2fdde01299b02a6e3225e848598a3c1e55539 upstream. |
| |
| Commit 383212425c926 ("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: 383212425c926 ("hwrng: omap - Add device variant for SafeXcel IP-76 found in Armada 8K") |
| Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> |
| Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/char/hw_random/omap-rng.c | 3 ++- |
| 1 file changed, 2 insertions(+), 1 deletion(-) |
| |
| --- a/drivers/char/hw_random/omap-rng.c |
| +++ b/drivers/char/hw_random/omap-rng.c |
| @@ -397,7 +397,6 @@ static int of_get_omap_rng_device_detail |
| 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_detail |
| 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; |
| } |