From 2a4bfd023fa97c70006ab368c30c0bf84d0e905d Mon Sep 17 00:00:00 2001 From: Daniel Mack Date: Sat, 31 Aug 2019 13:55:55 +0200 Subject: hwrng: timeriomem - relax check on memory resource size The timeriomem_rng driver only accesses the first 4 bytes of the given memory area and currently, it also forces that memory resource to be exactly 4 bytes in size. This, however, is problematic when used with device-trees that are generated from things like FPGA toolchains, where the minimum size of an exposed memory block may be something like 4k. Hence, let's only check for what's needed for the driver to operate properly; namely that we have enough memory available to read the random data from. Signed-off-by: Daniel Mack Signed-off-by: Herbert Xu --- Documentation/devicetree/bindings/rng/timeriomem_rng.txt | 2 +- drivers/char/hw_random/timeriomem-rng.c | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/Documentation/devicetree/bindings/rng/timeriomem_rng.txt b/Documentation/devicetree/bindings/rng/timeriomem_rng.txt index 214940093b55..fb4846160047 100644 --- a/Documentation/devicetree/bindings/rng/timeriomem_rng.txt +++ b/Documentation/devicetree/bindings/rng/timeriomem_rng.txt @@ -12,7 +12,7 @@ Optional properties: which disables using this rng to automatically fill the kernel's entropy pool. -N.B. currently 'reg' must be four bytes wide and aligned +N.B. currently 'reg' must be at least four bytes wide and 32-bit aligned Example: diff --git a/drivers/char/hw_random/timeriomem-rng.c b/drivers/char/hw_random/timeriomem-rng.c index ccd1f6e0696b..e262445fed5f 100644 --- a/drivers/char/hw_random/timeriomem-rng.c +++ b/drivers/char/hw_random/timeriomem-rng.c @@ -117,9 +117,9 @@ static int timeriomem_rng_probe(struct platform_device *pdev) if (!res) return -ENXIO; - if (res->start % 4 != 0 || resource_size(res) != 4) { + if (res->start % 4 != 0 || resource_size(res) < 4) { dev_err(&pdev->dev, - "address must be four bytes wide and aligned\n"); + "address must be at least four bytes wide and 32-bit aligned\n"); return -EINVAL; } -- cgit v1.2.3