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2a4bfd023f
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 <daniel@zonque.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
26 lines
771 B
Plaintext
26 lines
771 B
Plaintext
HWRNG support for the timeriomem_rng driver
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Required properties:
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- compatible : "timeriomem_rng"
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- reg : base address to sample from
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- period : wait time in microseconds to use between samples
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Optional properties:
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- quality : estimated number of bits of true entropy per 1024 bits read from the
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rng. Defaults to zero which causes the kernel's default quality to
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be used instead. Note that the default quality is usually zero
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which disables using this rng to automatically fill the kernel's
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entropy pool.
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N.B. currently 'reg' must be at least four bytes wide and 32-bit aligned
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Example:
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hwrng@44 {
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#address-cells = <1>;
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#size-cells = <1>;
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compatible = "timeriomem_rng";
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reg = <0x44 0x04>;
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period = <1000000>;
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};
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