• Daniel Thompson's avatar
    hwrng: core - Improve description of the ->read() interface · ed0bd721
    Daniel Thompson authored
    Currently, very few RNG drivers support single byte reads using the
    ->read() interface. Of the 14 drivers in drivers/char/hw_random that
    support this interface only three of these actually support max == 1.
    The other behaviours vary between return 0, return 2, return 4 and return
    -EIO).
    
    This is not a problem in practice because the core hw_random code never
    performs a read shorter than 16 bytes. The documentation for this function
    already contrains the alignment of the buffer pointer, so let's also
    guarantee that the buffer is at least as large as its alignment.
    
    This constraint is intended to be the weakest guarantee neccessary to
    allow driver writers to safely simplify their code.
    Signed-off-by: default avatarDaniel Thompson <daniel.thompson@linaro.org>
    Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
    ed0bd721
hw_random.h 2.2 KB