Re: [PATCH v2 2/2] hwrng: iproc-rng200 - Add Broadcom IPROC RNG driver

[Arnd Bergmann]

On Saturday 28 February 2015 08:01:11 Scott Branden wrote:
> > The udelay(10) that the other drivers have seems about appropriate then,
> > and we can independently think of a way to refine the interface.
> > Please add a comment that explains the rate. Also, is there some kind
> > of FIFO present in the hwrng device? If it can store close to 1ms work
> > of data (1000 bits), you can just use an msleep(1) to wait for the
> > pool to recover.
> FIFO is 512 bits.  I will look as to whether we can live with 1/2 
> throughput.

In that case, I think usleep_range(min(len * 8, 500), 500)) would be
a good compromise: it waits at most until the fifo is full, but might
return earlier if enough bits are available to fulfill the request.

	Arnd
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