Re: [PATCH v2 2/2] hwrng: iproc-rng200 - Add Broadcom IPROC RNG driver
From: Scott Branden
Date: Mon Mar 02 2015 - 14:41:56 EST
Hi Arnd,
Thanks for the suggested change.
On 15-02-28 11:31 AM, Arnd Bergmann wrote:
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.
OK, will change in next version.
Arnd
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