Re: [PATCH 0/7] Raspberry Pi spi0 improvements

[Florian Fainelli <f.fainelli-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On 11/7/2018 11:06 PM, Lukas Wunner wrote:
> Here's a first batch of improvements for the spi0 master on the
> Raspberry Pi.  The meat of the series is in its last two patches:
> 
> * Patch [6/7] allows DMA for transfer buffers starting at an offset not a
>   multiple of 4.  This overcomes a limitation affecting Ethernet drivers
>   such as ks8851 which call netdev_alloc_skb_ip_align() to allocate
>   deliberately unaligned receive buffers.
> 
> * Patch [7/7] speeds up PIO transfers by not polling the RX FIFO when it
>   is known to contain data, or the TX FIFO when it is known to have free
>   space.
> 
> The preceding patches fix rarely encountered bugs, remove obsolete code
> and add documentation.
> 
> The series has been tested extensively on the "Revolution Pi" family of
> open source PLCs (https://revolution.kunbus.com/), but further testing
> would be welcome to raise the confidence.

Do you have some performance numbers that you could share before/after,
e.g: transfer latencies, number of interrupts and pure throughput?
Thanks for doing this work!
-- 
Florian