Re: [PATCH] r8169: fix broken register writes

[David Miller <davem@davemloft.net>]

From: François Romieu <romieu@fr.zoreil.com>
Date: Sun, 28 Mar 2010 01:31:43 +0100

> This is quite similar to b39fe41f481d20c201012e4483e76c203802dda7
> though said registers are not even documented as 64-bit registers
> - as opposed to the initial TxDescStartAddress ones - but as single
> bytes which must be combined into 32 bits at the MMIO read/write
> level before being merged into a 64 bit logical entity.
> 
> Credits go to Ben Hutchings <ben@decadent.org.uk> for the MAR
> registers (aka "multicast is broken for ages on ARM) and to
> Timo Teräs <timo.teras@iki.fi> for the MAC registers.
> 
> Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>

Applied, thanks Francois.

Probably the rest of the driver should be audited for other
areas where we may end up having this problem.

Or, we should create readq/writeq macros (like other drivers do on
32-bit platforms, f.e. see drivers/net/niu.c) which write the two
32-bit parts in this required order.  Then access the registers using
readq/writeq entities throughout the driver.

This would have two benefits:

1) Coverage for all possible bug cases.

2) Real 64-bit accesses on 64-bit platforms.

Just some suggestions.

Thanks.