linux-kernel - Re: [PATCH] watchdog, SP5100: Check if firmware has set correct value in tcobase.

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Date:	Wed, 16 Mar 2011 22:23:31 -0400
From:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To:	Yinghai Lu <yinghai@...nel.org>
Cc:	Mike Waychison <mikew@...gle.com>,
	Wim Van Sebroeck <wim@...ana.be>,
	Stefano Stabellini <stefano.stabellini@...citrix.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Jeremy Fitzhardinge <jeremy@...p.org>,
	"xen-devel@...ts.xensource.com" <xen-devel@...ts.xensource.com>,
	linux-watchdog@...r.kernel.org,
	Priyanka Gupta <priyankag@...gle.com>
Subject: Re: [PATCH] watchdog, SP5100: Check if firmware has set correct
 value in tcobase.

On Wed, Mar 16, 2011 at 02:18:17PM -0700, Yinghai Lu wrote:
> 
> 
> Stefano found SP5100 TCO watchdog driver using wrong address.
> 
> [    9.148536] SP5100 TCO timer: SP5100 TCO WatchDog Timer Driver v0.01
> [    9.148628] DEBUG __ioremap_caller WARNING address=b8fe00 size=8 valid=1 reserved=1
> 
> and e820 said that range is RAM.
> 
> We should check if we can use that reading out. BIOS could just program wrong address there.
> 
> -v2: Mike pointed out one path need one release.
> 
> Reported-by: Stefano Stabellini <stefano.stabellini@...citrix.com>
> Signed-off-by:Yinghai Lu <yinghai@...nel.org>
> Acked-by: Mike Waychison <mikew@...gle.com>

I have no idea why it worked the first time b/c this:


> +	if (request_mem_region_exclusive(val, SP5100_WDT_MEM_MAP_SIZE, "SP5100 TCO")) {

is wrong. It should have been "if (!request...")..

With that, and with Stefano's patches (stefano/2.6.38-rc6-mm-fix) on top of 2.6.39-rc0 it boots up fine.

Excerpt from the log:

[    0.000000] DEBUG find_early_table_space: _text=1000000 _end=1e33000 pgtable_start=9fc000 pgtable_end=9fc000
[    0.000000] DEBUG find_early_table_space: _text=1000000 _end=1e33000 pgtable_start=beba5000 pgtable_end=beba5000
[    9.064064] calling  sp5100_tco_init_module+0x0/0x1000 [sp5100_tco] @ 507
[    9.064067] SP5100 TCO timer: SP5100 TCO WatchDog Timer Driver v0.01
[    9.064180] SP5100 TCO timer: mmio address 0xb8fe00 already in use
[    9.064201] initcall sp5100_tco_init_module+0x0/0x1000 [sp5100_tco] returned 0 after 126 usecs

Attached is the full log if folks are curious.

View attachment "d" of type "text/plain" (260944 bytes)