[PATCH] ARM: OMAP4: execute initcall to reserve SRAM for I688 only on OMAP4

Grygorii Strashko grygorii.strashko at ti.com
Mon Nov 30 10:27:33 PST 2015

On 11/30/2015 07:27 PM, Lucas Stach wrote:
> Am Montag, den 16.11.2015, 14:24 +0200 schrieb Grygorii Strashko:
>> On 11/16/2015 01:25 PM, Lucas Stach wrote:
>>> omap_interconnect_sync() is the only user of the SRAM scratch area
>>> allocated in the omap4_sram_init initcall. The interconnect sync is
>>> used exclusively in the OMAP4 specific WFI implementation, so there
>>> is no point in allocating the SRAM scratch on other SoC types.
>>> Bail out of the initcall if the kernel is not running on OMAP4 to
>>> avoid a confusing warning about being unable to allocate the SRAM
>>> needed for I688 handling.
>>> Signed-off-by: Lucas Stach <l.stach at pengutronix.de>
>>> Tested-by: Bastian Stender <bst at pengutronix.de>
>>> ---
>>>    arch/arm/mach-omap2/omap4-common.c | 3 +++
>>>    1 file changed, 3 insertions(+)
>>> diff --git a/arch/arm/mach-omap2/omap4-common.c b/arch/arm/mach-omap2/omap4-common.c
>>> index 949696b6f17b..6db393a30a28 100644
>>> --- a/arch/arm/mach-omap2/omap4-common.c
>>> +++ b/arch/arm/mach-omap2/omap4-common.c
>>> @@ -131,6 +131,9 @@ static int __init omap4_sram_init(void)
>>>    	struct device_node *np;
>>>    	struct gen_pool *sram_pool;
>>> +	if (!cpu_is_omap44xx())
>>> +		return 0;
>> This one affects on am43xx also
> So you are saying this erratum is also present on AM43xx? I wasn't able
> to deduce this from the information provided by Richard Woodruff.

"..SOCs using similar chassis components of OMAP4430 time are impacted..."
"..But AM335x should be immune from this particular issue..."

Advisory 11 Asynchronous Bridge Corruption

>>> +
>>>    	np = of_find_compatible_node(NULL, NULL, "ti,omap4-mpu");
>>>    	if (!np)
>>>    		pr_warn("%s:Unable to allocate sram needed to handle errata I688\n",
>> Since all OMAP4+ platforms are now DT based why can't we just return from here silently?
> If we are unable to allocate the SRAM needed to work around I688 this is
> a real error on platforms that expose this erratum, so silently bailing
> out at this point may obscure a real issue.

SRAM is not allocated here - It's just check to understand do we need it or not
in case of multiplatform build where CONFIG_OMAP_INTERCONNECT_BARRIER will be selected most

And if "ti,omap4-mpu" was not found - it just means that this, particular, platform
is not affected by i688 errata.
If someone misses corresponding node in DT - we can't do nothing :)


More information about the linux-arm-kernel mailing list