On 07/29/2013 05:27 AM, Hiroshi Doyu wrote:
> Stephen Warren <swarren@xxxxxxxxxxxxx> wrote @ Thu, 18 Jul 2013 22:17:21 +0200:
>
>> On 07/05/2013 04:44 AM, Hiroshi Doyu wrote:
>>> Register platform_devices to IOMMU dynamically via
>>> ops->{add,remove}_device().
>>
>>> diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
>>
>>> +/*
>>> + * ASID[0] for the system default
>>> + * ASID[1] for PPCS, which has SDMMC
>>
>> I have no idea what PPCS is. The patch description for 21/22 implies
>> much more than SDMMC is "in PPCS"...
>
> "PPCS" is all AHB bus children/(client).
Just to be clear: I was hoping that the comment would be fixed.
>>> + * ASID[2][3].. open for drivers, first come, first served.
>>> + */
>>> +enum {
>>> + SYSTEM_DEFAULT,
>>> + SYSTEM_PROTECTED,
>>> +};
>>
>> Why hard-code this mapping? Can't devices be assigned to ASIDs based on
>> a DT property? I assume there's nothing in the SMMU HW that requires
>> specific ASIDs to be used?
>
> Right. Where should those policy be passed, board DT files?
Is the HW module (== SW group?) to ASID mapping policy or is a
particular mapping required by HW?
Can the ASID mapping just happen dynamically in SW rather than DT
dictating a particular mapping?
I assume the mapping must be set up before any HW is used, and can't be
modified later, so there's no much chance of deferring any policy
decisions to user-space etc.?
--
To unsubscribe from this list: send the line "unsubscribe linux-tegra" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
