On 07/29/2013 04:53 AM, Hiroshi Doyu wrote: > Stephen Warren <swarren@xxxxxxxxxxxxx> wrote @ Wed, 17 Jul 2013 01:07:12 +0200: > >> On 07/05/2013 04:44 AM, Hiroshi Doyu wrote: >>> Create a header file to define the swgroup IDs used by the IOMMU(SMMU) >>> binding. "swgroup" is a group of H/W clients in Tegra SoC from S/W POV. >>> >>> This will allow the same header to be used by both device tree files, >>> and drivers implementing this binding, which guarantees that the two >>> stay in sync. This also makes device trees more readable by using names >>> instead of magic numbers. >> >> Why does the driver need these constants; shouldn't it simply support >> 0..n SW group IDs that all work the same way? Or, is there some reason >> for it to know the identities? >> >>> diff --git a/include/dt-bindings/memory/tegra-swgroup.h b/include/dt-bindings/memory/tegra-swgroup.h >> >> s/memory/iommu/? > > This info would be used in PMC code as well, which H/W belongs to > which swgroup. So I use the term "memory(-client)" instead of "iommu". Why does the PMC care? An explanation of exactly what SW needs to know about these groups and why would be a good idea. >> s/tegra-swgroup.h/tegra-smmu.h/? > > Is "tegra-memory-clients.h" preferable, then? Perhaps, although aren't these IDs specific to the connection between modules and the SMMU? Or, are these IDs some more global concept; the HW modules in question pass the same IDs to both the SMMU and to other HW modules for some reason? >>> +#define TEGRA_SWGROUP_BIT(x) (1ULL << TEGRA_SWGROUP_##x) >>> + >>> +#define TEGRA30_SWGROUP_ALL <0x00000000 0x000779ff> >>> +#define TEGRA114_SWGROUP_ALL <0x00000000 0x01b659fe> >> >> Are those 3 values needed by DT files, or just the driver? > > Only from DT. If the values are only needed to write the DT content, I'd tend to prefer not defining them in a header in <dt-bindings/>; I consider that directory a definition of the constants that define the ABI itself, not as a random place to put useful things for DT. You can include headers in the *.dts directory itself. -- 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
