[PATCHv4 1/7] ARM: tegra: Create a DT header defining SWGROUP ID

On 11/15/2013 03:29 AM, Hiroshi Doyu wrote:

On Tue, 12 Nov 2013 23:48:22 +0100
Stephen Warren [off-list ref] wrote:

quoted

On 11/11/2013 01:31 AM, Hiroshi Doyu wrote:

quoted

Create a header file to define the swgroup IDs used by the IOMMU(SMMU)
binding. "swgroup" is a group of H/W clients which a Tegra SoC
supports. This unique ID can be used to calculate MC_SMMU_<swgroup
name>_ASID_0 register offset and MC_<swgroup name>_HOTRESET_*_0
register bit. 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. For HOTRESET
bit shifting we need another conversion table, which will come later.

quoted

diff --git a/include/dt-bindings/memory/tegra-swgroup.h b/include/dt-bindings/memory/tegra-swgroup.h

quoted

+#define TEGRA_SWGROUP_PPCS2	32	/* 0xab0 */
+
+#define TEGRA_SWGROUP_MAX	64
+
+#define TEGRA_SWGROUP_BIT(x)	(1ULL << TEGRA_SWGROUP_##x)

If I put the following into a DT and compile it:

#define TEGRA_SWGROUP_PPCS2	32	/* 0xab0 */
#define TEGRA_SWGROUP_BIT(x)	(1ULL << TEGRA_SWGROUP_##x)
/ {
	test-prop = <(TEGRA_SWGROUP_BIT(PPCS2))>;
};

I get:

Error: arch/arm/boot/dts/tegra20.dtsi:11.28-29 integer value out of
range 0000000000000020 (32 bits)
FATAL ERROR: Syntax error parsing input tree

Is TEGRA_SWGROUP_BIT() not meant to be used in DT files? If it is, the
definition is broken. If it is not, it should be defined in the driver
not the header, since DT files have no use for it.

I'd like to use the macro in DT but what I want is 2 cells from 64 bit.
For the above example, I want the following 2 cell to be generated but I
haven't found any ways yet.

#define TEGRA_SWGROUP_PPCS2	32	/* 0xab0 */
#define TEGRA_SWGROUP_BIT(x)	(1ULL << TEGRA_SWGROUP_##x)
/ {
 	test-prop = <0x00000000 0x00000001>;
};

I guess you'd need to do something like:

#define MSW_OF_U64(x) ((x) >> 32)
#define LSW_OF_U64(x) ((x) & 0xffffffff)

... and use those to construct the two cells explicitly.

Or, explicitly name TEGRA_SWGROUP_xxx so that it's obvious which go in
the MSW and which in the LSW, and then:

#define TEGRA_SWGROUP_BIT(x)	(1ULL << (TEGRA_SWGROUP_##x % 32))

It might also be possible to do:

#define TWO_U32_OF_U64(x) ((x) >> 32) ((x) & 0xffffffff)

... which expands to both cells at once, although that's verging on
hiding DT structure behind a macro, which isn't exceptionally great, but
might be acceptable in this limited case.