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SubjectRe: [PATCH V4 5/6] iommu/arm-smmu: Add support for MMU40x/500 clocks
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Hi Rob,


On 07/10/2017 09:07 AM, Rob Herring wrote:
> On Thu, Jul 06, 2017 at 03:07:04PM +0530, Vivek Gautam wrote:
>> From: Sricharan R<sricharan@codeaurora.org>
>>
>> The MMU400x/500 is the implementation of the SMMUv2
>> arch specification. It is split in to two blocks
>> TBU, TCU. TBU caches the page table, instantiated
>> for each master locally, clocked by the TBUn_clk.
>> TCU manages the address translation with PTW and has
>> the programming interface as well, clocked using the
>> TCU_CLK. The TBU can also be sharing the same clock
>> domain as TCU, in which case both are clocked using
>> the TCU_CLK.
> No TBU clock below. When is it shared or not? If that's an integration
> option then the binding should always have a TBU clock with the same
> parent as the TCU_CLK.

Right. This is something that the ARM spec also says.
The TBU clock can either be in the same clock and power domain as
the TCU clock, or in a separate.

As you said, we should have the TBU clock as well, and based on the
integration the TBU clock can either have same parent as TCU or
different.

I will change these bindings to include the TBU clock as well.


Best Regards
Vivek

>> This defines the clock bindings for the same and adds
>> the clock names to compatible data.
>>
>> Signed-off-by: Sricharan R<sricharan@codeaurora.org>
>> [vivek: clock rework and cleanup]
>> Signed-off-by: Vivek Gautam<vivek.gautam@codeaurora.org>
>> ---
>> .../devicetree/bindings/iommu/arm,smmu.txt | 24 ++++++++++++++++++++++
>> drivers/iommu/arm-smmu.c | 12 ++++++++++-
>> 2 files changed, 35 insertions(+), 1 deletion(-)
>>
>> diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.txt b/Documentation/devicetree/bindings/iommu/arm,smmu.txt
>> index 8a6ffce12af5..00331752d355 100644
>> --- a/Documentation/devicetree/bindings/iommu/arm,smmu.txt
>> +++ b/Documentation/devicetree/bindings/iommu/arm,smmu.txt
>> @@ -71,6 +71,26 @@ conditions.
>> or using stream matching with #iommu-cells = <2>, and
>> may be ignored if present in such cases.
>>
>> +- clock-names: Should be "tcu" and "iface" for "arm,mmu-400",
>> + "arm,mmu-401" and "arm,mmu-500"
>> +
>> + "tcu" clock is required for smmu's register access using the
>> + programming interface and ptw for downstream bus access. This
>> + clock is also used for access to the TBU connected to the
>> + master locally. Sometimes however, TBU is clocked along with
>> + the master.
>> +
>> + "iface" clock is required to access the TCU's programming
>> + interface, apart from the "tcu" clock.
>> +
>> +- clocks: Phandles for respective clocks described by clock-names.
>> +
>> +- power-domains: Phandles to SMMU's power domain specifier. This is
>> + required even if SMMU belongs to the master's power
>> + domain, as the SMMU will have to be enabled and
>> + accessed before master gets enabled and linked to its
>> + SMMU.
>> +
>> ** Deprecated properties:
>>
>> - mmu-masters (deprecated in favour of the generic "iommus" binding) :
>> @@ -95,6 +115,10 @@ conditions.
>> <0 36 4>,
>> <0 37 4>;
>> #iommu-cells = <1>;
>> + clocks = <&gcc GCC_SMMU_CFG_CLK>,
>> + <&gcc GCC_APSS_TCU_CLK>;
>> +
>> + clock-names = "iface", "tcu";
>> };
>>
>> /* device with two stream IDs, 0 and 7 */
>> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
>> index 75567d9698ab..7bb09280fa11 100644
>> --- a/drivers/iommu/arm-smmu.c
>> +++ b/drivers/iommu/arm-smmu.c
>> @@ -1947,9 +1947,19 @@ struct arm_smmu_match_data {
>> ARM_SMMU_MATCH_DATA(smmu_generic_v1, ARM_SMMU_V1, GENERIC_SMMU);
>> ARM_SMMU_MATCH_DATA(smmu_generic_v2, ARM_SMMU_V2, GENERIC_SMMU);
>> ARM_SMMU_MATCH_DATA(arm_mmu401, ARM_SMMU_V1_64K, GENERIC_SMMU);
>> -ARM_SMMU_MATCH_DATA(arm_mmu500, ARM_SMMU_V2, ARM_MMU500);
>> ARM_SMMU_MATCH_DATA(cavium_smmuv2, ARM_SMMU_V2, CAVIUM_SMMUV2);
>>
>> +static const char * const arm_mmu500_clks[] = {
>> + "tcu", "iface",
>> +};
>> +
>> +static const struct arm_smmu_match_data arm_mmu500 = {
>> + .version = ARM_SMMU_V2,
>> + .model = ARM_MMU500,
>> + .clks = arm_mmu500_clks,
>> + .num_clks = ARRAY_SIZE(arm_mmu500_clks),
>> +};
>> +
>> static const struct of_device_id arm_smmu_of_match[] = {
>> { .compatible = "arm,smmu-v1", .data = &smmu_generic_v1 },
>> { .compatible = "arm,smmu-v2", .data = &smmu_generic_v2 },
>> --
>> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
>> a Linux Foundation Collaborative Project
>>
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