On Thu, Mar 9, 2017 at 10:35 AM, Sricharan R <sricharan@xxxxxxxxxxxxxx> wrote:
> 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.
>
> This defines the clock bindings for the same and adds the
> init, enable and disable functions for handling the
> clocks.
>
> Signed-off-by: Sricharan R <sricharan@xxxxxxxxxxxxxx>
> ---
> .../devicetree/bindings/iommu/arm,smmu.txt | 27 ++++++
> drivers/iommu/arm-smmu.c | 95 +++++++++++++++++++++-
> 2 files changed, 121 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.txt b/Documentation/devicetree/bindings/iommu/arm,smmu.txt
> index 6cdf32d..b369c13 100644
> --- a/Documentation/devicetree/bindings/iommu/arm,smmu.txt
> +++ b/Documentation/devicetree/bindings/iommu/arm,smmu.txt
> @@ -60,6 +60,28 @@ conditions.
> aliases of secure registers have to be used during
> SMMU configuration.
>
> +- clock-names: Should be "tbu_clk" and "tcu_clk" and "cfg_clk" for
> + "arm,mmu-400", "arm,mmu-401" and "arm,mmu-500"
I guess that should be: "Should be "tbu_clk" *or* "tcu_clk" and
"cfg_clk" for..."
Also, possibly we should define our own compat strings for various
SoC's that require these clks so we can properly describe when they
are required? I guess that would address Rob H's comment.
BR,
-R
> + "tcu_clk" is required for smmu's register access using the
> + programming interface and ptw for downstream bus access.
> +
> + "tbu_clk" is required for access to the TBU connected to the
> + master locally. This clock is optional and not required when
> + TBU is in the same clock domain as the TCU or when the TBU is
> + clocked along with the master.
> +
> + "cfg_clk" is optional if required to access the TCU's programming
> + interface, apart from the "tcu_clk".
> +
> +- 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) :
> @@ -84,6 +106,11 @@ conditions.
> <0 36 4>,
> <0 37 4>;
> #iommu-cells = <1>;
> + clocks = <&gcc GCC_SMMU_CFG_CLK>,
> + <&gcc GCC_APSS_TCU_CLK>,
> + <&gcc GCC_MDP_TBU_CLK>;
> +
> + clock-names = "cfg_clk", "tcu_clk", "tbu_clk";
> };
>
> /* device with two stream IDs, 0 and 7 */
> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> index f7e11d3..720a1ef 100644
> --- a/drivers/iommu/arm-smmu.c
> +++ b/drivers/iommu/arm-smmu.c
> @@ -341,6 +341,12 @@ struct arm_smmu_master_cfg {
> #define for_each_cfg_sme(fw, i, idx) \
> for (i = 0; idx = fwspec_smendx(fw, i), i < fw->num_ids; ++i)
>
> +struct mmu500_clk {
> + struct clk *cfg_clk;
> + struct clk *tcu_clk;
> + struct clk *tbu_clk;
> +};
> +
> struct arm_smmu_clks {
> void *clks;
> int (*init_clocks)(struct arm_smmu_device *smmu);
> @@ -455,6 +461,92 @@ static struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom)
> return container_of(dom, struct arm_smmu_domain, domain);
> }
>
> +static int mmu500_enable_clocks(struct arm_smmu_device *smmu)
> +{
> + int ret = 0;
> + struct mmu500_clk *sclks = smmu->smmu_clks.clks;
> +
> + if (!sclks)
> + return 0;
> +
> + ret = clk_prepare_enable(sclks->cfg_clk);
> + if (ret) {
> + dev_err(smmu->dev, "Couldn't enable cfg_clk");
> + return ret;
> + }
> +
> + ret = clk_prepare_enable(sclks->tcu_clk);
> + if (ret) {
> + dev_err(smmu->dev, "Couldn't enable tcu_clk");
> + clk_disable_unprepare(sclks->cfg_clk);
> + return ret;
> + }
> +
> + ret = clk_prepare_enable(sclks->tbu_clk);
> + if (ret) {
> + dev_err(smmu->dev, "Couln't enable tbu_clk");
> + clk_disable_unprepare(sclks->tcu_clk);
> + clk_disable_unprepare(sclks->cfg_clk);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static void mmu500_disable_clocks(struct arm_smmu_device *smmu)
> +{
> + struct mmu500_clk *sclks = smmu->smmu_clks.clks;
> +
> + if (!sclks) {
> + clk_disable_unprepare(sclks->tbu_clk);
> + clk_disable_unprepare(sclks->tcu_clk);
> + clk_disable_unprepare(sclks->cfg_clk);
> + }
> +}
> +
> +static int mmu500_init_clocks(struct arm_smmu_device *smmu)
> +{
> + struct device *dev = smmu->dev;
> + struct mmu500_clk *sclks;
> + int err;
> +
> + if (!of_find_property(dev->of_node, "clocks", NULL))
> + return 0;
> +
> + sclks = devm_kzalloc(dev, sizeof(*sclks), GFP_KERNEL);
> + if (!sclks)
> + return -ENOMEM;
> +
> + sclks->cfg_clk = devm_clk_get(dev, "cfg_clk");
> + if (IS_ERR(sclks->cfg_clk)) {
> + err = PTR_ERR(sclks->cfg_clk);
> + /* Ignore all, except -EPROBE_DEFER for optional clocks */
> + if (err == -EPROBE_DEFER)
> + return err;
> + else
> + sclks->cfg_clk = NULL;
> + }
> +
> + sclks->tcu_clk = devm_clk_get(dev, "tcu_clk");
> + if (IS_ERR(sclks->tcu_clk)) {
> + dev_err(dev, "Couldn't get tcu_clk");
> + return PTR_ERR(sclks->tcu_clk);
> + }
> +
> + sclks->tbu_clk = devm_clk_get(dev, "tbu_clk");
> + if (IS_ERR(sclks->tbu_clk)) {
> + err = PTR_ERR(sclks->tbu_clk);
> + /* Ignore all, ecept -EPROBE_DEFER for optional clocks */
> + if (err == -EPROBE_DEFER)
> + return err;
> + else
> + sclks->tbu_clk = NULL;
> + }
> +
> + smmu->smmu_clks.clks = sclks;
> + return 0;
> +}
> +
> static void parse_driver_options(struct arm_smmu_device *smmu)
> {
> int i = 0;
> @@ -1981,7 +2073,8 @@ struct arm_smmu_match_data {
> NULL, NULL, NULL);
> ARM_SMMU_MATCH_DATA(arm_mmu401, ARM_SMMU_V1_64K, GENERIC_SMMU,
> NULL, NULL, NULL);
> -ARM_SMMU_MATCH_DATA(arm_mmu500, ARM_SMMU_V2, ARM_MMU500, NULL, NULL, NULL);
> +ARM_SMMU_MATCH_DATA(arm_mmu500, ARM_SMMU_V2, ARM_MMU500, mmu500_init_clocks,
> + mmu500_enable_clocks, mmu500_disable_clocks);
> ARM_SMMU_MATCH_DATA(cavium_smmuv2, ARM_SMMU_V2, CAVIUM_SMMUV2,
> NULL, NULL, NULL);
>
> --
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
>
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