[PATCHv3 2/2] iommu/arm-smmu: Add SMMU clock

thor.thayer
2018-10-03T22:26:06Z

Add a clock to the SMMU structure. In the device tree case,
check for a clock node and enable the clock if found.

This patch is dependent upon the following patches that add
a device tree bulk clock function.
"[V6, 1/4] clk: bulk: add of_clk_bulk_get()"
https://patchwork.kernel.org/patch/10583133/
"[V6, 2/4] clk: add new APIs to operation on all available
clocks"
https://patchwork.kernel.org/patch/10583131/
"[V6, 3/4] clk: add managerged version of clk_bulk_get_all"
https://patchwork.kernel.org/patch/10583139/

Signed-off-by: Thor Thayer <thor.thayer@linux.intel.com>
---
drivers/iommu/arm-smmu.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 5a28ae892504..0f4596b42ca7 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -213,6 +213,8 @@ struct arm_smmu_device {

/* IOMMU core code handle */
struct iommu_device iommu;
+ int num_clks;
+ struct clk_bulk_data *clks;
};

enum arm_smmu_context_fmt {
@@ -2038,6 +2040,17 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev,
const struct arm_smmu_match_data *data;
struct device *dev = &pdev->dev;
bool legacy_binding;
+ int ret;
+
+ /* If a clock is declared, enable it */
+ ret = devm_clk_bulk_get_all(smmu->dev, &smmu->clks);
+ if (IS_ERR(ret)) {
+ smmu->clks = NULL;
+ dev_dbg(dev, "cannot get smmu clock\n");
+ } else {
+ smmu->num_clks = ret;
+ clk_bulk_prepare_enable(smmu->num_clks, smmu->clks);
+ }

if (of_property_read_u32(dev->of_node, "#global-interrupts",
&smmu->num_global_irqs)) {
@@ -2236,6 +2249,10 @@ static int arm_smmu_device_remove(struct platform_device *pdev)

/* Turn the thing off */
writel(sCR0_CLIENTPD, ARM_SMMU_GR0_NS(smmu) + ARM_SMMU_GR0_sCR0);
+
+ if (smmu->clks)
+ clk_bulk_disable_unprepare(smmu->num_clks, smmu->clks);
+
return 0;
}

@@ -2248,6 +2265,9 @@ static int __maybe_unused arm_smmu_pm_resume(struct device *dev)
{
struct arm_smmu_device *smmu = dev_get_drvdata(dev);

+ if (smmu->clks)
+ clk_bulk_prepare_enable(smmu->num_clks, smmu->clks);
+
arm_smmu_device_reset(smmu);
return 0;
}
--
2.7.4