iommu/msm: Fix "scheduling while atomic" bug

In the msm iommu driver currently we incorrectly use clk_prepare_enable()
and clk_disable_unprepare() functions that are sleeping and should not be
called in atomic context. Fix this by preparing clocks in advance and use
only clk_enable() in atomic context.

Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>

diff --git a/drivers/iommu/msm_iommu.c b/drivers/iommu/msm_iommu.c
index 6ac0f58a09fedf87309474a9202748a6f0f97e3e..e6ed6cc660af98da83e6c565b1fa69192232c390 100644 (file)
--- a/drivers/iommu/msm_iommu.c
+++ b/drivers/iommu/msm_iommu.c
@@ -69,14 +69,14 @@ static int __enable_clocks(struct msm_iommu_dev *iommu)
 {
        int ret;
 
-       ret = clk_prepare_enable(iommu->pclk);
+       ret = clk_enable(iommu->pclk);
        if (ret)
                goto fail;
 
        if (iommu->clk) {
-               ret = clk_prepare_enable(iommu->clk);
+               ret = clk_enable(iommu->clk);
                if (ret)
-                       clk_disable_unprepare(iommu->pclk);
+                       clk_disable(iommu->pclk);
        }
 fail:
        return ret;
@@ -85,8 +85,8 @@ fail:
 static void __disable_clocks(struct msm_iommu_dev *iommu)
 {
        if (iommu->clk)
-               clk_disable_unprepare(iommu->clk);
-       clk_disable_unprepare(iommu->pclk);
+               clk_disable(iommu->clk);
+       clk_disable(iommu->pclk);
 }
 
 static void msm_iommu_reset(void __iomem *base, int ncb)
@@ -785,10 +785,8 @@ static int msm_iommu_probe(struct platform_device *pdev)
        int ret, par, val;
 
        iommu = devm_kzalloc(&pdev->dev, sizeof(*iommu), GFP_KERNEL);
-       if (!iommu) {
-               ret = -ENODEV;
-               goto fail;
-       }
+       if (!iommu)
+               return -ENODEV;
 
        iommu->dev = &pdev->dev;
        INIT_LIST_HEAD(&iommu->ctx_list);
@@ -796,16 +794,25 @@ static int msm_iommu_probe(struct platform_device *pdev)
        iommu->pclk = devm_clk_get(iommu->dev, "smmu_pclk");
        if (IS_ERR(iommu->pclk)) {
                dev_err(iommu->dev, "could not get smmu_pclk\n");
-               ret = PTR_ERR(iommu->pclk);
-               goto fail;
+               return PTR_ERR(iommu->pclk);
+       }
+       ret = clk_prepare(iommu->pclk);
+       if (ret) {
+               dev_err(iommu->dev, "could not prepare smmu_pclk\n");
+               return ret;
        }
 
        iommu->clk = devm_clk_get(iommu->dev, "iommu_clk");
        if (IS_ERR(iommu->clk)) {
                dev_err(iommu->dev, "could not get iommu_clk\n");
-               ret = PTR_ERR(iommu->clk);
-               iommu->pclk = NULL;
-               goto fail;
+               clk_unprepare(iommu->pclk);
+               return PTR_ERR(iommu->clk);
+       }
+       ret = clk_prepare(iommu->clk);
+       if (ret) {
+               dev_err(iommu->dev, "could not prepare iommu_clk\n");
+               clk_unprepare(iommu->pclk);
+               return ret;
        }
 
        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -830,8 +837,6 @@ static int msm_iommu_probe(struct platform_device *pdev)
        }
        iommu->ncb = val;
 
-       __enable_clocks(iommu);
-
        msm_iommu_reset(iommu->base, iommu->ncb);
        SET_M(iommu->base, 0, 1);
        SET_PAR(iommu->base, 0, 0);
@@ -841,8 +846,6 @@ static int msm_iommu_probe(struct platform_device *pdev)
        SET_V2PCFG(iommu->base, 0, 0);
        SET_M(iommu->base, 0, 0);
 
-       __disable_clocks(iommu);
-
        if (!par) {
                pr_err("Invalid PAR value detected\n");
                ret = -ENODEV;
@@ -862,9 +865,15 @@ static int msm_iommu_probe(struct platform_device *pdev)
        list_add(&iommu->dev_node, &qcom_iommu_devices);
        of_iommu_set_ops(pdev->dev.of_node, &msm_iommu_ops);
 
+       platform_set_drvdata(pdev, iommu);
+
        pr_info("device mapped at %p, irq %d with %d ctx banks\n",
                iommu->base, iommu->irq, iommu->ncb);
+
+       return 0;
 fail:
+       clk_unprepare(iommu->clk);
+       clk_unprepare(iommu->pclk);
        return ret;
 }
 
@@ -873,12 +882,22 @@ static const struct of_device_id msm_iommu_dt_match[] = {
        {}
 };
 
+static int msm_iommu_remove(struct platform_device *pdev)
+{
+       struct msm_iommu_dev *iommu = platform_get_drvdata(pdev);
+
+       clk_unprepare(iommu->clk);
+       clk_unprepare(iommu->pclk);
+       return 0;
+}
+
 static struct platform_driver msm_iommu_driver = {
        .driver = {
                .name   = "msm_iommu",
                .of_match_table = msm_iommu_dt_match,
        },
        .probe          = msm_iommu_probe,
+       .remove         = msm_iommu_remove,
 };
 
 static int __init msm_iommu_driver_init(void)