[PATCH 3/3] [PATCH][i.MX6Q]Removed MMDC Auto Power saving timeout error

[Nitin Chaudhary]

Moved the busy loop to check MMDC0_MAPSR bit[4] for MMDC Automatic
power saving mode enable to a deferred kernel workqueue ~5s after
probe. Now the check passes successfully and no failure logs are
seen. The power numbers are also lower on the board. The below are
relevant dmesg outputs:

root at RDU2:~ dmesg | grep -i mmdc
[    0.132669] imx-mmdc 21b0000.mmdc: No access to interrupts, using timer.
[    0.132775] imx-mmdc 21b0000.mmdc: imx_mmdc_probe success
[    5.210514] is_mmdc_auto_powersave: MMDC auto power saving enabled MAPSR: 0x00001076

Signed-off-by: Nitin Chaudhary <Nitin.Chaudhary at zii.aero>
---
 arch/arm/mach-imx/mmdc.c | 43 +++++++++++++++++++++++++++----------------
 1 file changed, 27 insertions(+), 16 deletions(-)

diff --git a/arch/arm/mach-imx/mmdc.c b/arch/arm/mach-imx/mmdc.c
index 45790f5..9f27814 100644
--- a/arch/arm/mach-imx/mmdc.c
+++ b/arch/arm/mach-imx/mmdc.c
@@ -80,6 +80,7 @@ struct mmdc_pmu
        struct hrtimer hrtimer;
        unsigned int irq;
        struct device *dev;
+       struct delayed_work init_work;
        struct perf_event *mmdc_events[MMDC_NUM_COUNTERS];
 };

@@ -149,6 +150,27 @@ static const struct attribute_group * attr_groups[] = {
        NULL,
 };

+static void is_mmdc_auto_powersave(struct work_struct *work)
+{
+
+       void __iomem *mmdc_base, *reg;
+       int timeout = 0x400;
+       mmdc_base = pmu_mmdc->mmdc_base;
+       reg = mmdc_base + MMDC_MAPSR;
+
+       /* Ensure Automatic Power saving mode is successfully enabled */
+       while (!(readl_relaxed(reg) & 1 << BP_MMDC_MAPSR_PSS) && --timeout)
+               cpu_relax();
+
+       if (unlikely(!timeout)) {
+               pr_warn("%s: failed to enable automatic power saving, recheck\n",
+                       __func__);
+       } else {
+               pr_info("%s: MMDC auto power saving enabled MAPSR: 0x%08x\n",
+                       __func__);
+       }
+}
+
 static u32 mmdc_read_counter(int cfg, u64 prev_val)
 {
        u32 val;
@@ -348,7 +370,6 @@ static int imx_mmdc_probe(struct platform_device *pdev)
        void __iomem *mmdc_base, *reg;
        char * name;
        u32 val;
-       int timeout = 0x800;
        int mmdc_num;
        int err;

@@ -368,20 +389,6 @@ static int imx_mmdc_probe(struct platform_device *pdev)
        val &= ~(1 << BP_MMDC_MAPSR_PSD);
        writel_relaxed(val, reg);

-       /* Ensure it's successfully enabled */
-       while (!(readl_relaxed(reg) & 1 << BP_MMDC_MAPSR_PSS) && --timeout)
-               cpu_relax();
-
-       if (unlikely(!timeout)) {
-               pr_warn("%s: failed to enable automatic power saving\n",
-                       __func__);
-
-               /*
-                * TODO: Need to check why Automatic Power saving is not
-                * getting enabled successfully.
-                * return -EBUSY;
-                */
-       }
        pmu_mmdc = kzalloc(sizeof(*pmu_mmdc), GFP_KERNEL);

        if (!pmu_mmdc) {
@@ -409,7 +416,11 @@ static int imx_mmdc_probe(struct platform_device *pdev)
        }
        platform_set_drvdata(pdev, pmu_mmdc);
        perf_pmu_register(&(pmu_mmdc->pmu), name, -1);
-
+
+       /* Check if automatic Power saving mode was enabled */
+       INIT_DELAYED_WORK(&pmu_mmdc->init_work, is_mmdc_auto_powersave);
+       schedule_delayed_work(&pmu_mmdc->init_work, msecs_to_jiffies(5000));
+
        dev_info(pmu_mmdc->dev, "%s success\n",__func__);

        return 0;
--
2.7.4


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