MIPS: Loongson64: Remove not used pci.c

[linux-2.6-microblaze.git] / drivers / perf / fsl_imx8_ddr_perf.c

diff --git a/drivers/perf/fsl_imx8_ddr_perf.c b/drivers/perf/fsl_imx8_ddr_perf.c
index 95dca2c..90884d1 100644 (file)
--- a/drivers/perf/fsl_imx8_ddr_perf.c
+++ b/drivers/perf/fsl_imx8_ddr_perf.c
@@ -388,9 +388,10 @@ static void ddr_perf_counter_enable(struct ddr_pmu *pmu, int config,
 
        if (enable) {
                /*
-                * must disable first, then enable again
-                * otherwise, cycle counter will not work
-                * if previous state is enabled.
+                * cycle counter is special which should firstly write 0 then
+                * write 1 into CLEAR bit to clear it. Other counters only
+                * need write 0 into CLEAR bit and it turns out to be 1 by
+                * hardware. Below enable flow is harmless for all counters.
                 */
                writel(0, pmu->base + reg);
                val = CNTL_EN | CNTL_CLEAR;
@@ -398,7 +399,8 @@ static void ddr_perf_counter_enable(struct ddr_pmu *pmu, int config,
                writel(val, pmu->base + reg);
        } else {
                /* Disable counter */
-               writel(0, pmu->base + reg);
+               val = readl_relaxed(pmu->base + reg) & CNTL_EN_MASK;
+               writel(val, pmu->base + reg);
        }
 }