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-rw-r--r--arch/arm/mach-imx/cpu-imx5.c45
1 files changed, 45 insertions, 0 deletions
diff --git a/arch/arm/mach-imx/cpu-imx5.c b/arch/arm/mach-imx/cpu-imx5.c
index 4f2d1c772f85..e210bac18840 100644
--- a/arch/arm/mach-imx/cpu-imx5.c
+++ b/arch/arm/mach-imx/cpu-imx5.c
@@ -117,3 +117,48 @@ int mx53_revision(void)
return mx5_cpu_rev;
}
EXPORT_SYMBOL(mx53_revision);
+
+#define ARM_GPC 0x4
+#define DBGEN BIT(16)
+
+/*
+ * This enables the DBGEN bit in ARM_GPC register, which is
+ * required for accessing some performance counter features.
+ * Technically it is only required while perf is used, but to
+ * keep the source code simple we just enable it all the time
+ * when the kernel configuration allows using the feature.
+ */
+void __init imx5_pmu_init(void)
+{
+ void __iomem *tigerp_base;
+ struct device_node *np;
+ u32 gpc;
+
+ if (!IS_ENABLED(CONFIG_ARM_PMU))
+ return;
+
+ np = of_find_compatible_node(NULL, NULL, "arm,cortex-a8-pmu");
+ if (!np)
+ return;
+
+ if (!of_property_read_bool(np, "secure-reg-access"))
+ goto exit;
+
+ of_node_put(np);
+
+ np = of_find_compatible_node(NULL, NULL, "fsl,imx51-tigerp");
+ if (!np)
+ return;
+
+ tigerp_base = of_iomap(np, 0);
+ if (!tigerp_base)
+ goto exit;
+
+ gpc = readl_relaxed(tigerp_base + ARM_GPC);
+ gpc |= DBGEN;
+ writel_relaxed(gpc, tigerp_base + ARM_GPC);
+ iounmap(tigerp_base);
+exit:
+ of_node_put(np);
+
+}