On i.MX51/i.MX53 it is necessary to set the DBGEN bit in
ARM_GPC register in order to turn on the debug clocks.
The DBGEN bit of ARM_GPC register has the following description
in the i.MX53 Reference Manual:
"This allows the user to manually activate clocks within the debug
system. This register bit directly controls the platform's dbgen_out
output signal which connects to the DAP_SYS to enable all debug clocks.
Once enabled, the clocks cannot be disabled except by asserting the
disable_trace input of the DAP_SYS."
Based on a previous patch from Sebastian Reichel.
Signed-off-by: Fabio Estevam <fabio.estevam@xxxxxxx>
---
Changes since v3:
- Add missing of_node_put()
arch/arm/mach-imx/common.h | 1 +
arch/arm/mach-imx/cpu-imx5.c | 45 ++++++++++++++++++++++++++++++++++++++++++
arch/arm/mach-imx/mach-imx51.c | 2 +-
arch/arm/mach-imx/mach-imx53.c | 2 +-
4 files changed, 48 insertions(+), 2 deletions(-)
diff --git a/arch/arm/mach-imx/common.h b/arch/arm/mach-imx/common.h
index 93225db7..423dd76 100644
--- a/arch/arm/mach-imx/common.h
+++ b/arch/arm/mach-imx/common.h
@@ -62,6 +62,7 @@ void imx_gpc_set_arm_power_up_timing(u32 sw2iso, u32 sw);
void imx_gpc_set_arm_power_down_timing(u32 sw2iso, u32 sw);
void imx25_pm_init(void);
void imx27_pm_init(void);
+void imx5_pmu_init(void);
enum mxc_cpu_pwr_mode {
WAIT_CLOCKED, /* wfi only */
diff --git a/arch/arm/mach-imx/cpu-imx5.c b/arch/arm/mach-imx/cpu-imx5.c
index 4f2d1c7..e210bac 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);
+
+}
diff --git a/arch/arm/mach-imx/mach-imx51.c b/arch/arm/mach-imx/mach-imx51.c
index 3835b6a..8838fba 100644
--- a/arch/arm/mach-imx/mach-imx51.c
+++ b/arch/arm/mach-imx/mach-imx51.c
@@ -52,7 +52,7 @@ static void __init imx51_dt_init(void)
{
imx51_ipu_mipi_setup();
imx_src_init();
-
+ imx5_pmu_init();
imx_aips_allow_unprivileged_access("fsl,imx51-aipstz");
}
diff --git a/arch/arm/mach-imx/mach-imx53.c b/arch/arm/mach-imx/mach-imx53.c
index 07c2e8d..5ec7100 100644
--- a/arch/arm/mach-imx/mach-imx53.c
+++ b/arch/arm/mach-imx/mach-imx53.c
@@ -31,7 +31,7 @@ static void __init imx53_init_early(void)
static void __init imx53_dt_init(void)
{
imx_src_init();
-
+ imx5_pmu_init();
imx_aips_allow_unprivileged_access("fsl,imx53-aipstz");
}
--
2.7.4
--
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