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Subject[PATCHv2 2/3] ARM: imx53: add SoC specific PMU setup
Date
From: Peter Senna Tschudin <peter.senna@collabora.com>

On i.MX53 it is necessary to set the DBG_EN bit in the
platform GPC register to enable access to PMU counters
other than the cycle counter.

Signed-off-by: Martin Fuzzey <mfuzzey@parkeon.com>
Signed-off-by: Peter Senna Tschudin <peter.senna@collabora.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
---
arch/arm/mach-imx/mach-imx53.c | 68 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 68 insertions(+)

diff --git a/arch/arm/mach-imx/mach-imx53.c b/arch/arm/mach-imx/mach-imx53.c
index 07c2e8dca494..da7c80371f32 100644
--- a/arch/arm/mach-imx/mach-imx53.c
+++ b/arch/arm/mach-imx/mach-imx53.c
@@ -17,6 +17,7 @@
#include <linux/irq.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
+#include <linux/perf/arm_pmu.h>
#include <asm/mach/arch.h>
#include <asm/mach/time.h>

@@ -28,10 +29,77 @@ static void __init imx53_init_early(void)
mxc_set_cpu_type(MXC_CPU_MX53);
}

+/* Hard code as this is i.Mx53 only file */
+#define MXC_CORTEXA8_PLAT_GPC 0x63fa0004
+#define GPC_DBG_EN (1 << 16)
+
+static void __iomem *imx53_pmu_get_gpc(void)
+{
+ static void __iomem *gpc;
+
+ if (!gpc) {
+ gpc = ioremap(MXC_CORTEXA8_PLAT_GPC, 4);
+ if (!gpc)
+ printk_once(KERN_INFO "unable to map GPC to enable perf\n");
+ }
+
+ return gpc;
+}
+
+static int imx53_pmu_reserve(struct arm_pmu *arm_pmu)
+{
+ void __iomem *gpc_reg;
+ u32 gpc;
+
+ gpc_reg = imx53_pmu_get_gpc();
+ if (!gpc_reg)
+ return 0;
+
+ gpc = __raw_readl(gpc_reg);
+ if (gpc & GPC_DBG_EN) {
+ arm_pmu->reserved_hardware = false;
+ } else {
+ gpc |= GPC_DBG_EN;
+ __raw_writel(gpc, gpc_reg);
+ arm_pmu->reserved_hardware = true;
+ }
+
+ return 0;
+}
+
+static void imx53_pmu_release(struct arm_pmu *arm_pmu)
+{
+ void __iomem *gpc_reg;
+ u32 gpc;
+
+ gpc_reg = imx53_pmu_get_gpc();
+ if (!gpc_reg)
+ return;
+
+ if (arm_pmu->reserved_hardware) {
+ gpc = __raw_readl(gpc_reg);
+ gpc &= ~GPC_DBG_EN;
+ __raw_writel(gpc, gpc_reg);
+ arm_pmu->reserved_hardware = false;
+ }
+}
+
+static struct arm_pmu_platdata imx53_pmu_platdata = {
+ .reserve_hardware = imx53_pmu_reserve,
+ .release_hardware = imx53_pmu_release,
+};
+
+static struct of_dev_auxdata imx53_auxdata_lookup[] __initdata = {
+ OF_DEV_AUXDATA("arm,cortex-a8-pmu", 0, "arm-pmu", &imx53_pmu_platdata),
+ {}
+};
+
static void __init imx53_dt_init(void)
{
imx_src_init();

+ of_platform_populate(NULL, of_default_bus_match_table,
+ imx53_auxdata_lookup, NULL);
imx_aips_allow_unprivileged_access("fsl,imx53-aipstz");
}

--
2.15.1
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