csky: Add count-width property for csky pmu

[sfrench/cifs-2.6.git] / arch / csky / kernel / perf_event.c

diff --git a/arch/csky/kernel/perf_event.c b/arch/csky/kernel/perf_event.c
index 2282554840c628a7daac1275bff5f01bbc3e681e..a15b397a96c284fe2cff76986d036c5bc82af4df 100644 (file)
--- a/arch/csky/kernel/perf_event.c
+++ b/arch/csky/kernel/perf_event.c
@@ -9,6 +9,7 @@
 #include <linux/platform_device.h>
 
 #define CSKY_PMU_MAX_EVENTS 32
+#define DEFAULT_COUNT_WIDTH 48
 
 #define HPCR           "<0, 0x0>"      /* PMU Control reg */
 #define HPCNTENR       "<0, 0x4>"      /* Count Enable reg */
@@ -18,6 +19,7 @@ static void (*hw_raw_write_mapping[CSKY_PMU_MAX_EVENTS])(uint64_t val);
 
 struct csky_pmu_t {
        struct pmu      pmu;
+       uint32_t        count_width;
        uint32_t        hpcr;
 } csky_pmu;
 
@@ -804,7 +806,12 @@ static void csky_perf_event_update(struct perf_event *event,
                                   struct hw_perf_event *hwc)
 {
        uint64_t prev_raw_count = local64_read(&hwc->prev_count);
-       uint64_t new_raw_count = hw_raw_read_mapping[hwc->idx]();
+       /*
+        * Sign extend count value to 64bit, otherwise delta calculation
+        * would be incorrect when overflow occurs.
+        */
+       uint64_t new_raw_count = sign_extend64(
+               hw_raw_read_mapping[hwc->idx](), csky_pmu.count_width - 1);
        int64_t delta = new_raw_count - prev_raw_count;
 
        /*
@@ -1032,6 +1039,7 @@ int init_hw_perf_events(void)
 int csky_pmu_device_probe(struct platform_device *pdev,
                          const struct of_device_id *of_table)
 {
+       struct device_node *node = pdev->dev.of_node;
        int ret;
 
        ret = init_hw_perf_events();
@@ -1040,6 +1048,11 @@ int csky_pmu_device_probe(struct platform_device *pdev,
                return ret;
        }
 
+       if (of_property_read_u32(node, "count-width",
+                                &csky_pmu.count_width)) {
+               csky_pmu.count_width = DEFAULT_COUNT_WIDTH;
+       }
+
        return ret;
 }