ARC: perf: don't bail setup if pct irq missing in device-tree

Current code inadventely bails if hardware supports sampling/overflow
interrupts, but the irq is missing from device tree.

|
| # perf stat -e cycles,instructions,major-faults,minor-faults ../hackbench
| Running with 10 groups 400 process
| Time: 0.921
|
| Performance counter stats for '../hackbench':
|
|   <not supported>      cycles
|   <not supported>      instructions
|                 0      major-faults
|              8679      minor-faults

This need not be as we can still do simple counting based perf stat.
This unborks perf on HSDK-4xD

Cc: <stable@vger.kernel.org>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

diff --git a/arch/arc/kernel/perf_event.c b/arch/arc/kernel/perf_event.c
index 661fd84..79849f3 100644 (file)
--- a/arch/arc/kernel/perf_event.c
+++ b/arch/arc/kernel/perf_event.c
@@ -562,7 +562,7 @@ static int arc_pmu_device_probe(struct platform_device *pdev)
 {
        struct arc_reg_pct_build pct_bcr;
        struct arc_reg_cc_build cc_bcr;
-       int i, has_interrupts;
+       int i, has_interrupts, irq;
        int counter_size;       /* in bits */
 
        union cc_name {
@@ -637,13 +637,7 @@ static int arc_pmu_device_probe(struct platform_device *pdev)
                .attr_groups    = arc_pmu->attr_groups,
        };
 
-       if (has_interrupts) {
-               int irq = platform_get_irq(pdev, 0);
-
-               if (irq < 0) {
-                       pr_err("Cannot get IRQ number for the platform\n");
-                       return -ENODEV;
-               }
+       if (has_interrupts && (irq = platform_get_irq(pdev, 0) >= 0)) {
 
                arc_pmu->irq = irq;
 
@@ -652,9 +646,9 @@ static int arc_pmu_device_probe(struct platform_device *pdev)
                                   this_cpu_ptr(&arc_pmu_cpu));
 
                on_each_cpu(arc_cpu_pmu_irq_init, &irq, 1);
-
-       } else
+       } else {
                arc_pmu->pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
+       }
 
        /*
         * perf parser doesn't really like '-' symbol in events name, so let's