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[PATCH] oprofile: VR5500 performance counter driver

To: linux-mips@linux-mips.org, oprofile-list@lists.sf.net
Subject: [PATCH] oprofile: VR5500 performance counter driver
From: Mark Asselstine <mark.asselstine@windriver.com>
Date: Mon, 23 Feb 2009 11:26:34 -0500
Original-recipient: rfc822;linux-mips@linux-mips.org
Sender: linux-mips-bounce@linux-mips.org
This is inspired by op_model_mipsxx.c with some modification
in regards to register layout and overflow handling. This has
been tested on a NEC VR5500 board and shown to produce sane
results.

Signed-off-by: Mark Asselstine <mark.asselstine@windriver.com>

diff --git a/arch/mips/oprofile/Makefile b/arch/mips/oprofile/Makefile
index cfd4b60..977a828 100644
--- a/arch/mips/oprofile/Makefile
+++ b/arch/mips/oprofile/Makefile
@@ -14,4 +14,5 @@ oprofile-$(CONFIG_CPU_MIPS32)         += op_model_mipsxx.o
 oprofile-$(CONFIG_CPU_MIPS64)          += op_model_mipsxx.o
 oprofile-$(CONFIG_CPU_R10000)          += op_model_mipsxx.o
 oprofile-$(CONFIG_CPU_SB1)             += op_model_mipsxx.o
+oprofile-$(CONFIG_CPU_VR5500)          += op_model_vr5500.o
 oprofile-$(CONFIG_CPU_RM9000)          += op_model_rm9000.o
diff --git a/arch/mips/oprofile/common.c b/arch/mips/oprofile/common.c
index e1bffab..68aad99 100644
--- a/arch/mips/oprofile/common.c
+++ b/arch/mips/oprofile/common.c
@@ -17,6 +17,7 @@
 
 extern struct op_mips_model op_model_mipsxx_ops __attribute__((weak));
 extern struct op_mips_model op_model_rm9000_ops __attribute__((weak));
+extern struct op_mips_model op_model_vr5500_ops __attribute__((weak));
 
 static struct op_mips_model *model;
 
@@ -94,6 +95,10 @@ int __init oprofile_arch_init(struct oprofile_operations 
*ops)
        case CPU_RM9000:
                lmodel = &op_model_rm9000_ops;
                break;
+
+       case CPU_R5500:
+               lmodel = &op_model_vr5500_ops;
+               break;
        };
 
 
diff --git a/arch/mips/oprofile/op_model_vr5500.c 
b/arch/mips/oprofile/op_model_vr5500.c
new file mode 100644
index 0000000..75fae6a
--- /dev/null
+++ b/arch/mips/oprofile/op_model_vr5500.c
@@ -0,0 +1,179 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (c) 2009 Wind River Systems, Inc.
+ */
+#include <linux/cpumask.h>
+#include <linux/oprofile.h>
+#include <linux/interrupt.h>
+#include <linux/smp.h>
+#include <asm/irq_regs.h>
+
+#include "op_impl.h"
+
+#define M_PERFCTL_EXL                  (1UL      <<  0)
+#define M_PERFCTL_KERNEL               (1UL      <<  1)
+#define M_PERFCTL_SUPERVISOR           (1UL      <<  2)
+#define M_PERFCTL_USER                 (1UL      <<  3)
+#define M_PERFCTL_INTERRUPT_ENABLE     (1UL      <<  4)
+#define M_PERFCTL_INTERRUPT            (1UL      <<  5)
+#define M_PERFCTL_EVENT(event)         (((event) & 0xf)  << 6)
+#define M_PERFCTL_COUNT_ENABLE         (1UL      <<  10)
+
+#define NUM_COUNTERS                    2
+
+static int (*save_perf_irq) (void);
+
+#define __define_perf_accessors(r, n)                                  \
+                                                                       \
+       static inline unsigned int r_c0_ ## r ## n(void)                \
+       {                                                               \
+               return read_c0_ ## r ## n();                            \
+       }                                                               \
+                                                                       \
+       static inline void w_c0_ ## r ## n(unsigned int value)          \
+       {                                                               \
+               write_c0_ ## r ## n(value);                             \
+       }                                                               \
+
+__define_perf_accessors(perfcntr, 0)
+__define_perf_accessors(perfcntr, 1)
+
+__define_perf_accessors(perfctrl, 0)
+__define_perf_accessors(perfctrl, 1)
+
+struct op_mips_model op_model_vr5500_ops;
+
+static struct vr5500_register_config {
+       unsigned int control[NUM_COUNTERS];
+       unsigned int counter[NUM_COUNTERS];
+} reg;
+
+/* Compute all of the registers in preparation for enabling profiling.  */
+static void vr5500_reg_setup(struct op_counter_config *ctr)
+{
+       int i;
+       unsigned int counters = NUM_COUNTERS;
+
+       /* Compute the performance counter control word.  */
+       for (i = 0; i < counters; i++) {
+               reg.control[i] = 0;
+               reg.counter[i] = 0;
+
+               if (!ctr[i].enabled)
+                       continue;
+
+               reg.control[i] = M_PERFCTL_EVENT(ctr[i].event) |
+                   M_PERFCTL_INTERRUPT_ENABLE | M_PERFCTL_COUNT_ENABLE;
+               if (ctr[i].kernel)
+                       reg.control[i] |= M_PERFCTL_KERNEL;
+               if (ctr[i].user)
+                       reg.control[i] |= M_PERFCTL_USER;
+               if (ctr[i].exl)
+                       reg.control[i] |= M_PERFCTL_EXL;
+
+               reg.counter[i] = 0xffffffff - ctr[i].count + 1;
+       }
+}
+
+/* Program all of the registers in preparation for enabling profiling.  */
+static void vr5500_cpu_setup(void *args)
+{
+       w_c0_perfctrl1(0);
+       w_c0_perfcntr1(reg.counter[1]);
+
+       w_c0_perfctrl0(0);
+       w_c0_perfcntr0(reg.counter[0]);
+}
+
+/* Start all counters on current CPU */
+static void vr5500_cpu_start(void *args)
+{
+       w_c0_perfctrl1(reg.control[1]);
+       w_c0_perfctrl0(reg.control[0]);
+}
+
+/* Stop all counters on current CPU */
+static void vr5500_cpu_stop(void *args)
+{
+       w_c0_perfctrl1(0);
+       w_c0_perfctrl0(0);
+}
+
+static int vr5500_perfcount_handler(void)
+{
+       unsigned int control;
+       unsigned int counter;
+       int handled = IRQ_NONE;
+       unsigned int counters = NUM_COUNTERS;
+
+       if (cpu_has_mips_r2 && !(read_c0_cause() & (1 << 26)))
+               return handled;
+
+       switch (counters) {
+       #define HANDLE_COUNTER(n)                                       \
+       case n + 1:                                                     \
+               control = r_c0_perfctrl ## n();                         \
+               counter = r_c0_perfcntr ## n();                         \
+               if ((control & M_PERFCTL_INTERRUPT_ENABLE) &&           \
+                       (control & M_PERFCTL_INTERRUPT)) {              \
+                       oprofile_add_sample(get_irq_regs(), n);         \
+                       w_c0_perfcntr ## n(reg.counter[n]);             \
+                       w_c0_perfctrl ## n(control & ~M_PERFCTL_INTERRUPT); \
+                       handled = IRQ_HANDLED;                          \
+               }
+       HANDLE_COUNTER(1)
+       HANDLE_COUNTER(0)
+       }
+
+       return handled;
+}
+
+static void reset_counters(void *arg)
+{
+       w_c0_perfctrl1(0);
+       w_c0_perfcntr1(0);
+
+       w_c0_perfctrl0(0);
+       w_c0_perfcntr0(0);
+}
+
+static int __init vr5500_init(void)
+{
+       on_each_cpu(reset_counters, NULL, 1);
+
+       switch (current_cpu_type()) {
+       case CPU_R5500:
+               op_model_vr5500_ops.cpu_type = "mips/vr5500";
+               break;
+
+       default:
+               printk(KERN_ERR "Profiling unsupported for this CPU\n");
+
+               return -ENODEV;
+       }
+
+       save_perf_irq = perf_irq;
+       perf_irq = vr5500_perfcount_handler;
+
+       return 0;
+}
+
+static void vr5500_exit(void)
+{
+       on_each_cpu(reset_counters, NULL, 1);
+
+       perf_irq = save_perf_irq;
+}
+
+struct op_mips_model op_model_vr5500_ops = {
+       .reg_setup = vr5500_reg_setup,
+       .cpu_setup = vr5500_cpu_setup,
+       .init = vr5500_init,
+       .exit = vr5500_exit,
+       .cpu_start = vr5500_cpu_start,
+       .cpu_stop = vr5500_cpu_stop,
+       .num_counters = NUM_COUNTERS,
+};

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