diff options
Diffstat (limited to 'driver/gator_ebs.c')
| -rw-r--r-- | driver/gator_ebs.c | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/driver/gator_ebs.c b/driver/gator_ebs.c new file mode 100644 index 0000000..9b55347 --- /dev/null +++ b/driver/gator_ebs.c @@ -0,0 +1,160 @@ +/** + * Copyright (C) ARM Limited 2011. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + */ + +/****************************************************************************** + * event based sampling handling + ******************************************************************************/ + +#if defined (__arm__) +#include "gator_events_armv7.h" +#include <linux/platform_device.h> +#include <linux/interrupt.h> +#include <linux/irq.h> + +#if LINUX_PMU_SUPPORT +#include <asm/pmu.h> + +static struct platform_device *pmu_device; + +static irqreturn_t armv7_pmnc_interrupt(int irq, void *arg) +{ + unsigned int cnt, cpu = smp_processor_id(), buftype = EVENT_BUF; + struct pt_regs * const regs = get_irq_regs(); + u32 flags; + + // Stop irq generation + armv7_pmnc_write(armv7_pmnc_read() & ~PMNC_E); + + // Get and reset overflow status flags + flags = armv7_pmnc_reset_interrupt(); + + // Counters header + gator_buffer_write_packed_int(cpu, buftype, MESSAGE_COUNTERS); // type + gator_buffer_write_packed_int64(cpu, buftype, gator_get_time()); // time + + // Cycle counter + if (flags & (1 << 31)) { + int value = armv7_ccnt_read(pmnc_count[CCNT]); // overrun + gator_buffer_write_packed_int(cpu, buftype, 2); // length + gator_buffer_write_packed_int(cpu, buftype, pmnc_key[CCNT]); // key + gator_buffer_write_packed_int(cpu, buftype, value); // value + } + + // PMNC counters + for (cnt = CNT0; cnt < CNTMAX; cnt++) { + if (flags & (1 << (cnt - CNT0))) { + int value = armv7_cntn_read(cnt, pmnc_count[cnt]); // overrun + gator_buffer_write_packed_int(cpu, buftype, 2); // length + gator_buffer_write_packed_int(cpu, buftype, pmnc_key[cnt]); // key + gator_buffer_write_packed_int(cpu, buftype, value); // value + } + } + + // End Counters, length of zero + gator_buffer_write_packed_int(cpu, buftype, 0); + + // Output backtrace + gator_add_sample(cpu, buftype, regs); + + // Check and commit; commit is set to occur once buffer is 3/4 full + event_buffer_check(cpu); + + // Allow irq generation + armv7_pmnc_write(armv7_pmnc_read() | PMNC_E); + + return IRQ_HANDLED; +} +#endif + +static int gator_event_sampling_start(void) +{ + int cnt; + + event_based_sampling = false; + for (cnt = CCNT; cnt < CNTMAX; cnt++) { + if (pmnc_count[cnt] > 0) { + event_based_sampling = true; + break; + } + } + +#if LINUX_PMU_SUPPORT + pmu_device = reserve_pmu(ARM_PMU_DEVICE_CPU); + if (IS_ERR(pmu_device) && (unsigned int)pmu_device != -ENODEV) { + pr_err("gator: unable to reserve the pmu\n"); + return -1; + } + + if (event_based_sampling) { + int irq, i; + + if (IS_ERR(pmu_device)) { + pr_err("gator: event based sampling is not supported as the kernel function reserve_pmu() failed"); + return -1; + } + + init_pmu(ARM_PMU_DEVICE_CPU); + if (pmu_device->num_resources == 0) { + pr_err("gator: no irqs for PMUs defined\n"); + release_pmu(pmu_device); + pmu_device = NULL; + return -1; + } + + for (i = 0; i < pmu_device->num_resources; ++i) { + irq = platform_get_irq(pmu_device, i); + if (irq < 0) + continue; + + if (request_irq(irq, armv7_pmnc_interrupt, IRQF_DISABLED | IRQF_NOBALANCING, "armpmu", NULL)) { + pr_err("gator: unable to request IRQ%d for ARM perf counters\n", irq); + + // clean up and exit + for (i = i - 1; i >= 0; --i) { + irq = platform_get_irq(pmu_device, i); + if (irq >= 0) + free_irq(irq, NULL); + } + release_pmu(pmu_device); + pmu_device = NULL; + return -1; + } + } + } +#else + if (event_based_sampling) { + pr_err("gator: event based sampling only supported in kernel versions 2.6.35 and higher and CONFIG_CPU_HAS_PMU=y\n"); + return -1; + } +#endif + + return 0; +} + +static void gator_event_sampling_stop(void) +{ +#if LINUX_PMU_SUPPORT + if (event_based_sampling) { + int i, irq; + for (i = pmu_device->num_resources - 1; i >= 0; --i) { + irq = platform_get_irq(pmu_device, i); + if (irq >= 0) + free_irq(irq, NULL); + } + } + if (!IS_ERR(pmu_device)) + release_pmu(pmu_device); + pmu_device = NULL; +#endif +} + +#else +static int gator_event_sampling_start(void) {return 0;} +static void gator_event_sampling_stop(void) {} +#endif |