diff options
Diffstat (limited to '')
| -rw-r--r-- | arch/mips/cavium-octeon/oct_ilm.c | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/arch/mips/cavium-octeon/oct_ilm.c b/arch/mips/cavium-octeon/oct_ilm.c new file mode 100644 index 000000000..99e27155b --- /dev/null +++ b/arch/mips/cavium-octeon/oct_ilm.c @@ -0,0 +1,182 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include <linux/fs.h> +#include <linux/interrupt.h> +#include <asm/octeon/octeon.h> +#include <asm/octeon/cvmx-ciu-defs.h> +#include <asm/octeon/cvmx.h> +#include <linux/debugfs.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/seq_file.h> + +#define TIMER_NUM 3 + +static bool reset_stats; + +struct latency_info { + u64 io_interval; + u64 cpu_interval; + u64 timer_start1; + u64 timer_start2; + u64 max_latency; + u64 min_latency; + u64 latency_sum; + u64 average_latency; + u64 interrupt_cnt; +}; + +static struct latency_info li; +static struct dentry *dir; + +static int show_latency(struct seq_file *m, void *v) +{ + u64 cpuclk, avg, max, min; + struct latency_info curr_li = li; + + cpuclk = octeon_get_clock_rate(); + + max = (curr_li.max_latency * 1000000000) / cpuclk; + min = (curr_li.min_latency * 1000000000) / cpuclk; + avg = (curr_li.latency_sum * 1000000000) / (cpuclk * curr_li.interrupt_cnt); + + seq_printf(m, "cnt: %10lld, avg: %7lld ns, max: %7lld ns, min: %7lld ns\n", + curr_li.interrupt_cnt, avg, max, min); + return 0; +} + +static int oct_ilm_open(struct inode *inode, struct file *file) +{ + return single_open(file, show_latency, NULL); +} + +static const struct file_operations oct_ilm_ops = { + .open = oct_ilm_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +static int reset_statistics(void *data, u64 value) +{ + reset_stats = true; + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(reset_statistics_ops, NULL, reset_statistics, "%llu\n"); + +static void init_debugfs(void) +{ + dir = debugfs_create_dir("oct_ilm", 0); + debugfs_create_file("statistics", 0222, dir, NULL, &oct_ilm_ops); + debugfs_create_file("reset", 0222, dir, NULL, &reset_statistics_ops); +} + +static void init_latency_info(struct latency_info *li, int startup) +{ + /* interval in milli seconds after which the interrupt will + * be triggered + */ + int interval = 1; + + if (startup) { + /* Calculating by the amounts io clock and cpu clock would + * increment in interval amount of ms + */ + li->io_interval = (octeon_get_io_clock_rate() * interval) / 1000; + li->cpu_interval = (octeon_get_clock_rate() * interval) / 1000; + } + li->timer_start1 = 0; + li->timer_start2 = 0; + li->max_latency = 0; + li->min_latency = (u64)-1; + li->latency_sum = 0; + li->interrupt_cnt = 0; +} + + +static void start_timer(int timer, u64 interval) +{ + union cvmx_ciu_timx timx; + unsigned long flags; + + timx.u64 = 0; + timx.s.one_shot = 1; + timx.s.len = interval; + raw_local_irq_save(flags); + li.timer_start1 = read_c0_cvmcount(); + cvmx_write_csr(CVMX_CIU_TIMX(timer), timx.u64); + /* Read it back to force wait until register is written. */ + timx.u64 = cvmx_read_csr(CVMX_CIU_TIMX(timer)); + li.timer_start2 = read_c0_cvmcount(); + raw_local_irq_restore(flags); +} + + +static irqreturn_t cvm_oct_ciu_timer_interrupt(int cpl, void *dev_id) +{ + u64 last_latency; + u64 last_int_cnt; + + if (reset_stats) { + init_latency_info(&li, 0); + reset_stats = false; + } else { + last_int_cnt = read_c0_cvmcount(); + last_latency = last_int_cnt - (li.timer_start1 + li.cpu_interval); + li.interrupt_cnt++; + li.latency_sum += last_latency; + if (last_latency > li.max_latency) + li.max_latency = last_latency; + if (last_latency < li.min_latency) + li.min_latency = last_latency; + } + start_timer(TIMER_NUM, li.io_interval); + return IRQ_HANDLED; +} + +static void disable_timer(int timer) +{ + union cvmx_ciu_timx timx; + + timx.s.one_shot = 0; + timx.s.len = 0; + cvmx_write_csr(CVMX_CIU_TIMX(timer), timx.u64); + /* Read it back to force immediate write of timer register*/ + timx.u64 = cvmx_read_csr(CVMX_CIU_TIMX(timer)); +} + +static __init int oct_ilm_module_init(void) +{ + int rc; + int irq = OCTEON_IRQ_TIMER0 + TIMER_NUM; + + init_debugfs(); + + rc = request_irq(irq, cvm_oct_ciu_timer_interrupt, IRQF_NO_THREAD, + "oct_ilm", 0); + if (rc) { + WARN(1, "Could not acquire IRQ %d", irq); + goto err_irq; + } + + init_latency_info(&li, 1); + start_timer(TIMER_NUM, li.io_interval); + + return 0; +err_irq: + debugfs_remove_recursive(dir); + return rc; +} + +static __exit void oct_ilm_module_exit(void) +{ + disable_timer(TIMER_NUM); + debugfs_remove_recursive(dir); + free_irq(OCTEON_IRQ_TIMER0 + TIMER_NUM, 0); +} + +module_exit(oct_ilm_module_exit); +module_init(oct_ilm_module_init); +MODULE_AUTHOR("Venkat Subbiah, Cavium"); +MODULE_DESCRIPTION("Measures interrupt latency on Octeon chips."); +MODULE_LICENSE("GPL"); |