James Hogan | a2c5d4e | 2012-10-09 10:54:39 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2005-2013 Imagination Technologies Ltd. |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License version 2 as |
| 6 | * published by the Free Software Foundation. |
| 7 | * |
| 8 | * This program is distributed in the hope that it will be useful, |
| 9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 11 | * GNU General Public License for more details. |
| 12 | * |
| 13 | * You should have received a copy of the GNU General Public License |
| 14 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 15 | * |
| 16 | * |
| 17 | * Support for Meta per-thread timers. |
| 18 | * |
| 19 | * Meta hardware threads have 2 timers. The background timer (TXTIMER) is used |
| 20 | * as a free-running time base (hz clocksource), and the interrupt timer |
| 21 | * (TXTIMERI) is used for the timer interrupt (clock event). Both counters |
| 22 | * traditionally count at approximately 1MHz. |
| 23 | */ |
| 24 | |
| 25 | #include <clocksource/metag_generic.h> |
| 26 | #include <linux/cpu.h> |
| 27 | #include <linux/errno.h> |
| 28 | #include <linux/sched.h> |
| 29 | #include <linux/kernel.h> |
| 30 | #include <linux/param.h> |
| 31 | #include <linux/time.h> |
| 32 | #include <linux/init.h> |
| 33 | #include <linux/proc_fs.h> |
| 34 | #include <linux/clocksource.h> |
| 35 | #include <linux/clockchips.h> |
| 36 | #include <linux/interrupt.h> |
| 37 | |
| 38 | #include <asm/clock.h> |
| 39 | #include <asm/hwthread.h> |
| 40 | #include <asm/core_reg.h> |
| 41 | #include <asm/metag_mem.h> |
| 42 | #include <asm/tbx.h> |
| 43 | |
| 44 | #define HARDWARE_FREQ 1000000 /* 1MHz */ |
| 45 | #define HARDWARE_DIV 1 /* divide by 1 = 1MHz clock */ |
| 46 | #define HARDWARE_TO_NS_SHIFT 10 /* convert ticks to ns */ |
| 47 | |
| 48 | static unsigned int hwtimer_freq = HARDWARE_FREQ; |
| 49 | static DEFINE_PER_CPU(struct clock_event_device, local_clockevent); |
| 50 | static DEFINE_PER_CPU(char [11], local_clockevent_name); |
| 51 | |
| 52 | static int metag_timer_set_next_event(unsigned long delta, |
| 53 | struct clock_event_device *dev) |
| 54 | { |
| 55 | __core_reg_set(TXTIMERI, -delta); |
| 56 | return 0; |
| 57 | } |
| 58 | |
| 59 | static void metag_timer_set_mode(enum clock_event_mode mode, |
| 60 | struct clock_event_device *evt) |
| 61 | { |
| 62 | switch (mode) { |
| 63 | case CLOCK_EVT_MODE_ONESHOT: |
| 64 | case CLOCK_EVT_MODE_RESUME: |
| 65 | break; |
| 66 | |
| 67 | case CLOCK_EVT_MODE_SHUTDOWN: |
| 68 | /* We should disable the IRQ here */ |
| 69 | break; |
| 70 | |
| 71 | case CLOCK_EVT_MODE_PERIODIC: |
| 72 | case CLOCK_EVT_MODE_UNUSED: |
| 73 | WARN_ON(1); |
| 74 | break; |
| 75 | }; |
| 76 | } |
| 77 | |
| 78 | static cycle_t metag_clocksource_read(struct clocksource *cs) |
| 79 | { |
| 80 | return __core_reg_get(TXTIMER); |
| 81 | } |
| 82 | |
| 83 | static struct clocksource clocksource_metag = { |
| 84 | .name = "META", |
| 85 | .rating = 200, |
| 86 | .mask = CLOCKSOURCE_MASK(32), |
| 87 | .read = metag_clocksource_read, |
| 88 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, |
| 89 | }; |
| 90 | |
| 91 | static irqreturn_t metag_timer_interrupt(int irq, void *dummy) |
| 92 | { |
| 93 | struct clock_event_device *evt = &__get_cpu_var(local_clockevent); |
| 94 | |
| 95 | evt->event_handler(evt); |
| 96 | |
| 97 | return IRQ_HANDLED; |
| 98 | } |
| 99 | |
| 100 | static struct irqaction metag_timer_irq = { |
| 101 | .name = "META core timer", |
| 102 | .handler = metag_timer_interrupt, |
| 103 | .flags = IRQF_TIMER | IRQF_IRQPOLL | IRQF_PERCPU, |
| 104 | }; |
| 105 | |
| 106 | unsigned long long sched_clock(void) |
| 107 | { |
| 108 | unsigned long long ticks = __core_reg_get(TXTIMER); |
| 109 | return ticks << HARDWARE_TO_NS_SHIFT; |
| 110 | } |
| 111 | |
Paul Gortmaker | 8c37bb3 | 2013-06-19 11:32:08 -0400 | [diff] [blame] | 112 | static void arch_timer_setup(unsigned int cpu) |
James Hogan | a2c5d4e | 2012-10-09 10:54:39 +0100 | [diff] [blame] | 113 | { |
| 114 | unsigned int txdivtime; |
| 115 | struct clock_event_device *clk = &per_cpu(local_clockevent, cpu); |
| 116 | char *name = per_cpu(local_clockevent_name, cpu); |
| 117 | |
| 118 | txdivtime = __core_reg_get(TXDIVTIME); |
| 119 | |
| 120 | txdivtime &= ~TXDIVTIME_DIV_BITS; |
| 121 | txdivtime |= (HARDWARE_DIV & TXDIVTIME_DIV_BITS); |
| 122 | |
| 123 | __core_reg_set(TXDIVTIME, txdivtime); |
| 124 | |
| 125 | sprintf(name, "META %d", cpu); |
| 126 | clk->name = name; |
| 127 | clk->features = CLOCK_EVT_FEAT_ONESHOT, |
| 128 | |
| 129 | clk->rating = 200, |
| 130 | clk->shift = 12, |
| 131 | clk->irq = tbisig_map(TBID_SIGNUM_TRT), |
| 132 | clk->set_mode = metag_timer_set_mode, |
| 133 | clk->set_next_event = metag_timer_set_next_event, |
| 134 | |
| 135 | clk->mult = div_sc(hwtimer_freq, NSEC_PER_SEC, clk->shift); |
| 136 | clk->max_delta_ns = clockevent_delta2ns(0x7fffffff, clk); |
| 137 | clk->min_delta_ns = clockevent_delta2ns(0xf, clk); |
| 138 | clk->cpumask = cpumask_of(cpu); |
| 139 | |
| 140 | clockevents_register_device(clk); |
| 141 | |
| 142 | /* |
| 143 | * For all non-boot CPUs we need to synchronize our free |
| 144 | * running clock (TXTIMER) with the boot CPU's clock. |
| 145 | * |
| 146 | * While this won't be accurate, it should be close enough. |
| 147 | */ |
| 148 | if (cpu) { |
| 149 | unsigned int thread0 = cpu_2_hwthread_id[0]; |
| 150 | unsigned long val; |
| 151 | |
| 152 | val = core_reg_read(TXUCT_ID, TXTIMER_REGNUM, thread0); |
| 153 | __core_reg_set(TXTIMER, val); |
| 154 | } |
| 155 | } |
| 156 | |
Paul Gortmaker | 8c37bb3 | 2013-06-19 11:32:08 -0400 | [diff] [blame] | 157 | static int arch_timer_cpu_notify(struct notifier_block *self, |
James Hogan | a2c5d4e | 2012-10-09 10:54:39 +0100 | [diff] [blame] | 158 | unsigned long action, void *hcpu) |
| 159 | { |
| 160 | int cpu = (long)hcpu; |
| 161 | |
| 162 | switch (action) { |
| 163 | case CPU_STARTING: |
| 164 | case CPU_STARTING_FROZEN: |
| 165 | arch_timer_setup(cpu); |
| 166 | break; |
| 167 | } |
| 168 | |
| 169 | return NOTIFY_OK; |
| 170 | } |
| 171 | |
Paul Gortmaker | 8c37bb3 | 2013-06-19 11:32:08 -0400 | [diff] [blame] | 172 | static struct notifier_block arch_timer_cpu_nb = { |
James Hogan | a2c5d4e | 2012-10-09 10:54:39 +0100 | [diff] [blame] | 173 | .notifier_call = arch_timer_cpu_notify, |
| 174 | }; |
| 175 | |
| 176 | int __init metag_generic_timer_init(void) |
| 177 | { |
| 178 | /* |
| 179 | * On Meta 2 SoCs, the actual frequency of the timer is based on the |
| 180 | * Meta core clock speed divided by an integer, so it is only |
| 181 | * approximately 1MHz. Calculating the real frequency here drastically |
| 182 | * reduces clock skew on these SoCs. |
| 183 | */ |
| 184 | #ifdef CONFIG_METAG_META21 |
| 185 | hwtimer_freq = get_coreclock() / (metag_in32(EXPAND_TIMER_DIV) + 1); |
| 186 | #endif |
James Hogan | cf07053 | 2013-01-15 15:27:45 +0000 | [diff] [blame] | 187 | pr_info("Timer frequency: %u Hz\n", hwtimer_freq); |
| 188 | |
James Hogan | a2c5d4e | 2012-10-09 10:54:39 +0100 | [diff] [blame] | 189 | clocksource_register_hz(&clocksource_metag, hwtimer_freq); |
| 190 | |
| 191 | setup_irq(tbisig_map(TBID_SIGNUM_TRT), &metag_timer_irq); |
| 192 | |
| 193 | /* Configure timer on boot CPU */ |
| 194 | arch_timer_setup(smp_processor_id()); |
| 195 | |
| 196 | /* Hook cpu boot to configure other CPU's timers */ |
| 197 | register_cpu_notifier(&arch_timer_cpu_nb); |
| 198 | |
| 199 | return 0; |
| 200 | } |