| 1 | /* |
| 2 | * Marvell Orion SoC timer handling. |
| 3 | * |
| 4 | * Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com> |
| 5 | * |
| 6 | * This file is licensed under the terms of the GNU General Public |
| 7 | * License version 2. This program is licensed "as is" without any |
| 8 | * warranty of any kind, whether express or implied. |
| 9 | * |
| 10 | * Timer 0 is used as free-running clocksource, while timer 1 is |
| 11 | * used as clock_event_device. |
| 12 | */ |
| 13 | |
| 14 | #include <linux/kernel.h> |
| 15 | #include <linux/bitops.h> |
| 16 | #include <linux/clk.h> |
| 17 | #include <linux/clockchips.h> |
| 18 | #include <linux/delay.h> |
| 19 | #include <linux/interrupt.h> |
| 20 | #include <linux/of_address.h> |
| 21 | #include <linux/of_irq.h> |
| 22 | #include <linux/spinlock.h> |
| 23 | #include <linux/sched_clock.h> |
| 24 | |
| 25 | #define TIMER_CTRL 0x00 |
| 26 | #define TIMER0_EN BIT(0) |
| 27 | #define TIMER0_RELOAD_EN BIT(1) |
| 28 | #define TIMER1_EN BIT(2) |
| 29 | #define TIMER1_RELOAD_EN BIT(3) |
| 30 | #define TIMER0_RELOAD 0x10 |
| 31 | #define TIMER0_VAL 0x14 |
| 32 | #define TIMER1_RELOAD 0x18 |
| 33 | #define TIMER1_VAL 0x1c |
| 34 | |
| 35 | #define ORION_ONESHOT_MIN 1 |
| 36 | #define ORION_ONESHOT_MAX 0xfffffffe |
| 37 | |
| 38 | static void __iomem *timer_base; |
| 39 | |
| 40 | static unsigned long notrace orion_read_timer(void) |
| 41 | { |
| 42 | return ~readl(timer_base + TIMER0_VAL); |
| 43 | } |
| 44 | |
| 45 | static struct delay_timer orion_delay_timer = { |
| 46 | .read_current_timer = orion_read_timer, |
| 47 | }; |
| 48 | |
| 49 | static void orion_delay_timer_init(unsigned long rate) |
| 50 | { |
| 51 | orion_delay_timer.freq = rate; |
| 52 | register_current_timer_delay(&orion_delay_timer); |
| 53 | } |
| 54 | |
| 55 | /* |
| 56 | * Free-running clocksource handling. |
| 57 | */ |
| 58 | static u64 notrace orion_read_sched_clock(void) |
| 59 | { |
| 60 | return ~readl(timer_base + TIMER0_VAL); |
| 61 | } |
| 62 | |
| 63 | /* |
| 64 | * Clockevent handling. |
| 65 | */ |
| 66 | static u32 ticks_per_jiffy; |
| 67 | |
| 68 | static int orion_clkevt_next_event(unsigned long delta, |
| 69 | struct clock_event_device *dev) |
| 70 | { |
| 71 | /* setup and enable one-shot timer */ |
| 72 | writel(delta, timer_base + TIMER1_VAL); |
| 73 | atomic_io_modify(timer_base + TIMER_CTRL, |
| 74 | TIMER1_RELOAD_EN | TIMER1_EN, TIMER1_EN); |
| 75 | |
| 76 | return 0; |
| 77 | } |
| 78 | |
| 79 | static int orion_clkevt_shutdown(struct clock_event_device *dev) |
| 80 | { |
| 81 | /* disable timer */ |
| 82 | atomic_io_modify(timer_base + TIMER_CTRL, |
| 83 | TIMER1_RELOAD_EN | TIMER1_EN, 0); |
| 84 | return 0; |
| 85 | } |
| 86 | |
| 87 | static int orion_clkevt_set_periodic(struct clock_event_device *dev) |
| 88 | { |
| 89 | /* setup and enable periodic timer at 1/HZ intervals */ |
| 90 | writel(ticks_per_jiffy - 1, timer_base + TIMER1_RELOAD); |
| 91 | writel(ticks_per_jiffy - 1, timer_base + TIMER1_VAL); |
| 92 | atomic_io_modify(timer_base + TIMER_CTRL, |
| 93 | TIMER1_RELOAD_EN | TIMER1_EN, |
| 94 | TIMER1_RELOAD_EN | TIMER1_EN); |
| 95 | return 0; |
| 96 | } |
| 97 | |
| 98 | static struct clock_event_device orion_clkevt = { |
| 99 | .name = "orion_event", |
| 100 | .features = CLOCK_EVT_FEAT_ONESHOT | |
| 101 | CLOCK_EVT_FEAT_PERIODIC, |
| 102 | .shift = 32, |
| 103 | .rating = 300, |
| 104 | .set_next_event = orion_clkevt_next_event, |
| 105 | .set_state_shutdown = orion_clkevt_shutdown, |
| 106 | .set_state_periodic = orion_clkevt_set_periodic, |
| 107 | .set_state_oneshot = orion_clkevt_shutdown, |
| 108 | .tick_resume = orion_clkevt_shutdown, |
| 109 | }; |
| 110 | |
| 111 | static irqreturn_t orion_clkevt_irq_handler(int irq, void *dev_id) |
| 112 | { |
| 113 | orion_clkevt.event_handler(&orion_clkevt); |
| 114 | return IRQ_HANDLED; |
| 115 | } |
| 116 | |
| 117 | static struct irqaction orion_clkevt_irq = { |
| 118 | .name = "orion_event", |
| 119 | .flags = IRQF_TIMER, |
| 120 | .handler = orion_clkevt_irq_handler, |
| 121 | }; |
| 122 | |
| 123 | static int __init orion_timer_init(struct device_node *np) |
| 124 | { |
| 125 | unsigned long rate; |
| 126 | struct clk *clk; |
| 127 | int irq, ret; |
| 128 | |
| 129 | /* timer registers are shared with watchdog timer */ |
| 130 | timer_base = of_iomap(np, 0); |
| 131 | if (!timer_base) { |
| 132 | pr_err("%s: unable to map resource\n", np->name); |
| 133 | return -ENXIO; |
| 134 | } |
| 135 | |
| 136 | clk = of_clk_get(np, 0); |
| 137 | if (IS_ERR(clk)) { |
| 138 | pr_err("%s: unable to get clk\n", np->name); |
| 139 | return PTR_ERR(clk); |
| 140 | } |
| 141 | |
| 142 | ret = clk_prepare_enable(clk); |
| 143 | if (ret) { |
| 144 | pr_err("Failed to prepare clock\n"); |
| 145 | return ret; |
| 146 | } |
| 147 | |
| 148 | /* we are only interested in timer1 irq */ |
| 149 | irq = irq_of_parse_and_map(np, 1); |
| 150 | if (irq <= 0) { |
| 151 | pr_err("%s: unable to parse timer1 irq\n", np->name); |
| 152 | return -EINVAL; |
| 153 | } |
| 154 | |
| 155 | rate = clk_get_rate(clk); |
| 156 | |
| 157 | /* setup timer0 as free-running clocksource */ |
| 158 | writel(~0, timer_base + TIMER0_VAL); |
| 159 | writel(~0, timer_base + TIMER0_RELOAD); |
| 160 | atomic_io_modify(timer_base + TIMER_CTRL, |
| 161 | TIMER0_RELOAD_EN | TIMER0_EN, |
| 162 | TIMER0_RELOAD_EN | TIMER0_EN); |
| 163 | |
| 164 | ret = clocksource_mmio_init(timer_base + TIMER0_VAL, |
| 165 | "orion_clocksource", rate, 300, 32, |
| 166 | clocksource_mmio_readl_down); |
| 167 | if (ret) { |
| 168 | pr_err("Failed to initialize mmio timer\n"); |
| 169 | return ret; |
| 170 | } |
| 171 | |
| 172 | sched_clock_register(orion_read_sched_clock, 32, rate); |
| 173 | |
| 174 | /* setup timer1 as clockevent timer */ |
| 175 | ret = setup_irq(irq, &orion_clkevt_irq); |
| 176 | if (ret) { |
| 177 | pr_err("%s: unable to setup irq\n", np->name); |
| 178 | return ret; |
| 179 | } |
| 180 | |
| 181 | ticks_per_jiffy = (clk_get_rate(clk) + HZ/2) / HZ; |
| 182 | orion_clkevt.cpumask = cpumask_of(0); |
| 183 | orion_clkevt.irq = irq; |
| 184 | clockevents_config_and_register(&orion_clkevt, rate, |
| 185 | ORION_ONESHOT_MIN, ORION_ONESHOT_MAX); |
| 186 | |
| 187 | |
| 188 | orion_delay_timer_init(rate); |
| 189 | |
| 190 | return 0; |
| 191 | } |
| 192 | TIMER_OF_DECLARE(orion_timer, "marvell,orion-timer", orion_timer_init); |