1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * arch/arm/mach-pxa/time.c 4 * 5 * PXA clocksource, clockevents, and OST interrupt handlers. 6 * Copyright (c) 2007 by Bill Gatliff <bgat@billgatliff.com>. 7 * 8 * Derived from Nicolas Pitre's PXA timer handler Copyright (c) 2001 9 * by MontaVista Software, Inc. (Nico, your code rocks!) 10 */ 11 12 #include <linux/kernel.h> 13 #include <linux/init.h> 14 #include <linux/interrupt.h> 15 #include <linux/clk.h> 16 #include <linux/clockchips.h> 17 #include <linux/of_address.h> 18 #include <linux/of_irq.h> 19 #include <linux/sched/clock.h> 20 #include <linux/sched_clock.h> 21 22 #include <clocksource/pxa.h> 23 24 #include <asm/div64.h> 25 26 #define OSMR0 0x00 /* OS Timer 0 Match Register */ 27 #define OSMR1 0x04 /* OS Timer 1 Match Register */ 28 #define OSMR2 0x08 /* OS Timer 2 Match Register */ 29 #define OSMR3 0x0C /* OS Timer 3 Match Register */ 30 31 #define OSCR 0x10 /* OS Timer Counter Register */ 32 #define OSSR 0x14 /* OS Timer Status Register */ 33 #define OWER 0x18 /* OS Timer Watchdog Enable Register */ 34 #define OIER 0x1C /* OS Timer Interrupt Enable Register */ 35 36 #define OSSR_M3 (1 << 3) /* Match status channel 3 */ 37 #define OSSR_M2 (1 << 2) /* Match status channel 2 */ 38 #define OSSR_M1 (1 << 1) /* Match status channel 1 */ 39 #define OSSR_M0 (1 << 0) /* Match status channel 0 */ 40 41 #define OIER_E0 (1 << 0) /* Interrupt enable channel 0 */ 42 43 /* 44 * This is PXA's sched_clock implementation. This has a resolution 45 * of at least 308 ns and a maximum value of 208 days. 46 * 47 * The return value is guaranteed to be monotonic in that range as 48 * long as there is always less than 582 seconds between successive 49 * calls to sched_clock() which should always be the case in practice. 50 */ 51 52 #define timer_readl(reg) readl_relaxed(timer_base + (reg)) 53 #define timer_writel(val, reg) writel_relaxed((val), timer_base + (reg)) 54 55 static void __iomem *timer_base; 56 57 static u64 notrace pxa_read_sched_clock(void) 58 { 59 return timer_readl(OSCR); 60 } 61 62 63 #define MIN_OSCR_DELTA 16 64 65 static irqreturn_t 66 pxa_ost0_interrupt(int irq, void *dev_id) 67 { 68 struct clock_event_device *c = dev_id; 69 70 /* Disarm the compare/match, signal the event. */ 71 timer_writel(timer_readl(OIER) & ~OIER_E0, OIER); 72 timer_writel(OSSR_M0, OSSR); 73 c->event_handler(c); 74 75 return IRQ_HANDLED; 76 } 77 78 static int 79 pxa_osmr0_set_next_event(unsigned long delta, struct clock_event_device *dev) 80 { 81 unsigned long next, oscr; 82 83 timer_writel(timer_readl(OIER) | OIER_E0, OIER); 84 next = timer_readl(OSCR) + delta; 85 timer_writel(next, OSMR0); 86 oscr = timer_readl(OSCR); 87 88 return (signed)(next - oscr) <= MIN_OSCR_DELTA ? -ETIME : 0; 89 } 90 91 static int pxa_osmr0_shutdown(struct clock_event_device *evt) 92 { 93 /* initializing, released, or preparing for suspend */ 94 timer_writel(timer_readl(OIER) & ~OIER_E0, OIER); 95 timer_writel(OSSR_M0, OSSR); 96 return 0; 97 } 98 99 #ifdef CONFIG_PM 100 static unsigned long osmr[4], oier, oscr; 101 102 static void pxa_timer_suspend(struct clock_event_device *cedev) 103 { 104 osmr[0] = timer_readl(OSMR0); 105 osmr[1] = timer_readl(OSMR1); 106 osmr[2] = timer_readl(OSMR2); 107 osmr[3] = timer_readl(OSMR3); 108 oier = timer_readl(OIER); 109 oscr = timer_readl(OSCR); 110 } 111 112 static void pxa_timer_resume(struct clock_event_device *cedev) 113 { 114 /* 115 * Ensure that we have at least MIN_OSCR_DELTA between match 116 * register 0 and the OSCR, to guarantee that we will receive 117 * the one-shot timer interrupt. We adjust OSMR0 in preference 118 * to OSCR to guarantee that OSCR is monotonically incrementing. 119 */ 120 if (osmr[0] - oscr < MIN_OSCR_DELTA) 121 osmr[0] += MIN_OSCR_DELTA; 122 123 timer_writel(osmr[0], OSMR0); 124 timer_writel(osmr[1], OSMR1); 125 timer_writel(osmr[2], OSMR2); 126 timer_writel(osmr[3], OSMR3); 127 timer_writel(oier, OIER); 128 timer_writel(oscr, OSCR); 129 } 130 #else 131 #define pxa_timer_suspend NULL 132 #define pxa_timer_resume NULL 133 #endif 134 135 static struct clock_event_device ckevt_pxa_osmr0 = { 136 .name = "osmr0", 137 .features = CLOCK_EVT_FEAT_ONESHOT, 138 .rating = 200, 139 .set_next_event = pxa_osmr0_set_next_event, 140 .set_state_shutdown = pxa_osmr0_shutdown, 141 .set_state_oneshot = pxa_osmr0_shutdown, 142 .suspend = pxa_timer_suspend, 143 .resume = pxa_timer_resume, 144 }; 145 146 static int __init pxa_timer_common_init(int irq, unsigned long clock_tick_rate) 147 { 148 int ret; 149 150 timer_writel(0, OIER); 151 timer_writel(OSSR_M0 | OSSR_M1 | OSSR_M2 | OSSR_M3, OSSR); 152 153 sched_clock_register(pxa_read_sched_clock, 32, clock_tick_rate); 154 155 ckevt_pxa_osmr0.cpumask = cpumask_of(0); 156 157 ret = request_irq(irq, pxa_ost0_interrupt, IRQF_TIMER | IRQF_IRQPOLL, 158 "ost0", &ckevt_pxa_osmr0); 159 if (ret) { 160 pr_err("Failed to setup irq\n"); 161 return ret; 162 } 163 164 ret = clocksource_mmio_init(timer_base + OSCR, "oscr0", clock_tick_rate, 200, 165 32, clocksource_mmio_readl_up); 166 if (ret) { 167 pr_err("Failed to init clocksource\n"); 168 return ret; 169 } 170 171 clockevents_config_and_register(&ckevt_pxa_osmr0, clock_tick_rate, 172 MIN_OSCR_DELTA * 2, 0x7fffffff); 173 174 return 0; 175 } 176 177 static int __init pxa_timer_dt_init(struct device_node *np) 178 { 179 struct clk *clk; 180 int irq, ret; 181 182 /* timer registers are shared with watchdog timer */ 183 timer_base = of_iomap(np, 0); 184 if (!timer_base) { 185 pr_err("%pOFn: unable to map resource\n", np); 186 return -ENXIO; 187 } 188 189 clk = of_clk_get(np, 0); 190 if (IS_ERR(clk)) { 191 pr_crit("%pOFn: unable to get clk\n", np); 192 return PTR_ERR(clk); 193 } 194 195 ret = clk_prepare_enable(clk); 196 if (ret) { 197 pr_crit("Failed to prepare clock\n"); 198 return ret; 199 } 200 201 /* we are only interested in OS-timer0 irq */ 202 irq = irq_of_parse_and_map(np, 0); 203 if (irq <= 0) { 204 pr_crit("%pOFn: unable to parse OS-timer0 irq\n", np); 205 return -EINVAL; 206 } 207 208 return pxa_timer_common_init(irq, clk_get_rate(clk)); 209 } 210 TIMER_OF_DECLARE(pxa_timer, "marvell,pxa-timer", pxa_timer_dt_init); 211 212 /* 213 * Legacy timer init for non device-tree boards. 214 */ 215 void __init pxa_timer_nodt_init(int irq, void __iomem *base) 216 { 217 struct clk *clk; 218 219 timer_base = base; 220 clk = clk_get(NULL, "OSTIMER0"); 221 if (clk && !IS_ERR(clk)) { 222 clk_prepare_enable(clk); 223 pxa_timer_common_init(irq, clk_get_rate(clk)); 224 } else { 225 pr_crit("%s: unable to get clk\n", __func__); 226 } 227 } 228