1 // SPDX-License-Identifier: GPL-2.0+ 2 // 3 // Copyright (C) 2000-2001 Deep Blue Solutions 4 // Copyright (C) 2002 Shane Nay (shane@minirl.com) 5 // Copyright (C) 2006-2007 Pavel Pisa (ppisa@pikron.com) 6 // Copyright (C) 2008 Juergen Beisert (kernel@pengutronix.de) 7 // Copyright (C) 2010 Freescale Semiconductor, Inc. All Rights Reserved. 8 9 #include <linux/err.h> 10 #include <linux/interrupt.h> 11 #include <linux/irq.h> 12 #include <linux/clockchips.h> 13 #include <linux/clk.h> 14 #include <linux/of.h> 15 #include <linux/of_address.h> 16 #include <linux/of_irq.h> 17 #include <linux/stmp_device.h> 18 #include <linux/sched_clock.h> 19 20 /* 21 * There are 2 versions of the timrot on Freescale MXS-based SoCs. 22 * The v1 on MX23 only gets 16 bits counter, while v2 on MX28 23 * extends the counter to 32 bits. 24 * 25 * The implementation uses two timers, one for clock_event and 26 * another for clocksource. MX28 uses timrot 0 and 1, while MX23 27 * uses 0 and 2. 28 */ 29 30 #define MX23_TIMROT_VERSION_OFFSET 0x0a0 31 #define MX28_TIMROT_VERSION_OFFSET 0x120 32 #define BP_TIMROT_MAJOR_VERSION 24 33 #define BV_TIMROT_VERSION_1 0x01 34 #define BV_TIMROT_VERSION_2 0x02 35 #define timrot_is_v1() (timrot_major_version == BV_TIMROT_VERSION_1) 36 37 /* 38 * There are 4 registers for each timrotv2 instance, and 2 registers 39 * for each timrotv1. So address step 0x40 in macros below strides 40 * one instance of timrotv2 while two instances of timrotv1. 41 * 42 * As the result, HW_TIMROT_XXXn(1) defines the address of timrot1 43 * on MX28 while timrot2 on MX23. 44 */ 45 /* common between v1 and v2 */ 46 #define HW_TIMROT_ROTCTRL 0x00 47 #define HW_TIMROT_TIMCTRLn(n) (0x20 + (n) * 0x40) 48 /* v1 only */ 49 #define HW_TIMROT_TIMCOUNTn(n) (0x30 + (n) * 0x40) 50 /* v2 only */ 51 #define HW_TIMROT_RUNNING_COUNTn(n) (0x30 + (n) * 0x40) 52 #define HW_TIMROT_FIXED_COUNTn(n) (0x40 + (n) * 0x40) 53 54 #define BM_TIMROT_TIMCTRLn_RELOAD (1 << 6) 55 #define BM_TIMROT_TIMCTRLn_UPDATE (1 << 7) 56 #define BM_TIMROT_TIMCTRLn_IRQ_EN (1 << 14) 57 #define BM_TIMROT_TIMCTRLn_IRQ (1 << 15) 58 #define BP_TIMROT_TIMCTRLn_SELECT 0 59 #define BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL 0x8 60 #define BV_TIMROTv2_TIMCTRLn_SELECT__32KHZ_XTAL 0xb 61 #define BV_TIMROTv2_TIMCTRLn_SELECT__TICK_ALWAYS 0xf 62 63 static struct clock_event_device mxs_clockevent_device; 64 65 static void __iomem *mxs_timrot_base; 66 static u32 timrot_major_version; 67 68 static inline void timrot_irq_disable(void) 69 { 70 __raw_writel(BM_TIMROT_TIMCTRLn_IRQ_EN, mxs_timrot_base + 71 HW_TIMROT_TIMCTRLn(0) + STMP_OFFSET_REG_CLR); 72 } 73 74 static inline void timrot_irq_enable(void) 75 { 76 __raw_writel(BM_TIMROT_TIMCTRLn_IRQ_EN, mxs_timrot_base + 77 HW_TIMROT_TIMCTRLn(0) + STMP_OFFSET_REG_SET); 78 } 79 80 static void timrot_irq_acknowledge(void) 81 { 82 __raw_writel(BM_TIMROT_TIMCTRLn_IRQ, mxs_timrot_base + 83 HW_TIMROT_TIMCTRLn(0) + STMP_OFFSET_REG_CLR); 84 } 85 86 static u64 timrotv1_get_cycles(struct clocksource *cs) 87 { 88 return ~((__raw_readl(mxs_timrot_base + HW_TIMROT_TIMCOUNTn(1)) 89 & 0xffff0000) >> 16); 90 } 91 92 static int timrotv1_set_next_event(unsigned long evt, 93 struct clock_event_device *dev) 94 { 95 /* timrot decrements the count */ 96 __raw_writel(evt, mxs_timrot_base + HW_TIMROT_TIMCOUNTn(0)); 97 98 return 0; 99 } 100 101 static int timrotv2_set_next_event(unsigned long evt, 102 struct clock_event_device *dev) 103 { 104 /* timrot decrements the count */ 105 __raw_writel(evt, mxs_timrot_base + HW_TIMROT_FIXED_COUNTn(0)); 106 107 return 0; 108 } 109 110 static irqreturn_t mxs_timer_interrupt(int irq, void *dev_id) 111 { 112 struct clock_event_device *evt = dev_id; 113 114 timrot_irq_acknowledge(); 115 evt->event_handler(evt); 116 117 return IRQ_HANDLED; 118 } 119 120 static void mxs_irq_clear(char *state) 121 { 122 /* Disable interrupt in timer module */ 123 timrot_irq_disable(); 124 125 /* Set event time into the furthest future */ 126 if (timrot_is_v1()) 127 __raw_writel(0xffff, mxs_timrot_base + HW_TIMROT_TIMCOUNTn(1)); 128 else 129 __raw_writel(0xffffffff, 130 mxs_timrot_base + HW_TIMROT_FIXED_COUNTn(1)); 131 132 /* Clear pending interrupt */ 133 timrot_irq_acknowledge(); 134 135 #ifdef DEBUG 136 pr_info("%s: changing mode to %s\n", __func__, state) 137 #endif /* DEBUG */ 138 } 139 140 static int mxs_shutdown(struct clock_event_device *evt) 141 { 142 mxs_irq_clear("shutdown"); 143 144 return 0; 145 } 146 147 static int mxs_set_oneshot(struct clock_event_device *evt) 148 { 149 if (clockevent_state_oneshot(evt)) 150 mxs_irq_clear("oneshot"); 151 timrot_irq_enable(); 152 return 0; 153 } 154 155 static struct clock_event_device mxs_clockevent_device = { 156 .name = "mxs_timrot", 157 .features = CLOCK_EVT_FEAT_ONESHOT, 158 .set_state_shutdown = mxs_shutdown, 159 .set_state_oneshot = mxs_set_oneshot, 160 .tick_resume = mxs_shutdown, 161 .set_next_event = timrotv2_set_next_event, 162 .rating = 200, 163 }; 164 165 static int __init mxs_clockevent_init(struct clk *timer_clk) 166 { 167 if (timrot_is_v1()) 168 mxs_clockevent_device.set_next_event = timrotv1_set_next_event; 169 mxs_clockevent_device.cpumask = cpumask_of(0); 170 clockevents_config_and_register(&mxs_clockevent_device, 171 clk_get_rate(timer_clk), 172 timrot_is_v1() ? 0xf : 0x2, 173 timrot_is_v1() ? 0xfffe : 0xfffffffe); 174 175 return 0; 176 } 177 178 static struct clocksource clocksource_mxs = { 179 .name = "mxs_timer", 180 .rating = 200, 181 .read = timrotv1_get_cycles, 182 .mask = CLOCKSOURCE_MASK(16), 183 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 184 }; 185 186 static u64 notrace mxs_read_sched_clock_v2(void) 187 { 188 return ~readl_relaxed(mxs_timrot_base + HW_TIMROT_RUNNING_COUNTn(1)); 189 } 190 191 static int __init mxs_clocksource_init(struct clk *timer_clk) 192 { 193 unsigned int c = clk_get_rate(timer_clk); 194 195 if (timrot_is_v1()) 196 clocksource_register_hz(&clocksource_mxs, c); 197 else { 198 clocksource_mmio_init(mxs_timrot_base + HW_TIMROT_RUNNING_COUNTn(1), 199 "mxs_timer", c, 200, 32, clocksource_mmio_readl_down); 200 sched_clock_register(mxs_read_sched_clock_v2, 32, c); 201 } 202 203 return 0; 204 } 205 206 static int __init mxs_timer_init(struct device_node *np) 207 { 208 struct clk *timer_clk; 209 int irq, ret; 210 211 mxs_timrot_base = of_iomap(np, 0); 212 WARN_ON(!mxs_timrot_base); 213 214 timer_clk = of_clk_get(np, 0); 215 if (IS_ERR(timer_clk)) { 216 pr_err("%s: failed to get clk\n", __func__); 217 return PTR_ERR(timer_clk); 218 } 219 220 ret = clk_prepare_enable(timer_clk); 221 if (ret) 222 return ret; 223 224 /* 225 * Initialize timers to a known state 226 */ 227 stmp_reset_block(mxs_timrot_base + HW_TIMROT_ROTCTRL); 228 229 /* get timrot version */ 230 timrot_major_version = __raw_readl(mxs_timrot_base + 231 (of_device_is_compatible(np, "fsl,imx23-timrot") ? 232 MX23_TIMROT_VERSION_OFFSET : 233 MX28_TIMROT_VERSION_OFFSET)); 234 timrot_major_version >>= BP_TIMROT_MAJOR_VERSION; 235 236 /* one for clock_event */ 237 __raw_writel((timrot_is_v1() ? 238 BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL : 239 BV_TIMROTv2_TIMCTRLn_SELECT__TICK_ALWAYS) | 240 BM_TIMROT_TIMCTRLn_UPDATE | 241 BM_TIMROT_TIMCTRLn_IRQ_EN, 242 mxs_timrot_base + HW_TIMROT_TIMCTRLn(0)); 243 244 /* another for clocksource */ 245 __raw_writel((timrot_is_v1() ? 246 BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL : 247 BV_TIMROTv2_TIMCTRLn_SELECT__TICK_ALWAYS) | 248 BM_TIMROT_TIMCTRLn_RELOAD, 249 mxs_timrot_base + HW_TIMROT_TIMCTRLn(1)); 250 251 /* set clocksource timer fixed count to the maximum */ 252 if (timrot_is_v1()) 253 __raw_writel(0xffff, 254 mxs_timrot_base + HW_TIMROT_TIMCOUNTn(1)); 255 else 256 __raw_writel(0xffffffff, 257 mxs_timrot_base + HW_TIMROT_FIXED_COUNTn(1)); 258 259 /* init and register the timer to the framework */ 260 ret = mxs_clocksource_init(timer_clk); 261 if (ret) 262 return ret; 263 264 ret = mxs_clockevent_init(timer_clk); 265 if (ret) 266 return ret; 267 268 /* Make irqs happen */ 269 irq = irq_of_parse_and_map(np, 0); 270 if (irq <= 0) 271 return -EINVAL; 272 273 return request_irq(irq, mxs_timer_interrupt, IRQF_TIMER | IRQF_IRQPOLL, 274 "MXS Timer Tick", &mxs_clockevent_device); 275 } 276 TIMER_OF_DECLARE(mxs, "fsl,timrot", mxs_timer_init); 277