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
timrot_irq_disable(void)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
timrot_irq_enable(void)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
timrot_irq_acknowledge(void)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
timrotv1_get_cycles(struct clocksource * cs)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
timrotv1_set_next_event(unsigned long evt,struct clock_event_device * dev)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
timrotv2_set_next_event(unsigned long evt,struct clock_event_device * dev)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
mxs_timer_interrupt(int irq,void * dev_id)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
mxs_irq_clear(char * state)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 pr_debug("%s: changing mode to %s\n", __func__, state);
135 }
136
mxs_shutdown(struct clock_event_device * evt)137 static int mxs_shutdown(struct clock_event_device *evt)
138 {
139 mxs_irq_clear("shutdown");
140
141 return 0;
142 }
143
mxs_set_oneshot(struct clock_event_device * evt)144 static int mxs_set_oneshot(struct clock_event_device *evt)
145 {
146 if (clockevent_state_oneshot(evt))
147 mxs_irq_clear("oneshot");
148 timrot_irq_enable();
149 return 0;
150 }
151
152 static struct clock_event_device mxs_clockevent_device = {
153 .name = "mxs_timrot",
154 .features = CLOCK_EVT_FEAT_ONESHOT,
155 .set_state_shutdown = mxs_shutdown,
156 .set_state_oneshot = mxs_set_oneshot,
157 .tick_resume = mxs_shutdown,
158 .set_next_event = timrotv2_set_next_event,
159 .rating = 200,
160 };
161
mxs_clockevent_init(struct clk * timer_clk)162 static int __init mxs_clockevent_init(struct clk *timer_clk)
163 {
164 if (timrot_is_v1())
165 mxs_clockevent_device.set_next_event = timrotv1_set_next_event;
166 mxs_clockevent_device.cpumask = cpumask_of(0);
167 clockevents_config_and_register(&mxs_clockevent_device,
168 clk_get_rate(timer_clk),
169 timrot_is_v1() ? 0xf : 0x2,
170 timrot_is_v1() ? 0xfffe : 0xfffffffe);
171
172 return 0;
173 }
174
175 static struct clocksource clocksource_mxs = {
176 .name = "mxs_timer",
177 .rating = 200,
178 .read = timrotv1_get_cycles,
179 .mask = CLOCKSOURCE_MASK(16),
180 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
181 };
182
mxs_read_sched_clock_v2(void)183 static u64 notrace mxs_read_sched_clock_v2(void)
184 {
185 return ~readl_relaxed(mxs_timrot_base + HW_TIMROT_RUNNING_COUNTn(1));
186 }
187
mxs_clocksource_init(struct clk * timer_clk)188 static int __init mxs_clocksource_init(struct clk *timer_clk)
189 {
190 unsigned int c = clk_get_rate(timer_clk);
191
192 if (timrot_is_v1())
193 clocksource_register_hz(&clocksource_mxs, c);
194 else {
195 clocksource_mmio_init(mxs_timrot_base + HW_TIMROT_RUNNING_COUNTn(1),
196 "mxs_timer", c, 200, 32, clocksource_mmio_readl_down);
197 sched_clock_register(mxs_read_sched_clock_v2, 32, c);
198 }
199
200 return 0;
201 }
202
mxs_timer_init(struct device_node * np)203 static int __init mxs_timer_init(struct device_node *np)
204 {
205 struct clk *timer_clk;
206 int irq, ret;
207
208 mxs_timrot_base = of_iomap(np, 0);
209 WARN_ON(!mxs_timrot_base);
210
211 timer_clk = of_clk_get(np, 0);
212 if (IS_ERR(timer_clk)) {
213 pr_err("%s: failed to get clk\n", __func__);
214 return PTR_ERR(timer_clk);
215 }
216
217 ret = clk_prepare_enable(timer_clk);
218 if (ret)
219 return ret;
220
221 /*
222 * Initialize timers to a known state
223 */
224 stmp_reset_block(mxs_timrot_base + HW_TIMROT_ROTCTRL);
225
226 /* get timrot version */
227 timrot_major_version = __raw_readl(mxs_timrot_base +
228 (of_device_is_compatible(np, "fsl,imx23-timrot") ?
229 MX23_TIMROT_VERSION_OFFSET :
230 MX28_TIMROT_VERSION_OFFSET));
231 timrot_major_version >>= BP_TIMROT_MAJOR_VERSION;
232
233 /* one for clock_event */
234 __raw_writel((timrot_is_v1() ?
235 BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL :
236 BV_TIMROTv2_TIMCTRLn_SELECT__TICK_ALWAYS) |
237 BM_TIMROT_TIMCTRLn_UPDATE |
238 BM_TIMROT_TIMCTRLn_IRQ_EN,
239 mxs_timrot_base + HW_TIMROT_TIMCTRLn(0));
240
241 /* another for clocksource */
242 __raw_writel((timrot_is_v1() ?
243 BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL :
244 BV_TIMROTv2_TIMCTRLn_SELECT__TICK_ALWAYS) |
245 BM_TIMROT_TIMCTRLn_RELOAD,
246 mxs_timrot_base + HW_TIMROT_TIMCTRLn(1));
247
248 /* set clocksource timer fixed count to the maximum */
249 if (timrot_is_v1())
250 __raw_writel(0xffff,
251 mxs_timrot_base + HW_TIMROT_TIMCOUNTn(1));
252 else
253 __raw_writel(0xffffffff,
254 mxs_timrot_base + HW_TIMROT_FIXED_COUNTn(1));
255
256 /* init and register the timer to the framework */
257 ret = mxs_clocksource_init(timer_clk);
258 if (ret)
259 return ret;
260
261 ret = mxs_clockevent_init(timer_clk);
262 if (ret)
263 return ret;
264
265 /* Make irqs happen */
266 irq = irq_of_parse_and_map(np, 0);
267 if (irq <= 0)
268 return -EINVAL;
269
270 return request_irq(irq, mxs_timer_interrupt, IRQF_TIMER | IRQF_IRQPOLL,
271 "MXS Timer Tick", &mxs_clockevent_device);
272 }
273 TIMER_OF_DECLARE(mxs, "fsl,timrot", mxs_timer_init);
274