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1/*
2 * Copyright (C) 2000-2001 Deep Blue Solutions
3 * Copyright (C) 2002 Shane Nay (shane@minirl.com)
4 * Copyright (C) 2006-2007 Pavel Pisa (ppisa@pikron.com)
5 * Copyright (C) 2008 Juergen Beisert (kernel@pengutronix.de)
6 * Copyright (C) 2010 Freescale Semiconductor, Inc. All Rights Reserved.
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version 2
11 * of the License, or (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
20 * MA 02110-1301, USA.
21 */
22
23#include <linux/err.h>
24#include <linux/interrupt.h>
25#include <linux/irq.h>
26#include <linux/clockchips.h>
27#include <linux/clk.h>
28#include <linux/of.h>
29#include <linux/of_address.h>
30#include <linux/of_irq.h>
31#include <linux/stmp_device.h>
32#include <linux/sched_clock.h>
33
34/*
35 * There are 2 versions of the timrot on Freescale MXS-based SoCs.
36 * The v1 on MX23 only gets 16 bits counter, while v2 on MX28
37 * extends the counter to 32 bits.
38 *
39 * The implementation uses two timers, one for clock_event and
40 * another for clocksource. MX28 uses timrot 0 and 1, while MX23
41 * uses 0 and 2.
42 */
43
44#define MX23_TIMROT_VERSION_OFFSET 0x0a0
45#define MX28_TIMROT_VERSION_OFFSET 0x120
46#define BP_TIMROT_MAJOR_VERSION 24
47#define BV_TIMROT_VERSION_1 0x01
48#define BV_TIMROT_VERSION_2 0x02
49#define timrot_is_v1() (timrot_major_version == BV_TIMROT_VERSION_1)
50
51/*
52 * There are 4 registers for each timrotv2 instance, and 2 registers
53 * for each timrotv1. So address step 0x40 in macros below strides
54 * one instance of timrotv2 while two instances of timrotv1.
55 *
56 * As the result, HW_TIMROT_XXXn(1) defines the address of timrot1
57 * on MX28 while timrot2 on MX23.
58 */
59/* common between v1 and v2 */
60#define HW_TIMROT_ROTCTRL 0x00
61#define HW_TIMROT_TIMCTRLn(n) (0x20 + (n) * 0x40)
62/* v1 only */
63#define HW_TIMROT_TIMCOUNTn(n) (0x30 + (n) * 0x40)
64/* v2 only */
65#define HW_TIMROT_RUNNING_COUNTn(n) (0x30 + (n) * 0x40)
66#define HW_TIMROT_FIXED_COUNTn(n) (0x40 + (n) * 0x40)
67
68#define BM_TIMROT_TIMCTRLn_RELOAD (1 << 6)
69#define BM_TIMROT_TIMCTRLn_UPDATE (1 << 7)
70#define BM_TIMROT_TIMCTRLn_IRQ_EN (1 << 14)
71#define BM_TIMROT_TIMCTRLn_IRQ (1 << 15)
72#define BP_TIMROT_TIMCTRLn_SELECT 0
73#define BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL 0x8
74#define BV_TIMROTv2_TIMCTRLn_SELECT__32KHZ_XTAL 0xb
75#define BV_TIMROTv2_TIMCTRLn_SELECT__TICK_ALWAYS 0xf
76
77static struct clock_event_device mxs_clockevent_device;
78
79static void __iomem *mxs_timrot_base;
80static u32 timrot_major_version;
81
82static inline void timrot_irq_disable(void)
83{
84 __raw_writel(BM_TIMROT_TIMCTRLn_IRQ_EN, mxs_timrot_base +
85 HW_TIMROT_TIMCTRLn(0) + STMP_OFFSET_REG_CLR);
86}
87
88static inline void timrot_irq_enable(void)
89{
90 __raw_writel(BM_TIMROT_TIMCTRLn_IRQ_EN, mxs_timrot_base +
91 HW_TIMROT_TIMCTRLn(0) + STMP_OFFSET_REG_SET);
92}
93
94static void timrot_irq_acknowledge(void)
95{
96 __raw_writel(BM_TIMROT_TIMCTRLn_IRQ, mxs_timrot_base +
97 HW_TIMROT_TIMCTRLn(0) + STMP_OFFSET_REG_CLR);
98}
99
100static u64 timrotv1_get_cycles(struct clocksource *cs)
101{
102 return ~((__raw_readl(mxs_timrot_base + HW_TIMROT_TIMCOUNTn(1))
103 & 0xffff0000) >> 16);
104}
105
106static int timrotv1_set_next_event(unsigned long evt,
107 struct clock_event_device *dev)
108{
109 /* timrot decrements the count */
110 __raw_writel(evt, mxs_timrot_base + HW_TIMROT_TIMCOUNTn(0));
111
112 return 0;
113}
114
115static int timrotv2_set_next_event(unsigned long evt,
116 struct clock_event_device *dev)
117{
118 /* timrot decrements the count */
119 __raw_writel(evt, mxs_timrot_base + HW_TIMROT_FIXED_COUNTn(0));
120
121 return 0;
122}
123
124static irqreturn_t mxs_timer_interrupt(int irq, void *dev_id)
125{
126 struct clock_event_device *evt = dev_id;
127
128 timrot_irq_acknowledge();
129 evt->event_handler(evt);
130
131 return IRQ_HANDLED;
132}
133
134static struct irqaction mxs_timer_irq = {
135 .name = "MXS Timer Tick",
136 .dev_id = &mxs_clockevent_device,
137 .flags = IRQF_TIMER | IRQF_IRQPOLL,
138 .handler = mxs_timer_interrupt,
139};
140
141static void mxs_irq_clear(char *state)
142{
143 /* Disable interrupt in timer module */
144 timrot_irq_disable();
145
146 /* Set event time into the furthest future */
147 if (timrot_is_v1())
148 __raw_writel(0xffff, mxs_timrot_base + HW_TIMROT_TIMCOUNTn(1));
149 else
150 __raw_writel(0xffffffff,
151 mxs_timrot_base + HW_TIMROT_FIXED_COUNTn(1));
152
153 /* Clear pending interrupt */
154 timrot_irq_acknowledge();
155
156#ifdef DEBUG
157 pr_info("%s: changing mode to %s\n", __func__, state)
158#endif /* DEBUG */
159}
160
161static int mxs_shutdown(struct clock_event_device *evt)
162{
163 mxs_irq_clear("shutdown");
164
165 return 0;
166}
167
168static int mxs_set_oneshot(struct clock_event_device *evt)
169{
170 if (clockevent_state_oneshot(evt))
171 mxs_irq_clear("oneshot");
172 timrot_irq_enable();
173 return 0;
174}
175
176static struct clock_event_device mxs_clockevent_device = {
177 .name = "mxs_timrot",
178 .features = CLOCK_EVT_FEAT_ONESHOT,
179 .set_state_shutdown = mxs_shutdown,
180 .set_state_oneshot = mxs_set_oneshot,
181 .tick_resume = mxs_shutdown,
182 .set_next_event = timrotv2_set_next_event,
183 .rating = 200,
184};
185
186static int __init mxs_clockevent_init(struct clk *timer_clk)
187{
188 if (timrot_is_v1())
189 mxs_clockevent_device.set_next_event = timrotv1_set_next_event;
190 mxs_clockevent_device.cpumask = cpumask_of(0);
191 clockevents_config_and_register(&mxs_clockevent_device,
192 clk_get_rate(timer_clk),
193 timrot_is_v1() ? 0xf : 0x2,
194 timrot_is_v1() ? 0xfffe : 0xfffffffe);
195
196 return 0;
197}
198
199static struct clocksource clocksource_mxs = {
200 .name = "mxs_timer",
201 .rating = 200,
202 .read = timrotv1_get_cycles,
203 .mask = CLOCKSOURCE_MASK(16),
204 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
205};
206
207static u64 notrace mxs_read_sched_clock_v2(void)
208{
209 return ~readl_relaxed(mxs_timrot_base + HW_TIMROT_RUNNING_COUNTn(1));
210}
211
212static int __init mxs_clocksource_init(struct clk *timer_clk)
213{
214 unsigned int c = clk_get_rate(timer_clk);
215
216 if (timrot_is_v1())
217 clocksource_register_hz(&clocksource_mxs, c);
218 else {
219 clocksource_mmio_init(mxs_timrot_base + HW_TIMROT_RUNNING_COUNTn(1),
220 "mxs_timer", c, 200, 32, clocksource_mmio_readl_down);
221 sched_clock_register(mxs_read_sched_clock_v2, 32, c);
222 }
223
224 return 0;
225}
226
227static int __init mxs_timer_init(struct device_node *np)
228{
229 struct clk *timer_clk;
230 int irq, ret;
231
232 mxs_timrot_base = of_iomap(np, 0);
233 WARN_ON(!mxs_timrot_base);
234
235 timer_clk = of_clk_get(np, 0);
236 if (IS_ERR(timer_clk)) {
237 pr_err("%s: failed to get clk\n", __func__);
238 return PTR_ERR(timer_clk);
239 }
240
241 ret = clk_prepare_enable(timer_clk);
242 if (ret)
243 return ret;
244
245 /*
246 * Initialize timers to a known state
247 */
248 stmp_reset_block(mxs_timrot_base + HW_TIMROT_ROTCTRL);
249
250 /* get timrot version */
251 timrot_major_version = __raw_readl(mxs_timrot_base +
252 (of_device_is_compatible(np, "fsl,imx23-timrot") ?
253 MX23_TIMROT_VERSION_OFFSET :
254 MX28_TIMROT_VERSION_OFFSET));
255 timrot_major_version >>= BP_TIMROT_MAJOR_VERSION;
256
257 /* one for clock_event */
258 __raw_writel((timrot_is_v1() ?
259 BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL :
260 BV_TIMROTv2_TIMCTRLn_SELECT__TICK_ALWAYS) |
261 BM_TIMROT_TIMCTRLn_UPDATE |
262 BM_TIMROT_TIMCTRLn_IRQ_EN,
263 mxs_timrot_base + HW_TIMROT_TIMCTRLn(0));
264
265 /* another for clocksource */
266 __raw_writel((timrot_is_v1() ?
267 BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL :
268 BV_TIMROTv2_TIMCTRLn_SELECT__TICK_ALWAYS) |
269 BM_TIMROT_TIMCTRLn_RELOAD,
270 mxs_timrot_base + HW_TIMROT_TIMCTRLn(1));
271
272 /* set clocksource timer fixed count to the maximum */
273 if (timrot_is_v1())
274 __raw_writel(0xffff,
275 mxs_timrot_base + HW_TIMROT_TIMCOUNTn(1));
276 else
277 __raw_writel(0xffffffff,
278 mxs_timrot_base + HW_TIMROT_FIXED_COUNTn(1));
279
280 /* init and register the timer to the framework */
281 ret = mxs_clocksource_init(timer_clk);
282 if (ret)
283 return ret;
284
285 ret = mxs_clockevent_init(timer_clk);
286 if (ret)
287 return ret;
288
289 /* Make irqs happen */
290 irq = irq_of_parse_and_map(np, 0);
291 if (irq <= 0)
292 return -EINVAL;
293
294 return setup_irq(irq, &mxs_timer_irq);
295}
296TIMER_OF_DECLARE(mxs, "fsl,timrot", mxs_timer_init);