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1#include <linux/init.h>
2#include <linux/clocksource.h>
3#include <linux/clockchips.h>
4#include <linux/interrupt.h>
5#include <linux/irq.h>
6
7#include <linux/clk.h>
8#include <linux/err.h>
9#include <linux/ioport.h>
10#include <linux/io.h>
11#include <linux/platform_device.h>
12#include <linux/atmel_tc.h>
13
14
15/*
16 * We're configured to use a specific TC block, one that's not hooked
17 * up to external hardware, to provide a time solution:
18 *
19 * - Two channels combine to create a free-running 32 bit counter
20 * with a base rate of 5+ MHz, packaged as a clocksource (with
21 * resolution better than 200 nsec).
22 *
23 * - The third channel may be used to provide a 16-bit clockevent
24 * source, used in either periodic or oneshot mode. This runs
25 * at 32 KiHZ, and can handle delays of up to two seconds.
26 *
27 * A boot clocksource and clockevent source are also currently needed,
28 * unless the relevant platforms (ARM/AT91, AVR32/AT32) are changed so
29 * this code can be used when init_timers() is called, well before most
30 * devices are set up. (Some low end AT91 parts, which can run uClinux,
31 * have only the timers in one TC block... they currently don't support
32 * the tclib code, because of that initialization issue.)
33 *
34 * REVISIT behavior during system suspend states... we should disable
35 * all clocks and save the power. Easily done for clockevent devices,
36 * but clocksources won't necessarily get the needed notifications.
37 * For deeper system sleep states, this will be mandatory...
38 */
39
40static void __iomem *tcaddr;
41
42static cycle_t tc_get_cycles(struct clocksource *cs)
43{
44 unsigned long flags;
45 u32 lower, upper;
46
47 raw_local_irq_save(flags);
48 do {
49 upper = __raw_readl(tcaddr + ATMEL_TC_REG(1, CV));
50 lower = __raw_readl(tcaddr + ATMEL_TC_REG(0, CV));
51 } while (upper != __raw_readl(tcaddr + ATMEL_TC_REG(1, CV)));
52
53 raw_local_irq_restore(flags);
54 return (upper << 16) | lower;
55}
56
57static struct clocksource clksrc = {
58 .name = "tcb_clksrc",
59 .rating = 200,
60 .read = tc_get_cycles,
61 .mask = CLOCKSOURCE_MASK(32),
62 .shift = 18,
63 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
64};
65
66#ifdef CONFIG_GENERIC_CLOCKEVENTS
67
68struct tc_clkevt_device {
69 struct clock_event_device clkevt;
70 struct clk *clk;
71 void __iomem *regs;
72};
73
74static struct tc_clkevt_device *to_tc_clkevt(struct clock_event_device *clkevt)
75{
76 return container_of(clkevt, struct tc_clkevt_device, clkevt);
77}
78
79/* For now, we always use the 32K clock ... this optimizes for NO_HZ,
80 * because using one of the divided clocks would usually mean the
81 * tick rate can never be less than several dozen Hz (vs 0.5 Hz).
82 *
83 * A divided clock could be good for high resolution timers, since
84 * 30.5 usec resolution can seem "low".
85 */
86static u32 timer_clock;
87
88static void tc_mode(enum clock_event_mode m, struct clock_event_device *d)
89{
90 struct tc_clkevt_device *tcd = to_tc_clkevt(d);
91 void __iomem *regs = tcd->regs;
92
93 if (tcd->clkevt.mode == CLOCK_EVT_MODE_PERIODIC
94 || tcd->clkevt.mode == CLOCK_EVT_MODE_ONESHOT) {
95 __raw_writel(0xff, regs + ATMEL_TC_REG(2, IDR));
96 __raw_writel(ATMEL_TC_CLKDIS, regs + ATMEL_TC_REG(2, CCR));
97 clk_disable(tcd->clk);
98 }
99
100 switch (m) {
101
102 /* By not making the gentime core emulate periodic mode on top
103 * of oneshot, we get lower overhead and improved accuracy.
104 */
105 case CLOCK_EVT_MODE_PERIODIC:
106 clk_enable(tcd->clk);
107
108 /* slow clock, count up to RC, then irq and restart */
109 __raw_writel(timer_clock
110 | ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO,
111 regs + ATMEL_TC_REG(2, CMR));
112 __raw_writel((32768 + HZ/2) / HZ, tcaddr + ATMEL_TC_REG(2, RC));
113
114 /* Enable clock and interrupts on RC compare */
115 __raw_writel(ATMEL_TC_CPCS, regs + ATMEL_TC_REG(2, IER));
116
117 /* go go gadget! */
118 __raw_writel(ATMEL_TC_CLKEN | ATMEL_TC_SWTRG,
119 regs + ATMEL_TC_REG(2, CCR));
120 break;
121
122 case CLOCK_EVT_MODE_ONESHOT:
123 clk_enable(tcd->clk);
124
125 /* slow clock, count up to RC, then irq and stop */
126 __raw_writel(timer_clock | ATMEL_TC_CPCSTOP
127 | ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO,
128 regs + ATMEL_TC_REG(2, CMR));
129 __raw_writel(ATMEL_TC_CPCS, regs + ATMEL_TC_REG(2, IER));
130
131 /* set_next_event() configures and starts the timer */
132 break;
133
134 default:
135 break;
136 }
137}
138
139static int tc_next_event(unsigned long delta, struct clock_event_device *d)
140{
141 __raw_writel(delta, tcaddr + ATMEL_TC_REG(2, RC));
142
143 /* go go gadget! */
144 __raw_writel(ATMEL_TC_CLKEN | ATMEL_TC_SWTRG,
145 tcaddr + ATMEL_TC_REG(2, CCR));
146 return 0;
147}
148
149static struct tc_clkevt_device clkevt = {
150 .clkevt = {
151 .name = "tc_clkevt",
152 .features = CLOCK_EVT_FEAT_PERIODIC
153 | CLOCK_EVT_FEAT_ONESHOT,
154 .shift = 32,
155 /* Should be lower than at91rm9200's system timer */
156 .rating = 125,
157 .set_next_event = tc_next_event,
158 .set_mode = tc_mode,
159 },
160};
161
162static irqreturn_t ch2_irq(int irq, void *handle)
163{
164 struct tc_clkevt_device *dev = handle;
165 unsigned int sr;
166
167 sr = __raw_readl(dev->regs + ATMEL_TC_REG(2, SR));
168 if (sr & ATMEL_TC_CPCS) {
169 dev->clkevt.event_handler(&dev->clkevt);
170 return IRQ_HANDLED;
171 }
172
173 return IRQ_NONE;
174}
175
176static struct irqaction tc_irqaction = {
177 .name = "tc_clkevt",
178 .flags = IRQF_TIMER | IRQF_DISABLED,
179 .handler = ch2_irq,
180};
181
182static void __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx)
183{
184 struct clk *t2_clk = tc->clk[2];
185 int irq = tc->irq[2];
186
187 clkevt.regs = tc->regs;
188 clkevt.clk = t2_clk;
189 tc_irqaction.dev_id = &clkevt;
190
191 timer_clock = clk32k_divisor_idx;
192
193 clkevt.clkevt.mult = div_sc(32768, NSEC_PER_SEC, clkevt.clkevt.shift);
194 clkevt.clkevt.max_delta_ns
195 = clockevent_delta2ns(0xffff, &clkevt.clkevt);
196 clkevt.clkevt.min_delta_ns = clockevent_delta2ns(1, &clkevt.clkevt) + 1;
197 clkevt.clkevt.cpumask = cpumask_of(0);
198
199 clockevents_register_device(&clkevt.clkevt);
200
201 setup_irq(irq, &tc_irqaction);
202}
203
204#else /* !CONFIG_GENERIC_CLOCKEVENTS */
205
206static void __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx)
207{
208 /* NOTHING */
209}
210
211#endif
212
213static int __init tcb_clksrc_init(void)
214{
215 static char bootinfo[] __initdata
216 = KERN_DEBUG "%s: tc%d at %d.%03d MHz\n";
217
218 struct platform_device *pdev;
219 struct atmel_tc *tc;
220 struct clk *t0_clk;
221 u32 rate, divided_rate = 0;
222 int best_divisor_idx = -1;
223 int clk32k_divisor_idx = -1;
224 int i;
225
226 tc = atmel_tc_alloc(CONFIG_ATMEL_TCB_CLKSRC_BLOCK, clksrc.name);
227 if (!tc) {
228 pr_debug("can't alloc TC for clocksource\n");
229 return -ENODEV;
230 }
231 tcaddr = tc->regs;
232 pdev = tc->pdev;
233
234 t0_clk = tc->clk[0];
235 clk_enable(t0_clk);
236
237 /* How fast will we be counting? Pick something over 5 MHz. */
238 rate = (u32) clk_get_rate(t0_clk);
239 for (i = 0; i < 5; i++) {
240 unsigned divisor = atmel_tc_divisors[i];
241 unsigned tmp;
242
243 /* remember 32 KiHz clock for later */
244 if (!divisor) {
245 clk32k_divisor_idx = i;
246 continue;
247 }
248
249 tmp = rate / divisor;
250 pr_debug("TC: %u / %-3u [%d] --> %u\n", rate, divisor, i, tmp);
251 if (best_divisor_idx > 0) {
252 if (tmp < 5 * 1000 * 1000)
253 continue;
254 }
255 divided_rate = tmp;
256 best_divisor_idx = i;
257 }
258
259 clksrc.mult = clocksource_hz2mult(divided_rate, clksrc.shift);
260
261 printk(bootinfo, clksrc.name, CONFIG_ATMEL_TCB_CLKSRC_BLOCK,
262 divided_rate / 1000000,
263 ((divided_rate + 500000) % 1000000) / 1000);
264
265 /* tclib will give us three clocks no matter what the
266 * underlying platform supports.
267 */
268 clk_enable(tc->clk[1]);
269
270 /* channel 0: waveform mode, input mclk/8, clock TIOA0 on overflow */
271 __raw_writel(best_divisor_idx /* likely divide-by-8 */
272 | ATMEL_TC_WAVE
273 | ATMEL_TC_WAVESEL_UP /* free-run */
274 | ATMEL_TC_ACPA_SET /* TIOA0 rises at 0 */
275 | ATMEL_TC_ACPC_CLEAR, /* (duty cycle 50%) */
276 tcaddr + ATMEL_TC_REG(0, CMR));
277 __raw_writel(0x0000, tcaddr + ATMEL_TC_REG(0, RA));
278 __raw_writel(0x8000, tcaddr + ATMEL_TC_REG(0, RC));
279 __raw_writel(0xff, tcaddr + ATMEL_TC_REG(0, IDR)); /* no irqs */
280 __raw_writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(0, CCR));
281
282 /* channel 1: waveform mode, input TIOA0 */
283 __raw_writel(ATMEL_TC_XC1 /* input: TIOA0 */
284 | ATMEL_TC_WAVE
285 | ATMEL_TC_WAVESEL_UP, /* free-run */
286 tcaddr + ATMEL_TC_REG(1, CMR));
287 __raw_writel(0xff, tcaddr + ATMEL_TC_REG(1, IDR)); /* no irqs */
288 __raw_writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(1, CCR));
289
290 /* chain channel 0 to channel 1, then reset all the timers */
291 __raw_writel(ATMEL_TC_TC1XC1S_TIOA0, tcaddr + ATMEL_TC_BMR);
292 __raw_writel(ATMEL_TC_SYNC, tcaddr + ATMEL_TC_BCR);
293
294 /* and away we go! */
295 clocksource_register(&clksrc);
296
297 /* channel 2: periodic and oneshot timer support */
298 setup_clkevents(tc, clk32k_divisor_idx);
299
300 return 0;
301}
302arch_initcall(tcb_clksrc_init);
1// SPDX-License-Identifier: GPL-2.0
2#include <linux/init.h>
3#include <linux/clocksource.h>
4#include <linux/clockchips.h>
5#include <linux/interrupt.h>
6#include <linux/irq.h>
7
8#include <linux/clk.h>
9#include <linux/err.h>
10#include <linux/ioport.h>
11#include <linux/io.h>
12#include <linux/platform_device.h>
13#include <linux/syscore_ops.h>
14#include <linux/atmel_tc.h>
15
16
17/*
18 * We're configured to use a specific TC block, one that's not hooked
19 * up to external hardware, to provide a time solution:
20 *
21 * - Two channels combine to create a free-running 32 bit counter
22 * with a base rate of 5+ MHz, packaged as a clocksource (with
23 * resolution better than 200 nsec).
24 * - Some chips support 32 bit counter. A single channel is used for
25 * this 32 bit free-running counter. the second channel is not used.
26 *
27 * - The third channel may be used to provide a 16-bit clockevent
28 * source, used in either periodic or oneshot mode. This runs
29 * at 32 KiHZ, and can handle delays of up to two seconds.
30 *
31 * A boot clocksource and clockevent source are also currently needed,
32 * unless the relevant platforms (ARM/AT91, AVR32/AT32) are changed so
33 * this code can be used when init_timers() is called, well before most
34 * devices are set up. (Some low end AT91 parts, which can run uClinux,
35 * have only the timers in one TC block... they currently don't support
36 * the tclib code, because of that initialization issue.)
37 *
38 * REVISIT behavior during system suspend states... we should disable
39 * all clocks and save the power. Easily done for clockevent devices,
40 * but clocksources won't necessarily get the needed notifications.
41 * For deeper system sleep states, this will be mandatory...
42 */
43
44static void __iomem *tcaddr;
45static struct
46{
47 u32 cmr;
48 u32 imr;
49 u32 rc;
50 bool clken;
51} tcb_cache[3];
52static u32 bmr_cache;
53
54static u64 tc_get_cycles(struct clocksource *cs)
55{
56 unsigned long flags;
57 u32 lower, upper;
58
59 raw_local_irq_save(flags);
60 do {
61 upper = readl_relaxed(tcaddr + ATMEL_TC_REG(1, CV));
62 lower = readl_relaxed(tcaddr + ATMEL_TC_REG(0, CV));
63 } while (upper != readl_relaxed(tcaddr + ATMEL_TC_REG(1, CV)));
64
65 raw_local_irq_restore(flags);
66 return (upper << 16) | lower;
67}
68
69static u64 tc_get_cycles32(struct clocksource *cs)
70{
71 return readl_relaxed(tcaddr + ATMEL_TC_REG(0, CV));
72}
73
74void tc_clksrc_suspend(struct clocksource *cs)
75{
76 int i;
77
78 for (i = 0; i < ARRAY_SIZE(tcb_cache); i++) {
79 tcb_cache[i].cmr = readl(tcaddr + ATMEL_TC_REG(i, CMR));
80 tcb_cache[i].imr = readl(tcaddr + ATMEL_TC_REG(i, IMR));
81 tcb_cache[i].rc = readl(tcaddr + ATMEL_TC_REG(i, RC));
82 tcb_cache[i].clken = !!(readl(tcaddr + ATMEL_TC_REG(i, SR)) &
83 ATMEL_TC_CLKSTA);
84 }
85
86 bmr_cache = readl(tcaddr + ATMEL_TC_BMR);
87}
88
89void tc_clksrc_resume(struct clocksource *cs)
90{
91 int i;
92
93 for (i = 0; i < ARRAY_SIZE(tcb_cache); i++) {
94 /* Restore registers for the channel, RA and RB are not used */
95 writel(tcb_cache[i].cmr, tcaddr + ATMEL_TC_REG(i, CMR));
96 writel(tcb_cache[i].rc, tcaddr + ATMEL_TC_REG(i, RC));
97 writel(0, tcaddr + ATMEL_TC_REG(i, RA));
98 writel(0, tcaddr + ATMEL_TC_REG(i, RB));
99 /* Disable all the interrupts */
100 writel(0xff, tcaddr + ATMEL_TC_REG(i, IDR));
101 /* Reenable interrupts that were enabled before suspending */
102 writel(tcb_cache[i].imr, tcaddr + ATMEL_TC_REG(i, IER));
103 /* Start the clock if it was used */
104 if (tcb_cache[i].clken)
105 writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(i, CCR));
106 }
107
108 /* Dual channel, chain channels */
109 writel(bmr_cache, tcaddr + ATMEL_TC_BMR);
110 /* Finally, trigger all the channels*/
111 writel(ATMEL_TC_SYNC, tcaddr + ATMEL_TC_BCR);
112}
113
114static struct clocksource clksrc = {
115 .name = "tcb_clksrc",
116 .rating = 200,
117 .read = tc_get_cycles,
118 .mask = CLOCKSOURCE_MASK(32),
119 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
120 .suspend = tc_clksrc_suspend,
121 .resume = tc_clksrc_resume,
122};
123
124#ifdef CONFIG_GENERIC_CLOCKEVENTS
125
126struct tc_clkevt_device {
127 struct clock_event_device clkevt;
128 struct clk *clk;
129 void __iomem *regs;
130};
131
132static struct tc_clkevt_device *to_tc_clkevt(struct clock_event_device *clkevt)
133{
134 return container_of(clkevt, struct tc_clkevt_device, clkevt);
135}
136
137/* For now, we always use the 32K clock ... this optimizes for NO_HZ,
138 * because using one of the divided clocks would usually mean the
139 * tick rate can never be less than several dozen Hz (vs 0.5 Hz).
140 *
141 * A divided clock could be good for high resolution timers, since
142 * 30.5 usec resolution can seem "low".
143 */
144static u32 timer_clock;
145
146static int tc_shutdown(struct clock_event_device *d)
147{
148 struct tc_clkevt_device *tcd = to_tc_clkevt(d);
149 void __iomem *regs = tcd->regs;
150
151 writel(0xff, regs + ATMEL_TC_REG(2, IDR));
152 writel(ATMEL_TC_CLKDIS, regs + ATMEL_TC_REG(2, CCR));
153 if (!clockevent_state_detached(d))
154 clk_disable(tcd->clk);
155
156 return 0;
157}
158
159static int tc_set_oneshot(struct clock_event_device *d)
160{
161 struct tc_clkevt_device *tcd = to_tc_clkevt(d);
162 void __iomem *regs = tcd->regs;
163
164 if (clockevent_state_oneshot(d) || clockevent_state_periodic(d))
165 tc_shutdown(d);
166
167 clk_enable(tcd->clk);
168
169 /* slow clock, count up to RC, then irq and stop */
170 writel(timer_clock | ATMEL_TC_CPCSTOP | ATMEL_TC_WAVE |
171 ATMEL_TC_WAVESEL_UP_AUTO, regs + ATMEL_TC_REG(2, CMR));
172 writel(ATMEL_TC_CPCS, regs + ATMEL_TC_REG(2, IER));
173
174 /* set_next_event() configures and starts the timer */
175 return 0;
176}
177
178static int tc_set_periodic(struct clock_event_device *d)
179{
180 struct tc_clkevt_device *tcd = to_tc_clkevt(d);
181 void __iomem *regs = tcd->regs;
182
183 if (clockevent_state_oneshot(d) || clockevent_state_periodic(d))
184 tc_shutdown(d);
185
186 /* By not making the gentime core emulate periodic mode on top
187 * of oneshot, we get lower overhead and improved accuracy.
188 */
189 clk_enable(tcd->clk);
190
191 /* slow clock, count up to RC, then irq and restart */
192 writel(timer_clock | ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO,
193 regs + ATMEL_TC_REG(2, CMR));
194 writel((32768 + HZ / 2) / HZ, tcaddr + ATMEL_TC_REG(2, RC));
195
196 /* Enable clock and interrupts on RC compare */
197 writel(ATMEL_TC_CPCS, regs + ATMEL_TC_REG(2, IER));
198
199 /* go go gadget! */
200 writel(ATMEL_TC_CLKEN | ATMEL_TC_SWTRG, regs +
201 ATMEL_TC_REG(2, CCR));
202 return 0;
203}
204
205static int tc_next_event(unsigned long delta, struct clock_event_device *d)
206{
207 writel_relaxed(delta, tcaddr + ATMEL_TC_REG(2, RC));
208
209 /* go go gadget! */
210 writel_relaxed(ATMEL_TC_CLKEN | ATMEL_TC_SWTRG,
211 tcaddr + ATMEL_TC_REG(2, CCR));
212 return 0;
213}
214
215static struct tc_clkevt_device clkevt = {
216 .clkevt = {
217 .name = "tc_clkevt",
218 .features = CLOCK_EVT_FEAT_PERIODIC |
219 CLOCK_EVT_FEAT_ONESHOT,
220 /* Should be lower than at91rm9200's system timer */
221 .rating = 125,
222 .set_next_event = tc_next_event,
223 .set_state_shutdown = tc_shutdown,
224 .set_state_periodic = tc_set_periodic,
225 .set_state_oneshot = tc_set_oneshot,
226 },
227};
228
229static irqreturn_t ch2_irq(int irq, void *handle)
230{
231 struct tc_clkevt_device *dev = handle;
232 unsigned int sr;
233
234 sr = readl_relaxed(dev->regs + ATMEL_TC_REG(2, SR));
235 if (sr & ATMEL_TC_CPCS) {
236 dev->clkevt.event_handler(&dev->clkevt);
237 return IRQ_HANDLED;
238 }
239
240 return IRQ_NONE;
241}
242
243static int __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx)
244{
245 int ret;
246 struct clk *t2_clk = tc->clk[2];
247 int irq = tc->irq[2];
248
249 ret = clk_prepare_enable(tc->slow_clk);
250 if (ret)
251 return ret;
252
253 /* try to enable t2 clk to avoid future errors in mode change */
254 ret = clk_prepare_enable(t2_clk);
255 if (ret) {
256 clk_disable_unprepare(tc->slow_clk);
257 return ret;
258 }
259
260 clk_disable(t2_clk);
261
262 clkevt.regs = tc->regs;
263 clkevt.clk = t2_clk;
264
265 timer_clock = clk32k_divisor_idx;
266
267 clkevt.clkevt.cpumask = cpumask_of(0);
268
269 ret = request_irq(irq, ch2_irq, IRQF_TIMER, "tc_clkevt", &clkevt);
270 if (ret) {
271 clk_unprepare(t2_clk);
272 clk_disable_unprepare(tc->slow_clk);
273 return ret;
274 }
275
276 clockevents_config_and_register(&clkevt.clkevt, 32768, 1, 0xffff);
277
278 return ret;
279}
280
281#else /* !CONFIG_GENERIC_CLOCKEVENTS */
282
283static int __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx)
284{
285 /* NOTHING */
286 return 0;
287}
288
289#endif
290
291static void __init tcb_setup_dual_chan(struct atmel_tc *tc, int mck_divisor_idx)
292{
293 /* channel 0: waveform mode, input mclk/8, clock TIOA0 on overflow */
294 writel(mck_divisor_idx /* likely divide-by-8 */
295 | ATMEL_TC_WAVE
296 | ATMEL_TC_WAVESEL_UP /* free-run */
297 | ATMEL_TC_ACPA_SET /* TIOA0 rises at 0 */
298 | ATMEL_TC_ACPC_CLEAR, /* (duty cycle 50%) */
299 tcaddr + ATMEL_TC_REG(0, CMR));
300 writel(0x0000, tcaddr + ATMEL_TC_REG(0, RA));
301 writel(0x8000, tcaddr + ATMEL_TC_REG(0, RC));
302 writel(0xff, tcaddr + ATMEL_TC_REG(0, IDR)); /* no irqs */
303 writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(0, CCR));
304
305 /* channel 1: waveform mode, input TIOA0 */
306 writel(ATMEL_TC_XC1 /* input: TIOA0 */
307 | ATMEL_TC_WAVE
308 | ATMEL_TC_WAVESEL_UP, /* free-run */
309 tcaddr + ATMEL_TC_REG(1, CMR));
310 writel(0xff, tcaddr + ATMEL_TC_REG(1, IDR)); /* no irqs */
311 writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(1, CCR));
312
313 /* chain channel 0 to channel 1*/
314 writel(ATMEL_TC_TC1XC1S_TIOA0, tcaddr + ATMEL_TC_BMR);
315 /* then reset all the timers */
316 writel(ATMEL_TC_SYNC, tcaddr + ATMEL_TC_BCR);
317}
318
319static void __init tcb_setup_single_chan(struct atmel_tc *tc, int mck_divisor_idx)
320{
321 /* channel 0: waveform mode, input mclk/8 */
322 writel(mck_divisor_idx /* likely divide-by-8 */
323 | ATMEL_TC_WAVE
324 | ATMEL_TC_WAVESEL_UP, /* free-run */
325 tcaddr + ATMEL_TC_REG(0, CMR));
326 writel(0xff, tcaddr + ATMEL_TC_REG(0, IDR)); /* no irqs */
327 writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(0, CCR));
328
329 /* then reset all the timers */
330 writel(ATMEL_TC_SYNC, tcaddr + ATMEL_TC_BCR);
331}
332
333static int __init tcb_clksrc_init(void)
334{
335 static char bootinfo[] __initdata
336 = KERN_DEBUG "%s: tc%d at %d.%03d MHz\n";
337
338 struct platform_device *pdev;
339 struct atmel_tc *tc;
340 struct clk *t0_clk;
341 u32 rate, divided_rate = 0;
342 int best_divisor_idx = -1;
343 int clk32k_divisor_idx = -1;
344 int i;
345 int ret;
346
347 tc = atmel_tc_alloc(CONFIG_ATMEL_TCB_CLKSRC_BLOCK);
348 if (!tc) {
349 pr_debug("can't alloc TC for clocksource\n");
350 return -ENODEV;
351 }
352 tcaddr = tc->regs;
353 pdev = tc->pdev;
354
355 t0_clk = tc->clk[0];
356 ret = clk_prepare_enable(t0_clk);
357 if (ret) {
358 pr_debug("can't enable T0 clk\n");
359 goto err_free_tc;
360 }
361
362 /* How fast will we be counting? Pick something over 5 MHz. */
363 rate = (u32) clk_get_rate(t0_clk);
364 for (i = 0; i < 5; i++) {
365 unsigned divisor = atmel_tc_divisors[i];
366 unsigned tmp;
367
368 /* remember 32 KiHz clock for later */
369 if (!divisor) {
370 clk32k_divisor_idx = i;
371 continue;
372 }
373
374 tmp = rate / divisor;
375 pr_debug("TC: %u / %-3u [%d] --> %u\n", rate, divisor, i, tmp);
376 if (best_divisor_idx > 0) {
377 if (tmp < 5 * 1000 * 1000)
378 continue;
379 }
380 divided_rate = tmp;
381 best_divisor_idx = i;
382 }
383
384
385 printk(bootinfo, clksrc.name, CONFIG_ATMEL_TCB_CLKSRC_BLOCK,
386 divided_rate / 1000000,
387 ((divided_rate % 1000000) + 500) / 1000);
388
389 if (tc->tcb_config && tc->tcb_config->counter_width == 32) {
390 /* use apropriate function to read 32 bit counter */
391 clksrc.read = tc_get_cycles32;
392 /* setup ony channel 0 */
393 tcb_setup_single_chan(tc, best_divisor_idx);
394 } else {
395 /* tclib will give us three clocks no matter what the
396 * underlying platform supports.
397 */
398 ret = clk_prepare_enable(tc->clk[1]);
399 if (ret) {
400 pr_debug("can't enable T1 clk\n");
401 goto err_disable_t0;
402 }
403 /* setup both channel 0 & 1 */
404 tcb_setup_dual_chan(tc, best_divisor_idx);
405 }
406
407 /* and away we go! */
408 ret = clocksource_register_hz(&clksrc, divided_rate);
409 if (ret)
410 goto err_disable_t1;
411
412 /* channel 2: periodic and oneshot timer support */
413 ret = setup_clkevents(tc, clk32k_divisor_idx);
414 if (ret)
415 goto err_unregister_clksrc;
416
417 return 0;
418
419err_unregister_clksrc:
420 clocksource_unregister(&clksrc);
421
422err_disable_t1:
423 if (!tc->tcb_config || tc->tcb_config->counter_width != 32)
424 clk_disable_unprepare(tc->clk[1]);
425
426err_disable_t0:
427 clk_disable_unprepare(t0_clk);
428
429err_free_tc:
430 atmel_tc_free(tc);
431 return ret;
432}
433arch_initcall(tcb_clksrc_init);