Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
2 * Copyright (C) 2010, 2011 Texas Instruments Incorporated
3 * Contributed by: Mark Salter (msalter@redhat.com)
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 */
9
10#include <linux/clockchips.h>
11#include <linux/interrupt.h>
12#include <linux/io.h>
13#include <linux/of.h>
14#include <linux/of_irq.h>
15#include <linux/of_address.h>
16#include <asm/soc.h>
17#include <asm/dscr.h>
18#include <asm/timer64.h>
19
20struct timer_regs {
21 u32 reserved0;
22 u32 emumgt;
23 u32 reserved1;
24 u32 reserved2;
25 u32 cntlo;
26 u32 cnthi;
27 u32 prdlo;
28 u32 prdhi;
29 u32 tcr;
30 u32 tgcr;
31 u32 wdtcr;
32};
33
34static struct timer_regs __iomem *timer;
35
36#define TCR_TSTATLO 0x001
37#define TCR_INVOUTPLO 0x002
38#define TCR_INVINPLO 0x004
39#define TCR_CPLO 0x008
40#define TCR_ENAMODELO_ONCE 0x040
41#define TCR_ENAMODELO_CONT 0x080
42#define TCR_ENAMODELO_MASK 0x0c0
43#define TCR_PWIDLO_MASK 0x030
44#define TCR_CLKSRCLO 0x100
45#define TCR_TIENLO 0x200
46#define TCR_TSTATHI (0x001 << 16)
47#define TCR_INVOUTPHI (0x002 << 16)
48#define TCR_CPHI (0x008 << 16)
49#define TCR_PWIDHI_MASK (0x030 << 16)
50#define TCR_ENAMODEHI_ONCE (0x040 << 16)
51#define TCR_ENAMODEHI_CONT (0x080 << 16)
52#define TCR_ENAMODEHI_MASK (0x0c0 << 16)
53
54#define TGCR_TIMLORS 0x001
55#define TGCR_TIMHIRS 0x002
56#define TGCR_TIMMODE_UD32 0x004
57#define TGCR_TIMMODE_WDT64 0x008
58#define TGCR_TIMMODE_CD32 0x00c
59#define TGCR_TIMMODE_MASK 0x00c
60#define TGCR_PSCHI_MASK (0x00f << 8)
61#define TGCR_TDDRHI_MASK (0x00f << 12)
62
63/*
64 * Timer clocks are divided down from the CPU clock
65 * The divisor is in the EMUMGTCLKSPD register
66 */
67#define TIMER_DIVISOR \
68 ((soc_readl(&timer->emumgt) & (0xf << 16)) >> 16)
69
70#define TIMER64_RATE (c6x_core_freq / TIMER_DIVISOR)
71
72#define TIMER64_MODE_DISABLED 0
73#define TIMER64_MODE_ONE_SHOT TCR_ENAMODELO_ONCE
74#define TIMER64_MODE_PERIODIC TCR_ENAMODELO_CONT
75
76static int timer64_mode;
77static int timer64_devstate_id = -1;
78
79static void timer64_config(unsigned long period)
80{
81 u32 tcr = soc_readl(&timer->tcr) & ~TCR_ENAMODELO_MASK;
82
83 soc_writel(tcr, &timer->tcr);
84 soc_writel(period - 1, &timer->prdlo);
85 soc_writel(0, &timer->cntlo);
86 tcr |= timer64_mode;
87 soc_writel(tcr, &timer->tcr);
88}
89
90static void timer64_enable(void)
91{
92 u32 val;
93
94 if (timer64_devstate_id >= 0)
95 dscr_set_devstate(timer64_devstate_id, DSCR_DEVSTATE_ENABLED);
96
97 /* disable timer, reset count */
98 soc_writel(soc_readl(&timer->tcr) & ~TCR_ENAMODELO_MASK, &timer->tcr);
99 soc_writel(0, &timer->prdlo);
100
101 /* use internal clock and 1 cycle pulse width */
102 val = soc_readl(&timer->tcr);
103 soc_writel(val & ~(TCR_CLKSRCLO | TCR_PWIDLO_MASK), &timer->tcr);
104
105 /* dual 32-bit unchained mode */
106 val = soc_readl(&timer->tgcr) & ~TGCR_TIMMODE_MASK;
107 soc_writel(val, &timer->tgcr);
108 soc_writel(val | (TGCR_TIMLORS | TGCR_TIMMODE_UD32), &timer->tgcr);
109}
110
111static void timer64_disable(void)
112{
113 /* disable timer, reset count */
114 soc_writel(soc_readl(&timer->tcr) & ~TCR_ENAMODELO_MASK, &timer->tcr);
115 soc_writel(0, &timer->prdlo);
116
117 if (timer64_devstate_id >= 0)
118 dscr_set_devstate(timer64_devstate_id, DSCR_DEVSTATE_DISABLED);
119}
120
121static int next_event(unsigned long delta,
122 struct clock_event_device *evt)
123{
124 timer64_config(delta);
125 return 0;
126}
127
128static void set_clock_mode(enum clock_event_mode mode,
129 struct clock_event_device *evt)
130{
131 switch (mode) {
132 case CLOCK_EVT_MODE_PERIODIC:
133 timer64_enable();
134 timer64_mode = TIMER64_MODE_PERIODIC;
135 timer64_config(TIMER64_RATE / HZ);
136 break;
137 case CLOCK_EVT_MODE_ONESHOT:
138 timer64_enable();
139 timer64_mode = TIMER64_MODE_ONE_SHOT;
140 break;
141 case CLOCK_EVT_MODE_UNUSED:
142 case CLOCK_EVT_MODE_SHUTDOWN:
143 timer64_mode = TIMER64_MODE_DISABLED;
144 timer64_disable();
145 break;
146 case CLOCK_EVT_MODE_RESUME:
147 break;
148 }
149}
150
151static struct clock_event_device t64_clockevent_device = {
152 .name = "TIMER64_EVT32_TIMER",
153 .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
154 .rating = 200,
155 .set_mode = set_clock_mode,
156 .set_next_event = next_event,
157};
158
159static irqreturn_t timer_interrupt(int irq, void *dev_id)
160{
161 struct clock_event_device *cd = &t64_clockevent_device;
162
163 cd->event_handler(cd);
164
165 return IRQ_HANDLED;
166}
167
168static struct irqaction timer_iact = {
169 .name = "timer",
170 .flags = IRQF_TIMER,
171 .handler = timer_interrupt,
172 .dev_id = &t64_clockevent_device,
173};
174
175void __init timer64_init(void)
176{
177 struct clock_event_device *cd = &t64_clockevent_device;
178 struct device_node *np, *first = NULL;
179 u32 val;
180 int err, found = 0;
181
182 for_each_compatible_node(np, NULL, "ti,c64x+timer64") {
183 err = of_property_read_u32(np, "ti,core-mask", &val);
184 if (!err) {
185 if (val & (1 << get_coreid())) {
186 found = 1;
187 break;
188 }
189 } else if (!first)
190 first = np;
191 }
192 if (!found) {
193 /* try first one with no core-mask */
194 if (first)
195 np = of_node_get(first);
196 else {
197 pr_debug("Cannot find ti,c64x+timer64 timer.\n");
198 return;
199 }
200 }
201
202 timer = of_iomap(np, 0);
203 if (!timer) {
204 pr_debug("%s: Cannot map timer registers.\n", np->full_name);
205 goto out;
206 }
207 pr_debug("%s: Timer registers=%p.\n", np->full_name, timer);
208
209 cd->irq = irq_of_parse_and_map(np, 0);
210 if (cd->irq == NO_IRQ) {
211 pr_debug("%s: Cannot find interrupt.\n", np->full_name);
212 iounmap(timer);
213 goto out;
214 }
215
216 /* If there is a device state control, save the ID. */
217 err = of_property_read_u32(np, "ti,dscr-dev-enable", &val);
218 if (!err) {
219 timer64_devstate_id = val;
220
221 /*
222 * It is necessary to enable the timer block here because
223 * the TIMER_DIVISOR macro needs to read a timer register
224 * to get the divisor.
225 */
226 dscr_set_devstate(timer64_devstate_id, DSCR_DEVSTATE_ENABLED);
227 }
228
229 pr_debug("%s: Timer irq=%d.\n", np->full_name, cd->irq);
230
231 clockevents_calc_mult_shift(cd, c6x_core_freq / TIMER_DIVISOR, 5);
232
233 cd->max_delta_ns = clockevent_delta2ns(0x7fffffff, cd);
234 cd->min_delta_ns = clockevent_delta2ns(250, cd);
235
236 cd->cpumask = cpumask_of(smp_processor_id());
237
238 clockevents_register_device(cd);
239 setup_irq(cd->irq, &timer_iact);
240
241out:
242 of_node_put(np);
243 return;
244}