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b85a3ef4 JL |
1 | /* |
2 | * This file contains driver for the Xilinx PS Timer Counter IP. | |
3 | * | |
4 | * Copyright (C) 2011 Xilinx | |
5 | * | |
6 | * based on arch/mips/kernel/time.c timer driver | |
7 | * | |
8 | * This software is licensed under the terms of the GNU General Public | |
9 | * License version 2, as published by the Free Software Foundation, and | |
10 | * may be copied, distributed, and modified under those terms. | |
11 | * | |
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 | ||
18 | #include <linux/kernel.h> | |
19 | #include <linux/init.h> | |
20 | #include <linux/interrupt.h> | |
21 | #include <linux/irq.h> | |
22 | #include <linux/types.h> | |
23 | #include <linux/clocksource.h> | |
24 | #include <linux/clockchips.h> | |
25 | #include <linux/io.h> | |
26 | ||
27 | #include <asm/mach/time.h> | |
28 | #include <mach/zynq_soc.h> | |
29 | #include "common.h" | |
30 | ||
31 | #define IRQ_TIMERCOUNTER0 42 | |
32 | ||
33 | /* | |
34 | * This driver configures the 2 16-bit count-up timers as follows: | |
35 | * | |
36 | * T1: Timer 1, clocksource for generic timekeeping | |
37 | * T2: Timer 2, clockevent source for hrtimers | |
38 | * T3: Timer 3, <unused> | |
39 | * | |
40 | * The input frequency to the timer module for emulation is 2.5MHz which is | |
41 | * common to all the timer channels (T1, T2, and T3). With a pre-scaler of 32, | |
42 | * the timers are clocked at 78.125KHz (12.8 us resolution). | |
43 | * | |
44 | * The input frequency to the timer module in silicon will be 200MHz. With the | |
45 | * pre-scaler of 32, the timers are clocked at 6.25MHz (160ns resolution). | |
46 | */ | |
47 | #define XTTCPSS_CLOCKSOURCE 0 /* Timer 1 as a generic timekeeping */ | |
48 | #define XTTCPSS_CLOCKEVENT 1 /* Timer 2 as a clock event */ | |
49 | ||
50 | #define XTTCPSS_TIMER_BASE TTC0_BASE | |
51 | #define XTTCPCC_EVENT_TIMER_IRQ (IRQ_TIMERCOUNTER0 + 1) | |
52 | /* | |
53 | * Timer Register Offset Definitions of Timer 1, Increment base address by 4 | |
54 | * and use same offsets for Timer 2 | |
55 | */ | |
56 | #define XTTCPSS_CLK_CNTRL_OFFSET 0x00 /* Clock Control Reg, RW */ | |
57 | #define XTTCPSS_CNT_CNTRL_OFFSET 0x0C /* Counter Control Reg, RW */ | |
58 | #define XTTCPSS_COUNT_VAL_OFFSET 0x18 /* Counter Value Reg, RO */ | |
59 | #define XTTCPSS_INTR_VAL_OFFSET 0x24 /* Interval Count Reg, RW */ | |
60 | #define XTTCPSS_MATCH_1_OFFSET 0x30 /* Match 1 Value Reg, RW */ | |
61 | #define XTTCPSS_MATCH_2_OFFSET 0x3C /* Match 2 Value Reg, RW */ | |
62 | #define XTTCPSS_MATCH_3_OFFSET 0x48 /* Match 3 Value Reg, RW */ | |
63 | #define XTTCPSS_ISR_OFFSET 0x54 /* Interrupt Status Reg, RO */ | |
64 | #define XTTCPSS_IER_OFFSET 0x60 /* Interrupt Enable Reg, RW */ | |
65 | ||
66 | #define XTTCPSS_CNT_CNTRL_DISABLE_MASK 0x1 | |
67 | ||
68 | /* Setup the timers to use pre-scaling */ | |
69 | ||
70 | #define TIMER_RATE (PERIPHERAL_CLOCK_RATE / 32) | |
71 | ||
72 | /** | |
73 | * struct xttcpss_timer - This definition defines local timer structure | |
74 | * | |
75 | * @base_addr: Base address of timer | |
76 | **/ | |
77 | struct xttcpss_timer { | |
78 | void __iomem *base_addr; | |
79 | }; | |
80 | ||
81 | static struct xttcpss_timer timers[2]; | |
82 | static struct clock_event_device xttcpss_clockevent; | |
83 | ||
84 | /** | |
85 | * xttcpss_set_interval - Set the timer interval value | |
86 | * | |
87 | * @timer: Pointer to the timer instance | |
88 | * @cycles: Timer interval ticks | |
89 | **/ | |
90 | static void xttcpss_set_interval(struct xttcpss_timer *timer, | |
91 | unsigned long cycles) | |
92 | { | |
93 | u32 ctrl_reg; | |
94 | ||
95 | /* Disable the counter, set the counter value and re-enable counter */ | |
96 | ctrl_reg = __raw_readl(timer->base_addr + XTTCPSS_CNT_CNTRL_OFFSET); | |
97 | ctrl_reg |= XTTCPSS_CNT_CNTRL_DISABLE_MASK; | |
98 | __raw_writel(ctrl_reg, timer->base_addr + XTTCPSS_CNT_CNTRL_OFFSET); | |
99 | ||
100 | __raw_writel(cycles, timer->base_addr + XTTCPSS_INTR_VAL_OFFSET); | |
101 | ||
102 | /* Reset the counter (0x10) so that it starts from 0, one-shot | |
103 | mode makes this needed for timing to be right. */ | |
104 | ctrl_reg |= 0x10; | |
105 | ctrl_reg &= ~XTTCPSS_CNT_CNTRL_DISABLE_MASK; | |
106 | __raw_writel(ctrl_reg, timer->base_addr + XTTCPSS_CNT_CNTRL_OFFSET); | |
107 | } | |
108 | ||
109 | /** | |
110 | * xttcpss_clock_event_interrupt - Clock event timer interrupt handler | |
111 | * | |
112 | * @irq: IRQ number of the Timer | |
113 | * @dev_id: void pointer to the xttcpss_timer instance | |
114 | * | |
115 | * returns: Always IRQ_HANDLED - success | |
116 | **/ | |
117 | static irqreturn_t xttcpss_clock_event_interrupt(int irq, void *dev_id) | |
118 | { | |
119 | struct clock_event_device *evt = &xttcpss_clockevent; | |
120 | struct xttcpss_timer *timer = dev_id; | |
121 | ||
122 | /* Acknowledge the interrupt and call event handler */ | |
123 | __raw_writel(__raw_readl(timer->base_addr + XTTCPSS_ISR_OFFSET), | |
124 | timer->base_addr + XTTCPSS_ISR_OFFSET); | |
125 | ||
126 | evt->event_handler(evt); | |
127 | ||
128 | return IRQ_HANDLED; | |
129 | } | |
130 | ||
131 | static struct irqaction event_timer_irq = { | |
132 | .name = "xttcpss clockevent", | |
133 | .flags = IRQF_DISABLED | IRQF_TIMER, | |
134 | .handler = xttcpss_clock_event_interrupt, | |
135 | }; | |
136 | ||
137 | /** | |
138 | * xttcpss_timer_hardware_init - Initialize the timer hardware | |
139 | * | |
140 | * Initialize the hardware to start the clock source, get the clock | |
141 | * event timer ready to use, and hook up the interrupt. | |
142 | **/ | |
143 | static void __init xttcpss_timer_hardware_init(void) | |
144 | { | |
145 | /* Setup the clock source counter to be an incrementing counter | |
146 | * with no interrupt and it rolls over at 0xFFFF. Pre-scale | |
147 | it by 32 also. Let it start running now. | |
148 | */ | |
149 | timers[XTTCPSS_CLOCKSOURCE].base_addr = XTTCPSS_TIMER_BASE; | |
150 | ||
151 | __raw_writel(0x0, timers[XTTCPSS_CLOCKSOURCE].base_addr + | |
152 | XTTCPSS_IER_OFFSET); | |
153 | __raw_writel(0x9, timers[XTTCPSS_CLOCKSOURCE].base_addr + | |
154 | XTTCPSS_CLK_CNTRL_OFFSET); | |
155 | __raw_writel(0x10, timers[XTTCPSS_CLOCKSOURCE].base_addr + | |
156 | XTTCPSS_CNT_CNTRL_OFFSET); | |
157 | ||
158 | /* Setup the clock event timer to be an interval timer which | |
159 | * is prescaled by 32 using the interval interrupt. Leave it | |
160 | * disabled for now. | |
161 | */ | |
162 | ||
163 | timers[XTTCPSS_CLOCKEVENT].base_addr = XTTCPSS_TIMER_BASE + 4; | |
164 | ||
165 | __raw_writel(0x23, timers[XTTCPSS_CLOCKEVENT].base_addr + | |
166 | XTTCPSS_CNT_CNTRL_OFFSET); | |
167 | __raw_writel(0x9, timers[XTTCPSS_CLOCKEVENT].base_addr + | |
168 | XTTCPSS_CLK_CNTRL_OFFSET); | |
169 | __raw_writel(0x1, timers[XTTCPSS_CLOCKEVENT].base_addr + | |
170 | XTTCPSS_IER_OFFSET); | |
171 | ||
172 | /* Setup IRQ the clock event timer */ | |
173 | event_timer_irq.dev_id = &timers[XTTCPSS_CLOCKEVENT]; | |
174 | setup_irq(XTTCPCC_EVENT_TIMER_IRQ, &event_timer_irq); | |
175 | } | |
176 | ||
177 | /** | |
178 | * __raw_readl_cycles - Reads the timer counter register | |
179 | * | |
180 | * returns: Current timer counter register value | |
181 | **/ | |
182 | static cycle_t __raw_readl_cycles(struct clocksource *cs) | |
183 | { | |
184 | struct xttcpss_timer *timer = &timers[XTTCPSS_CLOCKSOURCE]; | |
185 | ||
186 | return (cycle_t)__raw_readl(timer->base_addr + | |
187 | XTTCPSS_COUNT_VAL_OFFSET); | |
188 | } | |
189 | ||
190 | ||
191 | /* | |
192 | * Instantiate and initialize the clock source structure | |
193 | */ | |
194 | static struct clocksource clocksource_xttcpss = { | |
195 | .name = "xttcpss_timer1", | |
196 | .rating = 200, /* Reasonable clock source */ | |
197 | .read = __raw_readl_cycles, | |
198 | .mask = CLOCKSOURCE_MASK(16), | |
199 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, | |
200 | }; | |
201 | ||
202 | ||
203 | /** | |
204 | * xttcpss_set_next_event - Sets the time interval for next event | |
205 | * | |
206 | * @cycles: Timer interval ticks | |
207 | * @evt: Address of clock event instance | |
208 | * | |
209 | * returns: Always 0 - success | |
210 | **/ | |
211 | static int xttcpss_set_next_event(unsigned long cycles, | |
212 | struct clock_event_device *evt) | |
213 | { | |
214 | struct xttcpss_timer *timer = &timers[XTTCPSS_CLOCKEVENT]; | |
215 | ||
216 | xttcpss_set_interval(timer, cycles); | |
217 | return 0; | |
218 | } | |
219 | ||
220 | /** | |
221 | * xttcpss_set_mode - Sets the mode of timer | |
222 | * | |
223 | * @mode: Mode to be set | |
224 | * @evt: Address of clock event instance | |
225 | **/ | |
226 | static void xttcpss_set_mode(enum clock_event_mode mode, | |
227 | struct clock_event_device *evt) | |
228 | { | |
229 | struct xttcpss_timer *timer = &timers[XTTCPSS_CLOCKEVENT]; | |
230 | u32 ctrl_reg; | |
231 | ||
232 | switch (mode) { | |
233 | case CLOCK_EVT_MODE_PERIODIC: | |
234 | xttcpss_set_interval(timer, TIMER_RATE / HZ); | |
235 | break; | |
236 | case CLOCK_EVT_MODE_ONESHOT: | |
237 | case CLOCK_EVT_MODE_UNUSED: | |
238 | case CLOCK_EVT_MODE_SHUTDOWN: | |
239 | ctrl_reg = __raw_readl(timer->base_addr + | |
240 | XTTCPSS_CNT_CNTRL_OFFSET); | |
241 | ctrl_reg |= XTTCPSS_CNT_CNTRL_DISABLE_MASK; | |
242 | __raw_writel(ctrl_reg, | |
243 | timer->base_addr + XTTCPSS_CNT_CNTRL_OFFSET); | |
244 | break; | |
245 | case CLOCK_EVT_MODE_RESUME: | |
246 | ctrl_reg = __raw_readl(timer->base_addr + | |
247 | XTTCPSS_CNT_CNTRL_OFFSET); | |
248 | ctrl_reg &= ~XTTCPSS_CNT_CNTRL_DISABLE_MASK; | |
249 | __raw_writel(ctrl_reg, | |
250 | timer->base_addr + XTTCPSS_CNT_CNTRL_OFFSET); | |
251 | break; | |
252 | } | |
253 | } | |
254 | ||
255 | /* | |
256 | * Instantiate and initialize the clock event structure | |
257 | */ | |
258 | static struct clock_event_device xttcpss_clockevent = { | |
259 | .name = "xttcpss_timer2", | |
260 | .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, | |
261 | .set_next_event = xttcpss_set_next_event, | |
262 | .set_mode = xttcpss_set_mode, | |
263 | .rating = 200, | |
264 | }; | |
265 | ||
266 | /** | |
267 | * xttcpss_timer_init - Initialize the timer | |
268 | * | |
269 | * Initializes the timer hardware and register the clock source and clock event | |
270 | * timers with Linux kernal timer framework | |
271 | **/ | |
272 | static void __init xttcpss_timer_init(void) | |
273 | { | |
274 | xttcpss_timer_hardware_init(); | |
275 | clocksource_register_hz(&clocksource_xttcpss, TIMER_RATE); | |
276 | ||
277 | /* Calculate the parameters to allow the clockevent to operate using | |
278 | integer math | |
279 | */ | |
280 | clockevents_calc_mult_shift(&xttcpss_clockevent, TIMER_RATE, 4); | |
281 | ||
282 | xttcpss_clockevent.max_delta_ns = | |
283 | clockevent_delta2ns(0xfffe, &xttcpss_clockevent); | |
284 | xttcpss_clockevent.min_delta_ns = | |
285 | clockevent_delta2ns(1, &xttcpss_clockevent); | |
286 | ||
287 | /* Indicate that clock event is on 1st CPU as SMP boot needs it */ | |
288 | ||
289 | xttcpss_clockevent.cpumask = cpumask_of(0); | |
290 | clockevents_register_device(&xttcpss_clockevent); | |
291 | } | |
292 | ||
293 | /* | |
294 | * Instantiate and initialize the system timer structure | |
295 | */ | |
296 | struct sys_timer xttcpss_sys_timer = { | |
297 | .init = xttcpss_timer_init, | |
298 | }; |