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244 lines · 5.8 KiB

1// SPDX-License-Identifier: GPL-2.0+
2//
3// Copyright 2016 Freescale Semiconductor, Inc.
4// Copyright 2017 NXP
5
6#include <linux/clk.h>
7#include <linux/clockchips.h>
8#include <linux/clocksource.h>
9#include <linux/delay.h>
10#include <linux/interrupt.h>
11#include <linux/sched_clock.h>
12
13#include "timer-of.h"
14
15#define TPM_PARAM 0x4
16#define TPM_PARAM_WIDTH_SHIFT 16
17#define TPM_PARAM_WIDTH_MASK (0xff << 16)
18#define TPM_SC 0x10
19#define TPM_SC_CMOD_INC_PER_CNT (0x1 << 3)
20#define TPM_SC_CMOD_DIV_DEFAULT 0x3
21#define TPM_SC_CMOD_DIV_MAX 0x7
22#define TPM_SC_TOF_MASK (0x1 << 7)
23#define TPM_CNT 0x14
24#define TPM_MOD 0x18
25#define TPM_STATUS 0x1c
26#define TPM_STATUS_CH0F BIT(0)
27#define TPM_C0SC 0x20
28#define TPM_C0SC_CHIE BIT(6)
29#define TPM_C0SC_MODE_SHIFT 2
30#define TPM_C0SC_MODE_MASK 0x3c
31#define TPM_C0SC_MODE_SW_COMPARE 0x4
32#define TPM_C0SC_CHF_MASK (0x1 << 7)
33#define TPM_C0V 0x24
34
35static int counter_width __ro_after_init;
36static void __iomem *timer_base __ro_after_init;
37
38static inline void tpm_timer_disable(void)
39{
40 unsigned int val;
41
42 /* channel disable */
43 val = readl(timer_base + TPM_C0SC);
44 val &= ~(TPM_C0SC_MODE_MASK | TPM_C0SC_CHIE);
45 writel(val, timer_base + TPM_C0SC);
46}
47
48static inline void tpm_timer_enable(void)
49{
50 unsigned int val;
51
52 /* channel enabled in sw compare mode */
53 val = readl(timer_base + TPM_C0SC);
54 val |= (TPM_C0SC_MODE_SW_COMPARE << TPM_C0SC_MODE_SHIFT) |
55 TPM_C0SC_CHIE;
56 writel(val, timer_base + TPM_C0SC);
57}
58
59static inline void tpm_irq_acknowledge(void)
60{
61 writel(TPM_STATUS_CH0F, timer_base + TPM_STATUS);
62}
63
64static inline unsigned long tpm_read_counter(void)
65{
66 return readl(timer_base + TPM_CNT);
67}
68
69#if defined(CONFIG_ARM)
70static struct delay_timer tpm_delay_timer;
71
72static unsigned long tpm_read_current_timer(void)
73{
74 return tpm_read_counter();
75}
76
77static u64 notrace tpm_read_sched_clock(void)
78{
79 return tpm_read_counter();
80}
81#endif
82
83static int tpm_set_next_event(unsigned long delta,
84 struct clock_event_device *evt)
85{
86 unsigned long next, prev, now;
87
88 prev = tpm_read_counter();
89 next = prev + delta;
90 writel(next, timer_base + TPM_C0V);
91 now = tpm_read_counter();
92
93 /*
94 * Need to wait CNT increase at least 1 cycle to make sure
95 * the C0V has been updated into HW.
96 */
97 if ((next & 0xffffffff) != readl(timer_base + TPM_C0V))
98 while (now == tpm_read_counter())
99 ;
100
101 /*
102 * NOTE: We observed in a very small probability, the bus fabric
103 * contention between GPU and A7 may results a few cycles delay
104 * of writing CNT registers which may cause the min_delta event got
105 * missed, so we need add a ETIME check here in case it happened.
106 */
107 return (now - prev) >= delta ? -ETIME : 0;
108}
109
110static int tpm_set_state_oneshot(struct clock_event_device *evt)
111{
112 tpm_timer_enable();
113
114 return 0;
115}
116
117static int tpm_set_state_shutdown(struct clock_event_device *evt)
118{
119 tpm_timer_disable();
120
121 return 0;
122}
123
124static irqreturn_t tpm_timer_interrupt(int irq, void *dev_id)
125{
126 struct clock_event_device *evt = dev_id;
127
128 tpm_irq_acknowledge();
129
130 evt->event_handler(evt);
131
132 return IRQ_HANDLED;
133}
134
135static struct timer_of to_tpm = {
136 .flags = TIMER_OF_IRQ | TIMER_OF_BASE | TIMER_OF_CLOCK,
137 .clkevt = {
138 .name = "i.MX TPM Timer",
139 .rating = 200,
140 .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_DYNIRQ,
141 .set_state_shutdown = tpm_set_state_shutdown,
142 .set_state_oneshot = tpm_set_state_oneshot,
143 .set_next_event = tpm_set_next_event,
144 .cpumask = cpu_possible_mask,
145 },
146 .of_irq = {
147 .handler = tpm_timer_interrupt,
148 .flags = IRQF_TIMER,
149 },
150 .of_clk = {
151 .name = "per",
152 },
153};
154
155static int __init tpm_clocksource_init(void)
156{
157#if defined(CONFIG_ARM)
158 tpm_delay_timer.read_current_timer = &tpm_read_current_timer;
159 tpm_delay_timer.freq = timer_of_rate(&to_tpm) >> 3;
160 register_current_timer_delay(&tpm_delay_timer);
161
162 sched_clock_register(tpm_read_sched_clock, counter_width,
163 timer_of_rate(&to_tpm) >> 3);
164#endif
165
166 return clocksource_mmio_init(timer_base + TPM_CNT,
167 "imx-tpm",
168 timer_of_rate(&to_tpm) >> 3,
169 to_tpm.clkevt.rating,
170 counter_width,
171 clocksource_mmio_readl_up);
172}
173
174static void __init tpm_clockevent_init(void)
175{
176 clockevents_config_and_register(&to_tpm.clkevt,
177 timer_of_rate(&to_tpm) >> 3,
178 300,
179 GENMASK(counter_width - 1,
180 1));
181}
182
183static int __init tpm_timer_init(struct device_node *np)
184{
185 struct clk *ipg;
186 int ret;
187
188 ipg = of_clk_get_by_name(np, "ipg");
189 if (IS_ERR(ipg)) {
190 pr_err("tpm: failed to get ipg clk\n");
191 return -ENODEV;
192 }
193 /* enable clk before accessing registers */
194 ret = clk_prepare_enable(ipg);
195 if (ret) {
196 pr_err("tpm: ipg clock enable failed (%d)\n", ret);
197 clk_put(ipg);
198 return ret;
199 }
200
201 ret = timer_of_init(np, &to_tpm);
202 if (ret)
203 return ret;
204
205 timer_base = timer_of_base(&to_tpm);
206
207 counter_width = (readl(timer_base + TPM_PARAM)
208 & TPM_PARAM_WIDTH_MASK) >> TPM_PARAM_WIDTH_SHIFT;
209 /* use rating 200 for 32-bit counter and 150 for 16-bit counter */
210 to_tpm.clkevt.rating = counter_width == 0x20 ? 200 : 150;
211
212 /*
213 * Initialize tpm module to a known state
214 * 1) Counter disabled
215 * 2) TPM counter operates in up counting mode
216 * 3) Timer Overflow Interrupt disabled
217 * 4) Channel0 disabled
218 * 5) DMA transfers disabled
219 */
220 /* make sure counter is disabled */
221 writel(0, timer_base + TPM_SC);
222 /* TOF is W1C */
223 writel(TPM_SC_TOF_MASK, timer_base + TPM_SC);
224 writel(0, timer_base + TPM_CNT);
225 /* CHF is W1C */
226 writel(TPM_C0SC_CHF_MASK, timer_base + TPM_C0SC);
227
228 /*
229 * increase per cnt,
230 * div 8 for 32-bit counter and div 128 for 16-bit counter
231 */
232 writel(TPM_SC_CMOD_INC_PER_CNT |
233 (counter_width == 0x20 ?
234 TPM_SC_CMOD_DIV_DEFAULT : TPM_SC_CMOD_DIV_MAX),
235 timer_base + TPM_SC);
236
237 /* set MOD register to maximum for free running mode */
238 writel(GENMASK(counter_width - 1, 0), timer_base + TPM_MOD);
239
240 tpm_clockevent_init();
241
242 return tpm_clocksource_init();
243}
244TIMER_OF_DECLARE(imx7ulp, "fsl,imx7ulp-tpm", tpm_timer_init);