1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
|
/*
* Copyright (C) 2014 Oleksij Rempel <linux@rempel-privat.de>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/clk.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/bitops.h>
#define DRIVER_NAME "asm9260-timer"
/*
* this device provide 4 offsets for each register:
* 0x0 - plain read write mode
* 0x4 - set mode, OR logic.
* 0x8 - clr mode, XOR logic.
* 0xc - togle mode.
*/
#define SET_REG 4
#define CLR_REG 8
#define HW_IR 0x0000 /* RW. Interrupt */
#define BM_IR_CR0 BIT(4)
#define BM_IR_MR3 BIT(3)
#define BM_IR_MR2 BIT(2)
#define BM_IR_MR1 BIT(1)
#define BM_IR_MR0 BIT(0)
#define HW_TCR 0x0010 /* RW. Timer controller */
/* BM_C*_RST
* Timer Counter and the Prescale Counter are synchronously reset on the
* next positive edge of PCLK. The counters remain reset until TCR[1] is
* returned to zero. */
#define BM_C3_RST BIT(7)
#define BM_C2_RST BIT(6)
#define BM_C1_RST BIT(5)
#define BM_C0_RST BIT(4)
/* BM_C*_EN
* 1 - Timer Counter and Prescale Counter are enabled for counting
* 0 - counters are disabled */
#define BM_C3_EN BIT(3)
#define BM_C2_EN BIT(2)
#define BM_C1_EN BIT(1)
#define BM_C0_EN BIT(0)
#define HW_DIR 0x0020 /* RW. Direction? */
/* 00 - count up
* 01 - count down
* 10 - ?? 2^n/2 */
#define BM_DIR_COUNT_UP 0
#define BM_DIR_COUNT_DOWN 1
#define BM_DIR0_SHIFT 0
#define BM_DIR1_SHIFT 4
#define BM_DIR2_SHIFT 8
#define BM_DIR3_SHIFT 12
#define BM_DIR_DEFAULT (BM_DIR_COUNT_UP << BM_DIR0_SHIFT | \
BM_DIR_COUNT_UP << BM_DIR1_SHIFT | \
BM_DIR_COUNT_UP << BM_DIR2_SHIFT | \
BM_DIR_COUNT_UP << BM_DIR3_SHIFT)
#define HW_TC0 0x0030 /* RO. Timer counter 0 */
/* HW_TC*. Timer counter owerflow (0xffff.ffff to 0x0000.0000) do not generate
* interrupt. This registers can be used to detect overflow */
#define HW_TC1 0x0040
#define HW_TC2 0x0050
#define HW_TC3 0x0060
#define HW_PR 0x0070 /* RW. prescaler */
#define BM_PR_DISABLE 0
#define HW_PC 0x0080 /* RO. Prescaler counter */
#define HW_MCR 0x0090 /* RW. Match control */
/* enable interrupt on match */
#define BM_MCR_INT_EN(n) (1 << (n * 3 + 0))
/* enable TC reset on match */
#define BM_MCR_RES_EN(n) (1 << (n * 3 + 1))
/* enable stop TC on match */
#define BM_MCR_STOP_EN(n) (1 << (n * 3 + 2))
#define HW_MR0 0x00a0 /* RW. Match reg */
#define HW_MR1 0x00b0
#define HW_MR2 0x00C0
#define HW_MR3 0x00D0
#define HW_CTCR 0x0180 /* Counter control */
#define BM_CTCR0_SHIFT 0
#define BM_CTCR1_SHIFT 2
#define BM_CTCR2_SHIFT 4
#define BM_CTCR3_SHIFT 6
#define BM_CTCR_TM 0 /* Timer mode. Every rising PCLK edge. */
#define BM_CTCR_DEFAULT (BM_CTCR_TM << BM_CTCR0_SHIFT | \
BM_CTCR_TM << BM_CTCR1_SHIFT | \
BM_CTCR_TM << BM_CTCR2_SHIFT | \
BM_CTCR_TM << BM_CTCR3_SHIFT)
static struct asm9260_timer_priv {
void __iomem *base;
unsigned long ticks_per_jiffy;
} priv;
static int asm9260_timer_set_next_event(unsigned long delta,
struct clock_event_device *evt)
{
/* configure match count for TC0 */
writel_relaxed(delta, priv.base + HW_MR0);
/* enable TC0 */
writel_relaxed(BM_C0_EN, priv.base + HW_TCR + SET_REG);
return 0;
}
static void asm9260_timer_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
/* stop timer0 */
writel_relaxed(BM_C0_EN, priv.base + HW_TCR + CLR_REG);
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
/* disable reset and stop on match */
writel_relaxed(BM_MCR_RES_EN(0) | BM_MCR_STOP_EN(0),
priv.base + HW_MCR + CLR_REG);
/* configure match count for TC0 */
writel_relaxed(priv.ticks_per_jiffy, priv.base + HW_MR0);
/* enable TC0 */
writel_relaxed(BM_C0_EN, priv.base + HW_TCR + SET_REG);
break;
case CLOCK_EVT_MODE_ONESHOT:
/* enable reset and stop on match */
writel_relaxed(BM_MCR_RES_EN(0) | BM_MCR_STOP_EN(0),
priv.base + HW_MCR + SET_REG);
break;
default:
break;
}
}
static struct clock_event_device event_dev = {
.name = DRIVER_NAME,
.rating = 200,
.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
.set_next_event = asm9260_timer_set_next_event,
.set_mode = asm9260_timer_set_mode,
};
static irqreturn_t asm9260_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = dev_id;
evt->event_handler(evt);
writel_relaxed(BM_IR_MR0, priv.base + HW_IR);
return IRQ_HANDLED;
}
/*
* ---------------------------------------------------------------------------
* Timer initialization
* ---------------------------------------------------------------------------
*/
static void __init asm9260_timer_init(struct device_node *np)
{
int irq;
struct clk *clk;
int ret;
unsigned long rate;
priv.base = of_io_request_and_map(np, 0, np->name);
if (IS_ERR(priv.base))
panic("%s: unable to map resource", np->name);
clk = of_clk_get(np, 0);
ret = clk_prepare_enable(clk);
if (ret)
panic("Failed to enable clk!\n");
irq = irq_of_parse_and_map(np, 0);
ret = request_irq(irq, asm9260_timer_interrupt, IRQF_TIMER,
DRIVER_NAME, &event_dev);
if (ret)
panic("Failed to setup irq!\n");
/* set all timers for count-up */
writel_relaxed(BM_DIR_DEFAULT, priv.base + HW_DIR);
/* disable divider */
writel_relaxed(BM_PR_DISABLE, priv.base + HW_PR);
/* make sure all timers use every rising PCLK edge. */
writel_relaxed(BM_CTCR_DEFAULT, priv.base + HW_CTCR);
/* enable interrupt for TC0 and clean setting for all other lines */
writel_relaxed(BM_MCR_INT_EN(0) , priv.base + HW_MCR);
rate = clk_get_rate(clk);
clocksource_mmio_init(priv.base + HW_TC1, DRIVER_NAME, rate,
200, 32, clocksource_mmio_readl_up);
/* Seems like we can't use counter without match register even if
* actions for MR are disabled. So, set MR to max value. */
writel_relaxed(0xffffffff, priv.base + HW_MR1);
/* enable TC1 */
writel_relaxed(BM_C1_EN, priv.base + HW_TCR + SET_REG);
priv.ticks_per_jiffy = DIV_ROUND_CLOSEST(rate, HZ);
event_dev.cpumask = cpumask_of(0);
clockevents_config_and_register(&event_dev, rate, 0x2c00, 0xfffffffe);
}
CLOCKSOURCE_OF_DECLARE(asm9260_timer, "alphascale,asm9260-timer",
asm9260_timer_init);
|
