Commit | Line | Data |
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1f2acc5a JC |
1 | /* |
2 | * This file is subject to the terms and conditions of the GNU General Public | |
3 | * License. See the file "COPYING" in the main directory of this archive | |
4 | * for more details. | |
5 | * | |
97b92108 | 6 | * Copyright (C) 2013 by John Crispin <john@phrozen.org> |
1f2acc5a JC |
7 | */ |
8 | ||
9 | #include <linux/clockchips.h> | |
10 | #include <linux/clocksource.h> | |
11 | #include <linux/interrupt.h> | |
12 | #include <linux/reset.h> | |
13 | #include <linux/init.h> | |
14 | #include <linux/time.h> | |
15 | #include <linux/of.h> | |
16 | #include <linux/of_irq.h> | |
17 | #include <linux/of_address.h> | |
18 | ||
19 | #include <asm/mach-ralink/ralink_regs.h> | |
20 | ||
21 | #define SYSTICK_FREQ (50 * 1000) | |
22 | ||
23 | #define SYSTICK_CONFIG 0x00 | |
24 | #define SYSTICK_COMPARE 0x04 | |
25 | #define SYSTICK_COUNT 0x08 | |
26 | ||
27 | /* route systick irq to mips irq 7 instead of the r4k-timer */ | |
28 | #define CFG_EXT_STK_EN 0x2 | |
29 | /* enable the counter */ | |
30 | #define CFG_CNT_EN 0x1 | |
31 | ||
32 | struct systick_device { | |
33 | void __iomem *membase; | |
34 | struct clock_event_device dev; | |
35 | int irq_requested; | |
36 | int freq_scale; | |
37 | }; | |
38 | ||
59113d93 VK |
39 | static int systick_set_oneshot(struct clock_event_device *evt); |
40 | static int systick_shutdown(struct clock_event_device *evt); | |
1f2acc5a JC |
41 | |
42 | static int systick_next_event(unsigned long delta, | |
43 | struct clock_event_device *evt) | |
44 | { | |
45 | struct systick_device *sdev; | |
46 | u32 count; | |
47 | ||
48 | sdev = container_of(evt, struct systick_device, dev); | |
49 | count = ioread32(sdev->membase + SYSTICK_COUNT); | |
50 | count = (count + delta) % SYSTICK_FREQ; | |
37bcc03f | 51 | iowrite32(count, sdev->membase + SYSTICK_COMPARE); |
1f2acc5a JC |
52 | |
53 | return 0; | |
54 | } | |
55 | ||
56 | static void systick_event_handler(struct clock_event_device *dev) | |
57 | { | |
58 | /* noting to do here */ | |
59 | } | |
60 | ||
61 | static irqreturn_t systick_interrupt(int irq, void *dev_id) | |
62 | { | |
63 | struct clock_event_device *dev = (struct clock_event_device *) dev_id; | |
64 | ||
65 | dev->event_handler(dev); | |
66 | ||
67 | return IRQ_HANDLED; | |
68 | } | |
69 | ||
70 | static struct systick_device systick = { | |
71 | .dev = { | |
72 | /* | |
73 | * cevt-r4k uses 300, make sure systick | |
74 | * gets used if available | |
75 | */ | |
59113d93 VK |
76 | .rating = 310, |
77 | .features = CLOCK_EVT_FEAT_ONESHOT, | |
78 | .set_next_event = systick_next_event, | |
79 | .set_state_shutdown = systick_shutdown, | |
80 | .set_state_oneshot = systick_set_oneshot, | |
81 | .event_handler = systick_event_handler, | |
1f2acc5a JC |
82 | }, |
83 | }; | |
84 | ||
85 | static struct irqaction systick_irqaction = { | |
86 | .handler = systick_interrupt, | |
87 | .flags = IRQF_PERCPU | IRQF_TIMER, | |
88 | .dev_id = &systick.dev, | |
89 | }; | |
90 | ||
59113d93 | 91 | static int systick_shutdown(struct clock_event_device *evt) |
1f2acc5a JC |
92 | { |
93 | struct systick_device *sdev; | |
94 | ||
95 | sdev = container_of(evt, struct systick_device, dev); | |
96 | ||
59113d93 VK |
97 | if (sdev->irq_requested) |
98 | free_irq(systick.dev.irq, &systick_irqaction); | |
99 | sdev->irq_requested = 0; | |
100 | iowrite32(0, systick.membase + SYSTICK_CONFIG); | |
101 | ||
102 | return 0; | |
103 | } | |
104 | ||
105 | static int systick_set_oneshot(struct clock_event_device *evt) | |
106 | { | |
107 | struct systick_device *sdev; | |
108 | ||
109 | sdev = container_of(evt, struct systick_device, dev); | |
110 | ||
111 | if (!sdev->irq_requested) | |
112 | setup_irq(systick.dev.irq, &systick_irqaction); | |
113 | sdev->irq_requested = 1; | |
114 | iowrite32(CFG_EXT_STK_EN | CFG_CNT_EN, | |
115 | systick.membase + SYSTICK_CONFIG); | |
116 | ||
117 | return 0; | |
1f2acc5a JC |
118 | } |
119 | ||
2712616f | 120 | static int __init ralink_systick_init(struct device_node *np) |
1f2acc5a | 121 | { |
2712616f DL |
122 | int ret; |
123 | ||
1f2acc5a JC |
124 | systick.membase = of_iomap(np, 0); |
125 | if (!systick.membase) | |
2712616f | 126 | return -ENXIO; |
1f2acc5a JC |
127 | |
128 | systick_irqaction.name = np->name; | |
129 | systick.dev.name = np->name; | |
130 | clockevents_calc_mult_shift(&systick.dev, SYSTICK_FREQ, 60); | |
131 | systick.dev.max_delta_ns = clockevent_delta2ns(0x7fff, &systick.dev); | |
132 | systick.dev.min_delta_ns = clockevent_delta2ns(0x3, &systick.dev); | |
133 | systick.dev.irq = irq_of_parse_and_map(np, 0); | |
134 | if (!systick.dev.irq) { | |
135 | pr_err("%s: request_irq failed", np->name); | |
2712616f | 136 | return -EINVAL; |
1f2acc5a JC |
137 | } |
138 | ||
2712616f DL |
139 | ret = clocksource_mmio_init(systick.membase + SYSTICK_COUNT, np->name, |
140 | SYSTICK_FREQ, 301, 16, | |
141 | clocksource_mmio_readl_up); | |
142 | if (ret) | |
143 | return ret; | |
1f2acc5a JC |
144 | |
145 | clockevents_register_device(&systick.dev); | |
146 | ||
77d84ff8 | 147 | pr_info("%s: running - mult: %d, shift: %d\n", |
1f2acc5a | 148 | np->name, systick.dev.mult, systick.dev.shift); |
2712616f DL |
149 | |
150 | return 0; | |
1f2acc5a JC |
151 | } |
152 | ||
177cf6e5 | 153 | CLOCKSOURCE_OF_DECLARE(systick, "ralink,cevt-systick", ralink_systick_init); |