blob: 6339c9c6d0abebbd9ef355740bad27cd233512ee (
plain)
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
|
/*
* arch/metag/kernel/clock.c
*
* Copyright (C) 2012 Imagination Technologies Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/of.h>
#include <asm/param.h>
#include <asm/clock.h>
struct meta_clock_desc _meta_clock;
/* Default machine get_core_freq callback. */
static unsigned long get_core_freq_default(void)
{
#ifdef CONFIG_METAG_META21
/*
* Meta 2 cores divide down the core clock for the Meta timers, so we
* can estimate the core clock from the divider.
*/
return (metag_in32(EXPAND_TIMER_DIV) + 1) * 1000000;
#else
/*
* On Meta 1 we don't know the core clock, but assuming the Meta timer
* is correct it can be estimated based on loops_per_jiffy.
*/
return (loops_per_jiffy * HZ * 5) >> 1;
#endif
}
static struct clk *clk_core;
/* Clk based get_core_freq callback. */
static unsigned long get_core_freq_clk(void)
{
return clk_get_rate(clk_core);
}
/**
* init_metag_core_clock() - Set up core clock from devicetree.
*
* Checks to see if a "core" clock is provided in the device tree, and overrides
* the get_core_freq callback to use it.
*/
static void __init init_metag_core_clock(void)
{
/*
* See if a core clock is provided by the devicetree (and
* registered by the init callback above).
*/
struct device_node *node;
node = of_find_compatible_node(NULL, NULL, "img,meta");
if (!node) {
pr_warn("%s: no compatible img,meta DT node found\n",
__func__);
return;
}
clk_core = of_clk_get_by_name(node, "core");
if (IS_ERR(clk_core)) {
pr_warn("%s: no core clock found in DT\n",
__func__);
return;
}
/*
* Override the core frequency callback to use
* this clk.
*/
_meta_clock.get_core_freq = get_core_freq_clk;
}
/**
* init_metag_clocks() - Set up clocks from devicetree.
*
* Set up important clocks from device tree. In particular any needed for clock
* sources.
*/
void __init init_metag_clocks(void)
{
init_metag_core_clock();
pr_info("Core clock frequency: %lu Hz\n", get_coreclock());
}
/**
* setup_meta_clocks() - Early set up of the Meta clock.
* @desc: Clock descriptor usually provided by machine description
*
* Ensures all callbacks are valid.
*/
void __init setup_meta_clocks(struct meta_clock_desc *desc)
{
/* copy callbacks */
if (desc)
_meta_clock = *desc;
/* set fallback functions */
if (!_meta_clock.get_core_freq)
_meta_clock.get_core_freq = get_core_freq_default;
}
|
