Linux Kernel  3.7.1
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
rstc.c
Go to the documentation of this file.
1 /*
2  * reset controller for CSR SiRFprimaII
3  *
4  * Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
5  *
6  * Licensed under GPLv2 or later.
7  */
8 
9 #include <linux/kernel.h>
10 #include <linux/mutex.h>
11 #include <linux/io.h>
12 #include <linux/delay.h>
13 #include <linux/device.h>
14 #include <linux/of.h>
15 #include <linux/of_address.h>
16 
18 static DEFINE_MUTEX(rstc_lock);
19 
20 static struct of_device_id rstc_ids[] = {
21  { .compatible = "sirf,prima2-rstc" },
22  {},
23 };
24 
25 static int __init sirfsoc_of_rstc_init(void)
26 {
27  struct device_node *np;
28 
29  np = of_find_matching_node(NULL, rstc_ids);
30  if (!np)
31  panic("unable to find compatible rstc node in dtb\n");
32 
33  sirfsoc_rstc_base = of_iomap(np, 0);
34  if (!sirfsoc_rstc_base)
35  panic("unable to map rstc cpu registers\n");
36 
37  of_node_put(np);
38 
39  return 0;
40 }
41 early_initcall(sirfsoc_of_rstc_init);
42 
44 {
45  const unsigned int *prop = of_get_property(dev->of_node, "reset-bit", NULL);
46  unsigned int reset_bit;
47 
48  if (!prop)
49  return -ENODEV;
50 
51  reset_bit = be32_to_cpup(prop);
52 
53  mutex_lock(&rstc_lock);
54 
55  /*
56  * Writing 1 to this bit resets corresponding block. Writing 0 to this
57  * bit de-asserts reset signal of the corresponding block.
58  * datasheet doesn't require explicit delay between the set and clear
59  * of reset bit. it could be shorter if tests pass.
60  */
61  writel(readl(sirfsoc_rstc_base + (reset_bit / 32) * 4) | reset_bit,
62  sirfsoc_rstc_base + (reset_bit / 32) * 4);
63  msleep(10);
64  writel(readl(sirfsoc_rstc_base + (reset_bit / 32) * 4) & ~reset_bit,
65  sirfsoc_rstc_base + (reset_bit / 32) * 4);
66 
67  mutex_unlock(&rstc_lock);
68 
69  return 0;
70 }
71 
72 #define SIRFSOC_SYS_RST_BIT BIT(31)
73 
74 void sirfsoc_restart(char mode, const char *cmd)
75 {
77 }