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1/* leon_pmc.c: LEON Power-down cpu_idle() handler
2 *
3 * Copyright (C) 2011 Daniel Hellstrom (daniel@gaisler.com) Aeroflex Gaisler AB
4 */
5
6#include <linux/init.h>
7#include <linux/pm.h>
8
9#include <asm/leon_amba.h>
10#include <asm/leon.h>
11
12/* List of Systems that need fixup instructions around power-down instruction */
13unsigned int pmc_leon_fixup_ids[] = {
14 AEROFLEX_UT699,
15 GAISLER_GR712RC,
16 LEON4_NEXTREME1,
17 0
18};
19
20int pmc_leon_need_fixup(void)
21{
22 unsigned int systemid = amba_system_id >> 16;
23 unsigned int *id;
24
25 id = &pmc_leon_fixup_ids[0];
26 while (*id != 0) {
27 if (*id == systemid)
28 return 1;
29 id++;
30 }
31
32 return 0;
33}
34
35/*
36 * CPU idle callback function for systems that need some extra handling
37 * See .../arch/sparc/kernel/process.c
38 */
39void pmc_leon_idle_fixup(void)
40{
41 /* Prepare an address to a non-cachable region. APB is always
42 * none-cachable. One instruction is executed after the Sleep
43 * instruction, we make sure to read the bus and throw away the
44 * value by accessing a non-cachable area, also we make sure the
45 * MMU does not get a TLB miss here by using the MMU BYPASS ASI.
46 */
47 register unsigned int address = (unsigned int)leon3_irqctrl_regs;
48 __asm__ __volatile__ (
49 "mov %%g0, %%asr19\n"
50 "lda [%0] %1, %%g0\n"
51 :
52 : "r"(address), "i"(ASI_LEON_BYPASS));
53}
54
55/*
56 * CPU idle callback function
57 * See .../arch/sparc/kernel/process.c
58 */
59void pmc_leon_idle(void)
60{
61 /* For systems without power-down, this will be no-op */
62 __asm__ __volatile__ ("mov %g0, %asr19\n\t");
63}
64
65/* Install LEON Power Down function */
66static int __init leon_pmc_install(void)
67{
68 /* Assign power management IDLE handler */
69 if (pmc_leon_need_fixup())
70 pm_idle = pmc_leon_idle_fixup;
71 else
72 pm_idle = pmc_leon_idle;
73
74 printk(KERN_INFO "leon: power management initialized\n");
75
76 return 0;
77}
78
79/* This driver is not critical to the boot process, don't care
80 * if initialized late.
81 */
82late_initcall(leon_pmc_install);