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 */
13 unsigned int pmc_leon_fixup_ids[] = {
14 AEROFLEX_UT699,
15 GAISLER_GR712RC,
16 LEON4_NEXTREME1,
17 0
18 };
19
pmc_leon_need_fixup(void)20 int 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 */
pmc_leon_idle_fixup(void)39 void 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 */
pmc_leon_idle(void)59 void 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 */
leon_pmc_install(void)66 static 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 */
82 late_initcall(leon_pmc_install);
83