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7279b82c DH |
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> | |
556626ad | 10 | #include <asm/cpu_type.h> |
7279b82c | 11 | #include <asm/leon.h> |
d472ba84 | 12 | #include <asm/processor.h> |
7279b82c DH |
13 | |
14 | /* List of Systems that need fixup instructions around power-down instruction */ | |
15 | unsigned int pmc_leon_fixup_ids[] = { | |
16 | AEROFLEX_UT699, | |
17 | GAISLER_GR712RC, | |
18 | LEON4_NEXTREME1, | |
19 | 0 | |
20 | }; | |
21 | ||
22 | int pmc_leon_need_fixup(void) | |
23 | { | |
24 | unsigned int systemid = amba_system_id >> 16; | |
25 | unsigned int *id; | |
26 | ||
27 | id = &pmc_leon_fixup_ids[0]; | |
28 | while (*id != 0) { | |
29 | if (*id == systemid) | |
30 | return 1; | |
31 | id++; | |
32 | } | |
33 | ||
34 | return 0; | |
35 | } | |
36 | ||
37 | /* | |
38 | * CPU idle callback function for systems that need some extra handling | |
39 | * See .../arch/sparc/kernel/process.c | |
40 | */ | |
41 | void pmc_leon_idle_fixup(void) | |
42 | { | |
43 | /* Prepare an address to a non-cachable region. APB is always | |
44 | * none-cachable. One instruction is executed after the Sleep | |
45 | * instruction, we make sure to read the bus and throw away the | |
46 | * value by accessing a non-cachable area, also we make sure the | |
47 | * MMU does not get a TLB miss here by using the MMU BYPASS ASI. | |
48 | */ | |
49 | register unsigned int address = (unsigned int)leon3_irqctrl_regs; | |
d72ee6be AL |
50 | |
51 | /* Interrupts need to be enabled to not hang the CPU */ | |
52 | local_irq_enable(); | |
53 | ||
7279b82c | 54 | __asm__ __volatile__ ( |
598ec971 | 55 | "wr %%g0, %%asr19\n" |
7279b82c DH |
56 | "lda [%0] %1, %%g0\n" |
57 | : | |
58 | : "r"(address), "i"(ASI_LEON_BYPASS)); | |
59 | } | |
60 | ||
61 | /* | |
62 | * CPU idle callback function | |
63 | * See .../arch/sparc/kernel/process.c | |
64 | */ | |
65 | void pmc_leon_idle(void) | |
66 | { | |
d72ee6be AL |
67 | /* Interrupts need to be enabled to not hang the CPU */ |
68 | local_irq_enable(); | |
69 | ||
7279b82c | 70 | /* For systems without power-down, this will be no-op */ |
598ec971 | 71 | __asm__ __volatile__ ("wr %g0, %asr19\n\t"); |
7279b82c DH |
72 | } |
73 | ||
74 | /* Install LEON Power Down function */ | |
75 | static int __init leon_pmc_install(void) | |
76 | { | |
556626ad SR |
77 | if (sparc_cpu_model == sparc_leon) { |
78 | /* Assign power management IDLE handler */ | |
79 | if (pmc_leon_need_fixup()) | |
d472ba84 | 80 | sparc_idle = pmc_leon_idle_fixup; |
556626ad | 81 | else |
d472ba84 | 82 | sparc_idle = pmc_leon_idle; |
7279b82c | 83 | |
556626ad SR |
84 | printk(KERN_INFO "leon: power management initialized\n"); |
85 | } | |
7279b82c DH |
86 | |
87 | return 0; | |
88 | } | |
89 | ||
90 | /* This driver is not critical to the boot process, don't care | |
91 | * if initialized late. | |
92 | */ | |
93 | late_initcall(leon_pmc_install); |