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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
7279b82c DH |
2 | /* leon_pmc.c: LEON Power-down cpu_idle() handler |
3 | * | |
4 | * Copyright (C) 2011 Daniel Hellstrom (daniel@gaisler.com) Aeroflex Gaisler AB | |
5 | */ | |
6 | ||
7 | #include <linux/init.h> | |
8 | #include <linux/pm.h> | |
9 | ||
10 | #include <asm/leon_amba.h> | |
556626ad | 11 | #include <asm/cpu_type.h> |
7279b82c | 12 | #include <asm/leon.h> |
d472ba84 | 13 | #include <asm/processor.h> |
7279b82c DH |
14 | |
15 | /* List of Systems that need fixup instructions around power-down instruction */ | |
8b45c796 | 16 | static unsigned int pmc_leon_fixup_ids[] = { |
7279b82c DH |
17 | AEROFLEX_UT699, |
18 | GAISLER_GR712RC, | |
19 | LEON4_NEXTREME1, | |
20 | 0 | |
21 | }; | |
22 | ||
8b45c796 | 23 | static int pmc_leon_need_fixup(void) |
7279b82c DH |
24 | { |
25 | unsigned int systemid = amba_system_id >> 16; | |
26 | unsigned int *id; | |
27 | ||
28 | id = &pmc_leon_fixup_ids[0]; | |
29 | while (*id != 0) { | |
30 | if (*id == systemid) | |
31 | return 1; | |
32 | id++; | |
33 | } | |
34 | ||
35 | return 0; | |
36 | } | |
37 | ||
38 | /* | |
39 | * CPU idle callback function for systems that need some extra handling | |
40 | * See .../arch/sparc/kernel/process.c | |
41 | */ | |
8b45c796 | 42 | static void pmc_leon_idle_fixup(void) |
7279b82c DH |
43 | { |
44 | /* Prepare an address to a non-cachable region. APB is always | |
45 | * none-cachable. One instruction is executed after the Sleep | |
46 | * instruction, we make sure to read the bus and throw away the | |
47 | * value by accessing a non-cachable area, also we make sure the | |
48 | * MMU does not get a TLB miss here by using the MMU BYPASS ASI. | |
49 | */ | |
50 | register unsigned int address = (unsigned int)leon3_irqctrl_regs; | |
d72ee6be AL |
51 | |
52 | /* Interrupts need to be enabled to not hang the CPU */ | |
58c644ba | 53 | raw_local_irq_enable(); |
d72ee6be | 54 | |
7279b82c | 55 | __asm__ __volatile__ ( |
598ec971 | 56 | "wr %%g0, %%asr19\n" |
7279b82c DH |
57 | "lda [%0] %1, %%g0\n" |
58 | : | |
59 | : "r"(address), "i"(ASI_LEON_BYPASS)); | |
89b30987 PZ |
60 | |
61 | raw_local_irq_disable(); | |
7279b82c DH |
62 | } |
63 | ||
64 | /* | |
65 | * CPU idle callback function | |
66 | * See .../arch/sparc/kernel/process.c | |
67 | */ | |
8b45c796 | 68 | static void pmc_leon_idle(void) |
7279b82c | 69 | { |
d72ee6be | 70 | /* Interrupts need to be enabled to not hang the CPU */ |
58c644ba | 71 | raw_local_irq_enable(); |
d72ee6be | 72 | |
7279b82c | 73 | /* For systems without power-down, this will be no-op */ |
598ec971 | 74 | __asm__ __volatile__ ("wr %g0, %asr19\n\t"); |
89b30987 PZ |
75 | |
76 | raw_local_irq_disable(); | |
7279b82c DH |
77 | } |
78 | ||
79 | /* Install LEON Power Down function */ | |
80 | static int __init leon_pmc_install(void) | |
81 | { | |
556626ad SR |
82 | if (sparc_cpu_model == sparc_leon) { |
83 | /* Assign power management IDLE handler */ | |
84 | if (pmc_leon_need_fixup()) | |
d472ba84 | 85 | sparc_idle = pmc_leon_idle_fixup; |
556626ad | 86 | else |
d472ba84 | 87 | sparc_idle = pmc_leon_idle; |
7279b82c | 88 | |
556626ad SR |
89 | printk(KERN_INFO "leon: power management initialized\n"); |
90 | } | |
7279b82c DH |
91 | |
92 | return 0; | |
93 | } | |
94 | ||
95 | /* This driver is not critical to the boot process, don't care | |
96 | * if initialized late. | |
97 | */ | |
98 | late_initcall(leon_pmc_install); |