Daniel Hellstrom | 7279b82 | 2011-01-27 01:26:58 +0000 | [diff] [blame] | 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 | |
| 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 | */ |
| 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 | */ |
| 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 */ |
| 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); |