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); 83