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