1 /* leon_pmc.c: LEON Power-down cpu_idle() handler
3 * Copyright (C) 2011 Daniel Hellstrom (daniel@gaisler.com) Aeroflex Gaisler AB
6 #include <linux/init.h>
9 #include <asm/leon_amba.h>
10 #include <asm/cpu_type.h>
12 #include <asm/processor.h>
14 /* List of Systems that need fixup instructions around power-down instruction */
15 unsigned int pmc_leon_fixup_ids[] = {
22 int pmc_leon_need_fixup(void)
24 unsigned int systemid = amba_system_id >> 16;
27 id = &pmc_leon_fixup_ids[0];
38 * CPU idle callback function for systems that need some extra handling
39 * See .../arch/sparc/kernel/process.c
41 void pmc_leon_idle_fixup(void)
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.
49 register unsigned int address = (unsigned int)leon3_irqctrl_regs;
50 __asm__ __volatile__ (
54 : "r"(address), "i"(ASI_LEON_BYPASS));
58 * CPU idle callback function
59 * See .../arch/sparc/kernel/process.c
61 void pmc_leon_idle(void)
63 /* For systems without power-down, this will be no-op */
64 __asm__ __volatile__ ("wr %g0, %asr19\n\t");
67 /* Install LEON Power Down function */
68 static int __init leon_pmc_install(void)
70 if (sparc_cpu_model == sparc_leon) {
71 /* Assign power management IDLE handler */
72 if (pmc_leon_need_fixup())
73 sparc_idle = pmc_leon_idle_fixup;
75 sparc_idle = pmc_leon_idle;
77 printk(KERN_INFO "leon: power management initialized\n");
83 /* This driver is not critical to the boot process, don't care
84 * if initialized late.
86 late_initcall(leon_pmc_install);