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/* leon_pmc.c: LEON Power-down cpu_idle() handler
*
* Copyright (C) 2011 Daniel Hellstrom (daniel@gaisler.com) Aeroflex Gaisler AB
*/
#include <linux/init.h>
#include <linux/pm.h>
#include <asm/leon_amba.h>
#include <asm/cpu_type.h>
#include <asm/leon.h>
#include <asm/processor.h>
/* List of Systems that need fixup instructions around power-down instruction */
static unsigned int pmc_leon_fixup_ids[] = {
AEROFLEX_UT699,
GAISLER_GR712RC,
LEON4_NEXTREME1,
0
};
static int pmc_leon_need_fixup(void)
{
unsigned int systemid = amba_system_id >> 16;
unsigned int *id;
id = &pmc_leon_fixup_ids[0];
while (*id != 0) {
if (*id == systemid)
return 1;
id++;
}
return 0;
}
/*
* CPU idle callback function for systems that need some extra handling
* See .../arch/sparc/kernel/process.c
*/
static void pmc_leon_idle_fixup(void)
{
/* Prepare an address to a non-cachable region. APB is always
* none-cachable. One instruction is executed after the Sleep
* instruction, we make sure to read the bus and throw away the
* value by accessing a non-cachable area, also we make sure the
* MMU does not get a TLB miss here by using the MMU BYPASS ASI.
*/
register unsigned int address = (unsigned int)leon3_irqctrl_regs;
/* Interrupts need to be enabled to not hang the CPU */
local_irq_enable();
__asm__ __volatile__ (
"wr %%g0, %%asr19\n"
"lda [%0] %1, %%g0\n"
:
: "r"(address), "i"(ASI_LEON_BYPASS));
}
/*
* CPU idle callback function
* See .../arch/sparc/kernel/process.c
*/
static void pmc_leon_idle(void)
{
/* Interrupts need to be enabled to not hang the CPU */
local_irq_enable();
/* For systems without power-down, this will be no-op */
__asm__ __volatile__ ("wr %g0, %asr19\n\t");
}
/* Install LEON Power Down function */
static int __init leon_pmc_install(void)
{
if (sparc_cpu_model == sparc_leon) {
/* Assign power management IDLE handler */
if (pmc_leon_need_fixup())
sparc_idle = pmc_leon_idle_fixup;
else
sparc_idle = pmc_leon_idle;
printk(KERN_INFO "leon: power management initialized\n");
}
return 0;
}
/* This driver is not critical to the boot process, don't care
* if initialized late.
*/
late_initcall(leon_pmc_install);
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