// SPDX-License-Identifier: GPL-2.0
|
/* 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 */
|
raw_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 */
|
raw_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);
|
