[deliverable/linux.git] / arch / sparc / kernel / leon_pmc.c

/* 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);
Commit	Line	Data
7279b82c DH	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>
556626ad	10	#include <asm/cpu_type.h>
7279b82c	11	#include <asm/leon.h>
d472ba84	12	#include <asm/processor.h>
7279b82c DH	13
7279b82c DH	14	/* List of Systems that need fixup instructions around power-down instruction */
8b45c796	15	static unsigned int pmc_leon_fixup_ids[] = {
7279b82c DH	16	AEROFLEX_UT699,
	17	GAISLER_GR712RC,
	18	LEON4_NEXTREME1,
	19	0
	20	};
	21
8b45c796	22	static int pmc_leon_need_fixup(void)
7279b82c DH	23	{
	24	unsigned int systemid = amba_system_id >> 16;
	25	unsigned int *id;
	26
	27	id = &pmc_leon_fixup_ids[0];
	28	while (*id != 0) {
	29	if (*id == systemid)
	30	return 1;
	31	id++;
	32	}
	33
	34	return 0;
	35	}
	36
	37	/*
	38	* CPU idle callback function for systems that need some extra handling
	39	* See .../arch/sparc/kernel/process.c
	40	*/
8b45c796	41	static void pmc_leon_idle_fixup(void)
7279b82c DH	42	{
	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.
	48	*/
	49	register unsigned int address = (unsigned int)leon3_irqctrl_regs;
d72ee6be AL	50
	51	/* Interrupts need to be enabled to not hang the CPU */
	52	local_irq_enable();
	53
7279b82c	54	__asm__ __volatile__ (
598ec971	55	"wr %%g0, %%asr19\n"
7279b82c DH	56	"lda [%0] %1, %%g0\n"
	57	:
	58	: "r"(address), "i"(ASI_LEON_BYPASS));
	59	}
	60
	61	/*
	62	* CPU idle callback function
	63	* See .../arch/sparc/kernel/process.c
	64	*/
8b45c796	65	static void pmc_leon_idle(void)
7279b82c	66	{
d72ee6be AL	67	/* Interrupts need to be enabled to not hang the CPU */
	68	local_irq_enable();
	69
7279b82c	70	/* For systems without power-down, this will be no-op */
598ec971	71	__asm__ __volatile__ ("wr %g0, %asr19\n\t");
7279b82c DH	72	}
	73
	74	/* Install LEON Power Down function */
	75	static int __init leon_pmc_install(void)
	76	{
556626ad SR	77	if (sparc_cpu_model == sparc_leon) {
	78	/* Assign power management IDLE handler */
	79	if (pmc_leon_need_fixup())
d472ba84	80	sparc_idle = pmc_leon_idle_fixup;
556626ad	81	else
d472ba84	82	sparc_idle = pmc_leon_idle;
7279b82c	83
556626ad SR	84	printk(KERN_INFO "leon: power management initialized\n");
556626ad SR	85	}
7279b82c DH	86
	87	return 0;
	88	}
	89
	90	/* This driver is not critical to the boot process, don't care
	91	* if initialized late.
	92	*/
	93	late_initcall(leon_pmc_install);