[mirror_ubuntu-hirsute-kernel.git] / arch / sparc / kernel / leon_pmc.c

// 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 */
	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
b2441318	1	// SPDX-License-Identifier: GPL-2.0
7279b82c DH	2	/* leon_pmc.c: LEON Power-down cpu_idle() handler
	3	*
	4	* Copyright (C) 2011 Daniel Hellstrom (daniel@gaisler.com) Aeroflex Gaisler AB
	5	*/
	6
	7	#include <linux/init.h>
	8	#include <linux/pm.h>
	9
	10	#include <asm/leon_amba.h>
556626ad	11	#include <asm/cpu_type.h>
7279b82c	12	#include <asm/leon.h>
d472ba84	13	#include <asm/processor.h>
7279b82c DH	14
7279b82c DH	15	/* List of Systems that need fixup instructions around power-down instruction */
8b45c796	16	static unsigned int pmc_leon_fixup_ids[] = {
7279b82c DH	17	AEROFLEX_UT699,
	18	GAISLER_GR712RC,
	19	LEON4_NEXTREME1,
	20	0
	21	};
	22
8b45c796	23	static int pmc_leon_need_fixup(void)
7279b82c DH	24	{
	25	unsigned int systemid = amba_system_id >> 16;
	26	unsigned int *id;
	27
	28	id = &pmc_leon_fixup_ids[0];
	29	while (*id != 0) {
	30	if (*id == systemid)
	31	return 1;
	32	id++;
	33	}
	34
	35	return 0;
	36	}
	37
	38	/*
	39	* CPU idle callback function for systems that need some extra handling
	40	* See .../arch/sparc/kernel/process.c
	41	*/
8b45c796	42	static void pmc_leon_idle_fixup(void)
7279b82c DH	43	{
	44	/* Prepare an address to a non-cachable region. APB is always
	45	* none-cachable. One instruction is executed after the Sleep
	46	* instruction, we make sure to read the bus and throw away the
	47	* value by accessing a non-cachable area, also we make sure the
	48	* MMU does not get a TLB miss here by using the MMU BYPASS ASI.
	49	*/
	50	register unsigned int address = (unsigned int)leon3_irqctrl_regs;
d72ee6be AL	51
	52	/* Interrupts need to be enabled to not hang the CPU */
	53	local_irq_enable();
	54
7279b82c	55	__asm__ __volatile__ (
598ec971	56	"wr %%g0, %%asr19\n"
7279b82c DH	57	"lda [%0] %1, %%g0\n"
	58	:
	59	: "r"(address), "i"(ASI_LEON_BYPASS));
	60	}
	61
	62	/*
	63	* CPU idle callback function
	64	* See .../arch/sparc/kernel/process.c
	65	*/
8b45c796	66	static void pmc_leon_idle(void)
7279b82c	67	{
d72ee6be AL	68	/* Interrupts need to be enabled to not hang the CPU */
	69	local_irq_enable();
	70
7279b82c	71	/* For systems without power-down, this will be no-op */
598ec971	72	__asm__ __volatile__ ("wr %g0, %asr19\n\t");
7279b82c DH	73	}
	74
	75	/* Install LEON Power Down function */
	76	static int __init leon_pmc_install(void)
	77	{
556626ad SR	78	if (sparc_cpu_model == sparc_leon) {
	79	/* Assign power management IDLE handler */
	80	if (pmc_leon_need_fixup())
d472ba84	81	sparc_idle = pmc_leon_idle_fixup;
556626ad	82	else
d472ba84	83	sparc_idle = pmc_leon_idle;
7279b82c	84
556626ad SR	85	printk(KERN_INFO "leon: power management initialized\n");
556626ad SR	86	}
7279b82c DH	87
	88	return 0;
	89	}
	90
	91	/* This driver is not critical to the boot process, don't care
	92	* if initialized late.
	93	*/
	94	late_initcall(leon_pmc_install);