1// SPDX-License-Identifier: GPL-2.0
 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>
11#include <asm/cpu_type.h>
12#include <asm/leon.h>
13#include <asm/processor.h>
14
15/* List of Systems that need fixup instructions around power-down instruction */
16static unsigned int pmc_leon_fixup_ids[] = {
17	AEROFLEX_UT699,
18	GAISLER_GR712RC,
19	LEON4_NEXTREME1,
20	0
21};
22
23static int pmc_leon_need_fixup(void)
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 */
42static void pmc_leon_idle_fixup(void)
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;
51
52	/* Interrupts need to be enabled to not hang the CPU */
53	local_irq_enable();
54
55	__asm__ __volatile__ (
56		"wr	%%g0, %%asr19\n"
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 */
66static void pmc_leon_idle(void)
67{
68	/* Interrupts need to be enabled to not hang the CPU */
69	local_irq_enable();
70
71	/* For systems without power-down, this will be no-op */
72	__asm__ __volatile__ ("wr	%g0, %asr19\n\t");
73}
74
75/* Install LEON Power Down function */
76static int __init leon_pmc_install(void)
77{
78	if (sparc_cpu_model == sparc_leon) {
79		/* Assign power management IDLE handler */
80		if (pmc_leon_need_fixup())
81			sparc_idle = pmc_leon_idle_fixup;
82		else
83			sparc_idle = pmc_leon_idle;
84
85		printk(KERN_INFO "leon: power management initialized\n");
86	}
87
88	return 0;
89}
90
91/* This driver is not critical to the boot process, don't care
92 * if initialized late.
93 */
94late_initcall(leon_pmc_install);

 
 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>
10#include <asm/cpu_type.h>
11#include <asm/leon.h>
12#include <asm/processor.h>
13
14/* List of Systems that need fixup instructions around power-down instruction */
15static unsigned int pmc_leon_fixup_ids[] = {
16	AEROFLEX_UT699,
17	GAISLER_GR712RC,
18	LEON4_NEXTREME1,
19	0
20};
21
22static int pmc_leon_need_fixup(void)
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 */
41static void pmc_leon_idle_fixup(void)
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;
50
51	/* Interrupts need to be enabled to not hang the CPU */
52	local_irq_enable();
53
54	__asm__ __volatile__ (
55		"wr	%%g0, %%asr19\n"
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 */
65static void pmc_leon_idle(void)
66{
67	/* Interrupts need to be enabled to not hang the CPU */
68	local_irq_enable();
69
70	/* For systems without power-down, this will be no-op */
71	__asm__ __volatile__ ("wr	%g0, %asr19\n\t");
72}
73
74/* Install LEON Power Down function */
75static int __init leon_pmc_install(void)
76{
77	if (sparc_cpu_model == sparc_leon) {
78		/* Assign power management IDLE handler */
79		if (pmc_leon_need_fixup())
80			sparc_idle = pmc_leon_idle_fixup;
81		else
82			sparc_idle = pmc_leon_idle;
83
84		printk(KERN_INFO "leon: power management initialized\n");
85	}
86
87	return 0;
88}
89
90/* This driver is not critical to the boot process, don't care
91 * if initialized late.
92 */
93late_initcall(leon_pmc_install);