1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2006-2007 PA Semi, Inc
4 *
5 * Maintained by: Olof Johansson <olof@lixom.net>
6 */
7
8 #undef DEBUG
9
10 #include <linux/kernel.h>
11 #include <linux/string.h>
12 #include <linux/irq.h>
13
14 #include <asm/machdep.h>
15 #include <asm/reg.h>
16 #include <asm/smp.h>
17
18 #include "pasemi.h"
19
20 struct sleep_mode {
21 char *name;
22 void (*entry)(void);
23 };
24
25 static struct sleep_mode modes[] = {
26 { .name = "spin", .entry = &idle_spin },
27 { .name = "doze", .entry = &idle_doze },
28 };
29
30 static int current_mode = 0;
31
32 static int pasemi_system_reset_exception(struct pt_regs *regs)
33 {
34 /* If we were woken up from power savings, we need to return
35 * to the calling function, since nip is not saved across
36 * all modes.
37 */
38
39 if (regs->msr & SRR1_WAKEMASK)
40 regs_set_return_ip(regs, regs->link);
41
42 switch (regs->msr & SRR1_WAKEMASK) {
43 case SRR1_WAKEDEC:
44 set_dec(1);
45 break;
46 case SRR1_WAKEEE:
47 /*
48 * Handle these when interrupts get re-enabled and we take
49 * them as regular exceptions. We are in an NMI context
50 * and can't handle these here.
51 */
52 break;
53 default:
54 /* do system reset */
55 return 0;
56 }
57
58 /* Set higher astate since we come out of power savings at 0 */
59 restore_astate(hard_smp_processor_id());
60
61 /* everything handled */
62 regs_set_recoverable(regs);
63 return 1;
64 }
65
66 static int __init pasemi_idle_init(void)
67 {
68 #ifndef CONFIG_PPC_PASEMI_CPUFREQ
69 pr_warn("No cpufreq driver, powersavings modes disabled\n");
70 current_mode = 0;
71 #endif
72
73 ppc_md.system_reset_exception = pasemi_system_reset_exception;
74 ppc_md.power_save = modes[current_mode].entry;
75 pr_info("Using PA6T idle loop (%s)\n", modes[current_mode].name);
76
77 return 0;
78 }
79 machine_late_initcall(pasemi, pasemi_idle_init);
80
81 static int __init idle_param(char *p)
82 {
83 int i;
84 for (i = 0; i < ARRAY_SIZE(modes); i++) {
85 if (!strcmp(modes[i].name, p)) {
86 current_mode = i;
87 break;
88 }
89 }
90 return 0;
91 }
92
93 early_param("idle", idle_param);
94
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