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687b12ba AJ |
1 | /* |
2 | * Port on Texas Instruments TMS320C6x architecture | |
3 | * | |
4 | * Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated | |
5 | * Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com) | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | * | |
11 | */ | |
12 | #include <linux/module.h> | |
13 | #include <linux/unistd.h> | |
14 | #include <linux/ptrace.h> | |
15 | #include <linux/init_task.h> | |
16 | #include <linux/tick.h> | |
17 | #include <linux/mqueue.h> | |
18 | #include <linux/syscalls.h> | |
19 | #include <linux/reboot.h> | |
29930025 | 20 | #include <linux/sched/task.h> |
68db0cf1 | 21 | #include <linux/sched/task_stack.h> |
687b12ba AJ |
22 | |
23 | #include <asm/syscalls.h> | |
24 | ||
25 | /* hooks for board specific support */ | |
26 | void (*c6x_restart)(void); | |
27 | void (*c6x_halt)(void); | |
28 | ||
29 | extern asmlinkage void ret_from_fork(void); | |
46f15067 | 30 | extern asmlinkage void ret_from_kernel_thread(void); |
687b12ba | 31 | |
687b12ba AJ |
32 | /* |
33 | * power off function, if any | |
34 | */ | |
35 | void (*pm_power_off)(void); | |
36 | EXPORT_SYMBOL(pm_power_off); | |
37 | ||
e46746cd | 38 | void arch_cpu_idle(void) |
687b12ba AJ |
39 | { |
40 | unsigned long tmp; | |
41 | ||
42 | /* | |
43 | * Put local_irq_enable and idle in same execute packet | |
44 | * to make them atomic and avoid race to idle with | |
45 | * interrupts enabled. | |
46 | */ | |
47 | asm volatile (" mvc .s2 CSR,%0\n" | |
48 | " or .d2 1,%0,%0\n" | |
49 | " mvc .s2 %0,CSR\n" | |
50 | "|| idle\n" | |
51 | : "=b"(tmp)); | |
52 | } | |
53 | ||
687b12ba AJ |
54 | static void halt_loop(void) |
55 | { | |
56 | printk(KERN_EMERG "System Halted, OK to turn off power\n"); | |
57 | local_irq_disable(); | |
58 | while (1) | |
59 | asm volatile("idle\n"); | |
60 | } | |
61 | ||
62 | void machine_restart(char *__unused) | |
63 | { | |
64 | if (c6x_restart) | |
65 | c6x_restart(); | |
66 | halt_loop(); | |
67 | } | |
68 | ||
69 | void machine_halt(void) | |
70 | { | |
71 | if (c6x_halt) | |
72 | c6x_halt(); | |
73 | halt_loop(); | |
74 | } | |
75 | ||
76 | void machine_power_off(void) | |
77 | { | |
78 | if (pm_power_off) | |
79 | pm_power_off(); | |
80 | halt_loop(); | |
81 | } | |
82 | ||
687b12ba AJ |
83 | void flush_thread(void) |
84 | { | |
85 | } | |
86 | ||
687b12ba AJ |
87 | /* |
88 | * Do necessary setup to start up a newly executed thread. | |
89 | */ | |
90 | void start_thread(struct pt_regs *regs, unsigned int pc, unsigned long usp) | |
91 | { | |
92 | /* | |
93 | * The binfmt loader will setup a "full" stack, but the C6X | |
94 | * operates an "empty" stack. So we adjust the usp so that | |
95 | * argc doesn't get destroyed if an interrupt is taken before | |
96 | * it is read from the stack. | |
97 | * | |
98 | * NB: Library startup code needs to match this. | |
99 | */ | |
100 | usp -= 8; | |
101 | ||
687b12ba AJ |
102 | regs->pc = pc; |
103 | regs->sp = usp; | |
104 | regs->tsr |= 0x40; /* set user mode */ | |
105 | current->thread.usp = usp; | |
106 | } | |
107 | ||
108 | /* | |
109 | * Copy a new thread context in its stack. | |
110 | */ | |
111 | int copy_thread(unsigned long clone_flags, unsigned long usp, | |
112 | unsigned long ustk_size, | |
afa86fc4 | 113 | struct task_struct *p) |
687b12ba AJ |
114 | { |
115 | struct pt_regs *childregs; | |
116 | ||
117 | childregs = task_pt_regs(p); | |
118 | ||
951b3961 | 119 | if (unlikely(p->flags & PF_KTHREAD)) { |
687b12ba | 120 | /* case of __kernel_thread: we return to supervisor space */ |
5687580b | 121 | memset(childregs, 0, sizeof(struct pt_regs)); |
687b12ba | 122 | childregs->sp = (unsigned long)(childregs + 1); |
46f15067 | 123 | p->thread.pc = (unsigned long) ret_from_kernel_thread; |
5687580b AV |
124 | childregs->a0 = usp; /* function */ |
125 | childregs->a1 = ustk_size; /* argument */ | |
46f15067 | 126 | } else { |
687b12ba | 127 | /* Otherwise use the given stack */ |
951b3961 AV |
128 | *childregs = *current_pt_regs(); |
129 | if (usp) | |
130 | childregs->sp = usp; | |
46f15067 MS |
131 | p->thread.pc = (unsigned long) ret_from_fork; |
132 | } | |
687b12ba AJ |
133 | |
134 | /* Set usp/ksp */ | |
135 | p->thread.usp = childregs->sp; | |
687b12ba | 136 | thread_saved_ksp(p) = (unsigned long)childregs - 8; |
46f15067 | 137 | p->thread.wchan = p->thread.pc; |
687b12ba AJ |
138 | #ifdef __DSBT__ |
139 | { | |
140 | unsigned long dp; | |
141 | ||
142 | asm volatile ("mv .S2 b14,%0\n" : "=b"(dp)); | |
143 | ||
144 | thread_saved_dp(p) = dp; | |
145 | if (usp == -1) | |
146 | childregs->dp = dp; | |
147 | } | |
148 | #endif | |
149 | return 0; | |
150 | } | |
151 | ||
687b12ba AJ |
152 | unsigned long get_wchan(struct task_struct *p) |
153 | { | |
154 | return p->thread.wchan; | |
155 | } |