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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> | |
20 | ||
21 | #include <asm/syscalls.h> | |
22 | ||
23 | /* hooks for board specific support */ | |
24 | void (*c6x_restart)(void); | |
25 | void (*c6x_halt)(void); | |
26 | ||
27 | extern asmlinkage void ret_from_fork(void); | |
46f15067 | 28 | extern asmlinkage void ret_from_kernel_thread(void); |
687b12ba | 29 | |
687b12ba AJ |
30 | /* |
31 | * power off function, if any | |
32 | */ | |
33 | void (*pm_power_off)(void); | |
34 | EXPORT_SYMBOL(pm_power_off); | |
35 | ||
36 | static void c6x_idle(void) | |
37 | { | |
38 | unsigned long tmp; | |
39 | ||
40 | /* | |
41 | * Put local_irq_enable and idle in same execute packet | |
42 | * to make them atomic and avoid race to idle with | |
43 | * interrupts enabled. | |
44 | */ | |
45 | asm volatile (" mvc .s2 CSR,%0\n" | |
46 | " or .d2 1,%0,%0\n" | |
47 | " mvc .s2 %0,CSR\n" | |
48 | "|| idle\n" | |
49 | : "=b"(tmp)); | |
50 | } | |
51 | ||
52 | /* | |
53 | * The idle loop for C64x | |
54 | */ | |
55 | void cpu_idle(void) | |
56 | { | |
57 | /* endless idle loop with no priority at all */ | |
58 | while (1) { | |
166c0eae MS |
59 | tick_nohz_idle_enter(); |
60 | rcu_idle_enter(); | |
687b12ba AJ |
61 | while (1) { |
62 | local_irq_disable(); | |
63 | if (need_resched()) { | |
64 | local_irq_enable(); | |
65 | break; | |
66 | } | |
67 | c6x_idle(); /* enables local irqs */ | |
68 | } | |
166c0eae MS |
69 | rcu_idle_exit(); |
70 | tick_nohz_idle_exit(); | |
687b12ba AJ |
71 | |
72 | preempt_enable_no_resched(); | |
73 | schedule(); | |
74 | preempt_disable(); | |
75 | } | |
76 | } | |
77 | ||
78 | static void halt_loop(void) | |
79 | { | |
80 | printk(KERN_EMERG "System Halted, OK to turn off power\n"); | |
81 | local_irq_disable(); | |
82 | while (1) | |
83 | asm volatile("idle\n"); | |
84 | } | |
85 | ||
86 | void machine_restart(char *__unused) | |
87 | { | |
88 | if (c6x_restart) | |
89 | c6x_restart(); | |
90 | halt_loop(); | |
91 | } | |
92 | ||
93 | void machine_halt(void) | |
94 | { | |
95 | if (c6x_halt) | |
96 | c6x_halt(); | |
97 | halt_loop(); | |
98 | } | |
99 | ||
100 | void machine_power_off(void) | |
101 | { | |
102 | if (pm_power_off) | |
103 | pm_power_off(); | |
104 | halt_loop(); | |
105 | } | |
106 | ||
687b12ba AJ |
107 | void flush_thread(void) |
108 | { | |
109 | } | |
110 | ||
111 | void exit_thread(void) | |
112 | { | |
113 | } | |
114 | ||
687b12ba AJ |
115 | /* |
116 | * Do necessary setup to start up a newly executed thread. | |
117 | */ | |
118 | void start_thread(struct pt_regs *regs, unsigned int pc, unsigned long usp) | |
119 | { | |
120 | /* | |
121 | * The binfmt loader will setup a "full" stack, but the C6X | |
122 | * operates an "empty" stack. So we adjust the usp so that | |
123 | * argc doesn't get destroyed if an interrupt is taken before | |
124 | * it is read from the stack. | |
125 | * | |
126 | * NB: Library startup code needs to match this. | |
127 | */ | |
128 | usp -= 8; | |
129 | ||
130 | set_fs(USER_DS); | |
131 | regs->pc = pc; | |
132 | regs->sp = usp; | |
133 | regs->tsr |= 0x40; /* set user mode */ | |
134 | current->thread.usp = usp; | |
135 | } | |
136 | ||
137 | /* | |
138 | * Copy a new thread context in its stack. | |
139 | */ | |
140 | int copy_thread(unsigned long clone_flags, unsigned long usp, | |
141 | unsigned long ustk_size, | |
951b3961 | 142 | struct task_struct *p, struct pt_regs *unused) |
687b12ba AJ |
143 | { |
144 | struct pt_regs *childregs; | |
145 | ||
146 | childregs = task_pt_regs(p); | |
147 | ||
951b3961 | 148 | if (unlikely(p->flags & PF_KTHREAD)) { |
687b12ba | 149 | /* case of __kernel_thread: we return to supervisor space */ |
5687580b | 150 | memset(childregs, 0, sizeof(struct pt_regs)); |
687b12ba | 151 | childregs->sp = (unsigned long)(childregs + 1); |
46f15067 | 152 | p->thread.pc = (unsigned long) ret_from_kernel_thread; |
5687580b AV |
153 | childregs->a0 = usp; /* function */ |
154 | childregs->a1 = ustk_size; /* argument */ | |
46f15067 | 155 | } else { |
687b12ba | 156 | /* Otherwise use the given stack */ |
951b3961 AV |
157 | *childregs = *current_pt_regs(); |
158 | if (usp) | |
159 | childregs->sp = usp; | |
46f15067 MS |
160 | p->thread.pc = (unsigned long) ret_from_fork; |
161 | } | |
687b12ba AJ |
162 | |
163 | /* Set usp/ksp */ | |
164 | p->thread.usp = childregs->sp; | |
687b12ba | 165 | thread_saved_ksp(p) = (unsigned long)childregs - 8; |
46f15067 | 166 | p->thread.wchan = p->thread.pc; |
687b12ba AJ |
167 | #ifdef __DSBT__ |
168 | { | |
169 | unsigned long dp; | |
170 | ||
171 | asm volatile ("mv .S2 b14,%0\n" : "=b"(dp)); | |
172 | ||
173 | thread_saved_dp(p) = dp; | |
174 | if (usp == -1) | |
175 | childregs->dp = dp; | |
176 | } | |
177 | #endif | |
178 | return 0; | |
179 | } | |
180 | ||
687b12ba AJ |
181 | unsigned long get_wchan(struct task_struct *p) |
182 | { | |
183 | return p->thread.wchan; | |
184 | } |