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);
28 extern asmlinkage void ret_from_kernel_thread(void);
29
30 /*
31 * power off function, if any
32 */
33 void (*pm_power_off)(void);
34 EXPORT_SYMBOL(pm_power_off);
35
36 void arch_cpu_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 static void halt_loop(void)
53 {
54 printk(KERN_EMERG "System Halted, OK to turn off power\n");
55 local_irq_disable();
56 while (1)
57 asm volatile("idle\n");
58 }
59
60 void machine_restart(char *__unused)
61 {
62 if (c6x_restart)
63 c6x_restart();
64 halt_loop();
65 }
66
67 void machine_halt(void)
68 {
69 if (c6x_halt)
70 c6x_halt();
71 halt_loop();
72 }
73
74 void machine_power_off(void)
75 {
76 if (pm_power_off)
77 pm_power_off();
78 halt_loop();
79 }
80
81 void flush_thread(void)
82 {
83 }
84
85 void exit_thread(void)
86 {
87 }
88
89 /*
90 * Do necessary setup to start up a newly executed thread.
91 */
92 void start_thread(struct pt_regs *regs, unsigned int pc, unsigned long usp)
93 {
94 /*
95 * The binfmt loader will setup a "full" stack, but the C6X
96 * operates an "empty" stack. So we adjust the usp so that
97 * argc doesn't get destroyed if an interrupt is taken before
98 * it is read from the stack.
99 *
100 * NB: Library startup code needs to match this.
101 */
102 usp -= 8;
103
104 set_fs(USER_DS);
105 regs->pc = pc;
106 regs->sp = usp;
107 regs->tsr |= 0x40; /* set user mode */
108 current->thread.usp = usp;
109 }
110
111 /*
112 * Copy a new thread context in its stack.
113 */
114 int copy_thread(unsigned long clone_flags, unsigned long usp,
115 unsigned long ustk_size,
116 struct task_struct *p)
117 {
118 struct pt_regs *childregs;
119
120 childregs = task_pt_regs(p);
121
122 if (unlikely(p->flags & PF_KTHREAD)) {
123 /* case of __kernel_thread: we return to supervisor space */
124 memset(childregs, 0, sizeof(struct pt_regs));
125 childregs->sp = (unsigned long)(childregs + 1);
126 p->thread.pc = (unsigned long) ret_from_kernel_thread;
127 childregs->a0 = usp; /* function */
128 childregs->a1 = ustk_size; /* argument */
129 } else {
130 /* Otherwise use the given stack */
131 *childregs = *current_pt_regs();
132 if (usp)
133 childregs->sp = usp;
134 p->thread.pc = (unsigned long) ret_from_fork;
135 }
136
137 /* Set usp/ksp */
138 p->thread.usp = childregs->sp;
139 thread_saved_ksp(p) = (unsigned long)childregs - 8;
140 p->thread.wchan = p->thread.pc;
141 #ifdef __DSBT__
142 {
143 unsigned long dp;
144
145 asm volatile ("mv .S2 b14,%0\n" : "=b"(dp));
146
147 thread_saved_dp(p) = dp;
148 if (usp == -1)
149 childregs->dp = dp;
150 }
151 #endif
152 return 0;
153 }
154
155 unsigned long get_wchan(struct task_struct *p)
156 {
157 return p->thread.wchan;
158 }
159
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