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