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/*
* Port on Texas Instruments TMS320C6x architecture
*
* Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated
* Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/module.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/init_task.h>
#include <linux/tick.h>
#include <linux/mqueue.h>
#include <linux/syscalls.h>
#include <linux/reboot.h>
#include <asm/syscalls.h>
/* hooks for board specific support */
void (*c6x_restart)(void);
void (*c6x_halt)(void);
extern asmlinkage void ret_from_fork(void);
extern asmlinkage void ret_from_kernel_thread(void);
/*
* power off function, if any
*/
void (*pm_power_off)(void);
EXPORT_SYMBOL(pm_power_off);
static void c6x_idle(void)
{
unsigned long tmp;
/*
* Put local_irq_enable and idle in same execute packet
* to make them atomic and avoid race to idle with
* interrupts enabled.
*/
asm volatile (" mvc .s2 CSR,%0\n"
" or .d2 1,%0,%0\n"
" mvc .s2 %0,CSR\n"
"|| idle\n"
: "=b"(tmp));
}
/*
* The idle loop for C64x
*/
void cpu_idle(void)
{
/* endless idle loop with no priority at all */
while (1) {
tick_nohz_idle_enter();
rcu_idle_enter();
while (1) {
local_irq_disable();
if (need_resched()) {
local_irq_enable();
break;
}
c6x_idle(); /* enables local irqs */
}
rcu_idle_exit();
tick_nohz_idle_exit();
preempt_enable_no_resched();
schedule();
preempt_disable();
}
}
static void halt_loop(void)
{
printk(KERN_EMERG "System Halted, OK to turn off power\n");
local_irq_disable();
while (1)
asm volatile("idle\n");
}
void machine_restart(char *__unused)
{
if (c6x_restart)
c6x_restart();
halt_loop();
}
void machine_halt(void)
{
if (c6x_halt)
c6x_halt();
halt_loop();
}
void machine_power_off(void)
{
if (pm_power_off)
pm_power_off();
halt_loop();
}
/*
* Create a kernel thread
*/
int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
{
struct pt_regs regs = {
.a0 = (unsigned long)fn,
.a1 = (unsigned long)arg,
.tsr = 0, /* kernel mode */
};
/* Ok, create the new process.. */
return do_fork(flags | CLONE_VM | CLONE_UNTRACED, -1, ®s,
0, NULL, NULL);
}
void flush_thread(void)
{
}
void exit_thread(void)
{
}
SYSCALL_DEFINE1(c6x_clone, struct pt_regs *, regs)
{
unsigned long clone_flags;
unsigned long newsp;
/* syscall puts clone_flags in A4 and usp in B4 */
clone_flags = regs->orig_a4;
if (regs->b4)
newsp = regs->b4;
else
newsp = regs->sp;
return do_fork(clone_flags, newsp, regs, 0, (int __user *)regs->a6,
(int __user *)regs->b6);
}
/*
* Do necessary setup to start up a newly executed thread.
*/
void start_thread(struct pt_regs *regs, unsigned int pc, unsigned long usp)
{
/*
* The binfmt loader will setup a "full" stack, but the C6X
* operates an "empty" stack. So we adjust the usp so that
* argc doesn't get destroyed if an interrupt is taken before
* it is read from the stack.
*
* NB: Library startup code needs to match this.
*/
usp -= 8;
set_fs(USER_DS);
regs->pc = pc;
regs->sp = usp;
regs->tsr |= 0x40; /* set user mode */
current->thread.usp = usp;
}
/*
* Copy a new thread context in its stack.
*/
int copy_thread(unsigned long clone_flags, unsigned long usp,
unsigned long ustk_size,
struct task_struct *p, struct pt_regs *regs)
{
struct pt_regs *childregs;
childregs = task_pt_regs(p);
*childregs = *regs;
if (usp == -1) {
/* case of __kernel_thread: we return to supervisor space */
childregs->sp = (unsigned long)(childregs + 1);
p->thread.pc = (unsigned long) ret_from_kernel_thread;
} else {
/* Otherwise use the given stack */
childregs->sp = usp;
p->thread.pc = (unsigned long) ret_from_fork;
}
/* Set usp/ksp */
p->thread.usp = childregs->sp;
thread_saved_ksp(p) = (unsigned long)childregs - 8;
p->thread.wchan = p->thread.pc;
#ifdef __DSBT__
{
unsigned long dp;
asm volatile ("mv .S2 b14,%0\n" : "=b"(dp));
thread_saved_dp(p) = dp;
if (usp == -1)
childregs->dp = dp;
}
#endif
return 0;
}
unsigned long get_wchan(struct task_struct *p)
{
return p->thread.wchan;
}
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