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