2 * Port on Texas Instruments TMS320C6x architecture
4 * Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated
5 * Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
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.
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>
21 #include <asm/syscalls.h>
23 /* hooks for board specific support */
24 void (*c6x_restart)(void);
25 void (*c6x_halt)(void);
27 extern asmlinkage void ret_from_fork(void);
30 * power off function, if any
32 void (*pm_power_off)(void);
33 EXPORT_SYMBOL(pm_power_off);
35 static void c6x_idle(void)
40 * Put local_irq_enable and idle in same execute packet
41 * to make them atomic and avoid race to idle with
44 asm volatile (" mvc .s2 CSR,%0\n"
52 * The idle loop for C64x
56 /* endless idle loop with no priority at all */
58 tick_nohz_idle_enter();
66 c6x_idle(); /* enables local irqs */
69 tick_nohz_idle_exit();
71 preempt_enable_no_resched();
77 static void halt_loop(void)
79 printk(KERN_EMERG "System Halted, OK to turn off power\n");
82 asm volatile("idle\n");
85 void machine_restart(char *__unused)
92 void machine_halt(void)
99 void machine_power_off(void)
106 static void kernel_thread_helper(int dummy, void *arg, int (*fn)(void *))
112 * Create a kernel thread
114 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
119 * copy_thread sets a4 to zero (child return from fork)
120 * so we can't just set things up to directly return to
123 memset(®s, 0, sizeof(regs));
124 regs.b4 = (unsigned long) arg;
125 regs.a6 = (unsigned long) fn;
126 regs.pc = (unsigned long) kernel_thread_helper;
127 local_save_flags(regs.csr);
129 regs.tsr = 5; /* Set GEE and GIE in TSR */
131 /* Ok, create the new process.. */
132 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, -1, ®s,
135 EXPORT_SYMBOL(kernel_thread);
137 void flush_thread(void)
141 void exit_thread(void)
145 SYSCALL_DEFINE1(c6x_clone, struct pt_regs *, regs)
147 unsigned long clone_flags;
150 /* syscall puts clone_flags in A4 and usp in B4 */
151 clone_flags = regs->orig_a4;
157 return do_fork(clone_flags, newsp, regs, 0, (int __user *)regs->a6,
158 (int __user *)regs->b6);
162 * Do necessary setup to start up a newly executed thread.
164 void start_thread(struct pt_regs *regs, unsigned int pc, unsigned long usp)
167 * The binfmt loader will setup a "full" stack, but the C6X
168 * operates an "empty" stack. So we adjust the usp so that
169 * argc doesn't get destroyed if an interrupt is taken before
170 * it is read from the stack.
172 * NB: Library startup code needs to match this.
179 regs->tsr |= 0x40; /* set user mode */
180 current->thread.usp = usp;
184 * Copy a new thread context in its stack.
186 int copy_thread(unsigned long clone_flags, unsigned long usp,
187 unsigned long ustk_size,
188 struct task_struct *p, struct pt_regs *regs)
190 struct pt_regs *childregs;
192 childregs = task_pt_regs(p);
198 /* case of __kernel_thread: we return to supervisor space */
199 childregs->sp = (unsigned long)(childregs + 1);
201 /* Otherwise use the given stack */
205 p->thread.usp = childregs->sp;
206 /* switch_to uses stack to save/restore 14 callee-saved regs */
207 thread_saved_ksp(p) = (unsigned long)childregs - 8;
208 p->thread.pc = (unsigned int) ret_from_fork;
209 p->thread.wchan = (unsigned long) ret_from_fork;
214 asm volatile ("mv .S2 b14,%0\n" : "=b"(dp));
216 thread_saved_dp(p) = dp;
225 * c6x_execve() executes a new program.
227 SYSCALL_DEFINE4(c6x_execve, const char __user *, name,
228 const char __user *const __user *, argv,
229 const char __user *const __user *, envp,
230 struct pt_regs *, regs)
235 filename = getname(name);
236 error = PTR_ERR(filename);
237 if (IS_ERR(filename))
240 error = do_execve(filename, argv, envp, regs);
246 unsigned long get_wchan(struct task_struct *p)
248 return p->thread.wchan;