1/*
2 *  Copyright (C) 2000-2003  Axis Communications AB
3 *
4 *  Authors:   Bjorn Wesen (bjornw@axis.com)
5 *             Mikael Starvik (starvik@axis.com)
6 *             Tobias Anderberg (tobiasa@axis.com), CRISv32 port.
7 *
8 * This file handles the architecture-dependent parts of process handling..
9 */
10
11#include <linux/sched.h>
12#include <linux/slab.h>
13#include <linux/err.h>
14#include <linux/fs.h>
15#include <hwregs/reg_rdwr.h>
16#include <hwregs/reg_map.h>
17#include <hwregs/timer_defs.h>
18#include <hwregs/intr_vect_defs.h>
19#include <linux/ptrace.h>
20
21extern void stop_watchdog(void);
22
23/* We use this if we don't have any better idle routine. */
24void default_idle(void)
25{
26	/* Halt until exception. */
27	__asm__ volatile("ei    \n\t"
28			 "halt      ");
29}
30
31/*
32 * Free current thread data structures etc..
33 */
34
35extern void deconfigure_bp(long pid);
36void exit_thread(void)
37{
38	deconfigure_bp(current->pid);
39}
40
41/*
42 * If the watchdog is enabled, disable interrupts and enter an infinite loop.
43 * The watchdog will reset the CPU after 0.1s. If the watchdog isn't enabled
44 * then enable it and wait.
45 */
46extern void arch_enable_nmi(void);
47
48void
49hard_reset_now(void)
50{
51	/*
52	 * Don't declare this variable elsewhere.  We don't want any other
53	 * code to know about it than the watchdog handler in entry.S and
54	 * this code, implementing hard reset through the watchdog.
55	 */
56#if defined(CONFIG_ETRAX_WATCHDOG)
57	extern int cause_of_death;
58#endif
59
60	printk("*** HARD RESET ***\n");
61	local_irq_disable();
62
63#if defined(CONFIG_ETRAX_WATCHDOG)
64	cause_of_death = 0xbedead;
65#else
66{
67	reg_timer_rw_wd_ctrl wd_ctrl = {0};
68
69	stop_watchdog();
70
71	wd_ctrl.key = 16;	/* Arbitrary key. */
72	wd_ctrl.cnt = 1;	/* Minimum time. */
73	wd_ctrl.cmd = regk_timer_start;
74
75        arch_enable_nmi();
76	REG_WR(timer, regi_timer0, rw_wd_ctrl, wd_ctrl);
77}
78#endif
79
80	while (1)
81		; /* Wait for reset. */
82}
83
84/*
85 * Return saved PC of a blocked thread.
86 */
87unsigned long thread_saved_pc(struct task_struct *t)
88{
89	return task_pt_regs(t)->erp;
90}
91
92/*
93 * Setup the child's kernel stack with a pt_regs and call switch_stack() on it.
94 * It will be unnested during _resume and _ret_from_sys_call when the new thread
95 * is scheduled.
96 *
97 * Also setup the thread switching structure which is used to keep
98 * thread-specific data during _resumes.
99 */
100
101extern asmlinkage void ret_from_fork(void);
102extern asmlinkage void ret_from_kernel_thread(void);
103
104int
105copy_thread(unsigned long clone_flags, unsigned long usp,
106	unsigned long arg, struct task_struct *p)
107{
108	struct pt_regs *childregs = task_pt_regs(p);
109	struct switch_stack *swstack = ((struct switch_stack *) childregs) - 1;
110
111	/*
112	 * Put the pt_regs structure at the end of the new kernel stack page and
113	 * fix it up. Note: the task_struct doubles as the kernel stack for the
114	 * task.
115	 */
116	if (unlikely(p->flags & PF_KTHREAD)) {
117		memset(swstack, 0,
118			sizeof(struct switch_stack) + sizeof(struct pt_regs));
119		swstack->r1 = usp;
120		swstack->r2 = arg;
121		childregs->ccs = 1 << (I_CCS_BITNR + CCS_SHIFT);
122		swstack->return_ip = (unsigned long) ret_from_kernel_thread;
123		p->thread.ksp = (unsigned long) swstack;
124		p->thread.usp = 0;
125		return 0;
126	}
127	*childregs = *current_pt_regs();	/* Struct copy of pt_regs. */
128        childregs->r10 = 0;	/* Child returns 0 after a fork/clone. */
129
130	/* Set a new TLS ?
131	 * The TLS is in $mof because it is the 5th argument to sys_clone.
132	 */
133	if (p->mm && (clone_flags & CLONE_SETTLS)) {
134		task_thread_info(p)->tls = childregs->mof;
135	}
136
137	/* Put the switch stack right below the pt_regs. */
138
139	/* Parameter to ret_from_sys_call. 0 is don't restart the syscall. */
140	swstack->r9 = 0;
141
142	/*
143	 * We want to return into ret_from_sys_call after the _resume.
144	 * ret_from_fork will call ret_from_sys_call.
145	 */
146	swstack->return_ip = (unsigned long) ret_from_fork;
147
148	/* Fix the user-mode and kernel-mode stackpointer. */
149	p->thread.usp = usp ?: rdusp();
150	p->thread.ksp = (unsigned long) swstack;
151
152	return 0;
153}
154
155unsigned long
156get_wchan(struct task_struct *p)
157{
158	/* TODO */
159	return 0;
160}
161#undef last_sched
162#undef first_sched
163
164void show_regs(struct pt_regs * regs)
165{
166	unsigned long usp = rdusp();
167
168	show_regs_print_info(KERN_DEFAULT);
169
170        printk("ERP: %08lx SRP: %08lx  CCS: %08lx USP: %08lx MOF: %08lx\n",
171		regs->erp, regs->srp, regs->ccs, usp, regs->mof);
172
173	printk(" r0: %08lx  r1: %08lx   r2: %08lx  r3: %08lx\n",
174		regs->r0, regs->r1, regs->r2, regs->r3);
175
176	printk(" r4: %08lx  r5: %08lx   r6: %08lx  r7: %08lx\n",
177		regs->r4, regs->r5, regs->r6, regs->r7);
178
179	printk(" r8: %08lx  r9: %08lx  r10: %08lx r11: %08lx\n",
180		regs->r8, regs->r9, regs->r10, regs->r11);
181
182	printk("r12: %08lx r13: %08lx oR10: %08lx\n",
183		regs->r12, regs->r13, regs->orig_r10);
184}
185