aboutsummaryrefslogtreecommitdiffstats
path: root/arch/blackfin/kernel/ipipe.c
blob: b8d22034b9a6ce8f829efa2dfd3f41afa42df16f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
/* -*- linux-c -*-
 * linux/arch/blackfin/kernel/ipipe.c
 *
 * Copyright (C) 2005-2007 Philippe Gerum.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, Inc., 675 Mass Ave, Cambridge MA 02139,
 * USA; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 * Architecture-dependent I-pipe support for the Blackfin.
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/percpu.h>
#include <linux/bitops.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/kthread.h>
#include <asm/unistd.h>
#include <asm/system.h>
#include <asm/atomic.h>
#include <asm/io.h>

DEFINE_PER_CPU(struct pt_regs, __ipipe_tick_regs);

asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs);

static void __ipipe_no_irqtail(void);

unsigned long __ipipe_irq_tail_hook = (unsigned long)&__ipipe_no_irqtail;
EXPORT_SYMBOL(__ipipe_irq_tail_hook);

unsigned long __ipipe_core_clock;
EXPORT_SYMBOL(__ipipe_core_clock);

unsigned long __ipipe_freq_scale;
EXPORT_SYMBOL(__ipipe_freq_scale);

atomic_t __ipipe_irq_lvdepth[IVG15 + 1];

unsigned long __ipipe_irq_lvmask = bfin_no_irqs;
EXPORT_SYMBOL(__ipipe_irq_lvmask);

static void __ipipe_ack_irq(unsigned irq, struct irq_desc *desc)
{
	desc->ipipe_ack(irq, desc);
}

/*
 * __ipipe_enable_pipeline() -- We are running on the boot CPU, hw
 * interrupts are off, and secondary CPUs are still lost in space.
 */
void __ipipe_enable_pipeline(void)
{
	unsigned irq;

	__ipipe_core_clock = get_cclk(); /* Fetch this once. */
	__ipipe_freq_scale = 1000000000UL / __ipipe_core_clock;

	for (irq = 0; irq < NR_IRQS; ++irq)
		ipipe_virtualize_irq(ipipe_root_domain,
				     irq,
				     (ipipe_irq_handler_t)&asm_do_IRQ,
				     NULL,
				     &__ipipe_ack_irq,
				     IPIPE_HANDLE_MASK | IPIPE_PASS_MASK);
}

/*
 * __ipipe_handle_irq() -- IPIPE's generic IRQ handler. An optimistic
 * interrupt protection log is maintained here for each domain. Hw
 * interrupts are masked on entry.
 */
void __ipipe_handle_irq(unsigned irq, struct pt_regs *regs)
{
	struct ipipe_percpu_domain_data *p = ipipe_root_cpudom_ptr();
	struct ipipe_domain *this_domain, *next_domain;
	struct list_head *head, *pos;
	int m_ack, s = -1;

	/*
	 * Software-triggered IRQs do not need any ack.  The contents
	 * of the register frame should only be used when processing
	 * the timer interrupt, but not for handling any other
	 * interrupt.
	 */
	m_ack = (regs == NULL || irq == IRQ_SYSTMR || irq == IRQ_CORETMR);
	this_domain = __ipipe_current_domain;

	if (unlikely(test_bit(IPIPE_STICKY_FLAG, &this_domain->irqs[irq].control)))
		head = &this_domain->p_link;
	else {
		head = __ipipe_pipeline.next;
		next_domain = list_entry(head, struct ipipe_domain, p_link);
		if (likely(test_bit(IPIPE_WIRED_FLAG, &next_domain->irqs[irq].control))) {
			if (!m_ack && next_domain->irqs[irq].acknowledge != NULL)
				next_domain->irqs[irq].acknowledge(irq, irq_to_desc(irq));
			if (test_bit(IPIPE_SYNCDEFER_FLAG, &p->status))
				s = __test_and_set_bit(IPIPE_STALL_FLAG, &p->status);
			__ipipe_dispatch_wired(next_domain, irq);
			goto out;
		}
	}

	/* Ack the interrupt. */

	pos = head;
	while (pos != &__ipipe_pipeline) {
		next_domain = list_entry(pos, struct ipipe_domain, p_link);
		if (test_bit(IPIPE_HANDLE_FLAG, &next_domain->irqs[irq].control)) {
			__ipipe_set_irq_pending(next_domain, irq);
			if (!m_ack && next_domain->irqs[irq].acknowledge != NULL) {
				next_domain->irqs[irq].acknowledge(irq, irq_to_desc(irq));
				m_ack = 1;
			}
		}
		if (!test_bit(IPIPE_PASS_FLAG, &next_domain->irqs[irq].control))
			break;
		pos = next_domain->p_link.next;
	}

	/*
	 * Now walk the pipeline, yielding control to the highest
	 * priority domain that has pending interrupt(s) or
	 * immediately to the current domain if the interrupt has been
	 * marked as 'sticky'. This search does not go beyond the
	 * current domain in the pipeline. We also enforce the
	 * additional root stage lock (blackfin-specific).
	 */
	if (test_bit(IPIPE_SYNCDEFER_FLAG, &p->status))
		s = __test_and_set_bit(IPIPE_STALL_FLAG, &p->status);

	/*
	 * If the interrupt preempted the head domain, then do not
	 * even try to walk the pipeline, unless an interrupt is
	 * pending for it.
	 */
	if (test_bit(IPIPE_AHEAD_FLAG, &this_domain->flags) &&
	    ipipe_head_cpudom_var(irqpend_himask) == 0)
		goto out;

	__ipipe_walk_pipeline(head);
out:
	if (!s)
		__clear_bit(IPIPE_STALL_FLAG, &p->status);
}

int __ipipe_check_root(void)
{
	return ipipe_root_domain_p;
}

void __ipipe_enable_irqdesc(struct ipipe_domain *ipd, unsigned irq)
{
	struct irq_desc *desc = irq_to_desc(irq);
	int prio = __ipipe_get_irq_priority(irq);

	desc->depth = 0;
	if (ipd != &ipipe_root &&
	    atomic_inc_return(&__ipipe_irq_lvdepth[prio]) == 1)
		__set_bit(prio, &__ipipe_irq_lvmask);
}
EXPORT_SYMBOL(__ipipe_enable_irqdesc);

void __ipipe_disable_irqdesc(struct ipipe_domain *ipd, unsigned irq)
{
	int prio = __ipipe_get_irq_priority(irq);

	if (ipd != &ipipe_root &&
	    atomic_dec_and_test(&__ipipe_irq_lvdepth[prio]))
		__clear_bit(prio, &__ipipe_irq_lvmask);
}
EXPORT_SYMBOL(__ipipe_disable_irqdesc);

void __ipipe_stall_root_raw(void)
{
	/*
	 * This code is called by the ins{bwl} routines (see
	 * arch/blackfin/lib/ins.S), which are heavily used by the
	 * network stack. It masks all interrupts but those handled by
	 * non-root domains, so that we keep decent network transfer
	 * rates for Linux without inducing pathological jitter for
	 * the real-time domain.
	 */
	__asm__ __volatile__ ("sti %0;" : : "d"(__ipipe_irq_lvmask));

	__set_bit(IPIPE_STALL_FLAG,
		  &ipipe_root_cpudom_var(status));
}

void __ipipe_unstall_root_raw(void)
{
	__clear_bit(IPIPE_STALL_FLAG,
		    &ipipe_root_cpudom_var(status));

	__asm__ __volatile__ ("sti %0;" : : "d"(bfin_irq_flags));
}

int __ipipe_syscall_root(struct pt_regs *regs)
{
	struct ipipe_percpu_domain_data *p;
	unsigned long flags;
	int ret;

	/*
	 * We need to run the IRQ tail hook whenever we don't
	 * propagate a syscall to higher domains, because we know that
	 * important operations might be pending there (e.g. Xenomai
	 * deferred rescheduling).
	 */

	if (regs->orig_p0 < NR_syscalls) {
		void (*hook)(void) = (void (*)(void))__ipipe_irq_tail_hook;
		hook();
		if ((current->flags & PF_EVNOTIFY) == 0)
			return 0;
	}

	/*
	 * This routine either returns:
	 * 0 -- if the syscall is to be passed to Linux;
	 * >0 -- if the syscall should not be passed to Linux, and no
	 * tail work should be performed;
	 * <0 -- if the syscall should not be passed to Linux but the
	 * tail work has to be performed (for handling signals etc).
	 */

	if (!__ipipe_event_monitored_p(IPIPE_EVENT_SYSCALL))
		return 0;

	ret = __ipipe_dispatch_event(IPIPE_EVENT_SYSCALL, regs);

	local_irq_save_hw(flags);

	if (!__ipipe_root_domain_p) {
		local_irq_restore_hw(flags);
		return 1;
	}

	p = ipipe_root_cpudom_ptr();
	if ((p->irqpend_himask & IPIPE_IRQMASK_VIRT) != 0)
		__ipipe_sync_pipeline(IPIPE_IRQMASK_VIRT);

	local_irq_restore_hw(flags);

	return -ret;
}

unsigned long ipipe_critical_enter(void (*syncfn) (void))
{
	unsigned long flags;

	local_irq_save_hw(flags);

	return flags;
}

void ipipe_critical_exit(unsigned long flags)
{
	local_irq_restore_hw(flags);
}

static void __ipipe_no_irqtail(void)
{
}

int ipipe_get_sysinfo(struct ipipe_sysinfo *info)
{
	info->ncpus = num_online_cpus();
	info->cpufreq = ipipe_cpu_freq();
	info->archdep.tmirq = IPIPE_TIMER_IRQ;
	info->archdep.tmfreq = info->cpufreq;

	return 0;
}

/*
 * ipipe_trigger_irq() -- Push the interrupt at front of the pipeline
 * just like if it has been actually received from a hw source. Also
 * works for virtual interrupts.
 */
int ipipe_trigger_irq(unsigned irq)
{
	unsigned long flags;

#ifdef CONFIG_IPIPE_DEBUG
	if (irq >= IPIPE_NR_IRQS ||
	    (ipipe_virtual_irq_p(irq)
	     && !test_bit(irq - IPIPE_VIRQ_BASE, &__ipipe_virtual_irq_map)))
		return -EINVAL;
#endif

	local_irq_save_hw(flags);
	__ipipe_handle_irq(irq, NULL);
	local_irq_restore_hw(flags);

	return 1;
}

asmlinkage void __ipipe_sync_root(void)
{
	void (*irq_tail_hook)(void) = (void (*)(void))__ipipe_irq_tail_hook;
	unsigned long flags;

	BUG_ON(irqs_disabled());

	local_irq_save_hw(flags);

	if (irq_tail_hook)
		irq_tail_hook();

	clear_thread_flag(TIF_IRQ_SYNC);

	if (ipipe_root_cpudom_var(irqpend_himask) != 0)
		__ipipe_sync_pipeline(IPIPE_IRQMASK_ANY);

	local_irq_restore_hw(flags);
}

void ___ipipe_sync_pipeline(unsigned long syncmask)
{
	if (__ipipe_root_domain_p) {
		if (test_bit(IPIPE_SYNCDEFER_FLAG, &ipipe_root_cpudom_var(status)))
			return;
	}

	__ipipe_sync_stage(syncmask);
}

EXPORT_SYMBOL(show_stack);