1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License.  See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 2005 MIPS Technologies, Inc.  All rights reserved.
7 * Copyright (C) 2013 Imagination Technologies Ltd.
8 */
9#include <linux/device.h>
10#include <linux/fs.h>
11#include <linux/err.h>
12#include <linux/wait.h>
13#include <linux/sched.h>
14#include <linux/interrupt.h>
15#include <linux/irq.h>
16
17#include <asm/mips_mt.h>
18#include <asm/vpe.h>
19#include <asm/rtlx.h>
20
21static int major;
22
23static void rtlx_dispatch(void)
24{
25	if (read_c0_cause() & read_c0_status() & C_SW0)
26		do_IRQ(MIPS_CPU_IRQ_BASE + MIPS_CPU_RTLX_IRQ);
27}
28
29/*
30 * Interrupt handler may be called before rtlx_init has otherwise had
31 * a chance to run.
32 */
33static irqreturn_t rtlx_interrupt(int irq, void *dev_id)
34{
35	unsigned int vpeflags;
36	unsigned long flags;
37	int i;
38
39	local_irq_save(flags);
40	vpeflags = dvpe();
41	set_c0_status(0x100 << MIPS_CPU_RTLX_IRQ);
42	irq_enable_hazard();
43	evpe(vpeflags);
44	local_irq_restore(flags);
45
46	for (i = 0; i < RTLX_CHANNELS; i++) {
47		wake_up(&channel_wqs[i].lx_queue);
48		wake_up(&channel_wqs[i].rt_queue);
49	}
50
51	return IRQ_HANDLED;
52}
53
54static struct irqaction rtlx_irq = {
55	.handler	= rtlx_interrupt,
56	.name		= "RTLX",
57};
58
59static int rtlx_irq_num = MIPS_CPU_IRQ_BASE + MIPS_CPU_RTLX_IRQ;
60
61void _interrupt_sp(void)
62{
63	unsigned long flags;
64
65	local_irq_save(flags);
66	dvpe();
67	settc(1);
68	write_vpe_c0_cause(read_vpe_c0_cause() | C_SW0);
69	evpe(EVPE_ENABLE);
70	local_irq_restore(flags);
71}
72
73int __init rtlx_module_init(void)
74{
75	struct device *dev;
76	int i, err;
77
78	if (!cpu_has_mipsmt) {
79		pr_warn("VPE loader: not a MIPS MT capable processor\n");
80		return -ENODEV;
81	}
82
83	if (aprp_cpu_index() == 0) {
84		pr_warn("No TCs reserved for AP/SP, not initializing RTLX.\n"
85			"Pass maxtcs=<n> argument as kernel argument\n");
86
87		return -ENODEV;
88	}
89
90	major = register_chrdev(0, RTLX_MODULE_NAME, &rtlx_fops);
91	if (major < 0) {
92		pr_err("rtlx_module_init: unable to register device\n");
93		return major;
94	}
95
96	/* initialise the wait queues */
97	for (i = 0; i < RTLX_CHANNELS; i++) {
98		init_waitqueue_head(&channel_wqs[i].rt_queue);
99		init_waitqueue_head(&channel_wqs[i].lx_queue);
100		atomic_set(&channel_wqs[i].in_open, 0);
101		mutex_init(&channel_wqs[i].mutex);
102
103		dev = device_create(mt_class, NULL, MKDEV(major, i), NULL,
104				    "%s%d", RTLX_MODULE_NAME, i);
105		if (IS_ERR(dev)) {
106			while (i--)
107				device_destroy(mt_class, MKDEV(major, i));
108
109			err = PTR_ERR(dev);
110			goto out_chrdev;
111		}
112	}
113
114	/* set up notifiers */
115	rtlx_notify.start = rtlx_starting;
116	rtlx_notify.stop = rtlx_stopping;
117	vpe_notify(aprp_cpu_index(), &rtlx_notify);
118
119	if (cpu_has_vint) {
120		aprp_hook = rtlx_dispatch;
121	} else {
122		pr_err("APRP RTLX init on non-vectored-interrupt processor\n");
123		err = -ENODEV;
124		goto out_class;
125	}
126
127	rtlx_irq.dev_id = rtlx;
128	err = setup_irq(rtlx_irq_num, &rtlx_irq);
129	if (err)
130		goto out_class;
131
132	return 0;
133
134out_class:
135	for (i = 0; i < RTLX_CHANNELS; i++)
136		device_destroy(mt_class, MKDEV(major, i));
137out_chrdev:
138	unregister_chrdev(major, RTLX_MODULE_NAME);
139
140	return err;
141}
142
143void __exit rtlx_module_exit(void)
144{
145	int i;
146
147	for (i = 0; i < RTLX_CHANNELS; i++)
148		device_destroy(mt_class, MKDEV(major, i));
149
150	unregister_chrdev(major, RTLX_MODULE_NAME);
151
152	aprp_hook = NULL;
153}
154