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 
21 static int major;
22 
rtlx_dispatch(void)23 static 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  */
rtlx_interrupt(int irq,void * dev_id)33 static 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 
54 static int rtlx_irq_num = MIPS_CPU_IRQ_BASE + MIPS_CPU_RTLX_IRQ;
55 
_interrupt_sp(void)56 void _interrupt_sp(void)
57 {
58 	unsigned long flags;
59 
60 	local_irq_save(flags);
61 	dvpe();
62 	settc(1);
63 	write_vpe_c0_cause(read_vpe_c0_cause() | C_SW0);
64 	evpe(EVPE_ENABLE);
65 	local_irq_restore(flags);
66 }
67 
rtlx_module_init(void)68 int __init rtlx_module_init(void)
69 {
70 	struct device *dev;
71 	int i, err;
72 
73 	if (!cpu_has_mipsmt) {
74 		pr_warn("VPE loader: not a MIPS MT capable processor\n");
75 		return -ENODEV;
76 	}
77 
78 	if (aprp_cpu_index() == 0) {
79 		pr_warn("No TCs reserved for AP/SP, not initializing RTLX.\n"
80 			"Pass maxtcs=<n> argument as kernel argument\n");
81 
82 		return -ENODEV;
83 	}
84 
85 	major = register_chrdev(0, RTLX_MODULE_NAME, &rtlx_fops);
86 	if (major < 0) {
87 		pr_err("rtlx_module_init: unable to register device\n");
88 		return major;
89 	}
90 
91 	/* initialise the wait queues */
92 	for (i = 0; i < RTLX_CHANNELS; i++) {
93 		init_waitqueue_head(&channel_wqs[i].rt_queue);
94 		init_waitqueue_head(&channel_wqs[i].lx_queue);
95 		atomic_set(&channel_wqs[i].in_open, 0);
96 		mutex_init(&channel_wqs[i].mutex);
97 
98 		dev = device_create(mt_class, NULL, MKDEV(major, i), NULL,
99 				    "%s%d", RTLX_MODULE_NAME, i);
100 		if (IS_ERR(dev)) {
101 			while (i--)
102 				device_destroy(mt_class, MKDEV(major, i));
103 
104 			err = PTR_ERR(dev);
105 			goto out_chrdev;
106 		}
107 	}
108 
109 	/* set up notifiers */
110 	rtlx_notify.start = rtlx_starting;
111 	rtlx_notify.stop = rtlx_stopping;
112 	vpe_notify(aprp_cpu_index(), &rtlx_notify);
113 
114 	if (cpu_has_vint) {
115 		aprp_hook = rtlx_dispatch;
116 	} else {
117 		pr_err("APRP RTLX init on non-vectored-interrupt processor\n");
118 		err = -ENODEV;
119 		goto out_class;
120 	}
121 
122 	err = request_irq(rtlx_irq_num, rtlx_interrupt, 0, "RTLX", rtlx);
123 	if (err)
124 		goto out_class;
125 
126 	return 0;
127 
128 out_class:
129 	for (i = 0; i < RTLX_CHANNELS; i++)
130 		device_destroy(mt_class, MKDEV(major, i));
131 out_chrdev:
132 	unregister_chrdev(major, RTLX_MODULE_NAME);
133 
134 	return err;
135 }
136 
rtlx_module_exit(void)137 void __exit rtlx_module_exit(void)
138 {
139 	int i;
140 
141 	for (i = 0; i < RTLX_CHANNELS; i++)
142 		device_destroy(mt_class, MKDEV(major, i));
143 
144 	unregister_chrdev(major, RTLX_MODULE_NAME);
145 
146 	aprp_hook = NULL;
147 }
148