1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3  * hvc_console.h
4  * Copyright (C) 2005 IBM Corporation
5  *
6  * Author(s):
7  * 	Ryan S. Arnold <rsa@us.ibm.com>
8  *
9  * hvc_console header information:
10  *      moved here from arch/powerpc/include/asm/hvconsole.h
11  *      and drivers/char/hvc_console.c
12  */
13 
14 #ifndef HVC_CONSOLE_H
15 #define HVC_CONSOLE_H
16 #include <linux/kref.h>
17 #include <linux/tty.h>
18 #include <linux/spinlock.h>
19 
20 /*
21  * This is the max number of console adapters that can/will be found as
22  * console devices on first stage console init.  Any number beyond this range
23  * can't be used as a console device but is still a valid tty device.
24  */
25 #define MAX_NR_HVC_CONSOLES	16
26 
27 /*
28  * The Linux TTY code does not support dynamic addition of tty derived devices
29  * so we need to know how many tty devices we might need when space is allocated
30  * for the tty device.  Since this driver supports hotplug of vty adapters we
31  * need to make sure we have enough allocated.
32  */
33 #define HVC_ALLOC_TTY_ADAPTERS	8
34 
35 struct hvc_struct {
36 	struct tty_port port;
37 	spinlock_t lock;
38 	int index;
39 	int do_wakeup;
40 	char *outbuf;
41 	int outbuf_size;
42 	int n_outbuf;
43 	uint32_t vtermno;
44 	const struct hv_ops *ops;
45 	int irq_requested;
46 	int data;
47 	struct winsize ws;
48 	struct work_struct tty_resize;
49 	struct list_head next;
50 	unsigned long flags;
51 };
52 
53 /* implemented by a low level driver */
54 struct hv_ops {
55 	int (*get_chars)(uint32_t vtermno, char *buf, int count);
56 	int (*put_chars)(uint32_t vtermno, const char *buf, int count);
57 	int (*flush)(uint32_t vtermno, bool wait);
58 
59 	/* Callbacks for notification. Called in open, close and hangup */
60 	int (*notifier_add)(struct hvc_struct *hp, int irq);
61 	void (*notifier_del)(struct hvc_struct *hp, int irq);
62 	void (*notifier_hangup)(struct hvc_struct *hp, int irq);
63 
64 	/* tiocmget/set implementation */
65 	int (*tiocmget)(struct hvc_struct *hp);
66 	int (*tiocmset)(struct hvc_struct *hp, unsigned int set, unsigned int clear);
67 
68 	/* Callbacks to handle tty ports */
69 	void (*dtr_rts)(struct hvc_struct *hp, int raise);
70 };
71 
72 /* Register a vterm and a slot index for use as a console (console_init) */
73 extern int hvc_instantiate(uint32_t vtermno, int index,
74 			   const struct hv_ops *ops);
75 
76 /* register a vterm for hvc tty operation (module_init or hotplug add) */
77 extern struct hvc_struct * hvc_alloc(uint32_t vtermno, int data,
78 				     const struct hv_ops *ops, int outbuf_size);
79 /* remove a vterm from hvc tty operation (module_exit or hotplug remove) */
80 extern int hvc_remove(struct hvc_struct *hp);
81 
82 /* data available */
83 int hvc_poll(struct hvc_struct *hp);
84 void hvc_kick(void);
85 
86 /* Resize hvc tty terminal window */
87 extern void __hvc_resize(struct hvc_struct *hp, struct winsize ws);
88 
hvc_resize(struct hvc_struct * hp,struct winsize ws)89 static inline void hvc_resize(struct hvc_struct *hp, struct winsize ws)
90 {
91 	unsigned long flags;
92 
93 	spin_lock_irqsave(&hp->lock, flags);
94 	__hvc_resize(hp, ws);
95 	spin_unlock_irqrestore(&hp->lock, flags);
96 }
97 
98 /* default notifier for irq based notification */
99 extern int notifier_add_irq(struct hvc_struct *hp, int data);
100 extern void notifier_del_irq(struct hvc_struct *hp, int data);
101 extern void notifier_hangup_irq(struct hvc_struct *hp, int data);
102 
103 
104 #if defined(CONFIG_XMON) && defined(CONFIG_SMP)
105 #include <asm/xmon.h>
106 #else
cpus_are_in_xmon(void)107 static inline int cpus_are_in_xmon(void)
108 {
109 	return 0;
110 }
111 #endif
112 
113 #endif // HVC_CONSOLE_H
114