xref: /kernel/linux/linux-6.6/drivers/tty/hvc/hvc_console.h

/* SPDX-License-Identifier: GPL-2.0+ */
/*
 * hvc_console.h
 * Copyright (C) 2005 IBM Corporation
 *
 * Author(s):
 * 	Ryan S. Arnold <rsa@us.ibm.com>
 *
 * hvc_console header information:
 *      moved here from arch/powerpc/include/asm/hvconsole.h
 *      and drivers/char/hvc_console.c
 */

#ifndef HVC_CONSOLE_H
#define HVC_CONSOLE_H
#include <linux/kref.h>
#include <linux/tty.h>
#include <linux/spinlock.h>

/*
 * This is the max number of console adapters that can/will be found as
 * console devices on first stage console init.  Any number beyond this range
 * can't be used as a console device but is still a valid tty device.
 */
#define MAX_NR_HVC_CONSOLES	16

/*
 * The Linux TTY code does not support dynamic addition of tty derived devices
 * so we need to know how many tty devices we might need when space is allocated
 * for the tty device.  Since this driver supports hotplug of vty adapters we
 * need to make sure we have enough allocated.
 */
#define HVC_ALLOC_TTY_ADAPTERS	8

struct hvc_struct {
	struct tty_port port;
	spinlock_t lock;
	int index;
	int do_wakeup;
	char *outbuf;
	int outbuf_size;
	int n_outbuf;
	uint32_t vtermno;
	const struct hv_ops *ops;
	int irq_requested;
	int data;
	struct winsize ws;
	struct work_struct tty_resize;
	struct list_head next;
	unsigned long flags;
};

/* implemented by a low level driver */
struct hv_ops {
	int (*get_chars)(uint32_t vtermno, char *buf, int count);
	int (*put_chars)(uint32_t vtermno, const char *buf, int count);
	int (*flush)(uint32_t vtermno, bool wait);

	/* Callbacks for notification. Called in open, close and hangup */
	int (*notifier_add)(struct hvc_struct *hp, int irq);
	void (*notifier_del)(struct hvc_struct *hp, int irq);
	void (*notifier_hangup)(struct hvc_struct *hp, int irq);

	/* tiocmget/set implementation */
	int (*tiocmget)(struct hvc_struct *hp);
	int (*tiocmset)(struct hvc_struct *hp, unsigned int set, unsigned int clear);

	/* Callbacks to handle tty ports */
	void (*dtr_rts)(struct hvc_struct *hp, bool active);
};

/* Register a vterm and a slot index for use as a console (console_init) */
extern int hvc_instantiate(uint32_t vtermno, int index,
			   const struct hv_ops *ops);

/* register a vterm for hvc tty operation (module_init or hotplug add) */
extern struct hvc_struct * hvc_alloc(uint32_t vtermno, int data,
				     const struct hv_ops *ops, int outbuf_size);
/* remove a vterm from hvc tty operation (module_exit or hotplug remove) */
extern int hvc_remove(struct hvc_struct *hp);

/* data available */
int hvc_poll(struct hvc_struct *hp);
void hvc_kick(void);

/* Resize hvc tty terminal window */
extern void __hvc_resize(struct hvc_struct *hp, struct winsize ws);

static inline void hvc_resize(struct hvc_struct *hp, struct winsize ws)
{
	unsigned long flags;

	spin_lock_irqsave(&hp->lock, flags);
	__hvc_resize(hp, ws);
	spin_unlock_irqrestore(&hp->lock, flags);
}

/* default notifier for irq based notification */
extern int notifier_add_irq(struct hvc_struct *hp, int data);
extern void notifier_del_irq(struct hvc_struct *hp, int data);
extern void notifier_hangup_irq(struct hvc_struct *hp, int data);


#if defined(CONFIG_XMON) && defined(CONFIG_SMP)
#include <asm/xmon.h>
#else
static inline int cpus_are_in_xmon(void)
{
	return 0;
}
#endif

#endif // HVC_CONSOLE_H