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Use .flush to wait for drivers to flush their console outside of the spinlock, to reduce lock/irq latencies. Flush the hvc console driver after each write, which can help messages make it out to the console after a crash. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
114 lines
3.2 KiB
C
114 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* hvc_console.h
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* Copyright (C) 2005 IBM Corporation
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*
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* Author(s):
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* Ryan S. Arnold <rsa@us.ibm.com>
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*
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* hvc_console header information:
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* moved here from arch/powerpc/include/asm/hvconsole.h
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* and drivers/char/hvc_console.c
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*/
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#ifndef HVC_CONSOLE_H
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#define HVC_CONSOLE_H
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#include <linux/kref.h>
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#include <linux/tty.h>
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#include <linux/spinlock.h>
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/*
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* This is the max number of console adapters that can/will be found as
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* console devices on first stage console init. Any number beyond this range
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* can't be used as a console device but is still a valid tty device.
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*/
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#define MAX_NR_HVC_CONSOLES 16
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/*
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* The Linux TTY code does not support dynamic addition of tty derived devices
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* so we need to know how many tty devices we might need when space is allocated
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* for the tty device. Since this driver supports hotplug of vty adapters we
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* need to make sure we have enough allocated.
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*/
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#define HVC_ALLOC_TTY_ADAPTERS 8
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struct hvc_struct {
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struct tty_port port;
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spinlock_t lock;
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int index;
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int do_wakeup;
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char *outbuf;
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int outbuf_size;
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int n_outbuf;
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uint32_t vtermno;
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const struct hv_ops *ops;
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int irq_requested;
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int data;
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struct winsize ws;
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struct work_struct tty_resize;
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struct list_head next;
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unsigned long flags;
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};
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/* implemented by a low level driver */
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struct hv_ops {
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int (*get_chars)(uint32_t vtermno, char *buf, int count);
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int (*put_chars)(uint32_t vtermno, const char *buf, int count);
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int (*flush)(uint32_t vtermno, bool wait);
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/* Callbacks for notification. Called in open, close and hangup */
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int (*notifier_add)(struct hvc_struct *hp, int irq);
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void (*notifier_del)(struct hvc_struct *hp, int irq);
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void (*notifier_hangup)(struct hvc_struct *hp, int irq);
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/* tiocmget/set implementation */
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int (*tiocmget)(struct hvc_struct *hp);
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int (*tiocmset)(struct hvc_struct *hp, unsigned int set, unsigned int clear);
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/* Callbacks to handle tty ports */
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void (*dtr_rts)(struct hvc_struct *hp, int raise);
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};
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/* Register a vterm and a slot index for use as a console (console_init) */
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extern int hvc_instantiate(uint32_t vtermno, int index,
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const struct hv_ops *ops);
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/* register a vterm for hvc tty operation (module_init or hotplug add) */
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extern struct hvc_struct * hvc_alloc(uint32_t vtermno, int data,
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const struct hv_ops *ops, int outbuf_size);
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/* remove a vterm from hvc tty operation (module_exit or hotplug remove) */
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extern int hvc_remove(struct hvc_struct *hp);
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/* data available */
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int hvc_poll(struct hvc_struct *hp);
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void hvc_kick(void);
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/* Resize hvc tty terminal window */
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extern void __hvc_resize(struct hvc_struct *hp, struct winsize ws);
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static inline void hvc_resize(struct hvc_struct *hp, struct winsize ws)
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{
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unsigned long flags;
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spin_lock_irqsave(&hp->lock, flags);
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__hvc_resize(hp, ws);
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spin_unlock_irqrestore(&hp->lock, flags);
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}
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/* default notifier for irq based notification */
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extern int notifier_add_irq(struct hvc_struct *hp, int data);
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extern void notifier_del_irq(struct hvc_struct *hp, int data);
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extern void notifier_hangup_irq(struct hvc_struct *hp, int data);
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#if defined(CONFIG_XMON) && defined(CONFIG_SMP)
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#include <asm/xmon.h>
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#else
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static inline int cpus_are_in_xmon(void)
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{
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return 0;
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}
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#endif
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#endif // HVC_CONSOLE_H
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