33f0f88f1c
The API and code have been through various bits of initial review by
serial driver people but they definitely need to live somewhere for a
while so the unconverted drivers can get knocked into shape, existing
drivers that have been updated can be better tuned and bugs whacked out.
This replaces the tty flip buffers with kmalloc objects in rings. In the
normal situation for an IRQ driven serial port at typical speeds the
behaviour is pretty much the same, two buffers end up allocated and the
kernel cycles between them as before.
When there are delays or at high speed we now behave far better as the
buffer pool can grow a bit rather than lose characters. This also means
that we can operate at higher speeds reliably.
For drivers that receive characters in blocks (DMA based, USB and
especially virtualisation) the layer allows a lot of driver specific
code that works around the tty layer with private secondary queues to be
removed. The IBM folks need this sort of layer, the smart serial port
people do, the virtualisers do (because a virtualised tty typically
operates at infinite speed rather than emulating 9600 baud).
Finally many drivers had invalid and unsafe attempts to avoid buffer
overflows by directly invoking tty methods extracted out of the innards
of work queue structs. These are no longer needed and all go away. That
fixes various random hangs with serial ports on overflow.
The other change in here is to optimise the receive_room path that is
used by some callers. It turns out that only one ldisc uses receive room
except asa constant and it updates it far far less than the value is
read. We thus make it a variable not a function call.
I expect the code to contain bugs due to the size alone but I'll be
watching and squashing them and feeding out new patches as it goes.
Because the buffers now dynamically expand you should only run out of
buffering when the kernel runs out of memory for real. That means a lot of
the horrible hacks high performance drivers used to do just aren't needed any
more.
Description:
tty_insert_flip_char is an old API and continues to work as before, as does
tty_flip_buffer_push() [this is why many drivers dont need modification]. It
does now also return the number of chars inserted
There are also
tty_buffer_request_room(tty, len)
which asks for a buffer block of the length requested and returns the space
found. This improves efficiency with hardware that knows how much to
transfer.
and tty_insert_flip_string_flags(tty, str, flags, len)
to insert a string of characters and flags
For a smart interface the usual code is
len = tty_request_buffer_room(tty, amount_hardware_says);
tty_insert_flip_string(tty, buffer_from_card, len);
More description!
At the moment tty buffers are attached directly to the tty. This is causing a
lot of the problems related to tty layer locking, also problems at high speed
and also with bursty data (such as occurs in virtualised environments)
I'm working on ripping out the flip buffers and replacing them with a pool of
dynamically allocated buffers. This allows both for old style "byte I/O"
devices and also helps virtualisation and smart devices where large blocks of
data suddenely materialise and need storing.
So far so good. Lots of drivers reference tty->flip.*. Several of them also
call directly and unsafely into function pointers it provides. This will all
break. Most drivers can use tty_insert_flip_char which can be kept as an API
but others need more.
At the moment I've added the following interfaces, if people think more will
be needed now is a good time to say
int tty_buffer_request_room(tty, size)
Try and ensure at least size bytes are available, returns actual room (may be
zero). At the moment it just uses the flipbuf space but that will change.
Repeated calls without characters being added are not cumulative. (ie if you
call it with 1, 1, 1, and then 4 you'll have four characters of space. The
other functions will also try and grow buffers in future but this will be a
more efficient way when you know block sizes.
int tty_insert_flip_char(tty, ch, flag)
As before insert a character if there is room. Now returns 1 for success, 0
for failure.
int tty_insert_flip_string(tty, str, len)
Insert a block of non error characters. Returns the number inserted.
int tty_prepare_flip_string(tty, strptr, len)
Adjust the buffer to allow len characters to be added. Returns a buffer
pointer in strptr and the length available. This allows for hardware that
needs to use functions like insl or mencpy_fromio.
Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: John Hawkes <hawkes@sgi.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
158 lines
4.1 KiB
C
158 lines
4.1 KiB
C
#ifndef _KBD_KERN_H
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#define _KBD_KERN_H
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#include <linux/tty.h>
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#include <linux/interrupt.h>
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#include <linux/keyboard.h>
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extern struct tasklet_struct keyboard_tasklet;
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extern int shift_state;
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extern char *func_table[MAX_NR_FUNC];
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extern char func_buf[];
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extern char *funcbufptr;
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extern int funcbufsize, funcbufleft;
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/*
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* kbd->xxx contains the VC-local things (flag settings etc..)
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*
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* Note: externally visible are LED_SCR, LED_NUM, LED_CAP defined in kd.h
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* The code in KDGETLED / KDSETLED depends on the internal and
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* external order being the same.
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*
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* Note: lockstate is used as index in the array key_map.
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*/
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struct kbd_struct {
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unsigned char lockstate;
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/* 8 modifiers - the names do not have any meaning at all;
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they can be associated to arbitrarily chosen keys */
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#define VC_SHIFTLOCK KG_SHIFT /* shift lock mode */
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#define VC_ALTGRLOCK KG_ALTGR /* altgr lock mode */
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#define VC_CTRLLOCK KG_CTRL /* control lock mode */
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#define VC_ALTLOCK KG_ALT /* alt lock mode */
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#define VC_SHIFTLLOCK KG_SHIFTL /* shiftl lock mode */
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#define VC_SHIFTRLOCK KG_SHIFTR /* shiftr lock mode */
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#define VC_CTRLLLOCK KG_CTRLL /* ctrll lock mode */
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#define VC_CTRLRLOCK KG_CTRLR /* ctrlr lock mode */
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unsigned char slockstate; /* for `sticky' Shift, Ctrl, etc. */
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unsigned char ledmode:2; /* one 2-bit value */
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#define LED_SHOW_FLAGS 0 /* traditional state */
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#define LED_SHOW_IOCTL 1 /* only change leds upon ioctl */
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#define LED_SHOW_MEM 2 /* `heartbeat': peek into memory */
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unsigned char ledflagstate:4; /* flags, not lights */
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unsigned char default_ledflagstate:4;
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#define VC_SCROLLOCK 0 /* scroll-lock mode */
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#define VC_NUMLOCK 1 /* numeric lock mode */
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#define VC_CAPSLOCK 2 /* capslock mode */
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#define VC_KANALOCK 3 /* kanalock mode */
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unsigned char kbdmode:2; /* one 2-bit value */
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#define VC_XLATE 0 /* translate keycodes using keymap */
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#define VC_MEDIUMRAW 1 /* medium raw (keycode) mode */
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#define VC_RAW 2 /* raw (scancode) mode */
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#define VC_UNICODE 3 /* Unicode mode */
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unsigned char modeflags:5;
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#define VC_APPLIC 0 /* application key mode */
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#define VC_CKMODE 1 /* cursor key mode */
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#define VC_REPEAT 2 /* keyboard repeat */
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#define VC_CRLF 3 /* 0 - enter sends CR, 1 - enter sends CRLF */
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#define VC_META 4 /* 0 - meta, 1 - meta=prefix with ESC */
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};
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extern struct kbd_struct kbd_table[];
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extern int kbd_init(void);
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extern unsigned char getledstate(void);
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extern void setledstate(struct kbd_struct *kbd, unsigned int led);
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extern int do_poke_blanked_console;
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extern void (*kbd_ledfunc)(unsigned int led);
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extern void set_console(int nr);
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extern void schedule_console_callback(void);
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static inline void set_leds(void)
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{
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tasklet_schedule(&keyboard_tasklet);
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}
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static inline int vc_kbd_mode(struct kbd_struct * kbd, int flag)
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{
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return ((kbd->modeflags >> flag) & 1);
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}
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static inline int vc_kbd_led(struct kbd_struct * kbd, int flag)
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{
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return ((kbd->ledflagstate >> flag) & 1);
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}
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static inline void set_vc_kbd_mode(struct kbd_struct * kbd, int flag)
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{
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kbd->modeflags |= 1 << flag;
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}
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static inline void set_vc_kbd_led(struct kbd_struct * kbd, int flag)
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{
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kbd->ledflagstate |= 1 << flag;
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}
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static inline void clr_vc_kbd_mode(struct kbd_struct * kbd, int flag)
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{
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kbd->modeflags &= ~(1 << flag);
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}
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static inline void clr_vc_kbd_led(struct kbd_struct * kbd, int flag)
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{
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kbd->ledflagstate &= ~(1 << flag);
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}
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static inline void chg_vc_kbd_lock(struct kbd_struct * kbd, int flag)
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{
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kbd->lockstate ^= 1 << flag;
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}
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static inline void chg_vc_kbd_slock(struct kbd_struct * kbd, int flag)
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{
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kbd->slockstate ^= 1 << flag;
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}
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static inline void chg_vc_kbd_mode(struct kbd_struct * kbd, int flag)
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{
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kbd->modeflags ^= 1 << flag;
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}
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static inline void chg_vc_kbd_led(struct kbd_struct * kbd, int flag)
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{
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kbd->ledflagstate ^= 1 << flag;
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}
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#define U(x) ((x) ^ 0xf000)
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/* keyboard.c */
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struct console;
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int getkeycode(unsigned int scancode);
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int setkeycode(unsigned int scancode, unsigned int keycode);
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void compute_shiftstate(void);
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/* defkeymap.c */
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extern unsigned int keymap_count;
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/* console.c */
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static inline void con_schedule_flip(struct tty_struct *t)
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{
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schedule_work(&t->buf.work);
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}
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#endif
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