cc3116a938
The last half year I've been working on a replacement TTY layer for the FreeBSD kernel. The new TTY layer was designed to improve the following: - Improved driver model: The old TTY layer has a driver model that is not abstract enough to make it friendly to use. A good example is the output path, where the device drivers directly access the output buffers. This means that an in-kernel PPP implementation must always convert network buffers into TTY buffers. If a PPP implementation would be built on top of the new TTY layer (still needs a hooks layer, though), it would allow the PPP implementation to directly hand the data to the TTY driver. - Improved hotplugging: With the old TTY layer, it isn't entirely safe to destroy TTY's from the system. This implementation has a two-step destructing design, where the driver first abandons the TTY. After all threads have left the TTY, the TTY layer calls a routine in the driver, which can be used to free resources (unit numbers, etc). The pts(4) driver also implements this feature, which means posix_openpt() will now return PTY's that are created on the fly. - Improved performance: One of the major improvements is the per-TTY mutex, which is expected to improve scalability when compared to the old Giant locking. Another change is the unbuffered copying to userspace, which is both used on TTY device nodes and PTY masters. Upgrading should be quite straightforward. Unlike previous versions, existing kernel configuration files do not need to be changed, except when they reference device drivers that are listed in UPDATING. Obtained from: //depot/projects/mpsafetty/... Approved by: philip (ex-mentor) Discussed: on the lists, at BSDCan, at the DevSummit Sponsored by: Snow B.V., the Netherlands dcons(4) fixed by: kan
110 lines
3.5 KiB
C
110 lines
3.5 KiB
C
/*-
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* Copyright (C) 2002-2004
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* Hidetoshi Shimokawa. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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*
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* This product includes software developed by Hidetoshi Shimokawa.
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*
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* 4. Neither the name of the author nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: dcons.h,v 1.15 2003/10/23 15:05:31 simokawa Exp $
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* $FreeBSD$
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*/
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#if defined(_KERNEL) || defined(_BOOT)
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#define V volatile
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#else
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#define V
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#endif
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#define DCONS_NPORT 2
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#define DCONS_CON 0
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#define DCONS_GDB 1
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struct dcons_buf {
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#define DCONS_VERSION 2
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V u_int32_t version;
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V u_int32_t ooffset[DCONS_NPORT];
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V u_int32_t ioffset[DCONS_NPORT];
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V u_int32_t osize[DCONS_NPORT];
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V u_int32_t isize[DCONS_NPORT];
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#define DCONS_MAGIC 0x64636f6e /* "dcon" */
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V u_int32_t magic;
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#define DCONS_GEN_SHIFT (24)
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#define DCONS_GEN_MASK (0xff)
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#define DCONS_POS_MASK ((1<< DCONS_GEN_SHIFT) - 1)
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V u_int32_t optr[DCONS_NPORT];
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V u_int32_t iptr[DCONS_NPORT];
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V char buf[0];
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};
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#define DCONS_CSR_VAL_VER 0x64636f /* "dco" */
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#define DCONS_CSR_KEY_HI 0x3a
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#define DCONS_CSR_KEY_LO 0x3b
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#define DCONS_CSR_KEY_RESET_HI 0x3c
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#define DCONS_CSR_KEY_RESET_LO 0x3d
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#define DCONS_HEADER_SIZE sizeof(struct dcons_buf)
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#define DCONS_MAKE_PTR(x) htonl(((x)->gen << DCONS_GEN_SHIFT) | (x)->pos)
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#define DCONS_NEXT_GEN(x) (((x) + 1) & DCONS_GEN_MASK)
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struct dcons_ch {
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u_int32_t size;
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u_int32_t gen;
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u_int32_t pos;
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#if defined(_KERNEL) || defined(_BOOT)
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V u_int32_t *ptr;
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V char *buf;
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#else
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off_t buf;
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#endif
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};
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#define KEY_CTRLB 2 /* ^B */
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#define KEY_CR 13 /* CR '\r' */
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#define KEY_TILDE 126 /* ~ */
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#define STATE0 0
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#define STATE1 1
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#define STATE2 2
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#define STATE3 3
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#if defined(_KERNEL) || defined(_BOOT)
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struct dcons_softc {
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struct dcons_ch o, i;
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int brk_state;
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#define DC_GDB 1
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int flags;
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void *tty;
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};
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int dcons_checkc(struct dcons_softc *);
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int dcons_ischar(struct dcons_softc *);
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void dcons_putc(struct dcons_softc *, int);
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int dcons_load_buffer(struct dcons_buf *, int, struct dcons_softc *);
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void dcons_init(struct dcons_buf *, int, struct dcons_softc *);
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#endif
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