📄 serial.c
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<!doctype html public "-//W3C//DTD HTML 3.2//EN"><html><head><title>Linux/kernel/chr_drv/serial.c</title><base href="http://oldlinux.org/lxr/http/"></head><body bgcolor=white><div align=center> [<b><i>source navigation</i></b>] [<a href="diff/kernel/chr_drv/serial.c?v=0.97">diff markup</a>] [<a href="ident?v=0.97">identifier search</a>] [<a href="search?v=0.97">freetext search</a>] [<a href="find?v=0.97">file search</a>]</div><h1 align=center> <a href="http:/"> Oldlinux</a> <a href="http:blurb.html"> Cross Reference</a><br> <a href="source/?v=0.97">Linux</a>/<a href="source/kernel/?v=0.97">kernel</a>/<a href="source/kernel/chr_drv/?v=0.97">chr_drv</a>/<a href="source/kernel/chr_drv/serial.c?v=0.97">serial.c</a></h1><div align=center> <b>Version:</b> [<a href="source/kernel/chr_drv/serial.c?v=1.0">1.0</a>] [<a href="source/kernel/chr_drv/serial.c?v=0.99.11">0.99.11</a>] [<a href="source/kernel/chr_drv/serial.c?v=0.99">0.99</a>] [<a href="source/kernel/chr_drv/serial.c?v=0.98">0.98</a>] [<b><i>0.97</i></b>] [<a href="source/kernel/chr_drv/serial.c?v=0.96a">0.96a</a>] [<a href="source/kernel/chr_drv/serial.c?v=0.95">0.95</a>] [<a href="source/kernel/chr_drv/serial.c?v=0.12">0.12</a>] [<a href="source/kernel/chr_drv/serial.c">0.11</a>] [<a href="source/kernel/chr_drv/serial.c?v=0.01">0.01</a>] <br> <b>Architecture:</b> [<b><i>i386</i></b>] <br></div><hr><pre> <a name=L1 href="source/kernel/chr_drv/serial.c?v=0.97#L1">1</a> <b><i>/*</i></b> <a name=L2 href="source/kernel/chr_drv/serial.c?v=0.97#L2">2</a> <b><i> * linux/kernel/serial.c</i></b> <a name=L3 href="source/kernel/chr_drv/serial.c?v=0.97#L3">3</a> <b><i> *</i></b> <a name=L4 href="source/kernel/chr_drv/serial.c?v=0.97#L4">4</a> <b><i> * Copyright (C) 1991, 1992 Linus Torvalds</i></b> <a name=L5 href="source/kernel/chr_drv/serial.c?v=0.97#L5">5</a> <b><i> */</i></b> <a name=L6 href="source/kernel/chr_drv/serial.c?v=0.97#L6">6</a> <a name=L7 href="source/kernel/chr_drv/serial.c?v=0.97#L7">7</a> <b><i>/*</i></b> <a name=L8 href="source/kernel/chr_drv/serial.c?v=0.97#L8">8</a> <b><i> * serial.c</i></b> <a name=L9 href="source/kernel/chr_drv/serial.c?v=0.97#L9">9</a> <b><i> *</i></b> <a name=L10 href="source/kernel/chr_drv/serial.c?v=0.97#L10">10</a> <b><i> * This module implements the rs232 io functions</i></b> <a name=L11 href="source/kernel/chr_drv/serial.c?v=0.97#L11">11</a> <b><i> * void rs_write(struct tty_struct * queue);</i></b> <a name=L12 href="source/kernel/chr_drv/serial.c?v=0.97#L12">12</a> <b><i> * long rs_init(long);</i></b> <a name=L13 href="source/kernel/chr_drv/serial.c?v=0.97#L13">13</a> <b><i> * and all interrupts pertaining to serial IO.</i></b> <a name=L14 href="source/kernel/chr_drv/serial.c?v=0.97#L14">14</a> <b><i> */</i></b> <a name=L15 href="source/kernel/chr_drv/serial.c?v=0.97#L15">15</a> <a name=L16 href="source/kernel/chr_drv/serial.c?v=0.97#L16">16</a> #include <linux/errno.h> <a name=L17 href="source/kernel/chr_drv/serial.c?v=0.97#L17">17</a> #include <linux/signal.h> <a name=L18 href="source/kernel/chr_drv/serial.c?v=0.97#L18">18</a> #include <linux/sched.h> <a name=L19 href="source/kernel/chr_drv/serial.c?v=0.97#L19">19</a> #include <linux/timer.h> <a name=L20 href="source/kernel/chr_drv/serial.c?v=0.97#L20">20</a> #include <linux/tty.h> <a name=L21 href="source/kernel/chr_drv/serial.c?v=0.97#L21">21</a> <a name=L22 href="source/kernel/chr_drv/serial.c?v=0.97#L22">22</a> #include <asm/system.h> <a name=L23 href="source/kernel/chr_drv/serial.c?v=0.97#L23">23</a> #include <asm/io.h> <a name=L24 href="source/kernel/chr_drv/serial.c?v=0.97#L24">24</a> #include <asm/segment.h> <a name=L25 href="source/kernel/chr_drv/serial.c?v=0.97#L25">25</a> <a name=L26 href="source/kernel/chr_drv/serial.c?v=0.97#L26">26</a> #define <a href="ident?v=0.97;i=WAKEUP_CHARS">WAKEUP_CHARS</a> (3*<a href="ident?v=0.97;i=TTY_BUF_SIZE">TTY_BUF_SIZE</a>/4) <a name=L27 href="source/kernel/chr_drv/serial.c?v=0.97#L27">27</a> <a name=L28 href="source/kernel/chr_drv/serial.c?v=0.97#L28">28</a> struct <a href="ident?v=0.97;i=serial_struct">serial_struct</a> <a href="ident?v=0.97;i=serial_table">serial_table</a>[<a href="ident?v=0.97;i=NR_SERIALS">NR_SERIALS</a>] = { <a name=L29 href="source/kernel/chr_drv/serial.c?v=0.97#L29">29</a> { <a href="ident?v=0.97;i=PORT_UNKNOWN">PORT_UNKNOWN</a>, 0, 0x3F8, 4, <a href="ident?v=0.97;i=NULL">NULL</a>}, <a name=L30 href="source/kernel/chr_drv/serial.c?v=0.97#L30">30</a> { <a href="ident?v=0.97;i=PORT_UNKNOWN">PORT_UNKNOWN</a>, 1, 0x2F8, 3, <a href="ident?v=0.97;i=NULL">NULL</a>}, <a name=L31 href="source/kernel/chr_drv/serial.c?v=0.97#L31">31</a> { <a href="ident?v=0.97;i=PORT_UNKNOWN">PORT_UNKNOWN</a>, 2, 0x3E8, 4, <a href="ident?v=0.97;i=NULL">NULL</a>}, <a name=L32 href="source/kernel/chr_drv/serial.c?v=0.97#L32">32</a> { <a href="ident?v=0.97;i=PORT_UNKNOWN">PORT_UNKNOWN</a>, 3, 0x2E8, 3, <a href="ident?v=0.97;i=NULL">NULL</a>}, <a name=L33 href="source/kernel/chr_drv/serial.c?v=0.97#L33">33</a> }; <a name=L34 href="source/kernel/chr_drv/serial.c?v=0.97#L34">34</a> <a name=L35 href="source/kernel/chr_drv/serial.c?v=0.97#L35">35</a> void <a href="ident?v=0.97;i=send_break">send_break</a>(unsigned int line) <a name=L36 href="source/kernel/chr_drv/serial.c?v=0.97#L36">36</a> { <a name=L37 href="source/kernel/chr_drv/serial.c?v=0.97#L37">37</a> unsigned short port; <a name=L38 href="source/kernel/chr_drv/serial.c?v=0.97#L38">38</a> struct <a href="ident?v=0.97;i=serial_struct">serial_struct</a> * <a href="ident?v=0.97;i=info">info</a>; <a name=L39 href="source/kernel/chr_drv/serial.c?v=0.97#L39">39</a> <a name=L40 href="source/kernel/chr_drv/serial.c?v=0.97#L40">40</a> if (line >= <a href="ident?v=0.97;i=NR_SERIALS">NR_SERIALS</a>) <a name=L41 href="source/kernel/chr_drv/serial.c?v=0.97#L41">41</a> return; <a name=L42 href="source/kernel/chr_drv/serial.c?v=0.97#L42">42</a> <a href="ident?v=0.97;i=info">info</a> = <a href="ident?v=0.97;i=serial_table">serial_table</a> + line; <a name=L43 href="source/kernel/chr_drv/serial.c?v=0.97#L43">43</a> if (!(port = <a href="ident?v=0.97;i=info">info</a>->port)) <a name=L44 href="source/kernel/chr_drv/serial.c?v=0.97#L44">44</a> return; <a name=L45 href="source/kernel/chr_drv/serial.c?v=0.97#L45">45</a> port += 3; <a name=L46 href="source/kernel/chr_drv/serial.c?v=0.97#L46">46</a> <a href="ident?v=0.97;i=current">current</a>-><a href="ident?v=0.97;i=state">state</a> = <a href="ident?v=0.97;i=TASK_INTERRUPTIBLE">TASK_INTERRUPTIBLE</a>; <a name=L47 href="source/kernel/chr_drv/serial.c?v=0.97#L47">47</a> <a href="ident?v=0.97;i=current">current</a>->timeout = <a href="ident?v=0.97;i=jiffies">jiffies</a> + 25; <a name=L48 href="source/kernel/chr_drv/serial.c?v=0.97#L48">48</a> <a href="ident?v=0.97;i=outb_p">outb_p</a>(<a href="ident?v=0.97;i=inb_p">inb_p</a>(port) | 0x40,port); <a name=L49 href="source/kernel/chr_drv/serial.c?v=0.97#L49">49</a> <a href="ident?v=0.97;i=schedule">schedule</a>(); <a name=L50 href="source/kernel/chr_drv/serial.c?v=0.97#L50">50</a> <a href="ident?v=0.97;i=outb_p">outb_p</a>(<a href="ident?v=0.97;i=inb_p">inb_p</a>(port) & 0xbf,port); <a name=L51 href="source/kernel/chr_drv/serial.c?v=0.97#L51">51</a> } <a name=L52 href="source/kernel/chr_drv/serial.c?v=0.97#L52">52</a> <a name=L53 href="source/kernel/chr_drv/serial.c?v=0.97#L53">53</a> <b><i>/*</i></b> <a name=L54 href="source/kernel/chr_drv/serial.c?v=0.97#L54">54</a> <b><i> * There are several races here: we avoid most of them by disabling timer_active</i></b> <a name=L55 href="source/kernel/chr_drv/serial.c?v=0.97#L55">55</a> <b><i> * for the crucial part of the process.. That's a good idea anyway.</i></b> <a name=L56 href="source/kernel/chr_drv/serial.c?v=0.97#L56">56</a> <b><i> *</i></b> <a name=L57 href="source/kernel/chr_drv/serial.c?v=0.97#L57">57</a> <b><i> * The problem is that we have to output characters /both/ from interrupts</i></b> <a name=L58 href="source/kernel/chr_drv/serial.c?v=0.97#L58">58</a> <b><i> * and from the normal write: the latter to be sure the interrupts start up</i></b> <a name=L59 href="source/kernel/chr_drv/serial.c?v=0.97#L59">59</a> <b><i> * again. With serial lines, the interrupts can happen so often that the</i></b> <a name=L60 href="source/kernel/chr_drv/serial.c?v=0.97#L60">60</a> <b><i> * races actually are noticeable.</i></b> <a name=L61 href="source/kernel/chr_drv/serial.c?v=0.97#L61">61</a> <b><i> */</i></b> <a name=L62 href="source/kernel/chr_drv/serial.c?v=0.97#L62">62</a> static void <a href="ident?v=0.97;i=send_intr">send_intr</a>(struct <a href="ident?v=0.97;i=serial_struct">serial_struct</a> * <a href="ident?v=0.97;i=info">info</a>) <a name=L63 href="source/kernel/chr_drv/serial.c?v=0.97#L63">63</a> { <a name=L64 href="source/kernel/chr_drv/serial.c?v=0.97#L64">64</a> unsigned short port = <a href="ident?v=0.97;i=info">info</a>->port; <a name=L65 href="source/kernel/chr_drv/serial.c?v=0.97#L65">65</a> unsigned int timer = <a href="ident?v=0.97;i=SER1_TIMEOUT">SER1_TIMEOUT</a> + <a href="ident?v=0.97;i=info">info</a>->line; <a name=L66 href="source/kernel/chr_drv/serial.c?v=0.97#L66">66</a> struct <a href="ident?v=0.97;i=tty_queue">tty_queue</a> * queue = <a href="ident?v=0.97;i=info">info</a>->tty->write_q; <a name=L67 href="source/kernel/chr_drv/serial.c?v=0.97#L67">67</a> int c, i = 0; <a name=L68 href="source/kernel/chr_drv/serial.c?v=0.97#L68">68</a> <a name=L69 href="source/kernel/chr_drv/serial.c?v=0.97#L69">69</a> if (<a href="ident?v=0.97;i=info">info</a>->tty->stopped) return; <a name=L70 href="source/kernel/chr_drv/serial.c?v=0.97#L70">70</a> <a name=L71 href="source/kernel/chr_drv/serial.c?v=0.97#L71">71</a> <a href="ident?v=0.97;i=timer_active">timer_active</a> &= ~(1 << timer); <a name=L72 href="source/kernel/chr_drv/serial.c?v=0.97#L72">72</a> while (<a href="ident?v=0.97;i=inb_p">inb_p</a>(<a href="ident?v=0.97;i=info">info</a>->port+5) & 0x20) { <a name=L73 href="source/kernel/chr_drv/serial.c?v=0.97#L73">73</a> if (queue->tail == queue-><a href="ident?v=0.97;i=head">head</a>) <a name=L74 href="source/kernel/chr_drv/serial.c?v=0.97#L74">74</a> goto end_send;⌨️ 快捷键说明
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