147 lines
3.5 KiB
C
147 lines
3.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* linux/drivers/video/dummycon.c -- A dummy console driver
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*
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* To be used if there's no other console driver (e.g. for plain VGA text)
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* available, usually until fbcon takes console over.
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*/
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#include <linux/types.h>
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#include <linux/kdev_t.h>
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#include <linux/console.h>
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#include <linux/vt_kern.h>
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#include <linux/screen_info.h>
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#include <linux/init.h>
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#include <linux/module.h>
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/*
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* Dummy console driver
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*/
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#if defined(__arm__)
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#define DUMMY_COLUMNS screen_info.orig_video_cols
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#define DUMMY_ROWS screen_info.orig_video_lines
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#else
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/* set by Kconfig. Use 80x25 for 640x480 and 160x64 for 1280x1024 */
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#define DUMMY_COLUMNS CONFIG_DUMMY_CONSOLE_COLUMNS
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#define DUMMY_ROWS CONFIG_DUMMY_CONSOLE_ROWS
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#endif
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#ifdef CONFIG_FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER
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/* These are both protected by the console_lock */
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static RAW_NOTIFIER_HEAD(dummycon_output_nh);
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static bool dummycon_putc_called;
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void dummycon_register_output_notifier(struct notifier_block *nb)
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{
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WARN_CONSOLE_UNLOCKED();
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raw_notifier_chain_register(&dummycon_output_nh, nb);
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if (dummycon_putc_called)
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nb->notifier_call(nb, 0, NULL);
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}
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void dummycon_unregister_output_notifier(struct notifier_block *nb)
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{
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WARN_CONSOLE_UNLOCKED();
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raw_notifier_chain_unregister(&dummycon_output_nh, nb);
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}
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static void dummycon_putc(struct vc_data *vc, int c, int ypos, int xpos)
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{
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WARN_CONSOLE_UNLOCKED();
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dummycon_putc_called = true;
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raw_notifier_call_chain(&dummycon_output_nh, 0, NULL);
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}
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static void dummycon_putcs(struct vc_data *vc, const unsigned short *s,
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int count, int ypos, int xpos)
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{
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int i;
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if (!dummycon_putc_called) {
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/* Ignore erases */
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for (i = 0 ; i < count; i++) {
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if (s[i] != vc->vc_video_erase_char)
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break;
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}
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if (i == count)
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return;
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dummycon_putc_called = true;
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}
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raw_notifier_call_chain(&dummycon_output_nh, 0, NULL);
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}
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static int dummycon_blank(struct vc_data *vc, int blank, int mode_switch)
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{
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/* Redraw, so that we get putc(s) for output done while blanked */
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return 1;
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}
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#else
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static void dummycon_putc(struct vc_data *vc, int c, int ypos, int xpos) { }
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static void dummycon_putcs(struct vc_data *vc, const unsigned short *s,
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int count, int ypos, int xpos) { }
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static int dummycon_blank(struct vc_data *vc, int blank, int mode_switch)
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{
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return 0;
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}
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#endif
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static const char *dummycon_startup(void)
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{
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return "dummy device";
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}
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static void dummycon_init(struct vc_data *vc, int init)
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{
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vc->vc_can_do_color = 1;
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if (init) {
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vc->vc_cols = DUMMY_COLUMNS;
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vc->vc_rows = DUMMY_ROWS;
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} else
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vc_resize(vc, DUMMY_COLUMNS, DUMMY_ROWS);
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}
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static void dummycon_deinit(struct vc_data *vc) { }
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static void dummycon_clear(struct vc_data *vc, int sy, int sx, int height,
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int width) { }
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static void dummycon_cursor(struct vc_data *vc, int mode) { }
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static bool dummycon_scroll(struct vc_data *vc, unsigned int top,
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unsigned int bottom, enum con_scroll dir,
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unsigned int lines)
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{
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return false;
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}
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static int dummycon_switch(struct vc_data *vc)
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{
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return 0;
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}
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/*
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* The console `switch' structure for the dummy console
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*
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* Most of the operations are dummies.
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*/
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const struct consw dummy_con = {
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.owner = THIS_MODULE,
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.con_startup = dummycon_startup,
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.con_init = dummycon_init,
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.con_deinit = dummycon_deinit,
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.con_clear = dummycon_clear,
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.con_putc = dummycon_putc,
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.con_putcs = dummycon_putcs,
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.con_cursor = dummycon_cursor,
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.con_scroll = dummycon_scroll,
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.con_switch = dummycon_switch,
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.con_blank = dummycon_blank,
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};
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EXPORT_SYMBOL_GPL(dummy_con);
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