From dbf4f57913f71de7de3a27aa2d2a2da9416ffc9b Mon Sep 17 00:00:00 2001
From: Mark <alnyan@airmail.cc>
Date: Fri, 3 Jul 2020 11:19:24 +0300
Subject: [PATCH] Use hardware-provided cursor on text-mode displays

---
 arch/amd64/hw/con.c   | 11 +++++++++
 arch/amd64/hw/timer.c |  4 +++-
 include/sys/display.h |  1 +
 sys/console.c         | 54 ++++++++++++++++++++++++-------------------
 4 files changed, 45 insertions(+), 25 deletions(-)

diff --git a/arch/amd64/hw/con.c b/arch/amd64/hw/con.c
index 497c07c..5b8f2e0 100644
--- a/arch/amd64/hw/con.c
+++ b/arch/amd64/hw/con.c
@@ -1,4 +1,5 @@
 #include "arch/amd64/hw/con.h"
+#include "arch/amd64/hw/io.h"
 #include "sys/display.h"
 
 #define BUFFER      ((uint16_t volatile*) 0xFFFFFF00000B8000)
@@ -9,11 +10,21 @@ static void amd64_console_setc(uint16_t y, uint16_t x, uint16_t c) {
     BUFFER[y * 80 + x] = c;
 }
 
+static void amd64_console_cursor(uint16_t y, uint16_t x) {
+    uint16_t pos = y * 80 + x;
+
+    outb(0x3D4, 0x0F);
+    outb(0x3D5, (uint8_t) (pos & 0xFF));
+    outb(0x3D4, 0x0E);
+    outb(0x3D5, (uint8_t) ((pos >> 8) & 0xFF));
+}
+
 void amd64_console_init(void) {
     display_console.flags = 0;
     display_console.width_chars = 80;
     display_console.height_chars = 25;
     display_console.setc = amd64_console_setc;
+    display_console.cursor = amd64_console_cursor;
     list_head_init(&display_console.list);
 
     display_add(&display_console);
diff --git a/arch/amd64/hw/timer.c b/arch/amd64/hw/timer.c
index 618d2ed..c1cfe82 100644
--- a/arch/amd64/hw/timer.c
+++ b/arch/amd64/hw/timer.c
@@ -65,7 +65,9 @@ static uint32_t timer_tick(void *arg) {
             g_display_blink_state ^= 1;
             int_timer_ticks = 0;
         }
-        console_update_cursor();
+        if (int_timer_ticks % 2 == 0) {
+            console_update_cursor();
+        }
         // Each tick is approx. 1ms, so add 1ms to system time
         system_time += 1000000;
         break;
diff --git a/include/sys/display.h b/include/sys/display.h
index 13f319b..dab973a 100644
--- a/include/sys/display.h
+++ b/include/sys/display.h
@@ -10,6 +10,7 @@
 struct display {
     // Text modes: set character at y, x
     void (*setc) (uint16_t y, uint16_t x, uint16_t c);
+    void (*cursor) (uint16_t y, uint16_t x);
 
     uint32_t flags;
     // If DISP_GRAPHIC
diff --git a/sys/console.c b/sys/console.c
index bcbb06a..157419a 100644
--- a/sys/console.c
+++ b/sys/console.c
@@ -303,34 +303,40 @@ void console_update_cursor(void) {
     struct console *con;
     static int prev_blink = 0;
 
-    if (g_display_blink_state != prev_blink) {
-        list_for_each_entry(con, &g_consoles, list) {
-            if (con->display && con->buf_active) {
-                // TODO: don't blink on text-mode only consoles:
-                //       use hardware cursor
-                struct console_buffer *buf = con->buf_active;
-                uint16_t c = buf->data[buf->y * con->width_chars + buf->x];
-                if (g_display_blink_state) {
-                    // Swap attributes
-                    c = ((c >> 4) & 0xF00) |
-                        ((c & 0xF00) << 4) |
-                        (c & 0xFF);
-                }
-                display_setc(con->display, buf->y, buf->x, c);
-                if (buf->last_blink_x != buf->x || buf->last_blink_y != buf->y) {
-                    // Also redraw character at last blink position
-                    display_setc(con->display,
-                                 buf->last_blink_y,
-                                 buf->last_blink_x,
-                                 buf->data[buf->last_blink_y * con->width_chars +
-                                           buf->last_blink_x]);
-                    buf->last_blink_x = buf->x;
-                    buf->last_blink_y = buf->y;
+    list_for_each_entry(con, &g_consoles, list) {
+        if (con->display && con->buf_active) {
+            struct display *d = con->display;
+            struct console_buffer *buf = con->buf_active;
+
+            if (d->flags & DISP_GRAPHIC) {
+                if (g_display_blink_state != prev_blink) {
+                    uint16_t c = buf->data[buf->y * con->width_chars + buf->x];
+                    if (g_display_blink_state) {
+                        // Swap attributes
+                        c = ((c >> 4) & 0xF00) |
+                            ((c & 0xF00) << 4) |
+                            (c & 0xFF);
+                    }
+                    display_setc(d, buf->y, buf->x, c);
+                    if (buf->last_blink_x != buf->x || buf->last_blink_y != buf->y) {
+                        // Also redraw character at last blink position
+                        display_setc(d,
+                                     buf->last_blink_y,
+                                     buf->last_blink_x,
+                                     buf->data[buf->last_blink_y * con->width_chars +
+                                               buf->last_blink_x]);
+                        buf->last_blink_x = buf->x;
+                        buf->last_blink_y = buf->y;
+                    }
                 }
+            } else {
+                _assert(d->cursor);
+                d->cursor(buf->y, buf->x);
             }
         }
-        prev_blink = g_display_blink_state;
     }
+
+    prev_blink = g_display_blink_state;
 }
 
 void console_putc(struct console *con, struct chrdev *tty, int c) {