From 4c87a1868835d05f1cadae7b8ad6a7c95d9d9c0e Mon Sep 17 00:00:00 2001
From: Ross Philipson <philipsonr@ainfosec.com>
Date: Tue, 14 Mar 2017 15:40:33 -0400
Subject: Initial commit of EFI TBOOT work from internal project.

Signed-off-by: Ross Philipson <philipsonr@ainfosec.com>
---
 tboot/vga.c | 140 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 140 insertions(+)
 create mode 100644 tboot/vga.c

(limited to 'tboot/vga.c')

diff --git a/tboot/vga.c b/tboot/vga.c
new file mode 100644
index 0000000..8ddc2f5
--- /dev/null
+++ b/tboot/vga.c
@@ -0,0 +1,140 @@
+/*
+ * vga.c:  fns for outputting strings to VGA display
+ *
+ * Copyright (c) 2010, Intel Corporation
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above
+ *     copyright notice, this list of conditions and the following
+ *     disclaimer in the documentation and/or other materials provided
+ *     with the distribution.
+ *   * Neither the name of the Intel Corporation nor the names of its
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <config.h>
+#include <efibase.h>
+#include <types.h>
+#include <stdbool.h>
+#include <string.h>
+#include <misc.h>
+#include <io.h>
+#include <vga.h>
+
+static uint16_t * const screen = (uint16_t * const)VGA_BASE;
+static __data uint8_t cursor_x, cursor_y;
+static __data unsigned int num_lines;
+uint8_t g_vga_delay = 0;       /* default to no delay */
+
+static inline void reset_screen(void)
+{
+    memset(screen, 0, SCREEN_BUFFER);
+    cursor_x = 0;
+    cursor_y = 0;
+    num_lines = 0;
+
+    outb(CTL_ADDR_REG, START_ADD_HIGH_REG);
+    outb(CTL_DATA_REG, 0x00);
+    outb(CTL_ADDR_REG, START_ADD_LOW_REG);
+    outb(CTL_DATA_REG, 0x00);
+}
+
+static void scroll_screen(void)
+{
+    for ( long long y = 1; y < MAX_LINES; y++ ) {
+        for ( long long x = 0; x < MAX_COLS; x++ )
+            writew(VGA_ADDR(x, y-1), readw(VGA_ADDR(x, y)));
+    }
+    /* clear last line */
+    for ( long long x = 0; x < MAX_COLS; x++ )
+        writew(VGA_ADDR(x, MAX_LINES-1), 0x720);
+}
+
+static void __putc(uint8_t x, uint8_t y, int c)
+{
+    screen[(y * MAX_COLS) + x] = (COLOR << 8) | c;
+}
+
+static void vga_putc(int c)
+{
+    bool new_row = false;
+
+    switch ( c ) {
+        case '\n':
+            cursor_y++;
+            cursor_x = 0;
+            new_row = true;
+            break;
+        case '\r':
+            cursor_x = 0;
+            break;
+        case '\t':
+            cursor_x += 4;
+            break;
+        default:
+            __putc(cursor_x, cursor_y, c);
+            cursor_x++;
+            break;
+    }
+
+    if ( cursor_x >= MAX_COLS ) {
+        cursor_x %= MAX_COLS;
+        cursor_y++;
+        new_row = true;
+    }
+
+    if ( new_row ) {
+        num_lines++;
+        if ( cursor_y >= MAX_LINES ) {
+            scroll_screen();
+            cursor_y--;
+        }
+
+        /* (optionally) pause after every screenful */
+        if ( (num_lines % (MAX_LINES - 1)) == 0 && g_vga_delay > 0 )
+            delay(g_vga_delay * 1000);
+    }
+}
+
+void vga_init(void)
+{
+    reset_screen();
+}
+
+void vga_puts(const char *s, unsigned int cnt)
+{
+    while ( *s && cnt-- ) {
+        vga_putc(*s);
+        s++;
+    }
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-set-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
-- 
cgit v1.2.3