kern: io: Implement initial console logic

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 96 insertions, 0 deletions

diff --git a/src/sys/io/cons/cons.c b/src/sys/io/cons/cons.c
new file mode 100644
index 0000000..044f5ad
--- /dev/null
+++ b/src/sys/io/cons/cons.c
@@ -0,0 +1,96 @@
+/*
+ * Copyright (c) 2025 Ian Marco Moffett and L5 engineers
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. 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.
+ * 3. Neither the name of the project 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 <sys/types.h>
+#include <sys/errno.h>
+#include <sys/syslog.h>
+#include <io/cons/cons.h>
+#include <stdbool.h>
+#include <string.h>
+
+#define DEFAULT_BG 0x000000
+#define DEFAULT_FG 0xB57614
+
+struct cons_scr g_root_scr;
+
+/*
+ * Fill a screen with a desired background
+ * color
+ *
+ * @bg: Background color to fill screen
+ */
+static void
+fill_screen(struct cons_scr *scr, uint32_t bg)
+{
+    struct bootvar_fb *fbvars;
+    size_t len;
+
+    if (scr == NULL) {
+        return;
+    }
+
+    fbvars = &scr->fbvars;
+    len = fbvars->width * fbvars->pitch;
+    memset(fbvars->io, bg, len);
+}
+
+/*
+ * Initialize the console
+ */
+int
+cons_init(void)
+{
+    static bool is_init = false;
+    struct bootvars bv;
+    int error;
+
+    /* Only init once */
+    if (!is_init) {
+        is_init = true;
+    } else {
+        return -EPERM;
+    }
+
+    /*
+     * Attempt to acquire the bootvars so we
+     * can get the framebuffer
+     */
+    error = bootvars_read(&bv, 0);
+    if (error < 0) {
+        printf("cons_init: could not read bootvars\n");
+        is_init = false;
+        return error;
+    }
+
+    memcpy(&g_root_scr.fbvars, &bv.fbvars, sizeof(bv.fbvars));
+    g_root_scr.scr_bg = DEFAULT_BG;
+    g_root_scr.scr_fg = DEFAULT_FG;
+    fill_screen(&g_root_scr,  g_root_scr.scr_bg);
+    return 0;
+}