lib: debug: Introduce loglevels + many minor changes

Implement 8 loglevels to use with printk:

While at it, separate the font in a new "video" directory, which
also makes space for a proper video probing implementation. Fill
in the font from 32 to 256. Scale the font to render twice as big.
Implement dynamic line length detection. Change a few things here
and there to follow the linux kernel code style. Add a nice logo.

Signed-off-by: Ivaylo Ivanov <ivo.ivanov.ivanov1@gmail.com>

Kconfig

@@ -13,6 +13,10 @@ menu "Building options"
 		  need to set this unless you want the configured kernel build
 		  directory to select the cross-compiler automatically.
 
+	config LOGLEVEL
+		int "Verbosity of logs"
+		default 7
+
 	config EMBED_LINUX
 		bool "Embed linux kernel and device tree"
 		default y

include/lib/debug.h

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: GPL-2.0 */
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2022, Ivaylo Ivanov <ivo.ivanov.ivanov1@gmail.com>
  */
@@ -6,7 +6,16 @@
 #ifndef DEBUG_H_	/* Include guard */
 #define DEBUG_H_
 
-extern void draw_text(volatile char *fb, char *text, int textX, int textY, int width, int stride);
+// Sorted by importance
-long int debug_linecount = 0;
+#define KERN_EMERG	0
+#define KERN_ALERT	1
+#define KERN_CRIT	2
+#define KERN_ERR	3
+#define KERN_WARNING	4
+#define KERN_NOTICE	5
+#define KERN_INFO	6
+#define KERN_DEBUG	7
 
-#endif
+extern void printk(int loglevel, char *text);
+
+#endif // DEBUG_H_

include/lib/simplefb.h

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: GPL-2.0 */
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2022, Ivaylo Ivanov <ivo.ivanov.ivanov1@gmail.com>
  * Copyright (c) 2022, Markuss Broks <markuss.broks@gmail.com>
@@ -10,6 +10,8 @@
 
 #include <stdint.h>
 
+extern void __simplefb_raw_print(volatile char *fb, char *text, int text_x,
+				 int text_y, int width, int stride);
 extern void simplefb_probe(void *data);
 extern struct video *video_info;
 
@@ -34,4 +36,4 @@ typedef struct _font_params {
 
 font_params get_font_params(void);
 
-#endif
+#endif // SIMPLEFB_H_

include/lib/video/font.h

@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Based on https://github.com/torvalds/linux/blob/master/lib/fonts/font_8x16.c
+ */
+
+#ifndef FONT_H_	/* Include guard */
+#define FONT_H_
+
+#define FONTW 8
+#define FONTH 16
+
+// Define scaled font dimensions --> 8x16 becomes 16x32
+#define SCALE_FACTOR 2
+#define SCALED_FONTW (FONTW * SCALE_FACTOR)
+#define SCALED_FONTH (FONTH * SCALE_FACTOR)
+
+extern const unsigned char letters[256][16];
+extern int font_index(char a);
+
+#endif // FONT_H_

include/main.h

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: GPL-2.0 */
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2022, Ivaylo Ivanov <ivo.ivanov.ivanov1@gmail.com>
  */
@@ -12,9 +12,6 @@ extern unsigned long kernel_size;
 extern void load_kernel(void* dtb, void* x1, void* x2, void* x3, void* kernel);
 extern void soc_init(void);
 
-extern void clean_fb(volatile char *fb, int width, int height, int stride);
-extern void printk(char *text);
-
 extern void writel(unsigned int value, void* address);
 
 #endif // MAIN_H_

lib/Makefile

@@ -1,7 +1,10 @@
-# SIMPLEFB
+# simplefb
 lib-$(CONFIG_SIMPLE_FB) += simplefb/simplefb.o
 
-# DEBUG
+# video
+lib-$(CONFIG_SIMPLE_FB) += video/font.o
+
+# debug
 lib-y += debug/debug.o
 
 # unic (neatlibc still temporarily resides)

lib/debug/debug.c

@@ -1,20 +1,63 @@
-/* SPDX-License-Identifier: GPL-2.0 */
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2022, Ivaylo Ivanov <ivo.ivanov.ivanov1@gmail.com>
  */
+
+#include <stddef.h>
+#include <string.h>
 #include <lib/debug.h>
 #include <lib/simplefb.h>
-#include <stddef.h>
+#include <lib/video/font.h>
+
+long int debug_linecount = 0;
+
+// Global log level that controls the verbosity
+static int global_loglevel = CONFIG_LOGLEVEL;
+
+void printk(int log_level, char *text)
+{
+	if (log_level > global_loglevel)
+		return;
+
+	char *prefix;
+	switch (log_level) {
+	case KERN_EMERG:
+		prefix = "[EMERG] ";
+		break;
+	case KERN_ALERT:
+		prefix = "[ALERT] ";
+		break;
+	case KERN_CRIT:
+		prefix = "[CRIT] ";
+		break;
+	case KERN_ERR:
+		prefix = "[ERROR] ";
+		break;
+	case KERN_WARNING:
+		prefix = "[WARN] ";
+		break;
+	case KERN_NOTICE:
+		prefix = "[NOTICE] ";
+		break;
+	case KERN_INFO:
+		prefix = "[INFO] ";
+		break;
+	case KERN_DEBUG:
+		prefix = "[DEBUG] ";
+		break;
+	default:
+		prefix = "[LOG] ";
+		break;
+	}
 
-void printk(char *text) {
 #ifdef CONFIG_SIMPLE_FB
-	/* IMPORTANT: Limit the linecount */
+	// Actually the first line's Y pos. Scales in __simplefb_raw_print
-	if(debug_linecount > 100 || debug_linecount < 0)
+	int y_pos = 5;
-		debug_linecount = 0;
+	int prefix_width = strlen(prefix) * SCALED_FONTW;
 
-	draw_text((char*)CONFIG_FRAMEBUFFER_BASE, "[uniLoader] ", 0, (20 + (debug_linecount * 30)), CONFIG_FRAMEBUFFER_WIDTH, CONFIG_FRAMEBUFFER_STRIDE);
+	__simplefb_raw_print((char*)CONFIG_FRAMEBUFFER_BASE, prefix, 0, y_pos,
-	draw_text((char*)CONFIG_FRAMEBUFFER_BASE, text, 0 + (12 * 8), (20 + (debug_linecount * 30)), CONFIG_FRAMEBUFFER_WIDTH, CONFIG_FRAMEBUFFER_STRIDE);
+		  CONFIG_FRAMEBUFFER_WIDTH, CONFIG_FRAMEBUFFER_STRIDE);
-
+	__simplefb_raw_print((char*)CONFIG_FRAMEBUFFER_BASE, text, prefix_width, y_pos,
-	debug_linecount++;
+		  CONFIG_FRAMEBUFFER_WIDTH, CONFIG_FRAMEBUFFER_STRIDE);
 #endif
 }

lib/simplefb/simplefb.c

@@ -1,16 +1,17 @@
-/* SPDX-License-Identifier: GPL-2.0 */
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2022, Ivaylo Ivanov <ivo.ivanov.ivanov1@gmail.com>
  * Copyright (c) 2022, Markuss Broks <markuss.broks@gmail.com>
  * Copyright (c) 2022, Michael Srba <Michael.Srba@seznam.cz>
  */
-#include <drivers/framework.h>
-#include <lib/font.h>
-#include <lib/simplefb.h>
-#include <string.h>
 
-/* volatile char */
+#include <string.h>
-static void clean_fb(void *fb, int width, int height, int stride) {
+#include <drivers/framework.h>
+#include <lib/video/font.h>
+#include <lib/simplefb.h>
+
+static void clean_fbmem(void *fb, int width, int height, int stride)
+{
 	memset(fb, 0x0, (width * height * stride));
 }
 
@@ -19,7 +20,8 @@ static void clean_fb(void *fb, int width, int height, int stride) {
  * Unlike ARGB8888, we explicitly use 3 bytes to represent each pixel, making sure
  * no extra padding byte is added.
  */
-static void draw_pixel(volatile char *fb, int x, int y, int width, int stride, color c)
+static void draw_pixel(volatile char *fb, int x, int y, int width, int stride,
+		       color c)
 {
 	long int location = (x * stride) + (y * width * stride);
 #ifdef CONFIG_FRAMEBUFFER_BGRA
@@ -35,48 +37,54 @@ static void draw_pixel(volatile char *fb, int x, int y, int width, int stride, c
 #endif
 }
 
-static void draw_horizontal_line(volatile char *fb, int x1, int x2, int y, color c,
+static int current_y = 0;
-				 int width, int stride)
+void __simplefb_raw_print(volatile char *fb, char *text, int text_x, int text_y,
+			  int width, int stride)
 {
-	for (int i = x1; i < x2; i++)
-		draw_pixel(fb, i, y, width, stride, c);
-}
-
-static void draw_vertical_line(volatile char *fb, int x, int y1, int y2, color c,
-			       int width, int stride)
-{
-	for (int i = y1; i < y2; i++)
-		draw_pixel(fb, x, i, width, stride, c);
-}
-
-static void draw_filled_rectangle(volatile char *fb, int x1, int y1, int w, int h,
-				  color c, int width, int stride)
-{
-	for (int i = y1; i < (y1 + h); i++)
-		draw_horizontal_line(fb, x1, (x1 + w), i, c, width, stride);
-}
-
-void draw_text(volatile char *fb, char *text, int textX, int textY, int width, int stride)
-{
-	// loop through all characters in the text string
 	int l = strlen(text);
+	int current_x = text_x;
+	current_y = current_y == 0 ? text_y : current_y;
+
+	int max_x = width - SCALED_FONTW;
 
 	for (int i = 0; i < l; i++) {
+		// Special characters handling
+		switch (text[i]) {
+		case '\n':
+			current_x = text_x;
+			current_y += SCALED_FONTH;
+			break;
+		}
+
+		// Non-printable chars
 		if (text[i] < 32)
 			continue;
 
-		int ix = font_index(text[i]);
+		if (current_x > max_x) {
-		unsigned char *img = letters[ix];
+			current_x = text_x;
+			current_y += SCALED_FONTH;
+		}
 
+		int ix = font_index(text[i]);
+		const unsigned char *img = letters[ix];
+
+		// Draw the character as a scaled bitmap
 		for (int y = 0; y < FONTH; y++) {
 			unsigned char b = img[y];
 
 			for (int x = 0; x < FONTW; x++) {
-				if (((b << x) & 0b10000000) > 0)
+				if (((b << x) & 0b10000000) > 0) {
-					draw_pixel(fb, textX + i * FONTW + x, textY + y, width,
+					for (int dy = 0; dy < SCALE_FACTOR; dy++) {
-						   stride, (color){255, 255, 255});
+						for (int dx = 0; dx < SCALE_FACTOR; dx++) {
+							draw_pixel(fb, current_x + x * SCALE_FACTOR + dx,
+								   current_y + y * SCALE_FACTOR + dy,
+								   width, stride, (color){255, 255, 255});
+						}
+					}
+				}
 			}
 		}
+		current_x += SCALED_FONTW;
 	}
 }
 
@@ -84,7 +92,7 @@ void simplefb_probe(void *data)
 {
 	struct video *fb_info = data;
 
-	clean_fb((char*)fb_info->address, fb_info->width, fb_info->height,
+	clean_fbmem((char*)fb_info->address, fb_info->width, fb_info->height,
 		 fb_info->stride);
 
 	/* TODO: Introduce a full drivers framework that allows proper exiting */

main/main.c

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: GPL-2.0 */
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2022, Ivaylo Ivanov <ivo.ivanov.ivanov1@gmail.com>
  */
@@ -6,6 +6,7 @@
 #include <board.h>
 #include <main.h>
 #include <string.h>
+#include <lib/debug.h>
 
 /*
  * Provide an empty board config that has
@@ -31,15 +32,23 @@ void main(void* dt, void* kernel)
 	EXECUTE_BOARD_OP(board.ops[BOARD_OP_DRIVER_SETUP]);
 	EXECUTE_BOARD_OP(board.ops[BOARD_OP_LATE_INIT]);
 
-	printk("Passed board initialization!");
+	printk(-1, "             .__.____                     .___\n");
-	printk("Welcome to uniLoader!");
+	printk(-1, " __ __  ____ |__|    |    _________     __| _/___________\n");
+	printk(-1, "|  |  \\/    \\|  |    |   /  _ \\__  \\   / __ |/ __ \\_  __\\\n");
+	printk(-1, "|  |  /   |  \\  |    |__(  <_> ) __ \\_/ /_/ \\  ___/|  |\\/\n");
+	printk(-1, "|____/|___|  /__|_______ \\____(____  /\\____ |\\___  >__|\n");
+	printk(-1, "           \\/           \\/         \\/      \\/    \\/\n");
+
+	printk(-1, "Passed board initialization!\n");
+	printk(-1, "Welcome to uniLoader!\n");
 
 	/* Copy kernel to memory and boot  */
-	printk("Booting linux...");
+	printk(-1, "Booting linux...\n");
 
 	memcpy((void*)CONFIG_PAYLOAD_ENTRY, kernel, (unsigned long) &kernel_size);
 	load_kernel(dt, 0, 0, 0, (void*)CONFIG_PAYLOAD_ENTRY);
 
 	/* We shouldn't get there */
+	printk(KERN_WARNING, "Something wrong happened, we shouldn't be here. Hanging....\n");
 	while(1) {}
 }