kernel: add basic console registration system and printk()

kernel/console.c

@@ -1,12 +1,52 @@
 #include <socks/console.h>
-#include <socks/machine/console.h>
+#include <socks/queue.h>
+#include <socks/locks.h>
+#include <socks/libc/string.h>
 
-void console_init(void)
+static queue_t consoles;
+static spin_lock_t consoles_lock = SPIN_LOCK_INIT;
+
+kern_status_t console_register(console_t *con)
 {
-	ml_console_init();
+	unsigned long flags;
+	spin_lock_irqsave(&consoles_lock, &flags);
+
+	queue_foreach (console_t, cur, &consoles, c_list) {
+		if (!strcmp(cur->c_name, con->c_name)) {
+			spin_unlock_irqrestore(&consoles_lock, flags);
+			return KERN_NAME_EXISTS;
+		}
+	}
+
+	queue_push_back(&consoles, &con->c_list);
+	spin_unlock_irqrestore(&consoles_lock, flags);
+	return KERN_OK;
 }
 
-void console_putchar(int c)
+kern_status_t console_unregister(console_t *con)
 {
-	ml_console_putchar(c);
+	unsigned long flags;
+	spin_lock_irqsave(&consoles_lock, &flags);
+
+	queue_delete(&consoles, &con->c_list);
+	
+	spin_unlock_irqrestore(&consoles_lock, flags);
+	return KERN_OK;
+}
+
+void console_write(console_t *con, const char *s, unsigned int len)
+{
+	if (con->c_write) {
+		con->c_write(con, s, len);
+	}
+}
+
+int console_read(console_t *con, char *s, unsigned int len)
+{
+	int ret = -1;
+	if (con->c_read) {
+		ret = con->c_read(con, s, len);
+	}
+
+	return ret;
 }

kernel/printk.c

@@ -1,10 +1,74 @@
+#include <socks/printk.h>
+#include <socks/locks.h>
+#include <socks/console.h>
+#include <socks/libc/stdio.h>
+#include <stdarg.h>
 
 #define LOG_BUFFER_SIZE 0x40000
+#define LOG_MSG_SIZE    0x100
+
+static console_t *early_console = NULL;
+
+static spin_lock_t log_buffer_lock = SPIN_LOCK_INIT;
 
 static char log_buffer[LOG_BUFFER_SIZE] = {0};
+/* index of the last character in log_buffer that has been written
+   to the console */
+static unsigned int log_buffer_readp = 0;
+/* index of the last character in log_buffer that has been logged
+   (but not necessarily written to the console) */
+static unsigned int log_buffer_writep = 0;
+
+static void flush_log_buffer(void)
+{
+	if (!early_console) {
+		return;
+	}
+	
+	console_write(early_console, log_buffer + log_buffer_readp, log_buffer_writep - log_buffer_readp);
+	log_buffer_readp = log_buffer_writep;
+}
+
+static void save_log_message(const char *msg)
+{
+	unsigned int i = 0;
+	while (1) {
+		if (log_buffer_writep == LOG_BUFFER_SIZE - 1) {
+			log_buffer[log_buffer_writep] = '\0';
+			break;
+		}
+
+		if (msg[i] == '\0') {
+			break;
+		}
+				   
+		log_buffer[log_buffer_writep++] = msg[i++];
+	}
+}
+
+void early_printk_init(console_t *con)
+{
+	early_console = con;
+}
 
 int printk(const char *format, ...)
 {
-	(void)log_buffer;
-	return 0;
+	char msg[LOG_MSG_SIZE];
+
+	va_list arg;
+	va_start(arg, format);
+        int len = vsnprintf(msg, sizeof msg - 1, format, arg);
+	va_end(arg);
+
+	msg[len] = '\n';
+	msg[len + 1] = '\0';
+
+	unsigned long flags;
+	spin_lock_irqsave(&log_buffer_lock, &flags);
+	save_log_message(msg);
+	spin_unlock_irqrestore(&log_buffer_lock, flags);
+
+	flush_log_buffer();
+	
+        return 0;
 }