kern/console: new module

3 files changed, 142 insertions, 6 deletions

diff --git a/kern/console.c b/kern/console.c
new file mode 100644
index 00000000..138a4248
--- /dev/null
+++ b/kern/console.c
@@ -0,0 +1,69 @@
+/*
+ * Copyright (c) 2017 Richard Braun.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stddef.h>
+
+#include <kern/assert.h>
+#include <kern/init.h>
+#include <kern/console.h>
+#include <kern/list.h>
+#include <kern/spinlock.h>
+
+static struct list console_devs;
+static struct spinlock console_lock;
+
+static void
+console_putc(struct console *console, char c)
+{
+    unsigned long flags;
+
+    spinlock_lock_intr_save(&console->lock, &flags);
+    console->putc(console, c);
+    spinlock_unlock_intr_restore(&console->lock, flags);
+}
+
+void __init
+console_setup(void)
+{
+    list_init(&console_devs);
+    spinlock_init(&console_lock);
+}
+
+void __init
+console_register(struct console *console)
+{
+    assert(console->putc != NULL);
+
+    spinlock_lock(&console_lock);
+    list_insert_tail(&console_devs, &console->node);
+    spinlock_unlock(&console_lock);
+}
+
+void
+console_write_char(char c)
+{
+    struct console *console;
+    unsigned long flags;
+
+    spinlock_lock_intr_save(&console_lock, &flags);
+
+    list_for_each_entry(&console_devs, console, node) {
+        console_putc(console, c);
+    }
+
+    spinlock_unlock_intr_restore(&console_lock, flags);
+}
diff --git a/kern/console.h b/kern/console.h
new file mode 100644
index 00000000..8fdef160
--- /dev/null
+++ b/kern/console.h
@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2017 Richard Braun.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *
+ * Device-independent console interface.
+ */
+
+#ifndef _KERN_CONSOLE_H
+#define _KERN_CONSOLE_H
+
+#include <kern/list.h>
+#include <kern/spinlock.h>
+
+struct console;
+
+/*
+ * Type for character writing functions.
+ */
+typedef void (*console_putc_fn)(struct console *console, char c);
+
+/*
+ * Console device.
+ *
+ * This structure should be embedded in the hardware-specific console
+ * objects. Calls to console operations are all serialized by this module
+ * for each device.
+ */
+struct console {
+    struct spinlock lock;
+    struct list node;
+    console_putc_fn putc;
+};
+
+static inline void
+console_init(struct console *console, console_putc_fn putc)
+{
+    spinlock_init(&console->lock);
+    console->putc = putc;
+}
+
+/*
+ * Initialize the console module.
+ */
+void console_setup(void);
+
+/*
+ * Register a console device.
+ *
+ * The given console must be initialized before calling this function.
+ */
+void console_register(struct console *console);
+
+/*
+ * Write a single character to all registered console devices.
+ */
+void console_write_char(char c);
+
+#endif /* _KERN_CONSOLE_H */
diff --git a/kern/printf.c b/kern/printf.c
index 68ae1037..d7a1d100 100644
--- a/kern/printf.c
+++ b/kern/printf.c
@@ -17,6 +17,7 @@
 
 #include <stdio.h>
 
+#include <kern/console.h>
 #include <kern/spinlock.h>
 #include <machine/cpu.h>
 
@@ -25,11 +26,6 @@
  */
 #define PRINTF_BUFSIZE 1024
 
-/*
- * XXX Must be provided by a console driver.
- */
-extern void console_write_byte(char c);
-
 static char printf_buffer[PRINTF_BUFSIZE];
 static struct spinlock printf_lock;
 
@@ -58,7 +54,7 @@ vprintf(const char *format, va_list ap)
     length = vsnprintf(printf_buffer, sizeof(printf_buffer), format, ap);
 
     for (ptr = printf_buffer; *ptr != '\0'; ptr++) {
-        console_write_byte(*ptr);
+        console_write_char(*ptr);
     }
 
     spinlock_unlock_intr_restore(&printf_lock, flags);