Merge branch 'for-linus' of git://git.o-hand.com/linux-rpurdie-leds

[pandora-kernel.git] / kernel / printk.c

diff --git a/kernel/printk.c b/kernel/printk.c
index bd2cd06..89011bf 100644 (file)
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -22,6 +22,8 @@
 #include <linux/tty_driver.h>
 #include <linux/console.h>
 #include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/nmi.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/interrupt.h>                   /* For in_interrupt() */
@@ -162,6 +164,113 @@ out:
 
 __setup("log_buf_len=", log_buf_len_setup);
 
+#ifdef CONFIG_BOOT_PRINTK_DELAY
+
+static unsigned int boot_delay; /* msecs delay after each printk during bootup */
+static unsigned long long printk_delay_msec; /* per msec, based on boot_delay */
+
+static int __init boot_delay_setup(char *str)
+{
+       unsigned long lpj;
+       unsigned long long loops_per_msec;
+
+       lpj = preset_lpj ? preset_lpj : 1000000;        /* some guess */
+       loops_per_msec = (unsigned long long)lpj / 1000 * HZ;
+
+       get_option(&str, &boot_delay);
+       if (boot_delay > 10 * 1000)
+               boot_delay = 0;
+
+       printk_delay_msec = loops_per_msec;
+       printk(KERN_DEBUG "boot_delay: %u, preset_lpj: %ld, lpj: %lu, "
+               "HZ: %d, printk_delay_msec: %llu\n",
+               boot_delay, preset_lpj, lpj, HZ, printk_delay_msec);
+       return 1;
+}
+__setup("boot_delay=", boot_delay_setup);
+
+static void boot_delay_msec(void)
+{
+       unsigned long long k;
+       unsigned long timeout;
+
+       if (boot_delay == 0 || system_state != SYSTEM_BOOTING)
+               return;
+
+       k = (unsigned long long)printk_delay_msec * boot_delay;
+
+       timeout = jiffies + msecs_to_jiffies(boot_delay);
+       while (k) {
+               k--;
+               cpu_relax();
+               /*
+                * use (volatile) jiffies to prevent
+                * compiler reduction; loop termination via jiffies
+                * is secondary and may or may not happen.
+                */
+               if (time_after(jiffies, timeout))
+                       break;
+               touch_nmi_watchdog();
+       }
+}
+#else
+static inline void boot_delay_msec(void)
+{
+}
+#endif
+
+/*
+ * Return the number of unread characters in the log buffer.
+ */
+int log_buf_get_len(void)
+{
+       return logged_chars;
+}
+
+/*
+ * Copy a range of characters from the log buffer.
+ */
+int log_buf_copy(char *dest, int idx, int len)
+{
+       int ret, max;
+       bool took_lock = false;
+
+       if (!oops_in_progress) {
+               spin_lock_irq(&logbuf_lock);
+               took_lock = true;
+       }
+
+       max = log_buf_get_len();
+       if (idx < 0 || idx >= max) {
+               ret = -1;
+       } else {
+               if (len > max)
+                       len = max;
+               ret = len;
+               idx += (log_end - max);
+               while (len-- > 0)
+                       dest[len] = LOG_BUF(idx + len);
+       }
+
+       if (took_lock)
+               spin_unlock_irq(&logbuf_lock);
+
+       return ret;
+}
+
+/*
+ * Extract a single character from the log buffer.
+ */
+int log_buf_read(int idx)
+{
+       char ret;
+
+       if (log_buf_copy(&ret, idx, 1) == 1)
+               return ret;
+       else
+               return -1;
+}
+
 /*
  * Commands to do_syslog:
  *
@@ -527,6 +636,8 @@ asmlinkage int vprintk(const char *fmt, va_list args)
        static char printk_buf[1024];
        static int log_level_unknown = 1;
 
+       boot_delay_msec();
+
        preempt_disable();
        if (unlikely(oops_in_progress) && printk_cpu == smp_processor_id())
                /* If a crash is occurring during printk() on this CPU,
@@ -706,7 +817,7 @@ __setup("console=", console_setup);
  * commonly to provide a default console (ie from PROM variables) when
  * the user has not supplied one.
  */
-int __init add_preferred_console(char *name, int idx, char *options)
+int add_preferred_console(char *name, int idx, char *options)
 {
        struct console_cmdline *c;
        int i;
@@ -751,7 +862,16 @@ int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, cha
        return -1;
 }
 
-#ifndef CONFIG_DISABLE_CONSOLE_SUSPEND
+int console_suspend_enabled = 1;
+EXPORT_SYMBOL(console_suspend_enabled);
+
+static int __init console_suspend_disable(char *str)
+{
+       console_suspend_enabled = 0;
+       return 1;
+}
+__setup("no_console_suspend", console_suspend_disable);
+
 /**
  * suspend_console - suspend the console subsystem
  *
@@ -759,6 +879,8 @@ int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, cha
  */
 void suspend_console(void)
 {
+       if (!console_suspend_enabled)
+               return;
        printk("Suspending console(s)\n");
        acquire_console_sem();
        console_suspended = 1;
@@ -766,10 +888,11 @@ void suspend_console(void)
 
 void resume_console(void)
 {
+       if (!console_suspend_enabled)
+               return;
        console_suspended = 0;
        release_console_sem();
 }
-#endif /* CONFIG_DISABLE_CONSOLE_SUSPEND */
 
 /**
  * acquire_console_sem - lock the console system for exclusive use.
@@ -1083,6 +1206,19 @@ int unregister_console(struct console *console)
 }
 EXPORT_SYMBOL(unregister_console);
 
+static int __init disable_boot_consoles(void)
+{
+       if (console_drivers != NULL) {
+               if (console_drivers->flags & CON_BOOT) {
+                       printk(KERN_INFO "turn off boot console %s%d\n",
+                               console_drivers->name, console_drivers->index);
+                       return unregister_console(console_drivers);
+               }
+       }
+       return 0;
+}
+late_initcall(disable_boot_consoles);
+
 /**
  * tty_write_message - write a message to a certain tty, not just the console.
  * @tty: the destination tty_struct