Print `last logf lines on panic().

If logf is enabled, panic() will print the last lines. On small
screens this is more or less useless, but on large screens it
can be very useful for debugging.

Change-Id: I26dfc76e9ac4a2ddc2def8db1616a04f943dbba3
Reviewed-on: http://gerrit.rockbox.org/709
Reviewed-by: Thomas Martitz <kugel@rockbox.org>
Reviewed-by: Frank Gevaerts <frank@gevaerts.be>
Tested: Frank Gevaerts <frank@gevaerts.be>

firmware/export/logf.h

@@ -39,6 +39,8 @@ extern bool logfwrap;
 #define logf _logf
 void _logf(const char *format, ...) ATTRIBUTE_PRINTF(1, 2);
 
+void logf_panic_dump(int *y);
+
 #else /* !ROCKBOX_HAS_LOGF */
 
 /* built without logf() support enabled, replace logf() by DEBUGF() */

firmware/logf.c

@@ -32,6 +32,7 @@
 #include "config.h"
 #include "system.h"
 #include "font.h"
+#include "lcd.h"
 #ifdef HAVE_REMOTE_LCD
 #include "lcd-remote.h"
 #endif
@@ -254,6 +255,54 @@ void _logf(const char *fmt, ...)
 }
 #endif
 
+void logf_panic_dump(int *y)
+{
+    int i;
+    /* nothing to print ? */
+    if(logfindex == 0 && !logfwrap)
+    {
+        lcd_puts(1, (*y)++, "no logf data");
+        lcd_update();
+        return;
+    }
+
+    lcd_puts(1, (*y)++, "start of logf data");
+    lcd_update();
+    i = logfindex - 2; /* The last actual characer (i.e. not '\0') */
+
+    while(i >= 0)
+    {
+        while(logfbuffer[i] != 0 && i>=0)
+        {
+            i--;
+        }
+        if(strlen( &logfbuffer[i + 1]) > 0)
+        {
+            lcd_puts(1, (*y)++, &logfbuffer[i + 1]);
+            lcd_update();
+        }
+        i--;
+    }
+    if(logfwrap)
+    {
+        i = MAX_LOGF_SIZE - 1;
+        while(i >= logfindex)
+        {
+            while(logfbuffer[i] != 0 && i >= logfindex)
+            {
+                i--;
+            }
+            if(strlen( &logfbuffer[i + 1]) > 0)
+            {
+                lcd_putsf(1, (*y)++, "%*s", (MAX_LOGF_SIZE-i) &logfbuffer[i + 1]);
+                lcd_update();
+            }
+        }
+        i--;
+    }
+    lcd_puts(1, (*y)++, "end of logf data");
+    lcd_update();
+}
 #endif
 
 #ifdef ROCKBOX_HAS_LOGDISKF

firmware/panic.c

@@ -30,6 +30,7 @@
 #include "led.h"
 #include "power.h"
 #include "system.h"
+#include "logf.h"
 
 #if defined(CPU_ARM)
 #include "gcc_extensions.h"
@@ -115,6 +116,9 @@ void panicf( const char *fmt, ...)
 #if defined(CPU_ARM)
     backtrace(pc, sp, &y);
 #endif
+#ifdef ROCKBOX_HAS_LOGF
+    logf_panic_dump(&y);
+#endif
 #else
     /* no LCD */
 #endif