m68k/amiga: Provide mach_random_get_entropy()

Use the beam position registers, which provide at least 17 bits of data
changing at 1.79 MHz.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

diff --git a/arch/m68k/amiga/config.c b/arch/m68k/amiga/config.c
index 06920e8..c425fa6 100644 (file)
--- a/arch/m68k/amiga/config.c
+++ b/arch/m68k/amiga/config.c
@@ -360,6 +360,14 @@ static void __init amiga_identify(void)
 #undef AMIGAHW_ANNOUNCE
 }
 
+
+static unsigned long amiga_random_get_entropy(void)
+{
+       /* VPOSR/VHPOSR provide at least 17 bits of data changing at 1.79 MHz */
+       return *(unsigned long *)&amiga_custom.vposr;
+}
+
+
     /*
      *  Setup the Amiga configuration info
      */
@@ -397,6 +405,8 @@ void __init config_amiga(void)
        mach_heartbeat = amiga_heartbeat;
 #endif
 
+       mach_random_get_entropy = amiga_random_get_entropy;
+
        /* Fill in the clock value (based on the 700 kHz E-Clock) */
        amiga_colorclock = 5*amiga_eclock;      /* 3.5 MHz */