[PATCH v2 1/2] m68k: Add infrastructure for machine-specific random_get_entropy()

[PATCH v2 1/2] m68k: Add infrastructure for machine-specific random_get_entropy()

[Geert Uytterhoeven]

On m68k, get_cycles() (the default implementation for random_get_entropy())
always returns zero, providing no entropy for the random driver.

Add a hook where platforms can provide their own implementation, and wire
it up in the infrastructure provided by commit
61875f30daf60305712e25b209ef41ced2635bad ("random: allow architectures to
optionally define random_get_entropy()").

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
v2:
  - Hook for random_get_entropy() instead of get_cycles()

 arch/m68k/include/asm/timex.h |   10 ++++++++++
 arch/m68k/kernel/time.c       |    4 ++++
 2 files changed, 14 insertions(+)

diff --git a/arch/m68k/include/asm/timex.h b/arch/m68k/include/asm/timex.h
index 6759dad954f6..efc1f4892357 100644
--- a/arch/m68k/include/asm/timex.h
+++ b/arch/m68k/include/asm/timex.h
@@ -28,4 +28,14 @@ static inline cycles_t get_cycles(void)
 	return 0;
 }
 
+extern unsigned long (*mach_random_get_entropy)(void);
+
+static inline unsigned long random_get_entropy(void)
+{
+	if (mach_random_get_entropy)
+		return mach_random_get_entropy();
+	return 0;
+}
+#define random_get_entropy	random_get_entropy
+
 #endif
diff --git a/arch/m68k/kernel/time.c b/arch/m68k/kernel/time.c
index 7eb9792009f8..958f1adb9d0c 100644
--- a/arch/m68k/kernel/time.c
+++ b/arch/m68k/kernel/time.c
@@ -28,6 +28,10 @@
 #include <linux/timex.h>
 #include <linux/profile.h>
 
+
+unsigned long (*mach_random_get_entropy)(void);
+
+
 /*
  * timer_interrupt() needs to keep up the real-time clock,
  * as well as call the "xtime_update()" routine every clocktick
-- 
1.7.9.5

[PATCH v2 2/2] m68k/amiga: Provide mach_random_get_entropy()

[Geert Uytterhoeven]

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>
---
v2:
  - Use beam position registers (which provide a faster rate but less bits)
    instead of 24-bit Time-Of-Day clock in CIA B running at HSYNC.

 arch/m68k/amiga/config.c |   10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/m68k/amiga/config.c b/arch/m68k/amiga/config.c
index f78361bff623..0b46d32a345f 100644
--- a/arch/m68k/amiga/config.c
+++ b/arch/m68k/amiga/config.c
@@ -354,6 +354,14 @@ 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
      */
@@ -391,6 +399,8 @@ 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 */
 
-- 
1.7.9.5