Blackfin: workaround anomaly 05000283

Make sure our interrupt entry code with exact hardware errors handles
anomaly 05000283 (infinite stall in system MMR kill) so we don't stall
while under load.

Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

arch/blackfin/include/asm/entry.h

@@ -36,6 +36,21 @@
 # define LOAD_IPIPE_IPEND
 #endif
 
+/*
+ * Workaround for anomalies 05000283 and 05000315
+ */
+#if ANOMALY_05000283 || ANOMALY_05000315
+# define ANOMALY_283_315_WORKAROUND(preg, dreg)		\
+	cc = dreg == dreg;				\
+	preg.h = HI(CHIPID);				\
+	preg.l = LO(CHIPID);				\
+	if cc jump 1f;					\
+	dreg.l = W[preg];				\
+1:
+#else
+# define ANOMALY_283_315_WORKAROUND(preg, dreg)
+#endif /* ANOMALY_05000283 || ANOMALY_05000315 */
+
 #ifndef CONFIG_EXACT_HWERR
 /* As a debugging aid - we save IPEND when DEBUG_KERNEL is on,
  * otherwise it is a waste of cycles.
@@ -88,17 +103,22 @@
  * As you can see by the code - we actually need to do two SSYNCS - one to
  * make sure the read/writes complete, and another to make sure the hardware
  * error is recognized by the core.
+ *
+ * The extra nop before the SSYNC is to make sure we work around 05000244,
+ * since the 283/315 workaround includes a branch to the end
  */
 #define INTERRUPT_ENTRY(N)						\
-    SSYNC;								\
-    SSYNC;								\
     [--sp] = SYSCFG;							\
     [--sp] = P0;	/*orig_p0*/					\
     [--sp] = R0;	/*orig_r0*/					\
     [--sp] = (R7:0,P5:0);						\
     R1 = ASTAT;								\
+    ANOMALY_283_315_WORKAROUND(p0, r0)					\
     P0.L = LO(ILAT);							\
     P0.H = HI(ILAT);							\
+    NOP;								\
+    SSYNC;								\
+    SSYNC;								\
     R0 = [P0];								\
     CC = BITTST(R0, EVT_IVHW_P);					\
     IF CC JUMP 1f;							\
@@ -118,15 +138,17 @@
     RTI;
 
 #define TIMER_INTERRUPT_ENTRY(N)					\
-    SSYNC;								\
-    SSYNC;								\
     [--sp] = SYSCFG;							\
     [--sp] = P0;	/*orig_p0*/					\
     [--sp] = R0;	/*orig_r0*/					\
     [--sp] = (R7:0,P5:0);						\
     R1 = ASTAT;								\
+    ANOMALY_283_315_WORKAROUND(p0, r0)					\
     P0.L = LO(ILAT);							\
     P0.H = HI(ILAT);							\
+    NOP;								\
+    SSYNC;								\
+    SSYNC;								\
     R0 = [P0];								\
     CC = BITTST(R0, EVT_IVHW_P);					\
     IF CC JUMP 1f;							\

arch/blackfin/mach-common/entry.S

@@ -513,14 +513,7 @@ ENTRY(_trap) /* Exception: 4th entry into system event table(supervisor mode)*/
 	ssync;
 #endif
 
-#if ANOMALY_05000283 || ANOMALY_05000315
+	ANOMALY_283_315_WORKAROUND(p5, r7)
-	cc = r7 == r7;
-	p5.h = HI(CHIPID);
-	p5.l = LO(CHIPID);
-	if cc jump 1f;
-	r7.l = W[p5];
-1:
-#endif
 
 #ifdef CONFIG_DEBUG_DOUBLEFAULT
 	/*
@@ -1134,14 +1127,7 @@ ENTRY(_early_trap)
 	SAVE_ALL_SYS
 	trace_buffer_stop(p0,r0);
 
-#if ANOMALY_05000283 || ANOMALY_05000315
+	ANOMALY_283_315_WORKAROUND(p4, r5)
-	cc = r5 == r5;
-	p4.h = HI(CHIPID);
-	p4.l = LO(CHIPID);
-	if cc jump 1f;
-	r5.l = W[p4];
-1:
-#endif
 
 	/* Turn caches off, to ensure we don't get double exceptions */
 

arch/blackfin/mach-common/interrupt.S

@@ -119,14 +119,8 @@ __common_int_entry:
 	fp = 0;
 #endif
 
-#if ANOMALY_05000283 || ANOMALY_05000315
+	ANOMALY_283_315_WORKAROUND(p5, r7)
-	cc = r7 == r7;
+
-	p5.h = HI(CHIPID);
-	p5.l = LO(CHIPID);
-	if cc jump 1f;
-	r7.l = W[p5];
-1:
-#endif
 	r1 =  sp;
 	SP += -12;
 #ifdef CONFIG_IPIPE
@@ -158,14 +152,7 @@ ENTRY(_evt_ivhw)
 	fp = 0;
 #endif
 
-#if ANOMALY_05000283 || ANOMALY_05000315
+	ANOMALY_283_315_WORKAROUND(p5, r7)
-	cc = r7 == r7;
-	p5.h = HI(CHIPID);
-	p5.l = LO(CHIPID);
-	if cc jump 1f;
-	r7.l = W[p5];
-1:
-#endif
 
 	/* Handle all stacked hardware errors
 	 * To make sure we don't hang forever, only do it 10 times