Blackfin arch: Fix bug - HW Errors never recover on BF548

The kernel does not properly clear the EBIU Error Master (EBIU_ERRMST) Register
on BF548, which causes the kernel to panic.

We need to make sure that we clear the EBIU_ERRMST (necessary on BF54x)

Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

2 files changed, 22 insertions, 2 deletions

diff --git a/arch/blackfin/kernel/traps.c b/arch/blackfin/kernel/traps.c
index 1a3c4daf557a..709c247b7016 100644
--- a/arch/blackfin/kernel/traps.c
+++ b/arch/blackfin/kernel/traps.c
@@ -1025,8 +1025,19 @@ void show_regs(struct pt_regs *fp)
         printk(KERN_NOTICE "\n" KERN_NOTICE "SEQUENCER STATUS:\t\t%s\n", print_tainted());
         printk(KERN_NOTICE " SEQSTAT: %08lx  IPEND: %04lx  SYSCFG: %04lx\n",
                 (long)fp->seqstat, fp->ipend, fp->syscfg);
-        printk(KERN_NOTICE "  HWERRCAUSE: 0x%lx\n",
-                (fp->seqstat & SEQSTAT_HWERRCAUSE) >> 14);
+        if ((fp->seqstat & SEQSTAT_EXCAUSE) == VEC_HWERR) {
+                printk(KERN_NOTICE "  HWERRCAUSE: 0x%lx\n",
+                        (fp->seqstat & SEQSTAT_HWERRCAUSE) >> 14);
+#ifdef EBIU_ERRMST
+                /* If the error was from the EBIU, print it out */
+                if (bfin_read_EBIU_ERRMST() & CORE_ERROR) {
+                        printk(KERN_NOTICE "  EBIU Error Reason  : 0x%04x\n",
+                                bfin_read_EBIU_ERRMST());
+                        printk(KERN_NOTICE "  EBIU Error Address : 0x%08x\n",
+                                bfin_read_EBIU_ERRADD());
+                }
+#endif
+        }
         printk(KERN_NOTICE "  EXCAUSE   : 0x%lx\n",
                 fp->seqstat & SEQSTAT_EXCAUSE);
         for (i = 6; i <= 15 ; i++) {
diff --git a/arch/blackfin/mach-common/interrupt.S b/arch/blackfin/mach-common/interrupt.S
index 647f0f522910..4a2ec7a9675a 100644
--- a/arch/blackfin/mach-common/interrupt.S
+++ b/arch/blackfin/mach-common/interrupt.S
@@ -179,7 +179,16 @@ ENTRY(_evt_ivhw)
         call _trap_c;
         SP += 12;
 
+#ifdef EBIU_ERRMST
+        /* make sure EBIU_ERRMST is clear */
+        p0.l = LO(EBIU_ERRMST);
+        p0.h = HI(EBIU_ERRMST);
+        r0.l = (CORE_ERROR | CORE_MERROR);
+        w[p0] = r0.l;
+#endif
+
         call _ret_from_exception;
+
 .Lcommon_restore_all_sys:
         RESTORE_ALL_SYS
         rti;