Blackfin: cleanup code a bit with comments and defines

Improve the assembly with a few explanatory comments and use symbolic
defines rather than numeric values for bit positions.

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

1 files changed, 7 insertions, 5 deletions

diff --git a/arch/blackfin/mach-common/entry.S b/arch/blackfin/mach-common/entry.S
index 5a4e7c7fd92c..fb1795d5be2a 100644
--- a/arch/blackfin/mach-common/entry.S
+++ b/arch/blackfin/mach-common/entry.S
@@ -218,7 +218,7 @@ ENTRY(_ex_single_step)
         /* Single stepping only a single instruction, so clear the trace
          * bit here.  */
         r7 = syscfg;
-        bitclr (r7, 0);
+        bitclr (r7, SYSCFG_SSSTEP_P);
         syscfg = R7;
         jump _ex_trap_c;
 
@@ -251,7 +251,7 @@ ENTRY(_ex_single_step)
         if !cc jump _bfin_return_from_exception;
 
         r7 = syscfg;
-        bitclr (r7, 0);
+        bitclr (r7, SYSCFG_SSSTEP_P);   /* Turn off single step */
         syscfg = R7;
 
         /* Fall through to _bfin_return_from_exception.  */
@@ -342,9 +342,11 @@ ENTRY(_ex_trap_c)
         r6 = retx;
         [p5 + PDA_RETX] = r6;
 #endif
+        /* Save the state of single stepping */
         r6 = SYSCFG;
         [p5 + PDA_SYSCFG] = r6;
-        BITCLR(r6, 0);
+        /* Clear it while we handle the exception in IRQ5 mode */
+        BITCLR(r6, SYSCFG_SSSTEP_P);
         SYSCFG = r6;
 
         /* Disable all interrupts, but make sure level 5 is enabled so
@@ -367,7 +369,7 @@ ENDPROC(_ex_trap_c)
  * exception. This is a unrecoverable event, so crash.
  * Note: this cannot be ENTRY() as we jump here with "if cc jump" ...
  */
-_double_fault:
+ENTRY(_double_fault)
         /* Turn caches & protection off, to ensure we don't get any more
          * double exceptions
          */
@@ -872,7 +874,7 @@ ENTRY(_ret_from_exception)
         raise 15;               /* raise evt15 to do signal or reschedule */
 4:
         r0 = syscfg;
-        bitclr(r0, 0);
+        bitclr(r0, SYSCFG_SSSTEP_P);            /* Turn off single step */
         syscfg = r0;
 5:
         rts;