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>

diff --git a/arch/blackfin/mach-common/entry.S b/arch/blackfin/mach-common/entry.S
index 5a4e7c7fd92c4e0976ce58f1bf977b6911390775..fb1795d5be2af2e9765f31c1c40fafd90257580e 100644 (file)
--- 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;