MIPS: Alchemy: MIPS hazard workarounds are not required.
Manuel Lauss [Wed, 25 Mar 2009 16:49:30 +0000 (17:49 +0100)]
The Alchemy manuals state:

"All pipeline hazards and dependencies are enforced by hardware interlocks
 so that any sequence of instructions is guaranteed to execute correctly.
 Therefore, it is not necessary to pad legacy MIPS hazards (such as
 load delay slots and coprocessor accesses) with NOPs."

Run-tested on Au12x0, without any ill effects.

Signed-off-by: Manuel Lauss <mano@roarinelk.homelinux.net>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/hazards.h
arch/mips/mm/tlbex.c

index 134e1fc..a12d971 100644 (file)
@@ -87,7 +87,7 @@ do {                                                                  \
        : "=r" (tmp));                                                  \
 } while (0)
 
-#elif defined(CONFIG_CPU_MIPSR1)
+#elif defined(CONFIG_CPU_MIPSR1) && !defined(CONFIG_MACH_ALCHEMY)
 
 /*
  * These are slightly complicated by the fact that we guarantee R1 kernels to
@@ -139,7 +139,7 @@ do {                                                                        \
 } while (0)
 
 #elif defined(CONFIG_CPU_R10000) || defined(CONFIG_CPU_CAVIUM_OCTEON) || \
-      defined(CONFIG_CPU_R5500)
+      defined(CONFIG_CPU_R5500) || defined(CONFIG_MACH_ALCHEMY)
 
 /*
  * R10000 rocks - all hazards handled in hardware, so this becomes a nobrainer.
index 122c9c1..0615b62 100644 (file)
@@ -292,7 +292,6 @@ static void __cpuinit build_tlb_write_entry(u32 **p, struct uasm_label **l,
        case CPU_R4300:
        case CPU_5KC:
        case CPU_TX49XX:
-       case CPU_ALCHEMY:
        case CPU_PR4450:
                uasm_i_nop(p);
                tlbw(p);
@@ -315,6 +314,7 @@ static void __cpuinit build_tlb_write_entry(u32 **p, struct uasm_label **l,
        case CPU_R5500:
                if (m4kc_tlbp_war())
                        uasm_i_nop(p);
+       case CPU_ALCHEMY:
                tlbw(p);
                break;