[MIPS] TX49XX has prefetch.

    
The TX49XX has the prefetch instruction.  It supports only Pref_Load
(hint 0).  Actually changes in this patch except for Kconfig are not
have any effects, I added these changes to prevent misuse of unsupported
hints.
    
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

3 files changed, 10 insertions, 2 deletions

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 97a9769a9046..ac2012f033d6 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -1160,6 +1160,7 @@ config CPU_R4X00
 config CPU_TX49XX
         bool "R49XX"
         depends on SYS_HAS_CPU_TX49XX
+        select CPU_HAS_PREFETCH
         select CPU_SUPPORTS_32BIT_KERNEL
         select CPU_SUPPORTS_64BIT_KERNEL
 
diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c
index 9572ed44f0d5..32b7f6aeb983 100644
--- a/arch/mips/mm/c-r4k.c
+++ b/arch/mips/mm/c-r4k.c
@@ -786,6 +786,7 @@ static void __init probe_pcache(void)
                 c->dcache.waybit = 0;
 
                 c->options |= MIPS_CPU_CACHE_CDEX_P;
+                c->options |= MIPS_CPU_PREFETCH;
                 break;
 
         case CPU_R4000PC:
diff --git a/arch/mips/mm/pg-r4k.c b/arch/mips/mm/pg-r4k.c
index f51e180072e3..e4390dc3eb48 100644
--- a/arch/mips/mm/pg-r4k.c
+++ b/arch/mips/mm/pg-r4k.c
@@ -124,7 +124,7 @@ static inline void build_nop(void)
 
 static inline void build_src_pref(int advance)
 {
-        if (!(load_offset & (cpu_dcache_line_size() - 1))) {
+        if (!(load_offset & (cpu_dcache_line_size() - 1)) && advance) {
                 union mips_instruction mi;
 
                 mi.i_format.opcode     = pref_op;
@@ -166,7 +166,7 @@ static inline void build_load_reg(int reg)
 
 static inline void build_dst_pref(int advance)
 {
-        if (!(store_offset & (cpu_dcache_line_size() - 1))) {
+        if (!(store_offset & (cpu_dcache_line_size() - 1)) && advance) {
                 union mips_instruction mi;
 
                 mi.i_format.opcode     = pref_op;
@@ -340,6 +340,12 @@ void __init build_clear_page(void)
 
         if (cpu_has_prefetch) {
                 switch (current_cpu_data.cputype) {
+                case CPU_TX49XX:
+                        /* TX49 supports only Pref_Load */
+                        pref_offset_clear = 0;
+                        pref_offset_copy = 0;
+                        break;
+
                 case CPU_RM9000:
                         /*
                          * As a workaround for erratum G105 which make the