powerpc/47x: Base ppc476 support

This patch adds the base support for the 476 processor.  The code was
primarily written by Ben Herrenschmidt and Torez Smith, but I've been
maintaining it for a while.

The goal is to have a single binary that will run on 44x and 47x, but
we still have some details to work out.  The biggest is that the L1 cache
line size differs on the two platforms, but it's currently a compile-time
option.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Torez Smith  <lnxtorez@linux.vnet.ibm.com>
Signed-off-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/arch/powerpc/mm/mmu_context_nohash.c b/arch/powerpc/mm/mmu_context_nohash.c
index 1f2d9ff09895..ddfd7ad4e1d6 100644
--- a/arch/powerpc/mm/mmu_context_nohash.c
+++ b/arch/powerpc/mm/mmu_context_nohash.c
@@ -395,10 +395,18 @@ void __init mmu_context_init(void)
          * the PID/TID comparison is disabled, so we can use a TID of zero
          * to represent all kernel pages as shared among all contexts.
          *      -- Dan
+         *
+         * The IBM 47x core supports 16-bit PIDs, thus 65535 contexts. We
+         * should normally never have to steal though the facility is
+         * present if needed.
+         *      -- BenH
          */
         if (mmu_has_feature(MMU_FTR_TYPE_8xx)) {
                 first_context = 0;
                 last_context = 15;
+        } else if (mmu_has_feature(MMU_FTR_TYPE_47x)) {
+                first_context = 1;
+                last_context = 65535;
         } else {
                 first_context = 1;
                 last_context = 255;