sh: Support explicit L1 cache disabling.

This reworks the cache mode configuration in Kconfig, and allows for
explicit selection of write-back/write-through/off configurations.
All of the cache flushing routines are optimized away for the off
case.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 15 insertions, 10 deletions

diff --git a/arch/sh/mm/tlb-sh4.c b/arch/sh/mm/tlb-sh4.c
index f74cf667c8fa..13fde8cc7179 100644
--- a/arch/sh/mm/tlb-sh4.c
+++ b/arch/sh/mm/tlb-sh4.c
@@ -34,22 +34,27 @@ void update_mmu_cache(struct vm_area_struct * vma,
         unsigned long flags;
         unsigned long pteval;
         unsigned long vpn;
-        struct page *page;
-        unsigned long pfn;
 
         /* Ptrace may call this routine. */
         if (vma && current->active_mm != vma->vm_mm)
                 return;
 
-        pfn = pte_pfn(pte);
-        if (pfn_valid(pfn)) {
-                page = pfn_to_page(pfn);
-                if (!test_bit(PG_mapped, &page->flags)) {
-                        unsigned long phys = pte_val(pte) & PTE_PHYS_MASK;
-                        __flush_wback_region((void *)P1SEGADDR(phys), PAGE_SIZE);
-                        __set_bit(PG_mapped, &page->flags);
+#ifndef CONFIG_CACHE_OFF
+        {
+                unsigned long pfn = pte_pfn(pte);
+
+                if (pfn_valid(pfn)) {
+                        struct page *page = pfn_to_page(pfn);
+
+                        if (!test_bit(PG_mapped, &page->flags)) {
+                                unsigned long phys = pte_val(pte) & PTE_PHYS_MASK;
+                                __flush_wback_region((void *)P1SEGADDR(phys),
+                                                     PAGE_SIZE);
+                                __set_bit(PG_mapped, &page->flags);
+                        }
                 }
         }
+#endif
 
         local_irq_save(flags);
 
@@ -66,7 +71,7 @@ void update_mmu_cache(struct vm_area_struct * vma,
 
         /* Set PTEL register */
         pteval &= _PAGE_FLAGS_HARDWARE_MASK; /* drop software flags */
-#ifdef CONFIG_SH_WRITETHROUGH
+#ifdef CONFIG_CACHE_WRITETHROUGH
         pteval |= _PAGE_WT;
 #endif
         /* conveniently, we want all the software flags to be 0 anyway */