powerpc/dart: Use a cachable DART

Instead of punching a hole in the linear mapping, just use normal
cachable memory, and apply the flush sequence documented in the
CPC625 (aka U3) user manual.

This allows us to remove quite a bit of code related to the early
allocation of the DART and the hole in the linear mapping. We can
also get rid of the copy of the DART for suspend/resume as the
original memory can just be saved/restored now, as long as we
properly sync the caches.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[mpe: Integrate dart_init() fix to return ENODEV when DART disabled]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 0 insertions, 32 deletions

diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 7d0955e04f08..859ecaa928e9 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -87,10 +87,6 @@
  *
  */
 
-#ifdef CONFIG_U3_DART
-extern unsigned long dart_tablebase;
-#endif /* CONFIG_U3_DART */
-
 static unsigned long _SDR1;
 struct mmu_psize_def mmu_psize_defs[MMU_PAGE_COUNT];
 EXPORT_SYMBOL_GPL(mmu_psize_defs);
@@ -846,34 +842,6 @@ static void __init htab_initialize(void)
                 DBG("creating mapping for region: %lx..%lx (prot: %lx)\n",
                     base, size, prot);
 
-#ifdef CONFIG_U3_DART
-                /* Do not map the DART space. Fortunately, it will be aligned
-                 * in such a way that it will not cross two memblock regions and
-                 * will fit within a single 16Mb page.
-                 * The DART space is assumed to be a full 16Mb region even if
-                 * we only use 2Mb of that space. We will use more of it later
-                 * for AGP GART. We have to use a full 16Mb large page.
-                 */
-                DBG("DART base: %lx\n", dart_tablebase);
-
-                if (dart_tablebase != 0 && dart_tablebase >= base
-                    && dart_tablebase < (base + size)) {
-                        unsigned long dart_table_end = dart_tablebase + 16 * MB;
-                        if (base != dart_tablebase)
-                                BUG_ON(htab_bolt_mapping(base, dart_tablebase,
-                                                        __pa(base), prot,
-                                                        mmu_linear_psize,
-                                                        mmu_kernel_ssize));
-                        if ((base + size) > dart_table_end)
-                                BUG_ON(htab_bolt_mapping(dart_tablebase+16*MB,
-                                                        base + size,
-                                                        __pa(dart_table_end),
-                                                         prot,
-                                                         mmu_linear_psize,
-                                                         mmu_kernel_ssize));
-                        continue;
-                }
-#endif /* CONFIG_U3_DART */
                 BUG_ON(htab_bolt_mapping(base, base + size, __pa(base),
                                 prot, mmu_linear_psize, mmu_kernel_ssize));
         }