sh: Support fixed 32-bit PMB mappings from bootloader.

This provides a method for supporting fixed PMB mappings inherited from
the bootloader, as an alternative to the dynamic PMB mapping currently
used by the kernel. In the future these methods will be combined.

P1/P2 area is handled like a regular 29-bit physical address, and local
bus device are assigned P3 area addresses.

Signed-off-by: Yoshihiro Shimoda <shimoda.yoshihiro@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 28 insertions, 1 deletions

diff --git a/arch/sh/mm/Kconfig b/arch/sh/mm/Kconfig
index 555ec9714b9e..10c24356d2d5 100644
--- a/arch/sh/mm/Kconfig
+++ b/arch/sh/mm/Kconfig
@@ -57,7 +57,7 @@ config 32BIT
         bool
         default y if CPU_SH5
 
-config PMB
+config PMB_ENABLE
         bool "Support 32-bit physical addressing through PMB"
         depends on MMU && EXPERIMENTAL && (CPU_SUBTYPE_SH7780 || CPU_SUBTYPE_SH7785)
         select 32BIT
@@ -67,6 +67,33 @@ config PMB
           32-bits through the SH-4A PMB. If this is not set, legacy
           29-bit physical addressing will be used.
 
+choice
+        prompt "PMB handling type"
+        depends on PMB_ENABLE
+        default PMB_FIXED
+
+config PMB
+        bool "PMB"
+        depends on MMU && EXPERIMENTAL && (CPU_SUBTYPE_SH7780 || CPU_SUBTYPE_SH7785)
+        select 32BIT
+        help
+          If you say Y here, physical addressing will be extended to
+          32-bits through the SH-4A PMB. If this is not set, legacy
+          29-bit physical addressing will be used.
+
+config PMB_FIXED
+        bool "fixed PMB"
+        depends on MMU && EXPERIMENTAL && (CPU_SUBTYPE_SH7780 || \
+                                           CPU_SUBTYPE_SH7785)
+        select 32BIT
+        help
+          If this option is enabled, fixed PMB mappings are inherited
+          from the boot loader, and the kernel does not attempt dynamic
+          management. This is the closest to legacy 29-bit physical mode,
+          and allows systems to support up to 512MiB of system memory.
+
+endchoice
+
 config X2TLB
         bool "Enable extended TLB mode"
         depends on (CPU_SHX2 || CPU_SHX3) && MMU && EXPERIMENTAL