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>

4 files changed, 78 insertions, 3 deletions

diff --git a/arch/sh/mm/Kconfig b/arch/sh/mm/Kconfig
index 555ec97..10c2435 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
diff --git a/arch/sh/mm/Makefile_32 b/arch/sh/mm/Makefile_32
index cb2f3f2..469ff16 100644
--- a/arch/sh/mm/Makefile_32
+++ b/arch/sh/mm/Makefile_32
@@ -35,6 +35,7 @@ endif
 
 obj-$(CONFIG_HUGETLB_PAGE)	+= hugetlbpage.o
 obj-$(CONFIG_PMB)		+= pmb.o
+obj-$(CONFIG_PMB_FIXED)		+= pmb-fixed.o
 obj-$(CONFIG_NUMA)		+= numa.o
 
 EXTRA_CFLAGS += -Werror
diff --git a/arch/sh/mm/ioremap_32.c b/arch/sh/mm/ioremap_32.c
index 8dc7702..60cc486 100644
--- a/arch/sh/mm/ioremap_32.c
+++ b/arch/sh/mm/ioremap_32.c
@@ -59,11 +59,13 @@ void __iomem *__ioremap(unsigned long phys_addr, unsigned long size,
 	if (is_pci_memaddr(phys_addr) && is_pci_memaddr(last_addr))
 		return (void __iomem *)phys_addr;
 
+#if !defined(CONFIG_PMB_FIXED)
 	/*
 	 * Don't allow anybody to remap normal RAM that we're using..
 	 */
 	if (phys_addr < virt_to_phys(high_memory))
 		return NULL;
+#endif
 
 	/*
 	 * Mappings have to be page-aligned
@@ -81,7 +83,7 @@ void __iomem *__ioremap(unsigned long phys_addr, unsigned long size,
 	area->phys_addr = phys_addr;
 	orig_addr = addr = (unsigned long)area->addr;
 
-#ifdef CONFIG_32BIT
+#ifdef CONFIG_PMB
 	/*
 	 * First try to remap through the PMB once a valid VMA has been
 	 * established. Smaller allocations (or the rest of the size
@@ -122,7 +124,7 @@ void __iounmap(void __iomem *addr)
 	if (seg < P3SEG || vaddr >= P3_ADDR_MAX || is_pci_memaddr(vaddr))
 		return;
 
-#ifdef CONFIG_32BIT
+#ifdef CONFIG_PMB
 	/*
 	 * Purge any PMB entries that may have been established for this
 	 * mapping, then proceed with conventional VMA teardown.
diff --git a/arch/sh/mm/pmb-fixed.c b/arch/sh/mm/pmb-fixed.c
new file mode 100644
index 0000000..43c8eac
--- /dev/null
+++ b/arch/sh/mm/pmb-fixed.c
@@ -0,0 +1,45 @@
+/*
+ * arch/sh/mm/fixed_pmb.c
+ *
+ * Copyright (C) 2009  Renesas Solutions Corp.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/io.h>
+#include <asm/mmu.h>
+#include <asm/mmu_context.h>
+
+static int __uses_jump_to_uncached fixed_pmb_init(void)
+{
+	int i;
+	unsigned long addr, data;
+
+	jump_to_uncached();
+
+	for (i = 0; i < PMB_ENTRY_MAX; i++) {
+		addr = PMB_DATA + (i << PMB_E_SHIFT);
+		data = ctrl_inl(addr);
+		if (!(data & PMB_V))
+			continue;
+
+		if (data & PMB_C) {
+#if defined(CONFIG_CACHE_WRITETHROUGH)
+			data |= PMB_WT;
+#elif defined(CONFIG_CACHE_WRITEBACK)
+			data &= ~PMB_WT;
+#else
+			data &= ~(PMB_C | PMB_WT);
+#endif
+		}
+		ctrl_outl(data, addr);
+	}
+
+	back_to_cached();
+
+	return 0;
+}
+arch_initcall(fixed_pmb_init);