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>

arch/sh/boot/Makefile

@@ -33,20 +33,24 @@ $(obj)/zImage: $(obj)/compressed/vmlinux FORCE
 $(obj)/compressed/vmlinux: FORCE
 	$(Q)$(MAKE) $(build)=$(obj)/compressed $@
 
-ifeq ($(CONFIG_32BIT),y)
-KERNEL_LOAD	:= $(shell /bin/bash -c 'printf "0x%08x" \
-		     $$[$(CONFIG_PAGE_OFFSET)  + \
-			$(CONFIG_ZERO_PAGE_OFFSET)]')
-else
+KERNEL_MEMORY := 0x00000000
+ifeq ($(CONFIG_PMB_FIXED),y)
+KERNEL_MEMORY := $(shell /bin/bash -c 'printf "0x%08x" \
+		     $$[$(CONFIG_MEMORY_START) & 0x1fffffff]')
+endif
+ifeq ($(CONFIG_29BIT),y)
+KERNEL_MEMORY := $(shell /bin/bash -c 'printf "0x%08x" \
+		     $$[$(CONFIG_MEMORY_START)]')
+endif
+
 KERNEL_LOAD	:= $(shell /bin/bash -c 'printf "0x%08x" \
 		     $$[$(CONFIG_PAGE_OFFSET)  + \
-			$(CONFIG_MEMORY_START) + \
+			$(KERNEL_MEMORY) + \
 			$(CONFIG_ZERO_PAGE_OFFSET)]')
-endif
 
 KERNEL_ENTRY	:= $(shell /bin/bash -c 'printf "0x%08x" \
 		     $$[$(CONFIG_PAGE_OFFSET)  + \
-			$(CONFIG_MEMORY_START) + \
+			$(KERNEL_MEMORY) + \
 			$(CONFIG_ZERO_PAGE_OFFSET) + $(CONFIG_ENTRY_OFFSET)]')
 
 quiet_cmd_uimage = UIMAGE  $@

arch/sh/include/asm/addrspace.h

@@ -31,7 +31,7 @@
 /* Returns the physical address of a PnSEG (n=1,2) address   */
 #define PHYSADDR(a)	(((unsigned long)(a)) & 0x1fffffff)
 
-#ifdef CONFIG_29BIT
+#if defined(CONFIG_29BIT) || defined(CONFIG_PMB_FIXED)
 /*
  * Map an address to a certain privileged segment
  */
@@ -43,7 +43,7 @@
 	((__typeof__(a))(((unsigned long)(a) & 0x1fffffff) | P3SEG))
 #define P4SEGADDR(a)	\
 	((__typeof__(a))(((unsigned long)(a) & 0x1fffffff) | P4SEG))
-#endif /* 29BIT */
+#endif /* 29BIT || PMB_FIXED */
 #endif /* P1SEG */
 
 /* Check if an address can be reached in 29 bits */

arch/sh/include/asm/io.h

@@ -238,7 +238,7 @@ extern void onchip_unmap(unsigned long vaddr);
 static inline void __iomem *
 __ioremap_mode(unsigned long offset, unsigned long size, unsigned long flags)
 {
-#ifdef CONFIG_SUPERH32
+#if defined(CONFIG_SUPERH32) && !defined(CONFIG_PMB_FIXED)
 	unsigned long last_addr = offset + size - 1;
 #endif
 	void __iomem *ret;
@@ -247,7 +247,7 @@ __ioremap_mode(unsigned long offset, unsigned long size, unsigned long flags)
 	if (ret)
 		return ret;
 
-#ifdef CONFIG_SUPERH32
+#if defined(CONFIG_SUPERH32) && !defined(CONFIG_PMB_FIXED)
 	/*
 	 * For P1 and P2 space this is trivial, as everything is already
 	 * mapped. Uncached access for P1 addresses are done through P2.

arch/sh/include/asm/page.h

@@ -129,7 +129,12 @@ typedef struct page *pgtable_t;
  * is not visible (it is part of the PMB mapping) and so needs to be
  * added or subtracted as required.
  */
-#ifdef CONFIG_32BIT
+#if defined(CONFIG_PMB_FIXED)
+/* phys = virt - PAGE_OFFSET - (__MEMORY_START & 0xe0000000) */
+#define PMB_OFFSET	(PAGE_OFFSET - PXSEG(__MEMORY_START))
+#define __pa(x)	((unsigned long)(x) - PMB_OFFSET)
+#define __va(x)	((void *)((unsigned long)(x) + PMB_OFFSET))
+#elif defined(CONFIG_32BIT)
 #define __pa(x)	((unsigned long)(x)-PAGE_OFFSET+__MEMORY_START)
 #define __va(x)	((void *)((unsigned long)(x)+PAGE_OFFSET-__MEMORY_START))
 #else

arch/sh/kernel/vmlinux_32.lds.S

@@ -15,7 +15,10 @@ OUTPUT_ARCH(sh)
 ENTRY(_start)
 SECTIONS
 {
-#ifdef CONFIG_32BIT
+#ifdef CONFIG_PMB_FIXED
+	. = CONFIG_PAGE_OFFSET + (CONFIG_MEMORY_START & 0x1fffffff) +
+	    CONFIG_ZERO_PAGE_OFFSET;
+#elif defined(CONFIG_32BIT)
 	. = CONFIG_PAGE_OFFSET + CONFIG_ZERO_PAGE_OFFSET;
 #else
 	. = CONFIG_PAGE_OFFSET + CONFIG_MEMORY_START + CONFIG_ZERO_PAGE_OFFSET;

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

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

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.

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);