sh: move the ioremap implementation out of line

Move the internal implementation details of ioremap out of line, no need
to expose any of this to drivers for a slow path API.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Rich Felker <dalias@libc.org>

arch/sh/mm/ioremap.c

@@ -26,6 +26,51 @@
 #include <asm/mmu.h>
 #include "ioremap.h"
 
+/*
+ * On 32-bit SH, we traditionally have the whole physical address space mapped
+ * at all times (as MIPS does), so "ioremap()" and "iounmap()" do not need to do
+ * anything but place the address in the proper segment.  This is true for P1
+ * and P2 addresses, as well as some P3 ones.  However, most of the P3 addresses
+ * and newer cores using extended addressing need to map through page tables, so
+ * the ioremap() implementation becomes a bit more complicated.
+ */
+#ifdef CONFIG_29BIT
+static void __iomem *
+__ioremap_29bit(phys_addr_t offset, unsigned long size, pgprot_t prot)
+{
+	phys_addr_t last_addr = offset + size - 1;
+
+	/*
+	 * For P1 and P2 space this is trivial, as everything is already
+	 * mapped. Uncached access for P1 addresses are done through P2.
+	 * In the P3 case or for addresses outside of the 29-bit space,
+	 * mapping must be done by the PMB or by using page tables.
+	 */
+	if (likely(PXSEG(offset) < P3SEG && PXSEG(last_addr) < P3SEG)) {
+		u64 flags = pgprot_val(prot);
+
+		/*
+		 * Anything using the legacy PTEA space attributes needs
+		 * to be kicked down to page table mappings.
+		 */
+		if (unlikely(flags & _PAGE_PCC_MASK))
+			return NULL;
+		if (unlikely(flags & _PAGE_CACHABLE))
+			return (void __iomem *)P1SEGADDR(offset);
+
+		return (void __iomem *)P2SEGADDR(offset);
+	}
+
+	/* P4 above the store queues are always mapped. */
+	if (unlikely(offset >= P3_ADDR_MAX))
+		return (void __iomem *)P4SEGADDR(offset);
+
+	return NULL;
+}
+#else
+#define __ioremap_29bit(offset, size, prot)		NULL
+#endif /* CONFIG_29BIT */
+
 /*
  * Remap an arbitrary physical address space into the kernel virtual
  * address space. Needed when the kernel wants to access high addresses
@@ -43,6 +88,14 @@ __ioremap_caller(phys_addr_t phys_addr, unsigned long size,
 	unsigned long offset, last_addr, addr, orig_addr;
 	void __iomem *mapped;
 
+	mapped = __ioremap_trapped(phys_addr, size);
+	if (mapped)
+		return mapped;
+
+	mapped = __ioremap_29bit(phys_addr, size, pgprot);
+	if (mapped)
+		return mapped;
+
 	/* Don't allow wraparound or zero size */
 	last_addr = phys_addr + size - 1;
 	if (!size || last_addr < phys_addr)