[ARM] Kirkwood: only map peripheral register space once

Just like commit 1419468a, let's save some TLB entries by making
ioremap() return pointers into the boot-time Kirkwood peripheral
iotable mapping whenever someone tries to ioremap any part of the Kirkwood
peripheral register space.
Signed-off-by: Nicolas Pitre <nico@marvell.com>

arch/arm/mach-kirkwood/include/mach/io.h

@@ -19,6 +19,31 @@ static inline void __iomem *__io(unsigned long addr)
 					+ KIRKWOOD_PCIE_IO_VIRT_BASE);
 }
 
+static inline void __iomem *
+__arch_ioremap(unsigned long paddr, size_t size, unsigned int mtype)
+{
+	void __iomem *retval;
+	unsigned long offs = paddr - KIRKWOOD_REGS_PHYS_BASE;
+	if (mtype == MT_DEVICE && size && offs < KIRKWOOD_REGS_SIZE &&
+	    size <= KIRKWOOD_REGS_SIZE && offs + size <= KIRKWOOD_REGS_SIZE) {
+		retval = (void __iomem *)KIRKWOOD_REGS_VIRT_BASE + offs;
+	} else {
+		retval = __arm_ioremap(paddr, size, mtype);
+	}
+
+	return retval;
+}
+
+static inline void
+__arch_iounmap(void __iomem *addr)
+{
+	if (addr < (void __iomem *)KIRKWOOD_REGS_VIRT_BASE ||
+	    addr >= (void __iomem *)(KIRKWOOD_REGS_VIRT_BASE + KIRKWOOD_REGS_SIZE))
+		__iounmap(addr);
+}
+
+#define __arch_ioremap(p, s, m)	__arch_ioremap(p, s, m)
+#define __arch_iounmap(a)	__arch_iounmap(a)
 #define __io(a)			__io(a)
 #define __mem_pci(a)		(a)