m68k: fix read/write multi-byte IO for PCI on ColdFire

We need to treat built-in peripherals and bus based address ranges
differently. Local built-in peripherals (and the ColdFire SoC parts
have quite a lot of them) are always native endian - which is big
endian on m68k/ColdFire. Bus based address ranges, like the PCI bus,
are accessed little endian - so we need to byte swap those.

So implement readw/writew and readl/writel functions to deal with
memory mapped accesses correctly based on the address range being
accessed.

This fixes readw/writew and readl/writel so that they can be used in
drivers for native SoC hardware modules (many of which are shared with
other architectures (ARM in Freescale SoC parts for example). And also
drivers for PCI devices.

Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
Tested-by: Angelo Dureghello <angelo@sysam.it>

arch/m68k/include/asm/io_no.h

@@ -18,16 +18,95 @@
 #define __raw_writew(b, addr) (void)((*(volatile unsigned short *) (addr)) = (b))
 #define __raw_writel(b, addr) (void)((*(volatile unsigned int *) (addr)) = (b))
 
-#if defined(CONFIG_PCI) && defined(CONFIG_COLDFIRE)
+#if defined(CONFIG_COLDFIRE)
 /*
- * Support for PCI bus access uses the asm-generic access functions.
- * We need to supply the base address and masks for the normal memory
- * and IO address space mappings.
+ * For ColdFire platforms we may need to do some extra checks for what
+ * type of address range we are accessing. Include the ColdFire platform
+ * definitions so we can figure out if need to do something special.
  */
 #include <asm/byteorder.h>
 #include <asm/coldfire.h>
 #include <asm/mcfsim.h>
+#endif /* CONFIG_COLDFIRE */
+
+#if defined(IOMEMBASE)
+/*
+ * The ColdFire SoC internal peripherals are mapped into virtual address
+ * space using the ACR registers of the cache control unit. This means we
+ * are using a 1:1 physical:virtual mapping for them. We can quickly
+ * determine if we are accessing an internal peripheral device given the
+ * physical or vitrual address using the same range check. This check logic
+ * applies just the same of there is no MMU but something like a PCI bus
+ * is present.
+ */
+static int __cf_internalio(unsigned long addr)
+{
+	return (addr >= IOMEMBASE) && (addr <= IOMEMBASE + IOMEMSIZE - 1);
+}
+
+static int cf_internalio(const volatile void __iomem *addr)
+{
+	return __cf_internalio((unsigned long) addr);
+}
+
+/*
+ * We need to treat built-in peripherals and bus based address ranges
+ * differently. Local built-in peripherals (and the ColdFire SoC parts
+ * have quite a lot of them) are always native endian - which is big
+ * endian on m68k/ColdFire. Bus based address ranges, like the PCI bus,
+ * are accessed little endian - so we need to byte swap those.
+ */
+#define readw readw
+static inline u16 readw(const volatile void __iomem *addr)
+{
+	if (cf_internalio(addr))
+		return __raw_readw(addr);
+	return __le16_to_cpu(__raw_readw(addr));
+}
+
+#define readl readl
+static inline u32 readl(const volatile void __iomem *addr)
+{
+	if (cf_internalio(addr))
+		return __raw_readl(addr);
+	return __le32_to_cpu(__raw_readl(addr));
+}
+
+#define writew writew
+static inline void writew(u16 value, volatile void __iomem *addr)
+{
+	if (cf_internalio(addr))
+		__raw_writew(value, addr);
+	else
+		__raw_writew(__cpu_to_le16(value), addr);
+}
+
+#define writel writel
+static inline void writel(u32 value, volatile void __iomem *addr)
+{
+	if (cf_internalio(addr))
+		__raw_writel(value, addr);
+	else
+		__raw_writel(__cpu_to_le32(value), addr);
+}
+
+#else
+
+#define readb __raw_readb
+#define readw __raw_readw
+#define readl __raw_readl
+#define writeb __raw_writeb
+#define writew __raw_writew
+#define writel __raw_writel
 
+#endif /* IOMEMBASE */
+
+#if defined(CONFIG_PCI)
+/*
+ * Support for PCI bus access uses the asm-generic access functions.
+ * We need to supply the base address and masks for the normal memory
+ * and IO address space mappings.
+ */
 #define PCI_MEM_PA	0xf0000000		/* Host physical address */
 #define PCI_MEM_BA	0xf0000000		/* Bus physical address */
 #define PCI_MEM_SIZE	0x08000000		/* 128 MB */
@@ -44,17 +123,7 @@
 #define PIO_RESERVED	0x10000
 #define PCI_IOBASE	((void __iomem *) PCI_IO_PA)
 #define PCI_SPACE_LIMIT	PCI_IO_MASK
-
-#else
-
-#define readb __raw_readb
-#define readw __raw_readw
-#define readl __raw_readl
-#define writeb __raw_writeb
-#define writew __raw_writew
-#define writel __raw_writel
-
-#endif /* CONFIG_PCI && CONFIG_COLDFIRE */
+#endif /* CONFIG_PCI */
 
 /*
  * These are defined in kmap.h as static inline functions. To maintain