Re: iomapping a big endian area

[James Bottomley <James.Bottomley@SteelEye.com>]

On Mon, 2005-04-04 at 16:41 +0100, David Vrabel wrote:
> The Network Processing Engines in the Intel IXP425 are big-endian and
> its XScale core may be run in little-endian mode. There's a bunch of
> gotchas related to running in little-endian mode so you typically run
> the IXP425 in big-endian mode, though.

Yes, based on feedback from Mips people and others pointing out the
existence of the motorola rapidio bus, which is BE, I give in and agree
that the io{read,write}{16,32}be are the way to go.

How does the attached look?

James

===== arch/parisc/lib/iomap.c 1.1 vs edited =====
--- 1.1/arch/parisc/lib/iomap.c	2005-01-10 08:00:46 -06:00
+++ edited/arch/parisc/lib/iomap.c	2005-04-04 13:53:49 -05:00
@@ -43,10 +43,14 @@
 struct iomap_ops {
 	unsigned int (*read8)(void __iomem *);
 	unsigned int (*read16)(void __iomem *);
+	unsigned int (*read16be)(void __iomem *);
 	unsigned int (*read32)(void __iomem *);
+	unsigned int (*read32be)(void __iomem *);
 	void (*write8)(u8, void __iomem *);
 	void (*write16)(u16, void __iomem *);
+	void (*write16be)(u16, void __iomem *);
 	void (*write32)(u32, void __iomem *);
+	void (*write32be)(u32, void __iomem *);
 	void (*read8r)(void __iomem *, void *, unsigned long);
 	void (*read16r)(void __iomem *, void *, unsigned long);
 	void (*read32r)(void __iomem *, void *, unsigned long);
@@ -122,9 +126,13 @@
 static const struct iomap_ops ioport_ops = {
 	ioport_read8,
 	ioport_read16,
+	ioport_read16,
+	ioport_read32,
 	ioport_read32,
 	ioport_write8,
 	ioport_write16,
+	ioport_write16,
+	ioport_write32,
 	ioport_write32,
 	ioport_read8r,
 	ioport_read16r,
@@ -146,11 +154,21 @@
 	return readw(addr);
 }
 
+static unsigned int iomem_read16be(void __iomem *addr)
+{
+	return __raw_readw(addr);
+}
+
 static unsigned int iomem_read32(void __iomem *addr)
 {
 	return readl(addr);
 }
 
+static unsigned int iomem_read32be(void __iomem *addr)
+{
+	return __raw_readl(addr);
+}
+
 static void iomem_write8(u8 datum, void __iomem *addr)
 {
 	writeb(datum, addr);
@@ -161,11 +179,21 @@
 	writew(datum, addr);
 }
 
+static void iomem_write16be(u16 datum, void __iomem *addr)
+{
+	__raw_writew(datum, addr);
+}
+
 static void iomem_write32(u32 datum, void __iomem *addr)
 {
 	writel(datum, addr);
 }
 
+static void iomem_write32be(u32 datum, void __iomem *addr)
+{
+	__raw_writel(datum, addr);
+}
+
 static void iomem_read8r(void __iomem *addr, void *dst, unsigned long count)
 {
 	while (count--) {
@@ -217,10 +245,14 @@
 static const struct iomap_ops iomem_ops = {
 	iomem_read8,
 	iomem_read16,
+	iomem_read16be,
 	iomem_read32,
+	iomem_read32be,
 	iomem_write8,
 	iomem_write16,
+	iomem_write16be,
 	iomem_write32,
+	iomem_write32be,
 	iomem_read8r,
 	iomem_read16r,
 	iomem_read32r,
@@ -253,6 +285,13 @@
 	return le16_to_cpup((u16 *)addr);
 }
 
+unsigned int ioread16be(void __iomem *addr)
+{
+	if (unlikely(INDIRECT_ADDR(addr)))
+		return iomap_ops[ADDR_TO_REGION(addr)]->read16be(addr);
+	return *((u16 *)addr);
+}
+
 unsigned int ioread32(void __iomem *addr)
 {
 	if (unlikely(INDIRECT_ADDR(addr)))
@@ -260,6 +299,13 @@
 	return le32_to_cpup((u32 *)addr);
 }
 
+unsigned int ioread32be(void __iomem *addr)
+{
+	if (unlikely(INDIRECT_ADDR(addr)))
+		return iomap_ops[ADDR_TO_REGION(addr)]->read32be(addr);
+	return *((u32 *)addr);
+}
+
 void iowrite8(u8 datum, void __iomem *addr)
 {
 	if (unlikely(INDIRECT_ADDR(addr))) {
@@ -278,12 +324,30 @@
 	}
 }
 
+void iowrite16be(u16 datum, void __iomem *addr)
+{
+	if (unlikely(INDIRECT_ADDR(addr))) {
+		iomap_ops[ADDR_TO_REGION(addr)]->write16be(datum, addr);
+	} else {
+		*((u16 *)addr) = datum;
+	}
+}
+
 void iowrite32(u32 datum, void __iomem *addr)
 {
 	if (unlikely(INDIRECT_ADDR(addr))) {
 		iomap_ops[ADDR_TO_REGION(addr)]->write32(datum, addr);
 	} else {
 		*((u32 *)addr) = cpu_to_le32(datum);
+	}
+}
+
+void iowrite32be(u32 datum, void __iomem *addr)
+{
+	if (unlikely(INDIRECT_ADDR(addr))) {
+		iomap_ops[ADDR_TO_REGION(addr)]->write32be(datum, addr);
+	} else {
+		*((u32 *)addr) = datum;
 	}
 }
 
===== include/asm-generic/iomap.h 1.3 vs edited =====
--- 1.3/include/asm-generic/iomap.h	2004-09-14 18:28:47 -05:00
+++ edited/include/asm-generic/iomap.h	2005-04-04 12:06:14 -05:00
@@ -2,6 +2,7 @@
 #define __GENERIC_IO_H
 
 #include <linux/linkage.h>
+#include <asm/byteorder.h>
 
 /*
  * These are the "generic" interfaces for doing new-style
@@ -26,11 +27,15 @@
  */
 extern unsigned int fastcall ioread8(void __iomem *);
 extern unsigned int fastcall ioread16(void __iomem *);
+extern unsigned int fastcall ioread16be(void __iomem *);
 extern unsigned int fastcall ioread32(void __iomem *);
+extern unsigned int fastcall ioread32be(void __iomem *);
 
 extern void fastcall iowrite8(u8, void __iomem *);
 extern void fastcall iowrite16(u16, void __iomem *);
+extern void fastcall iowrite16be(u16, void __iomem *);
 extern void fastcall iowrite32(u32, void __iomem *);
+extern void fastcall iowrite32be(u32, void __iomem *);
 
 /*
  * "string" versions of the above. Note that they
===== lib/iomap.c 1.6 vs edited =====
--- 1.6/lib/iomap.c	2004-10-28 02:39:50 -05:00
+++ edited/lib/iomap.c	2005-04-04 13:52:51 -05:00
@@ -58,13 +58,23 @@
 {
 	IO_COND(addr, return inw(port), return readw(addr));
 }
+unsigned int fastcall ioread16be(void __iomem *addr)
+{
+	IO_COND(addr, return inw(port), return cpu_to_be16(__raw_readw(addr)));
+}
 unsigned int fastcall ioread32(void __iomem *addr)
 {
 	IO_COND(addr, return inl(port), return readl(addr));
 }
+unsigned int fastcall ioread32be(void __iomem *addr)
+{
+	IO_COND(addr, return inl(port), return cpu_to_be32(__raw_readl(addr)));
+}
 EXPORT_SYMBOL(ioread8);
 EXPORT_SYMBOL(ioread16);
+EXPORT_SYMBOL(ioread16be);
 EXPORT_SYMBOL(ioread32);
+EXPORT_SYMBOL(ioread32be);
 
 void fastcall iowrite8(u8 val, void __iomem *addr)
 {
@@ -74,13 +84,23 @@
 {
 	IO_COND(addr, outw(val,port), writew(val, addr));
 }
+void fastcall iowrite16be(u16 val, void __iomem *addr)
+{
+	IO_COND(addr, outw(val,port), __raw_writew(be16_to_cpu(val), addr));
+}
 void fastcall iowrite32(u32 val, void __iomem *addr)
 {
 	IO_COND(addr, outl(val,port), writel(val, addr));
 }
+void fastcall iowrite32be(u32 val, void __iomem *addr)
+{
+	IO_COND(addr, outl(val,port), __raw_writel(val, addr));
+}
 EXPORT_SYMBOL(iowrite8);
 EXPORT_SYMBOL(iowrite16);
+EXPORT_SYMBOL(iowrite16be);
 EXPORT_SYMBOL(iowrite32);
+EXPORT_SYMBOL(iowrite32be);
 
 /*
  * These are the "repeat MMIO read/write" functions.