diff --git a/arch/arm/configs/enp2611_defconfig b/arch/arm/configs/enp2611_defconfig
index af2153424560671ac8a87bea294a4b1c87ba4895..b8c51ee7f1bb05e530bdb252e5db4b55c8bfe405 100644
--- a/arch/arm/configs/enp2611_defconfig
+++ b/arch/arm/configs/enp2611_defconfig
@@ -99,6 +99,7 @@ CONFIG_ARCH_ENP2611=y
# CONFIG_ARCH_IXDP2800 is not set
# CONFIG_ARCH_IXDP2401 is not set
# CONFIG_ARCH_IXDP2801 is not set
+# CONFIG_IXP2000_SUPPORT_BROKEN_PCI_IO is not set
#
# Processor Type
diff --git a/arch/arm/configs/ixdp2400_defconfig b/arch/arm/configs/ixdp2400_defconfig
index a7ee1a442f34994c07f3be71a12d60d824abca1a..3cfbe2ec29ca6baeba87a066e486da5b259bb7dc 100644
--- a/arch/arm/configs/ixdp2400_defconfig
+++ b/arch/arm/configs/ixdp2400_defconfig
@@ -100,6 +100,7 @@ CONFIG_ARCH_IXDP2400=y
CONFIG_ARCH_IXDP2X00=y
# CONFIG_ARCH_IXDP2401 is not set
# CONFIG_ARCH_IXDP2801 is not set
+# CONFIG_IXP2000_SUPPORT_BROKEN_PCI_IO is not set
#
# Processor Type
diff --git a/arch/arm/configs/ixdp2401_defconfig b/arch/arm/configs/ixdp2401_defconfig
index 2da48fca5c1c15cc596c17ee4a69bc650b14c837..5c87e8e6969b1cb828158c853344d844a0071da7 100644
--- a/arch/arm/configs/ixdp2401_defconfig
+++ b/arch/arm/configs/ixdp2401_defconfig
@@ -100,6 +100,7 @@ CONFIG_ARCH_SUPPORTS_BIG_ENDIAN=y
CONFIG_ARCH_IXDP2401=y
# CONFIG_ARCH_IXDP2801 is not set
CONFIG_ARCH_IXDP2X01=y
+# CONFIG_IXP2000_SUPPORT_BROKEN_PCI_IO is not set
#
# Processor Type
diff --git a/arch/arm/configs/ixdp2800_defconfig b/arch/arm/configs/ixdp2800_defconfig
index 7ba867f751fd3aec364222e20b06c7739aabe1dd..3cb561a551cb598c5fe13033b7d8dffd4c2f886e 100644
--- a/arch/arm/configs/ixdp2800_defconfig
+++ b/arch/arm/configs/ixdp2800_defconfig
@@ -100,6 +100,7 @@ CONFIG_ARCH_IXDP2800=y
CONFIG_ARCH_IXDP2X00=y
# CONFIG_ARCH_IXDP2401 is not set
# CONFIG_ARCH_IXDP2801 is not set
+# CONFIG_IXP2000_SUPPORT_BROKEN_PCI_IO is not set
#
# Processor Type
diff --git a/arch/arm/configs/ixdp2801_defconfig b/arch/arm/configs/ixdp2801_defconfig
index c4df0ec34b085722e7d4fc935ac2e737cdd6d242..b1e162f29cb9490b64b59c0cd04d6973369e9c52 100644
--- a/arch/arm/configs/ixdp2801_defconfig
+++ b/arch/arm/configs/ixdp2801_defconfig
@@ -100,6 +100,7 @@ CONFIG_ARCH_SUPPORTS_BIG_ENDIAN=y
# CONFIG_ARCH_IXDP2401 is not set
CONFIG_ARCH_IXDP2801=y
CONFIG_ARCH_IXDP2X01=y
+# CONFIG_IXP2000_SUPPORT_BROKEN_PCI_IO is not set
#
# Processor Type
diff --git a/arch/arm/mach-ixp2000/Kconfig b/arch/arm/mach-ixp2000/Kconfig
index 9361e05f6fa39e5519608c6e13fd806bbffd250c..ecb58d83478e32e511a77937328cfd79ef5f290a 100644
--- a/arch/arm/mach-ixp2000/Kconfig
+++ b/arch/arm/mach-ixp2000/Kconfig
@@ -54,6 +54,14 @@ config ARCH_IXDP2X01
depends on ARCH_IXDP2401 || ARCH_IXDP2801
default y
+config IXP2000_SUPPORT_BROKEN_PCI_IO
+ bool "Support broken PCI I/O on older IXP2000s"
+ default y
+ help
+ Say 'N' here if you only intend to run your kernel on an
+ IXP2000 B0 or later model and do not need the PCI I/O
+ byteswap workaround. Say 'Y' otherwise.
+
endmenu
endif
diff --git a/arch/arm/mach-ixp2000/pci.c b/arch/arm/mach-ixp2000/pci.c
index 5ff2f2718c58c0762cfca0f3173cc74f80f09794..0788fb2b5c10e6ae6e2023649930205cc3afb016 100644
--- a/arch/arm/mach-ixp2000/pci.c
+++ b/arch/arm/mach-ixp2000/pci.c
@@ -198,6 +198,19 @@ clear_master_aborts(void)
void __init
ixp2000_pci_preinit(void)
{
+#ifndef CONFIG_IXP2000_SUPPORT_BROKEN_PCI_IO
+ /*
+ * Configure the PCI unit to properly byteswap I/O transactions,
+ * and verify that it worked.
+ */
+ ixp2000_reg_write(IXP2000_PCI_CONTROL,
+ (*IXP2000_PCI_CONTROL | PCI_CONTROL_IEE));
+
+ if ((*IXP2000_PCI_CONTROL & PCI_CONTROL_IEE) == 0)
+ panic("IXP2000: PCI I/O is broken on this ixp model, and "
+ "the needed workaround has not been configured in");
+#endif
+
hook_fault_code(16+6, ixp2000_pci_abort_handler, SIGBUS,
"PCI config cycle to non-existent device");
}
diff --git a/include/asm-arm/arch-ixp2000/io.h b/include/asm-arm/arch-ixp2000/io.h
index 5e56b47446e0c4a2ba6e8fe9ea1d7a5dd3ed9e02..3241cd6f0778e0384e188a945a8747f705f68750 100644
--- a/include/asm-arm/arch-ixp2000/io.h
+++ b/include/asm-arm/arch-ixp2000/io.h
@@ -17,16 +17,21 @@
#define IO_SPACE_LIMIT 0xffffffff
#define __mem_pci(a) (a)
-#define ___io(p) ((void __iomem *)((p)+IXP2000_PCI_IO_VIRT_BASE))
/*
- * The IXP2400 before revision B0 asserts byte lanes for PCI I/O
+ * The A? revisions of the IXP2000s assert byte lanes for PCI I/O
* transactions the other way round (MEM transactions don't have this
- * issue), so we need to override the standard functions. B0 and later
- * have a bit that can be set to 1 to get the 'proper' behavior, but
- * since that isn't available on the A? revisions we just keep doing
- * things manually.
+ * issue), so if we want to support those models, we need to override
+ * the standard I/O functions.
+ *
+ * B0 and later have a bit that can be set to 1 to get the proper
+ * behavior for I/O transactions, which then allows us to use the
+ * standard I/O functions. This is what we do if the user does not
+ * explicitly ask for support for pre-B0.
*/
+#ifdef CONFIG_IXP2000_SUPPORT_BROKEN_PCI_IO
+#define ___io(p) ((void __iomem *)((p)+IXP2000_PCI_IO_VIRT_BASE))
+
#define alignb(addr) (void __iomem *)((unsigned long)(addr) ^ 3)
#define alignw(addr) (void __iomem *)((unsigned long)(addr) ^ 2)
@@ -119,6 +124,9 @@
#define ioport_map(port, nr) ___io(port)
#define ioport_unmap(addr)
+#else
+#define __io(p) ((void __iomem *)((p)+IXP2000_PCI_IO_VIRT_BASE))
+#endif
#ifdef CONFIG_ARCH_IXDP2X01
diff --git a/include/asm-arm/arch-ixp2000/ixp2000-regs.h b/include/asm-arm/arch-ixp2000/ixp2000-regs.h
index a1d9e181b10f1c1d579cf4b3fa4d30db1a39b9a5..5eb47d4bfbf63e2ca1e555e75603d97fc8b634d6 100644
--- a/include/asm-arm/arch-ixp2000/ixp2000-regs.h
+++ b/include/asm-arm/arch-ixp2000/ixp2000-regs.h
@@ -241,7 +241,7 @@
#define PCI_CONTROL_BE_DEI (1 << 21) /* Big Endian Data Enable In */
#define PCI_CONTROL_BE_BEO (1 << 20) /* Big Endian Byte Enable Out */
#define PCI_CONTROL_BE_BEI (1 << 19) /* Big Endian Byte Enable In */
-#define PCI_CONTROL_PNR (1 << 17) /* PCI Not Reset bit */
+#define PCI_CONTROL_IEE (1 << 17) /* I/O cycle Endian swap Enable */
#define IXP2000_PCI_RST_REL (1 << 2)
#define CFG_RST_DIR (*IXP2000_PCI_CONTROL & IXP2000_PCICNTL_PCF)