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authorLennert Buytenhek <buytenh@wantstofly.org>2005-09-15 13:00:25 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2005-09-15 13:00:25 +0100
commit917afce1000d978dfd3f07da5da9d864bc49c77e (patch)
treefd8487f4cf64dc5be9559820a1f4c3e6c759aad2 /include
parentfea2efe3bba15f0aa8f840fbe052699808187cb6 (diff)
downloadop-kernel-dev-917afce1000d978dfd3f07da5da9d864bc49c77e.zip
op-kernel-dev-917afce1000d978dfd3f07da5da9d864bc49c77e.tar.gz
[ARM] 2911/1: ixp2000_reg_{read,write} accessors
Patch from Lennert Buytenhek This patch: - changes the ixp2000_reg_write accessor to take a 'volatile void *' instead of a 'volatile unsigned long *', which then allows passing in a u32 * as first argument without being greeted with a warning; and - adds an ixp2000_reg_read accessor. We can then use these accessors in ixp2000 code to access on-chip peripherals, instead of directly dereferencing pointers. This is for use by the ixp2000 microengine driver which was recently announced on netdev. We can't use readl/writel on the ixp2000 since it is usually run in big-endian mode, and on big-endian platforms, readl/writel perform byteswapping. A future patch will remove the readback from ixp2000_reg_write, since it's not needed to prevent erratum #66, and add manual readbacks to the places that need them (writes are not synchronous since we map in device space using XCB=101 nowadays), such as interrupt disabling and GPIO manipulation. See also: http://lists.arm.linux.org.uk/pipermail/linux-arm-kernel/2005-February/027084.html Patch has been ACKed by Jeff Garzik. Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'include')
-rw-r--r--include/asm-arm/arch-ixp2000/platform.h14
1 files changed, 9 insertions, 5 deletions
diff --git a/include/asm-arm/arch-ixp2000/platform.h b/include/asm-arm/arch-ixp2000/platform.h
index c0caf3e..6519498 100644
--- a/include/asm-arm/arch-ixp2000/platform.h
+++ b/include/asm-arm/arch-ixp2000/platform.h
@@ -31,20 +31,24 @@
#include <asm/system.h> /* Pickup local_irq_ functions */
-static inline void ixp2000_reg_write(volatile unsigned long *reg, unsigned long val)
+static inline void ixp2000_reg_write(volatile void *reg, unsigned long val)
{
- volatile unsigned long dummy;
+ unsigned long dummy;
unsigned long flags;
local_irq_save(flags);
- *reg = val;
+ *((volatile unsigned long *)reg) = val;
barrier();
- dummy = *reg;
+ dummy = *((volatile unsigned long *)reg);
local_irq_restore(flags);
}
#else
-#define ixp2000_reg_write(reg, val) (*reg = val)
+static inline void ixp2000_reg_write(volatile void *reg, unsigned long val)
+{
+ *((volatile unsigned long *)reg) = val;
+}
#endif /* IXDP2400 || IXDP2401 */
+#define ixp2000_reg_read(reg) (*((volatile unsigned long *)reg))
/*
* Boards may multiplex different devices on the 2nd channel of
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