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authorLennert Buytenhek <buytenh@wantstofly.org>2006-04-02 00:07:39 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2006-04-02 00:07:39 +0100
commit23759dc6430428897a36c4d493f611eca55c9481 (patch)
treec62050927599b36ed223753c35fd737e3c0c6762 /arch/arm/mach-ixp23xx/pci.c
parentd3f4c571b6e596f9d39c596426269006a309d3b8 (diff)
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[ARM] 3439/2: xsc3: add I/O coherency support
Patch from Lennert Buytenhek This patch adds support for the I/O coherent cache available on the xsc3. The approach is to provide a simple API to determine whether the chipset supports coherency by calling arch_is_coherent() and then setting the appropriate system memory PTE and PMD bits. In addition, we call this API on dma_alloc_coherent() and dma_map_single() calls. A generic version exists that will compile out all the coherency-related code that is not needed on the majority of ARM systems. Note that we do not check for coherency in the dma_alloc_writecombine() function as that still requires a special PTE setting. We also don't touch dma_mmap_coherent() as that is a special ARM-only API that is by definition only used on non-coherent system. Signed-off-by: Deepak Saxena <dsaxena@plexity.net> Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/mach-ixp23xx/pci.c')
-rw-r--r--arch/arm/mach-ixp23xx/pci.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/arm/mach-ixp23xx/pci.c b/arch/arm/mach-ixp23xx/pci.c
index ba6b4367a1d..ac72f94c5b4 100644
--- a/arch/arm/mach-ixp23xx/pci.c
+++ b/arch/arm/mach-ixp23xx/pci.c
@@ -219,6 +219,12 @@ static void __init ixp23xx_pci_common_init(void)
*IXP23XX_PCI_CPP_ADDR_BITS &= ~(1 << 1);
} else {
*IXP23XX_PCI_CPP_ADDR_BITS |= (1 << 1);
+
+ /*
+ * Enable coherency on A2 silicon.
+ */
+ if (arch_is_coherent())
+ *IXP23XX_CPP2XSI_CURR_XFER_REG3 &= ~IXP23XX_CPP2XSI_COH_OFF;
}
}