MIPS: ath25: use generic dma noncoherent ops

Provide phys_to_dma/dma_to_phys helpers only if PCI support is
enabled, everything else is generic.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Patchwork: https://patchwork.linux-mips.org/patch/19547/
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Tom Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Huacai Chen <chenhc@lemote.com>
Cc: iommu@lists.linux-foundation.org
Cc: linux-mips@linux-mips.org

1 files changed, 24 insertions, 0 deletions

diff --git a/arch/mips/pci/pci-ar2315.c b/arch/mips/pci/pci-ar2315.c
index b4fa6413c4e5..c539d0d2b0cf 100644
--- a/arch/mips/pci/pci-ar2315.c
+++ b/arch/mips/pci/pci-ar2315.c
@@ -149,6 +149,13 @@
 #define AR2315_PCI_HOST_SLOT	3
 #define AR2315_PCI_HOST_DEVID	((0xff18 << 16) | PCI_VENDOR_ID_ATHEROS)
 
+/*
+ * We need some arbitrary non-zero value to be programmed to the BAR1 register
+ * of PCI host controller to enable DMA. The same value should be used as the
+ * offset to calculate the physical address of DMA buffer for PCI devices.
+ */
+#define AR2315_PCI_HOST_SDRAM_BASEADDR	0x20000000
+
 /* ??? access BAR */
 #define AR2315_PCI_HOST_MBAR0		0x10000000
 /* RAM access BAR */
@@ -167,6 +174,23 @@ struct ar2315_pci_ctrl {
 	struct resource io_res;
 };
 
+static inline dma_addr_t ar2315_dev_offset(struct device *dev)
+{
+	if (dev && dev_is_pci(dev))
+		return AR2315_PCI_HOST_SDRAM_BASEADDR;
+	return 0;
+}
+
+dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
+{
+	return paddr + ar2315_dev_offset(dev);
+}
+
+phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t dma_addr)
+{
+	return dma_addr - ar2315_dev_offset(dev);
+}
+
 static inline struct ar2315_pci_ctrl *ar2315_pci_bus_to_apc(struct pci_bus *bus)
 {
 	struct pci_controller *hose = bus->sysdata;