From: Oliver Schinagl <oli...@schinagl.nl>

The Allwinner sunxi platforms have patched in the following to enable
DMA. This patch enables DMA controllers for the SUNXI Architecture.

Signed-off-by: Olliver Schinagl <oli...@schinagl.nl>
---
 drivers/ata/ahci.h    | 6 ++++++
 drivers/ata/libahci.c | 8 ++++++++
 2 files changed, 14 insertions(+)

diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
index 2289efdf..2bf2423 100644
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -138,6 +138,7 @@ enum {
        PORT_SCR_NTF            = 0x3c, /* SATA phy register: SNotification */
        PORT_FBS                = 0x40, /* FIS-based Switching */
        PORT_DEVSLP             = 0x44, /* device sleep */
+       PORT_DMA                = 0x70, /* direct memory access */
 
        /* PORT_IRQ_{STAT,MASK} bits */
        PORT_IRQ_COLD_PRES      = (1 << 31), /* cold presence detect */
@@ -209,6 +210,11 @@ enum {
        PORT_DEVSLP_DSP         = (1 << 1),       /* DevSlp present */
        PORT_DEVSLP_ADSE        = (1 << 0),       /* Aggressive DevSlp enable */
 
+       /* PORT_DMA bits */
+       PORT_DMA_SETUP_OFFSET   = 8, /* dma setup offset */
+       PORT_DMA_SETUP_MASK     = (0xff << PORT_DMA_SETUP_OFFSET),/* dma mask */
+       PORT_DMA_SETUP_INIT     = (0x44 << 0),
+
        /* hpriv->flags bits */
 
 #define AHCI_HFLAGS(flags)             .private_data   = (void *)(flags)
diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index c482f8c..d697a74 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -570,6 +570,14 @@ void ahci_start_engine(struct ata_port *ap)
        void __iomem *port_mmio = ahci_port_base(ap);
        u32 tmp;
 
+#ifdef CONFIG_ARCH_SUNXI
+       /* Setup DMA before DMA start */
+       tmp = readl(port_mmio + PORT_DMA);
+       tmp &= ~PORT_DMA_SETUP_MASK;
+       tmp |= PORT_DMA_SETUP_INIT << PORT_DMA_SETUP_OFFSET;
+       writel(tmp, port_mmio + PORT_DMA);
+#endif
+
        /* start DMA */
        tmp = readl(port_mmio + PORT_CMD);
        tmp |= PORT_CMD_START;
-- 
1.8.3.2

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