Re: [PATCH 1/3] RFC: AHCI: libahci is missing DMA

From: Sergei Shtylyov
Date: Wed Dec 04 2013 - 07:47:34 EST


Hello.

On 04-12-2013 16:10, oliver@xxxxxxxxxxx wrote:

From: Oliver Schinagl <oliver@xxxxxxxxxxx>

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 <oliver@xxxxxxxxxxx>
---
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
[...]
@@ -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),

Why not shift it right by PORT_DMA_SETUP_OFFSET if you do it in the next file anyway?

[...]
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
+

I don't think #ifdef is appropriate here.

WBR, Sergei

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