From: Oliver Schinagl <oliver@xxxxxxxxxxx>
Allwinner A10 and A20 ARM SoCs have an AHCI sata controller which needs a
special register to be poked before starting the DMA engine.
This register gets reset on an ahci_stop_engine call, so there is no other
place then ahci_start_engine where this poking can be done.
This commit allows drivers to override ahci_start_engine behavior for use by
the Allwinner AHCI driver (and potentially other drivers in the future).
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
drivers/ata/ahci.h | 2 ++
drivers/ata/libahci.c | 6 ++++++
2 files changed, 8 insertions(+)
diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
index 2289efd..8f60f33 100644
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -323,6 +323,8 @@ struct ahci_host_priv {
u32 em_msg_type; /* EM message type */
struct clk *clk; /* Only for platforms supporting clk */
void *plat_data; /* Other platform data */
+ /* Optional ahci_start_engine override */
+ void (*start_engine)(struct ata_port *ap);
};
extern int ahci_ignore_sss;
diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index c482f8c..f6eabbc 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -568,8 +568,14 @@ static int ahci_scr_write(struct ata_link *link, unsigned int sc_reg, u32 val)
void ahci_start_engine(struct ata_port *ap)
{
void __iomem *port_mmio = ahci_port_base(ap);
+ struct ahci_host_priv *hpriv = ap->host->private_data;
u32 tmp;
+ if (hpriv->start_engine) {
+ hpriv->start_engine(ap);
+ return;
+ }
+
/* start DMA */
tmp = readl(port_mmio + PORT_CMD);
tmp |= PORT_CMD_START;
--
1.8.4.2
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