libahci: Allow drivers to override start_engine

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@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index b6a49ce71f6e..1d4efe540604 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -563,6 +563,7 @@ static int ahci_vt8251_hardreset(struct ata_link *link, unsigned int *class,
                                  unsigned long deadline)
 {
         struct ata_port *ap = link->ap;
+        struct ahci_host_priv *hpriv = ap->host->private_data;
         bool online;
         int rc;
 
@@ -573,7 +574,7 @@ static int ahci_vt8251_hardreset(struct ata_link *link, unsigned int *class,
         rc = sata_link_hardreset(link, sata_ehc_deb_timing(&link->eh_context),
                                  deadline, &online, NULL);
 
-        ahci_start_engine(ap);
+        hpriv->start_engine(ap);
 
         DPRINTK("EXIT, rc=%d, class=%u\n", rc, *class);
 
@@ -588,6 +589,7 @@ static int ahci_p5wdh_hardreset(struct ata_link *link, unsigned int *class,
 {
         struct ata_port *ap = link->ap;
         struct ahci_port_priv *pp = ap->private_data;
+        struct ahci_host_priv *hpriv = ap->host->private_data;
         u8 *d2h_fis = pp->rx_fis + RX_FIS_D2H_REG;
         struct ata_taskfile tf;
         bool online;
@@ -603,7 +605,7 @@ static int ahci_p5wdh_hardreset(struct ata_link *link, unsigned int *class,
         rc = sata_link_hardreset(link, sata_ehc_deb_timing(&link->eh_context),
                                  deadline, &online, NULL);
 
-        ahci_start_engine(ap);
+        hpriv->start_engine(ap);
 
         /* The pseudo configuration device on SIMG4726 attached to
          * ASUS P5W-DH Deluxe doesn't send signature FIS after