ahci: imx: setup power saving methods

In order to save power consumption as much as possible.

* Disable sata phy internal pll reference clock when sysetem enter
  into suspend mode, enable it after resume.

* Setup module parameter used to enable imx ahci test power down
  mode(PDDQ) or not, when there is no device detected on the port

* minor modifications:
  - The format of the copyright is changed, because that the original
    one can't pass fsl internal patch reivew without the character
    '(c)'.
  - Exports ahci_platform_ops and ahci_error_handler().

NOTE:
* The hot-plug can't be supported when PDDQ mode is ever enabled.

* module parameter usage how-to:
  - default: enable PDDQ mode when no device detected.
  - add "ahci-imx.hotplug=1" into kernel command line if your don't
    want to enable PDDQ mode when no device detected on the port.

tj: Slightly updated description and comments.

Signed-off-by: Richard Zhu <r65037@freescale.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index b67086fde1f1..7e2a1b38093e 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -89,7 +89,6 @@ static int ahci_pmp_retry_softreset(struct ata_link *link, unsigned int *class,
 static int ahci_hardreset(struct ata_link *link, unsigned int *class,
                           unsigned long deadline);
 static void ahci_postreset(struct ata_link *link, unsigned int *class);
-static void ahci_error_handler(struct ata_port *ap);
 static void ahci_post_internal_cmd(struct ata_queued_cmd *qc);
 static void ahci_dev_config(struct ata_device *dev);
 #ifdef CONFIG_PM
@@ -1982,7 +1981,7 @@ static void ahci_thaw(struct ata_port *ap)
         writel(pp->intr_mask, port_mmio + PORT_IRQ_MASK);
 }
 
-static void ahci_error_handler(struct ata_port *ap)
+void ahci_error_handler(struct ata_port *ap)
 {
         if (!(ap->pflags & ATA_PFLAG_FROZEN)) {
                 /* restart engine */
@@ -1995,6 +1994,7 @@ static void ahci_error_handler(struct ata_port *ap)
         if (!ata_dev_enabled(ap->link.device))
                 ahci_stop_engine(ap);
 }
+EXPORT_SYMBOL_GPL(ahci_error_handler);
 
 static void ahci_post_internal_cmd(struct ata_queued_cmd *qc)
 {