sata: implement reset_sata for dwc_ahsata

Add reset_sata() to the sata driver interface and implement it
for dwc_ahsata. This function cleans up after sata_init(), and
therefore accepts a device number like sata_init() does.
A dummy implementation is provided for the rest of the drivers.

Signed-off-by: Nikita Kiryanov <nikita@compulab.co.il>
Cc: Simon Glass <sjg@chromium.org>
Cc: Stefano Babic <sbabic@denx.de>
diff --git a/drivers/block/ata_piix.c b/drivers/block/ata_piix.c
index 5cf91ad..3042684 100644
--- a/drivers/block/ata_piix.c
+++ b/drivers/block/ata_piix.c
@@ -192,6 +192,11 @@
 	return 0;
 }
 
+int reset_sata(int dev)
+{
+	return 0;
+}
+
 static inline u8 sata_inb(unsigned long ioaddr)
 {
 	return inb(ioaddr);
diff --git a/drivers/block/dwc_ahsata.c b/drivers/block/dwc_ahsata.c
index c68fd2f..9a2b547 100644
--- a/drivers/block/dwc_ahsata.c
+++ b/drivers/block/dwc_ahsata.c
@@ -592,6 +592,27 @@
 	return 0;
 }
 
+int reset_sata(int dev)
+{
+	struct ahci_probe_ent *probe_ent =
+			(struct ahci_probe_ent *)sata_dev_desc[dev].priv;
+	struct sata_host_regs *host_mmio =
+			(struct sata_host_regs *)probe_ent->mmio_base;
+
+	if (dev < 0 || dev > (CONFIG_SYS_SATA_MAX_DEVICE - 1)) {
+		printf("The sata index %d is out of ranges\n\r", dev);
+		return -1;
+	}
+
+	setbits_le32(&host_mmio->ghc, SATA_HOST_GHC_HR);
+	while (readl(&host_mmio->ghc) & SATA_HOST_GHC_HR)
+		udelay(100);
+
+	disable_sata_clock();
+
+	return 0;
+}
+
 static void dwc_ahsata_print_info(int dev)
 {
 	block_dev_desc_t *pdev = &(sata_dev_desc[dev]);
diff --git a/drivers/block/fsl_sata.c b/drivers/block/fsl_sata.c
index ebd6261..71d7cec 100644
--- a/drivers/block/fsl_sata.c
+++ b/drivers/block/fsl_sata.c
@@ -255,6 +255,11 @@
 	return 0;
 }
 
+int reset_sata(int dev)
+{
+	return 0;
+}
+
 static void fsl_sata_dump_regs(fsl_sata_reg_t __iomem *reg)
 {
 	printf("\n\rSATA:           %08x\n\r", (u32)reg);
diff --git a/drivers/block/pata_bfin.c b/drivers/block/pata_bfin.c
index b7fd1cd..c2673bd 100644
--- a/drivers/block/pata_bfin.c
+++ b/drivers/block/pata_bfin.c
@@ -1009,6 +1009,11 @@
 	return res;
 }
 
+int reset_sata(int dev)
+{
+	return 0;
+}
+
 /* Read up to 255 sectors
  *
  * Returns sectors read
diff --git a/drivers/block/sata_dwc.c b/drivers/block/sata_dwc.c
index efca5ea..9e8b067 100644
--- a/drivers/block/sata_dwc.c
+++ b/drivers/block/sata_dwc.c
@@ -423,6 +423,11 @@
 	return rc;
 }
 
+int reset_sata(int dev)
+{
+	return 0;
+}
+
 static u8 ata_check_altstatus(struct ata_port *ap)
 {
 	u8 val = 0;
diff --git a/drivers/block/sata_sil.c b/drivers/block/sata_sil.c
index 1f510cd..ea7d76a 100644
--- a/drivers/block/sata_sil.c
+++ b/drivers/block/sata_sil.c
@@ -571,6 +571,11 @@
 	return 0;
 }
 
+int reset_sata(int dev)
+{
+	return 0;
+}
+
 /*
  * SATA interface between low level driver and command layer
  */
diff --git a/drivers/block/sata_sil3114.c b/drivers/block/sata_sil3114.c
index 3aa6fc9..61ffb66 100644
--- a/drivers/block/sata_sil3114.c
+++ b/drivers/block/sata_sil3114.c
@@ -702,6 +702,11 @@
 	return res;
 }
 
+int reset_sata(int dev)
+{
+	return 0;
+}
+
 /* Check if device is connected to port */
 int sata_bus_probe (int portno)
 {