1 files changed, 109 insertions, 0 deletions

diff --git a/drivers/ata/libata-sata.c b/drivers/ata/libata-sata.c
index 04f1ecaf414c..1ef4c19864ac 100644
--- a/drivers/ata/libata-sata.c
+++ b/drivers/ata/libata-sata.c
@@ -13,6 +13,115 @@
 #include "libata.h"
 
 /**
+ *	sata_scr_valid - test whether SCRs are accessible
+ *	@link: ATA link to test SCR accessibility for
+ *
+ *	Test whether SCRs are accessible for @link.
+ *
+ *	LOCKING:
+ *	None.
+ *
+ *	RETURNS:
+ *	1 if SCRs are accessible, 0 otherwise.
+ */
+int sata_scr_valid(struct ata_link *link)
+{
+	struct ata_port *ap = link->ap;
+
+	return (ap->flags & ATA_FLAG_SATA) && ap->ops->scr_read;
+}
+EXPORT_SYMBOL_GPL(sata_scr_valid);
+
+/**
+ *	sata_scr_read - read SCR register of the specified port
+ *	@link: ATA link to read SCR for
+ *	@reg: SCR to read
+ *	@val: Place to store read value
+ *
+ *	Read SCR register @reg of @link into *@val.  This function is
+ *	guaranteed to succeed if @link is ap->link, the cable type of
+ *	the port is SATA and the port implements ->scr_read.
+ *
+ *	LOCKING:
+ *	None if @link is ap->link.  Kernel thread context otherwise.
+ *
+ *	RETURNS:
+ *	0 on success, negative errno on failure.
+ */
+int sata_scr_read(struct ata_link *link, int reg, u32 *val)
+{
+	if (ata_is_host_link(link)) {
+		if (sata_scr_valid(link))
+			return link->ap->ops->scr_read(link, reg, val);
+		return -EOPNOTSUPP;
+	}
+
+	return sata_pmp_scr_read(link, reg, val);
+}
+EXPORT_SYMBOL_GPL(sata_scr_read);
+
+/**
+ *	sata_scr_write - write SCR register of the specified port
+ *	@link: ATA link to write SCR for
+ *	@reg: SCR to write
+ *	@val: value to write
+ *
+ *	Write @val to SCR register @reg of @link.  This function is
+ *	guaranteed to succeed if @link is ap->link, the cable type of
+ *	the port is SATA and the port implements ->scr_read.
+ *
+ *	LOCKING:
+ *	None if @link is ap->link.  Kernel thread context otherwise.
+ *
+ *	RETURNS:
+ *	0 on success, negative errno on failure.
+ */
+int sata_scr_write(struct ata_link *link, int reg, u32 val)
+{
+	if (ata_is_host_link(link)) {
+		if (sata_scr_valid(link))
+			return link->ap->ops->scr_write(link, reg, val);
+		return -EOPNOTSUPP;
+	}
+
+	return sata_pmp_scr_write(link, reg, val);
+}
+EXPORT_SYMBOL_GPL(sata_scr_write);
+
+/**
+ *	sata_scr_write_flush - write SCR register of the specified port and flush
+ *	@link: ATA link to write SCR for
+ *	@reg: SCR to write
+ *	@val: value to write
+ *
+ *	This function is identical to sata_scr_write() except that this
+ *	function performs flush after writing to the register.
+ *
+ *	LOCKING:
+ *	None if @link is ap->link.  Kernel thread context otherwise.
+ *
+ *	RETURNS:
+ *	0 on success, negative errno on failure.
+ */
+int sata_scr_write_flush(struct ata_link *link, int reg, u32 val)
+{
+	if (ata_is_host_link(link)) {
+		int rc;
+
+		if (sata_scr_valid(link)) {
+			rc = link->ap->ops->scr_write(link, reg, val);
+			if (rc == 0)
+				rc = link->ap->ops->scr_read(link, reg, &val);
+			return rc;
+		}
+		return -EOPNOTSUPP;
+	}
+
+	return sata_pmp_scr_write(link, reg, val);
+}
+EXPORT_SYMBOL_GPL(sata_scr_write_flush);
+
+/**
  *	ata_tf_to_fis - Convert ATA taskfile to SATA FIS structure
  *	@tf: Taskfile to convert
  *	@pmp: Port multiplier port