2 files changed, 44 insertions, 0 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 13dcef809e5c..3fd7c7932707 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -240,6 +240,49 @@ int ata_rwcmd_protocol(struct ata_queued_cmd *qc)
 }
 
 /**
+ *      ata_tf_read_block - Read block address from ATA taskfile
+ *      @tf: ATA taskfile of interest
+ *      @dev: ATA device @tf belongs to
+ *
+ *      LOCKING:
+ *      None.
+ *
+ *      Read block address from @tf.  This function can handle all
+ *      three address formats - LBA, LBA48 and CHS.  tf->protocol and
+ *      flags select the address format to use.
+ *
+ *      RETURNS:
+ *      Block address read from @tf.
+ */
+u64 ata_tf_read_block(struct ata_taskfile *tf, struct ata_device *dev)
+{
+        u64 block = 0;
+
+        if (tf->flags & ATA_TFLAG_LBA) {
+                if (tf->flags & ATA_TFLAG_LBA48) {
+                        block |= (u64)tf->hob_lbah << 40;
+                        block |= (u64)tf->hob_lbam << 32;
+                        block |= tf->hob_lbal << 24;
+                } else
+                        block |= (tf->device & 0xf) << 24;
+
+                block |= tf->lbah << 16;
+                block |= tf->lbam << 8;
+                block |= tf->lbal;
+        } else {
+                u32 cyl, head, sect;
+
+                cyl = tf->lbam | (tf->lbah << 8);
+                head = tf->device & 0xf;
+                sect = tf->lbal;
+
+                block = (cyl * dev->heads + head) * dev->sectors + sect;
+        }
+
+        return block;
+}
+
+/**
  *      ata_pack_xfermask - Pack pio, mwdma and udma masks into xfer_mask
  *      @pio_mask: pio_mask
  *      @mwdma_mask: mwdma_mask
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index be2ac39f013b..2d532da8c398 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -52,6 +52,7 @@ extern int atapi_dmadir;
 extern int libata_fua;
 extern struct ata_queued_cmd *ata_qc_new_init(struct ata_device *dev);
 extern int ata_rwcmd_protocol(struct ata_queued_cmd *qc);
+extern u64 ata_tf_read_block(struct ata_taskfile *tf, struct ata_device *dev);
 extern void ata_dev_disable(struct ata_device *dev);
 extern void ata_port_flush_task(struct ata_port *ap);
 extern unsigned ata_exec_internal(struct ata_device *dev,