+/**
+ * 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_build_rw_tf - Build ATA taskfile for given read/write request
+ * @tf: Target ATA taskfile
+ * @dev: ATA device @tf belongs to
+ * @block: Block address
+ * @n_block: Number of blocks
+ * @tf_flags: RW/FUA etc...
+ * @tag: tag
+ *
+ * LOCKING:
+ * None.
+ *
+ * Build ATA taskfile @tf for read/write request described by
+ * @block, @n_block, @tf_flags and @tag on @dev.
+ *
+ * RETURNS:
+ *
+ * 0 on success, -ERANGE if the request is too large for @dev,
+ * -EINVAL if the request is invalid.
+ */
+int ata_build_rw_tf(struct ata_taskfile *tf, struct ata_device *dev,
+ u64 block, u32 n_block, unsigned int tf_flags,
+ unsigned int tag)
+{
+ tf->flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
+ tf->flags |= tf_flags;
+
+ if ((dev->flags & (ATA_DFLAG_PIO | ATA_DFLAG_NCQ_OFF |
+ ATA_DFLAG_NCQ)) == ATA_DFLAG_NCQ &&
+ likely(tag != ATA_TAG_INTERNAL)) {
+ /* yay, NCQ */
+ if (!lba_48_ok(block, n_block))
+ return -ERANGE;
+
+ tf->protocol = ATA_PROT_NCQ;
+ tf->flags |= ATA_TFLAG_LBA | ATA_TFLAG_LBA48;
+
+ if (tf->flags & ATA_TFLAG_WRITE)
+ tf->command = ATA_CMD_FPDMA_WRITE;
+ else
+ tf->command = ATA_CMD_FPDMA_READ;
+
+ tf->nsect = tag << 3;
+ tf->hob_feature = (n_block >> 8) & 0xff;
+ tf->feature = n_block & 0xff;
+
+ tf->hob_lbah = (block >> 40) & 0xff;
+ tf->hob_lbam = (block >> 32) & 0xff;
+ tf->hob_lbal = (block >> 24) & 0xff;
+ tf->lbah = (block >> 16) & 0xff;
+ tf->lbam = (block >> 8) & 0xff;
+ tf->lbal = block & 0xff;
+
+ tf->device = 1 << 6;
+ if (tf->flags & ATA_TFLAG_FUA)
+ tf->device |= 1 << 7;
+ } else if (dev->flags & ATA_DFLAG_LBA) {
+ tf->flags |= ATA_TFLAG_LBA;
+
+ if (lba_28_ok(block, n_block)) {
+ /* use LBA28 */
+ tf->device |= (block >> 24) & 0xf;
+ } else if (lba_48_ok(block, n_block)) {
+ if (!(dev->flags & ATA_DFLAG_LBA48))
+ return -ERANGE;
+
+ /* use LBA48 */
+ tf->flags |= ATA_TFLAG_LBA48;
+
+ tf->hob_nsect = (n_block >> 8) & 0xff;
+
+ tf->hob_lbah = (block >> 40) & 0xff;
+ tf->hob_lbam = (block >> 32) & 0xff;
+ tf->hob_lbal = (block >> 24) & 0xff;
+ } else
+ /* request too large even for LBA48 */
+ return -ERANGE;
+
+ if (unlikely(ata_rwcmd_protocol(tf, dev) < 0))
+ return -EINVAL;
+
+ tf->nsect = n_block & 0xff;
+
+ tf->lbah = (block >> 16) & 0xff;
+ tf->lbam = (block >> 8) & 0xff;
+ tf->lbal = block & 0xff;
+
+ tf->device |= ATA_LBA;
+ } else {
+ /* CHS */
+ u32 sect, head, cyl, track;
+
+ /* The request -may- be too large for CHS addressing. */
+ if (!lba_28_ok(block, n_block))
+ return -ERANGE;
+
+ if (unlikely(ata_rwcmd_protocol(tf, dev) < 0))
+ return -EINVAL;
+
+ /* Convert LBA to CHS */
+ track = (u32)block / dev->sectors;
+ cyl = track / dev->heads;
+ head = track % dev->heads;
+ sect = (u32)block % dev->sectors + 1;
+
+ DPRINTK("block %u track %u cyl %u head %u sect %u\n",
+ (u32)block, track, cyl, head, sect);
+
+ /* Check whether the converted CHS can fit.
+ Cylinder: 0-65535
+ Head: 0-15
+ Sector: 1-255*/
+ if ((cyl >> 16) || (head >> 4) || (sect >> 8) || (!sect))
+ return -ERANGE;
+
+ tf->nsect = n_block & 0xff; /* Sector count 0 means 256 sectors */
+ tf->lbal = sect;
+ tf->lbam = cyl;
+ tf->lbah = cyl >> 8;
+ tf->device |= head;
+ }
+
+ return 0;
+}
+