[PATCH] libata-ncq: implement NCQ device configuration

Now that all NCQ related stuff are in place, implement NCQ device
configuration and bump ATA_MAX_QUEUE to 32 thus activating NCQ
support.

Original implementation is from Jens Axboe.

Signed-off-by: Tejun Heo <htejun@gmail.com>

1 files changed, 29 insertions, 2 deletions

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 14ffb5264b6..9051b6821c1 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -1251,6 +1251,28 @@ static inline u8 ata_dev_knobble(struct ata_device *dev)
         return ((dev->ap->cbl == ATA_CBL_SATA) && (!ata_id_is_sata(dev->id)));
 }
 
+static void ata_dev_config_ncq(struct ata_device *dev,
+                               char *desc, size_t desc_sz)
+{
+        struct ata_port *ap = dev->ap;
+        int hdepth = 0, ddepth = ata_id_queue_depth(dev->id);
+
+        if (!ata_id_has_ncq(dev->id)) {
+                desc[0] = '\0';
+                return;
+        }
+
+        if (ap->flags & ATA_FLAG_NCQ) {
+                hdepth = min(ap->host->can_queue, ATA_MAX_QUEUE - 1);
+                dev->flags |= ATA_DFLAG_NCQ;
+        }
+
+        if (hdepth >= ddepth)
+                snprintf(desc, desc_sz, "NCQ (depth %d)", ddepth);
+        else
+                snprintf(desc, desc_sz, "NCQ (depth %d/%d)", hdepth, ddepth);
+}
+
 /**
  *      ata_dev_configure - Configure the specified ATA/ATAPI device
  *      @dev: Target device to configure
@@ -1311,6 +1333,7 @@ static int ata_dev_configure(struct ata_device *dev, int print_info)
 
                 if (ata_id_has_lba(id)) {
                         const char *lba_desc;
+                        char ncq_desc[20];
 
                         lba_desc = "LBA";
                         dev->flags |= ATA_DFLAG_LBA;
@@ -1319,14 +1342,17 @@ static int ata_dev_configure(struct ata_device *dev, int print_info)
                                 lba_desc = "LBA48";
                         }
 
+                        /* config NCQ */
+                        ata_dev_config_ncq(dev, ncq_desc, sizeof(ncq_desc));
+
                         /* print device info to dmesg */
                         if (print_info)
                                 ata_dev_printk(dev, KERN_INFO, "ATA-%d, "
-                                        "max %s, %Lu sectors: %s\n",
+                                        "max %s, %Lu sectors: %s %s\n",
                                         ata_id_major_version(id),
                                         ata_mode_string(xfer_mask),
                                         (unsigned long long)dev->n_sectors,
-                                        lba_desc);
+                                        lba_desc, ncq_desc);
                 } else {
                         /* CHS */
 
@@ -5675,6 +5701,7 @@ EXPORT_SYMBOL_GPL(ata_port_queue_task);
 EXPORT_SYMBOL_GPL(ata_scsi_ioctl);
 EXPORT_SYMBOL_GPL(ata_scsi_queuecmd);
 EXPORT_SYMBOL_GPL(ata_scsi_slave_config);
+EXPORT_SYMBOL_GPL(ata_scsi_change_queue_depth);
 EXPORT_SYMBOL_GPL(ata_scsi_release);
 EXPORT_SYMBOL_GPL(ata_host_intr);
 EXPORT_SYMBOL_GPL(sata_scr_valid);