libata-link: introduce ata_link

Introduce ata_link.  It abstracts PHY and sits between ata_port and
ata_device.  This new level of abstraction is necessary to support
SATA Port Multiplier, which basically adds a bunch of links (PHYs) to
a ATA host port.  Fields related to command execution, spd_limit and
EH are per-link and thus moved to ata_link.

This patch only defines the host link.  Multiple link handling will be
added later.  Also, a lot of ap->link derefences are added but many of
them will be removed as each part is converted to deal directly with
ata_link instead of ata_port.

This patch introduces no behavior change.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: James Bottomley <James.Bottomley@SteelEye.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 25 insertions, 15 deletions

diff --git a/include/linux/libata.h b/include/linux/libata.h
index a67bb9075e9b..ca4493125fa0 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -436,7 +436,7 @@ struct ata_ering {
 };
 
 struct ata_device {
-        struct ata_port         *ap;
+        struct ata_link         *link;
         unsigned int            devno;          /* 0 or 1 */
         unsigned long           flags;          /* ATA_DFLAG_xxx */
         unsigned int            horkage;        /* List of broken features */
@@ -510,6 +510,24 @@ struct ata_acpi_gtm {
         u32 flags;
 } __packed;
 
+struct ata_link {
+        struct ata_port         *ap;
+
+        unsigned int            active_tag;     /* active tag on this link */
+        u32                     sactive;        /* active NCQ commands */
+
+        unsigned int            hw_sata_spd_limit;
+        unsigned int            sata_spd_limit;
+        unsigned int            sata_spd;       /* current SATA PHY speed */
+
+        /* record runtime error info, protected by host_set lock */
+        struct ata_eh_info      eh_info;
+        /* EH context */
+        struct ata_eh_context   eh_context;
+
+        struct ata_device       device[ATA_MAX_DEVICES];
+};
+
 struct ata_port {
         struct Scsi_Host        *scsi_host; /* our co-allocated scsi host */
         const struct ata_port_operations *ops;
@@ -533,23 +551,12 @@ struct ata_port {
         unsigned int            mwdma_mask;
         unsigned int            udma_mask;
         unsigned int            cbl;    /* cable type; ATA_CBL_xxx */
-        unsigned int            hw_sata_spd_limit;
-        unsigned int            sata_spd_limit; /* SATA PHY speed limit */
-        unsigned int            sata_spd;       /* current SATA PHY speed */
-
-        /* record runtime error info, protected by host lock */
-        struct ata_eh_info      eh_info;
-        /* EH context owned by EH */
-        struct ata_eh_context   eh_context;
-
-        struct ata_device       device[ATA_MAX_DEVICES];
 
         struct ata_queued_cmd   qcmd[ATA_MAX_QUEUE];
         unsigned long           qc_allocated;
         unsigned int            qc_active;
 
-        unsigned int            active_tag;
-        u32                     sactive;
+        struct ata_link         link;   /* host default link */
 
         struct ata_port_stats   stats;
         struct ata_host         *host;
@@ -912,8 +919,11 @@ extern void ata_do_eh(struct ata_port *ap, ata_prereset_fn_t prereset,
 #define ata_port_printk(ap, lv, fmt, args...) \
         printk(lv"ata%u: "fmt, (ap)->print_id , ##args)
 
+#define ata_link_printk(link, lv, fmt, args...) \
+        printk(lv"ata%u: "fmt, (link)->ap->print_id , ##args)
+
 #define ata_dev_printk(dev, lv, fmt, args...) \
-        printk(lv"ata%u.%02u: "fmt, (dev)->ap->print_id, (dev)->devno , ##args)
+        printk(lv"ata%u.%02u: "fmt, (dev)->link->ap->print_id, (dev)->devno , ##args)
 
 /*
  * ata_eh_info helpers
@@ -1149,7 +1159,7 @@ static inline void ata_tf_init(struct ata_device *dev, struct ata_taskfile *tf)
 {
         memset(tf, 0, sizeof(*tf));
 
-        tf->ctl = dev->ap->ctl;
+        tf->ctl = dev->link->ap->ctl;
         if (dev->devno == 0)
                 tf->device = ATA_DEVICE_OBS;
         else