[SCSI] SAS transport class

The SAS transport class contains common code to deal with SAS HBAs, an
aproximated representation of SAS topologies in the driver model,
and various sysfs attributes to expose these topologies and managment
interfaces to userspace.

In addition to the basic SCSI core objects this transport class introduces
two additional intermediate objects:  The SAS PHY as represented by struct
sas_phy defines an "outgoing" PHY on a SAS HBA or Expander, and the SAS
remote PHY represented by struct sas_rphy defines an "incoming" PHY on a
SAS Expander or end device.  Note that this is purely a software concept, the
underlying hardware for a PHY and a remote PHY is the exactly the same.

There is no concept of a SAS port in this code, users can see what PHYs
form a wide port based on the port_identifier attribute, which is the same
for all PHYs in a port.

This submission doesn't handle hot-plug addition or removal of SAS devices
and thus doesn't do scanning in a workqueue yet, that will be added in
phase2 after this submission.  In a third phase I will add additional
managment infrastructure.

I think this submission is ready for 2.6.14, but additional comments are
of course very welcome.

I'd like to thanks James Smart a lot for his very useful input on the
design.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 100 insertions, 0 deletions

diff --git a/include/scsi/scsi_transport_sas.h b/include/scsi/scsi_transport_sas.h
new file mode 100644
index 000000000000..bc4aeb660dd3
--- /dev/null
+++ b/include/scsi/scsi_transport_sas.h
@@ -0,0 +1,100 @@
+#ifndef SCSI_TRANSPORT_SAS_H
+#define SCSI_TRANSPORT_SAS_H
+
+#include <linux/transport_class.h>
+#include <linux/types.h>
+
+struct scsi_transport_template;
+struct sas_rphy;
+
+
+enum sas_device_type {
+        SAS_PHY_UNUSED,
+        SAS_END_DEVICE,
+        SAS_EDGE_EXPANDER_DEVICE,
+        SAS_FANOUT_EXPANDER_DEVICE,
+};
+
+enum sas_protocol {
+        SAS_PROTOCOL_SATA               = 0x01,
+        SAS_PROTOCOL_SMP                = 0x02,
+        SAS_PROTOCOL_STP                = 0x04,
+        SAS_PROTOCOL_SSP                = 0x08,
+};
+
+enum sas_linkrate {
+        SAS_LINK_RATE_UNKNOWN,
+        SAS_PHY_DISABLED,
+        SAS_LINK_RATE_FAILED,
+        SAS_SATA_SPINUP_HOLD,
+        SAS_SATA_PORT_SELECTOR,
+        SAS_LINK_RATE_1_5_GBPS,
+        SAS_LINK_RATE_3_0_GBPS,
+        SAS_LINK_VIRTUAL,
+};
+
+struct sas_identify {
+        enum sas_device_type    device_type;
+        enum sas_protocol       initiator_port_protocols;
+        enum sas_protocol       target_port_protocols;
+        u64                     sas_address;
+        u8                      phy_identifier;
+};
+
+/* The functions by which the transport class and the driver communicate */
+struct sas_function_template {
+};
+
+struct sas_phy {
+        struct device           dev;
+        int                     number;
+        struct sas_identify     identify;
+        enum sas_linkrate       negotiated_linkrate;
+        enum sas_linkrate       minimum_linkrate_hw;
+        enum sas_linkrate       minimum_linkrate;
+        enum sas_linkrate       maximum_linkrate_hw;
+        enum sas_linkrate       maximum_linkrate;
+        u8                      port_identifier;
+        struct sas_rphy         *rphy;
+};
+
+#define dev_to_phy(d) \
+        container_of((d), struct sas_phy, dev)
+#define transport_class_to_phy(cdev) \
+        dev_to_phy((cdev)->dev)
+#define phy_to_shost(phy) \
+        dev_to_shost((phy)->dev.parent)
+
+struct sas_rphy {
+        struct device           dev;
+        struct sas_identify     identify;
+        struct list_head        list;
+        u32                     scsi_target_id;
+};
+
+#define dev_to_rphy(d) \
+        container_of((d), struct sas_rphy, dev)
+#define transport_class_to_rphy(cdev) \
+        dev_to_rphy((cdev)->dev)
+#define rphy_to_shost(rphy) \
+        dev_to_shost((rphy)->dev.parent)
+
+extern void sas_remove_host(struct Scsi_Host *);
+
+extern struct sas_phy *sas_phy_alloc(struct device *, int);
+extern void sas_phy_free(struct sas_phy *);
+extern int sas_phy_add(struct sas_phy *);
+extern void sas_phy_delete(struct sas_phy *);
+extern int scsi_is_sas_phy(const struct device *);
+
+extern struct sas_rphy *sas_rphy_alloc(struct sas_phy *);
+void sas_rphy_free(struct sas_rphy *);
+extern int sas_rphy_add(struct sas_rphy *);
+extern void sas_rphy_delete(struct sas_rphy *);
+extern int scsi_is_sas_rphy(const struct device *);
+
+extern struct scsi_transport_template *
+sas_attach_transport(struct sas_function_template *);
+extern void sas_release_transport(struct scsi_transport_template *);
+
+#endif /* SCSI_TRANSPORT_SAS_H */