[SCSI] scsi_transport_sas: make minimum and maximum linkrate settable quantities

According to SPEC, the minimum_linkrate and maximum_linkrate should be
settable by the user.  This patch introduces a callback that allows the
sas class to pass these settings on to the driver.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

2 files changed, 73 insertions, 6 deletions

diff --git a/drivers/scsi/scsi_transport_sas.c b/drivers/scsi/scsi_transport_sas.c
index d518c1207fb4..b5b0c2cba96b 100644
--- a/drivers/scsi/scsi_transport_sas.c
+++ b/drivers/scsi/scsi_transport_sas.c
@@ -77,6 +77,24 @@ get_sas_##title##_names(u32 table_key, char *buf)		\
         return len;                                             \
 }
 
+#define sas_bitfield_name_set(title, table)                     \
+static ssize_t                                                  \
+set_sas_##title##_names(u32 *table_key, const char *buf)        \
+{                                                               \
+        ssize_t len = 0;                                        \
+        int i;                                                  \
+                                                                \
+        for (i = 0; i < ARRAY_SIZE(table); i++) {               \
+                len = strlen(table[i].name);                    \
+                if (strncmp(buf, table[i].name, len) == 0 &&    \
+                    (buf[len] == '\n' || buf[len] == '\0')) {   \
+                        *table_key = table[i].value;            \
+                        return 0;                               \
+                }                                               \
+        }                                                       \
+        return -EINVAL;                                         \
+}
+
 #define sas_bitfield_name_search(title, table)                  \
 static ssize_t                                                  \
 get_sas_##title##_names(u32 table_key, char *buf)               \
@@ -131,7 +149,7 @@ static struct {
         { SAS_LINK_RATE_6_0_GBPS,       "6.0 Gbit" },
 };
 sas_bitfield_name_search(linkspeed, sas_linkspeed_names)
-
+sas_bitfield_name_set(linkspeed, sas_linkspeed_names)
 
 /*
  * SAS host attributes
@@ -253,10 +271,39 @@ show_sas_phy_##field(struct class_device *cdev, char *buf)		\
         return get_sas_linkspeed_names(phy->field, buf);                \
 }
 
+/* Fudge to tell if we're minimum or maximum */
+#define sas_phy_store_linkspeed(field)                                  \
+static ssize_t                                                          \
+store_sas_phy_##field(struct class_device *cdev, const char *buf,       \
+                      size_t count)                                     \
+{                                                                       \
+        struct sas_phy *phy = transport_class_to_phy(cdev);             \
+        struct Scsi_Host *shost = dev_to_shost(phy->dev.parent);        \
+        struct sas_internal *i = to_sas_internal(shost->transportt);    \
+        u32 value;                                                      \
+        struct sas_phy_linkrates rates = {0};                           \
+        int error;                                                      \
+                                                                        \
+        error = set_sas_linkspeed_names(&value, buf);                   \
+        if (error)                                                      \
+                return error;                                           \
+        rates.field = value;                                            \
+        error = i->f->set_phy_speed(phy, &rates);                       \
+                                                                        \
+        return error ? error : count;                                   \
+}
+
+#define sas_phy_linkspeed_rw_attr(field)                                \
+        sas_phy_show_linkspeed(field)                                   \
+        sas_phy_store_linkspeed(field)                                  \
+static CLASS_DEVICE_ATTR(field, S_IRUGO, show_sas_phy_##field,          \
+        store_sas_phy_##field)
+
 #define sas_phy_linkspeed_attr(field)                                   \
         sas_phy_show_linkspeed(field)                                   \
 static CLASS_DEVICE_ATTR(field, S_IRUGO, show_sas_phy_##field, NULL)
 
+
 #define sas_phy_show_linkerror(field)                                   \
 static ssize_t                                                          \
 show_sas_phy_##field(struct class_device *cdev, char *buf)              \
@@ -326,9 +373,9 @@ sas_phy_simple_attr(identify.phy_identifier, phy_identifier, "%d\n", u8);
 //sas_phy_simple_attr(port_identifier, port_identifier, "%d\n", int);
 sas_phy_linkspeed_attr(negotiated_linkrate);
 sas_phy_linkspeed_attr(minimum_linkrate_hw);
-sas_phy_linkspeed_attr(minimum_linkrate);
+sas_phy_linkspeed_rw_attr(minimum_linkrate);
 sas_phy_linkspeed_attr(maximum_linkrate_hw);
-sas_phy_linkspeed_attr(maximum_linkrate);
+sas_phy_linkspeed_rw_attr(maximum_linkrate);
 sas_phy_linkerror_attr(invalid_dword_count);
 sas_phy_linkerror_attr(running_disparity_error_count);
 sas_phy_linkerror_attr(loss_of_dword_sync_count);
@@ -1310,13 +1357,23 @@ static int sas_user_scan(struct Scsi_Host *shost, uint channel,
  * Setup / Teardown code
  */
 
-#define SETUP_TEMPLATE(attrb, field, perm, test)                                \
+#define SETUP_TEMPLATE(attrb, field, perm, test)                        \
         i->private_##attrb[count] = class_device_attr_##field;          \
         i->private_##attrb[count].attr.mode = perm;                     \
         i->attrb[count] = &i->private_##attrb[count];                   \
         if (test)                                                       \
                 count++
 
+#define SETUP_TEMPLATE_RW(attrb, field, perm, test, ro_test, ro_perm)   \
+        i->private_##attrb[count] = class_device_attr_##field;          \
+        i->private_##attrb[count].attr.mode = perm;                     \
+        if (ro_test) {                                                  \
+                i->private_##attrb[count].attr.mode = ro_perm;          \
+                i->private_##attrb[count].store = NULL;                 \
+        }                                                               \
+        i->attrb[count] = &i->private_##attrb[count];                   \
+        if (test)                                                       \
+                count++
 
 #define SETUP_RPORT_ATTRIBUTE(field)                                    \
         SETUP_TEMPLATE(rphy_attrs, field, S_IRUGO, 1)
@@ -1327,6 +1384,10 @@ static int sas_user_scan(struct Scsi_Host *shost, uint channel,
 #define SETUP_PHY_ATTRIBUTE(field)                                      \
         SETUP_TEMPLATE(phy_attrs, field, S_IRUGO, 1)
 
+#define SETUP_PHY_ATTRIBUTE_RW(field)                                   \
+        SETUP_TEMPLATE_RW(phy_attrs, field, S_IRUGO | S_IWUSR, 1,       \
+                        !i->f->set_phy_speed, S_IRUGO)
+
 #define SETUP_PORT_ATTRIBUTE(field)                                     \
         SETUP_TEMPLATE(port_attrs, field, S_IRUGO, 1)
 
@@ -1407,9 +1468,9 @@ sas_attach_transport(struct sas_function_template *ft)
         //SETUP_PHY_ATTRIBUTE(port_identifier);
         SETUP_PHY_ATTRIBUTE(negotiated_linkrate);
         SETUP_PHY_ATTRIBUTE(minimum_linkrate_hw);
-        SETUP_PHY_ATTRIBUTE(minimum_linkrate);
+        SETUP_PHY_ATTRIBUTE_RW(minimum_linkrate);
         SETUP_PHY_ATTRIBUTE(maximum_linkrate_hw);
-        SETUP_PHY_ATTRIBUTE(maximum_linkrate);
+        SETUP_PHY_ATTRIBUTE_RW(maximum_linkrate);
 
         SETUP_PHY_ATTRIBUTE(invalid_dword_count);
         SETUP_PHY_ATTRIBUTE(running_disparity_error_count);
diff --git a/include/scsi/scsi_transport_sas.h b/include/scsi/scsi_transport_sas.h
index 87de518960c1..53024377f3b8 100644
--- a/include/scsi/scsi_transport_sas.h
+++ b/include/scsi/scsi_transport_sas.h
@@ -150,12 +150,18 @@ struct sas_port {
 #define transport_class_to_sas_port(cdev) \
         dev_to_sas_port((cdev)->dev)
 
+struct sas_phy_linkrates {
+        enum sas_linkrate maximum_linkrate;
+        enum sas_linkrate minimum_linkrate;
+};
+
 /* The functions by which the transport class and the driver communicate */
 struct sas_function_template {
         int (*get_linkerrors)(struct sas_phy *);
         int (*get_enclosure_identifier)(struct sas_rphy *, u64 *);
         int (*get_bay_identifier)(struct sas_rphy *);
         int (*phy_reset)(struct sas_phy *, int);
+        int (*set_phy_speed)(struct sas_phy *, struct sas_phy_linkrates *);
 };