[SCSI] libsas: Add a sysfs knob to enable/disable a phy
This patch lets a user arbitrarily enable or disable a phy via sysfs.
Potential applications include shutting down a phy to replace one
lane of wide port, and (more importantly) providing a method for the
libata SATL to control the phy.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/scsi/scsi_transport_sas.c b/drivers/scsi/scsi_transport_sas.c
index 5c0b75b..9e38c18 100644
--- a/drivers/scsi/scsi_transport_sas.c
+++ b/drivers/scsi/scsi_transport_sas.c
@@ -336,6 +336,51 @@
}
static CLASS_DEVICE_ATTR(device_type, S_IRUGO, show_sas_device_type, NULL);
+static ssize_t do_sas_phy_enable(struct class_device *cdev,
+ size_t count, int enable)
+{
+ 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);
+ int error;
+
+ error = i->f->phy_enable(phy, enable);
+ if (error)
+ return error;
+ phy->enabled = enable;
+ return count;
+};
+
+static ssize_t store_sas_phy_enable(struct class_device *cdev,
+ const char *buf, size_t count)
+{
+ if (count < 1)
+ return -EINVAL;
+
+ switch (buf[0]) {
+ case '0':
+ do_sas_phy_enable(cdev, count, 0);
+ break;
+ case '1':
+ do_sas_phy_enable(cdev, count, 1);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return count;
+}
+
+static ssize_t show_sas_phy_enable(struct class_device *cdev, char *buf)
+{
+ struct sas_phy *phy = transport_class_to_phy(cdev);
+
+ return snprintf(buf, 20, "%d", phy->enabled);
+}
+
+static CLASS_DEVICE_ATTR(enable, S_IRUGO | S_IWUSR, show_sas_phy_enable,
+ store_sas_phy_enable);
+
static ssize_t do_sas_phy_reset(struct class_device *cdev,
size_t count, int hard_reset)
{
@@ -435,6 +480,7 @@
return NULL;
phy->number = number;
+ phy->enabled = 1;
device_initialize(&phy->dev);
phy->dev.parent = get_device(parent);
@@ -1389,6 +1435,10 @@
SETUP_TEMPLATE_RW(phy_attrs, field, S_IRUGO | S_IWUSR, 1, \
!i->f->set_phy_speed, S_IRUGO)
+#define SETUP_OPTIONAL_PHY_ATTRIBUTE_RW(field, func) \
+ SETUP_TEMPLATE_RW(phy_attrs, field, S_IRUGO | S_IWUSR, 1, \
+ !i->f->func, S_IRUGO)
+
#define SETUP_PORT_ATTRIBUTE(field) \
SETUP_TEMPLATE(port_attrs, field, S_IRUGO, 1)
@@ -1479,6 +1529,7 @@
SETUP_PHY_ATTRIBUTE(phy_reset_problem_count);
SETUP_OPTIONAL_PHY_ATTRIBUTE_WRONLY(link_reset, phy_reset);
SETUP_OPTIONAL_PHY_ATTRIBUTE_WRONLY(hard_reset, phy_reset);
+ SETUP_OPTIONAL_PHY_ATTRIBUTE_RW(enable, phy_enable);
i->phy_attrs[count] = NULL;
count = 0;
