ahci: Add functions to manage runtime PM of AHCI ports
Add new functions ahci_rpm_get_port()/ahci_rpm_put_port() that change
runtime PM status of AHCI ports. Depending if the AHCI host has runtime PM
enabled or disabled calling these may trigger runtime suspend/resume of the
host controller.
We also call these functions in appropriate places to make sure host
controller registers are available before using them.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index 8cdf0af..2d21b46 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -225,6 +225,31 @@
WARN_ON(1);
}
+/**
+ * ahci_rpm_get_port - Make sure the port is powered on
+ * @ap: Port to power on
+ *
+ * Whenever there is need to access the AHCI host registers outside of
+ * normal execution paths, call this function to make sure the host is
+ * actually powered on.
+ */
+static int ahci_rpm_get_port(struct ata_port *ap)
+{
+ return pm_runtime_get_sync(ap->dev);
+}
+
+/**
+ * ahci_rpm_put_port - Undoes ahci_rpm_get_port()
+ * @ap: Port to power down
+ *
+ * Undoes ahci_rpm_get_port() and possibly powers down the AHCI host
+ * if it has no more active users.
+ */
+static void ahci_rpm_put_port(struct ata_port *ap)
+{
+ pm_runtime_put(ap->dev);
+}
+
static ssize_t ahci_show_host_caps(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -261,8 +286,13 @@
struct Scsi_Host *shost = class_to_shost(dev);
struct ata_port *ap = ata_shost_to_port(shost);
void __iomem *port_mmio = ahci_port_base(ap);
+ ssize_t ret;
- return sprintf(buf, "%x\n", readl(port_mmio + PORT_CMD));
+ ahci_rpm_get_port(ap);
+ ret = sprintf(buf, "%x\n", readl(port_mmio + PORT_CMD));
+ ahci_rpm_put_port(ap);
+
+ return ret;
}
static ssize_t ahci_read_em_buffer(struct device *dev,
@@ -278,17 +308,20 @@
size_t count;
int i;
+ ahci_rpm_get_port(ap);
spin_lock_irqsave(ap->lock, flags);
em_ctl = readl(mmio + HOST_EM_CTL);
if (!(ap->flags & ATA_FLAG_EM) || em_ctl & EM_CTL_XMT ||
!(hpriv->em_msg_type & EM_MSG_TYPE_SGPIO)) {
spin_unlock_irqrestore(ap->lock, flags);
+ ahci_rpm_put_port(ap);
return -EINVAL;
}
if (!(em_ctl & EM_CTL_MR)) {
spin_unlock_irqrestore(ap->lock, flags);
+ ahci_rpm_put_port(ap);
return -EAGAIN;
}
@@ -316,6 +349,7 @@
}
spin_unlock_irqrestore(ap->lock, flags);
+ ahci_rpm_put_port(ap);
return i;
}
@@ -340,11 +374,13 @@
size % 4 || size > hpriv->em_buf_sz)
return -EINVAL;
+ ahci_rpm_get_port(ap);
spin_lock_irqsave(ap->lock, flags);
em_ctl = readl(mmio + HOST_EM_CTL);
if (em_ctl & EM_CTL_TM) {
spin_unlock_irqrestore(ap->lock, flags);
+ ahci_rpm_put_port(ap);
return -EBUSY;
}
@@ -357,6 +393,7 @@
writel(em_ctl | EM_CTL_TM, mmio + HOST_EM_CTL);
spin_unlock_irqrestore(ap->lock, flags);
+ ahci_rpm_put_port(ap);
return size;
}
@@ -370,7 +407,9 @@
void __iomem *mmio = hpriv->mmio;
u32 em_ctl;
+ ahci_rpm_get_port(ap);
em_ctl = readl(mmio + HOST_EM_CTL);
+ ahci_rpm_put_port(ap);
return sprintf(buf, "%s%s%s%s\n",
em_ctl & EM_CTL_LED ? "led " : "",
@@ -1014,6 +1053,7 @@
else
return -EINVAL;
+ ahci_rpm_get_port(ap);
spin_lock_irqsave(ap->lock, flags);
/*
@@ -1023,6 +1063,7 @@
em_ctl = readl(mmio + HOST_EM_CTL);
if (em_ctl & EM_CTL_TM) {
spin_unlock_irqrestore(ap->lock, flags);
+ ahci_rpm_put_port(ap);
return -EBUSY;
}
@@ -1050,6 +1091,8 @@
emp->led_state = state;
spin_unlock_irqrestore(ap->lock, flags);
+ ahci_rpm_put_port(ap);
+
return size;
}
@@ -2216,6 +2259,8 @@
int ahci_port_resume(struct ata_port *ap)
{
+ ahci_rpm_get_port(ap);
+
ahci_power_up(ap);
ahci_start_port(ap);
@@ -2242,6 +2287,7 @@
ata_port_freeze(ap);
}
+ ahci_rpm_put_port(ap);
return rc;
}
#endif