This patch expands the definition of link power management to
include the notion of simply powering the entire port off.
We add a new valid value for link_power_management_policy:
power_off: phy is not on at all.
min_power: driver uses minimum possible power. hotplug
may or may not be available.
medium_power: best power/performance tradeoff. hotplug
may or may not be available
max_performance: max performance without regard to power
hot plug is available.
Additionally - this patch modifies the libata-core to
power off the port automatically at init time if the
driver marks the port as not hotpluggable.
The user may not power off a port if it is occupied.
If the port is powered off, and a new drive is plugged
in, the drive will not be detected until the port is
powered back up by setting the link_power_management_policy
to "max_performance".
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@xxxxxxxxx>
---
drivers/ata/libata-core.c | 58 +++++++++++++++++++++++++++++++++++++++++++++-
drivers/ata/libata-scsi.c | 1
include/linux/libata.h | 2 +
3 files changed, 60 insertions(+), 1 deletion(-)
Index: linux-ahci-phy/drivers/ata/libata-core.c
===================================================================
--- linux-ahci-phy.orig/drivers/ata/libata-core.c 2008-06-27 13:32:51.000000000 -0700
+++ linux-ahci-phy/drivers/ata/libata-core.c 2008-07-01 16:33:00.000000000 -0700
@@ -162,6 +162,19 @@ MODULE_DESCRIPTION("Library module for A
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);
+static void ata_phy_offline(struct ata_link *link)
+{
+ u32 scontrol;
+ int rc;
+
+ /* set DET to 4 */
+ rc = sata_scr_read(link, SCR_CONTROL, &scontrol);
+ if (rc)
+ return;
+ scontrol &= ~0xf;
+ scontrol |= (1 << 2);
+ sata_scr_write(link, SCR_CONTROL, scontrol);
+}
/**
* ata_force_cbl - force cable type according to libata.force
@@ -953,6 +966,7 @@ static int ata_dev_set_dipm(struct ata_d
* disallow all transitions which effectively
* disable DIPM anyway.
*/
+ default:
break;
}
@@ -980,6 +994,22 @@ void ata_dev_enable_pm(struct ata_device
int rc = 0;
struct ata_port *ap = dev->link->ap;
+ /*
+ * if we don't have a device attached, all we can
+ * do is power off
+ */
+ if (!ata_dev_enabled(dev) && policy == POWER_OFF) {
+ ap->flags |= ATA_FLAG_NO_HOTPLUG;
+ ata_phy_offline(&ap->link);
+ goto enable_pm_out;
+ }
+
+ /*
+ * if there's no device attached, we are done
+ */
+ if (!ata_dev_enabled(dev))
+ return;
+
/* set HIPM first, then DIPM */
if (ap->ops->enable_pm)
rc = ap->ops->enable_pm(ap, policy);
@@ -1020,10 +1050,24 @@ static void ata_dev_disable_pm(struct at
void ata_lpm_schedule(struct ata_port *ap, enum link_pm policy)
{
- ap->pm_policy = policy;
ap->link.eh_info.action |= ATA_EH_LPM;
+
+ /*
+ * if we are coming from a state of OFF to ON, we need
+ * to reset the link and scan for devices in case someone
+ * plugged something in while we were off.
+ * Clear the NO_HOTPLUG flag because we are leaving the
+ * phy on now.
+ */
+ if (ap->pm_policy == POWER_OFF && policy != POWER_OFF) {
+ ap->flags &= ~ATA_FLAG_NO_HOTPLUG;
+ ap->link.eh_info.probe_mask |= ATA_ALL_DEVICES;
+ ap->link.eh_info.flags |= ATA_EH_RESET;
+ }
ap->link.eh_info.flags |= ATA_EHI_NO_AUTOPSY;
+ ap->pm_policy = policy;
ata_port_schedule_eh(ap);
+ ata_port_wait_eh(ap);
}
#ifdef CONFIG_PM
@@ -2678,6 +2722,7 @@ void ata_port_disable(struct ata_port *a
ap->link.device[0].class = ATA_DEV_NONE;
ap->link.device[1].class = ATA_DEV_NONE;
ap->flags |= ATA_FLAG_DISABLED;
+ ata_phy_offline(&ap->link);
}
/**
@@ -5614,6 +5659,8 @@ int ata_host_register(struct ata_host *h
if (ap->ops->error_handler) {
struct ata_eh_info *ehi = &ap->link.eh_info;
unsigned long flags;
+ int device_attached = 0;
+ struct ata_device *dev;
ata_port_probe(ap);
@@ -5632,6 +5679,15 @@ int ata_host_register(struct ata_host *h
/* wait for EH to finish */
ata_port_wait_eh(ap);
+ ata_link_for_each_dev(dev, &ap->link)
+ if (ata_dev_enabled(dev))
+ device_attached++;
+ if (!device_attached &&
+ (ap->flags & ATA_FLAG_NO_HOTPLUG)) {
+ /* no device present, disable port */
+ ap->pm_policy = POWER_OFF;
+ ata_port_disable(ap);
+ }
} else {
DPRINTK("ata%u: bus probe begin\n", ap->print_id);
rc = ata_bus_probe(ap);
Index: linux-ahci-phy/include/linux/libata.h
===================================================================
--- linux-ahci-phy.orig/include/linux/libata.h 2008-06-27 13:32:57.000000000 -0700
+++ linux-ahci-phy/include/linux/libata.h 2008-06-27 13:38:11.000000000 -0700
@@ -190,6 +190,7 @@ enum {
ATA_FLAG_AN = (1 << 18), /* controller supports AN */
ATA_FLAG_PMP = (1 << 19), /* controller supports PMP */
ATA_FLAG_IPM = (1 << 20), /* driver can handle IPM */
+ ATA_FLAG_NO_HOTPLUG = (1 << 21), /* port doesn't support HP */
/* The following flag belongs to ap->pflags but is kept in
* ap->flags because it's referenced in many LLDs and will be
@@ -439,6 +440,7 @@ enum link_pm {
MIN_POWER,
MAX_PERFORMANCE,
MEDIUM_POWER,
+ POWER_OFF,
};
extern struct device_attribute dev_attr_link_power_management_policy;
Index: linux-ahci-phy/drivers/ata/libata-scsi.c
===================================================================
--- linux-ahci-phy.orig/drivers/ata/libata-scsi.c 2008-06-27 13:32:51.000000000 -0700
+++ linux-ahci-phy/drivers/ata/libata-scsi.c 2008-06-27 13:38:11.000000000 -0700
@@ -122,6 +122,7 @@ static const struct {
{ MIN_POWER, "min_power" },
{ MAX_PERFORMANCE, "max_performance" },
{ MEDIUM_POWER, "medium_power" },
+ { POWER_OFF, "power_off" },
};
static const char *ata_scsi_lpm_get(enum link_pm policy)
--
--
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