1 files changed, 24 insertions, 3 deletions

diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index d61740e78d6d..402967902cbe 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -496,8 +496,8 @@ void ahci_save_initial_config(struct device *dev, struct ahci_host_priv *hpriv)
                 }
         }
 
-        /* fabricate port_map from cap.nr_ports */
-        if (!port_map) {
+        /* fabricate port_map from cap.nr_ports for < AHCI 1.3 */
+        if (!port_map && vers < 0x10300) {
                 port_map = (1 << ahci_nr_ports(cap)) - 1;
                 dev_warn(dev, "forcing PORTS_IMPL to 0x%x\n", port_map);
 
@@ -593,8 +593,22 @@ EXPORT_SYMBOL_GPL(ahci_start_engine);
 int ahci_stop_engine(struct ata_port *ap)
 {
         void __iomem *port_mmio = ahci_port_base(ap);
+        struct ahci_host_priv *hpriv = ap->host->private_data;
         u32 tmp;
 
+        /*
+         * On some controllers, stopping a port's DMA engine while the port
+         * is in ALPM state (partial or slumber) results in failures on
+         * subsequent DMA engine starts.  For those controllers, put the
+         * port back in active state before stopping its DMA engine.
+         */
+        if ((hpriv->flags & AHCI_HFLAG_WAKE_BEFORE_STOP) &&
+            (ap->link.lpm_policy > ATA_LPM_MAX_POWER) &&
+            ahci_set_lpm(&ap->link, ATA_LPM_MAX_POWER, ATA_LPM_WAKE_ONLY)) {
+                dev_err(ap->host->dev, "Failed to wake up port before engine stop\n");
+                return -EIO;
+        }
+
         tmp = readl(port_mmio + PORT_CMD);
 
         /* check if the HBA is idle */
@@ -689,6 +703,9 @@ static int ahci_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
         void __iomem *port_mmio = ahci_port_base(ap);
 
         if (policy != ATA_LPM_MAX_POWER) {
+                /* wakeup flag only applies to the max power policy */
+                hints &= ~ATA_LPM_WAKE_ONLY;
+
                 /*
                  * Disable interrupts on Phy Ready. This keeps us from
                  * getting woken up due to spurious phy ready
@@ -704,7 +721,8 @@ static int ahci_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
                 u32 cmd = readl(port_mmio + PORT_CMD);
 
                 if (policy == ATA_LPM_MAX_POWER || !(hints & ATA_LPM_HIPM)) {
-                        cmd &= ~(PORT_CMD_ASP | PORT_CMD_ALPE);
+                        if (!(hints & ATA_LPM_WAKE_ONLY))
+                                cmd &= ~(PORT_CMD_ASP | PORT_CMD_ALPE);
                         cmd |= PORT_CMD_ICC_ACTIVE;
 
                         writel(cmd, port_mmio + PORT_CMD);
@@ -712,6 +730,9 @@ static int ahci_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
 
                         /* wait 10ms to be sure we've come out of LPM state */
                         ata_msleep(ap, 10);
+
+                        if (hints & ATA_LPM_WAKE_ONLY)
+                                return 0;
                 } else {
                         cmd |= PORT_CMD_ALPE;
                         if (policy == ATA_LPM_MIN_POWER)