libata: Add the AHCI_HFLAG_YES_ALPM flag

Some hardware is capable of supporting Aggresive Link Power Management
even though it is not indicated by the Host Capability register.

This commit adds the AHCI_HFLAG_YES_ALPM flag to the AHCI library to
allow indication of this quirk when the Host Capability register is
Read Only and therefore cannot be changed.

Signed-off-by: Doug Berger <opendmb@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

2 files changed, 6 insertions, 0 deletions

diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
index 30f67a1a4f54..ee176e4af97a 100644
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -248,6 +248,7 @@ enum {
         AHCI_HFLAG_MULTI_MSI            = 0,
 #endif
         AHCI_HFLAG_WAKE_BEFORE_STOP     = (1 << 22), /* wake before DMA stop */
+        AHCI_HFLAG_YES_ALPM             = (1 << 23), /* force ALPM cap on */
 
         /* ap->flags bits */
 
diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index b3a685ad9b87..4462f8a8cf2c 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -504,6 +504,11 @@ void ahci_save_initial_config(struct device *dev, struct ahci_host_priv *hpriv)
                 cap &= ~HOST_CAP_FBS;
         }
 
+        if (!(cap & HOST_CAP_ALPM) && (hpriv->flags & AHCI_HFLAG_YES_ALPM)) {
+                dev_info(dev, "controller can do ALPM, turning on CAP_ALPM\n");
+                cap |= HOST_CAP_ALPM;
+        }
+
         if (hpriv->force_port_map && port_map != hpriv->force_port_map) {
                 dev_info(dev, "forcing port_map 0x%x -> 0x%x\n",
                          port_map, hpriv->force_port_map);