PCI ASPM: introduce disable flag

Introduce 'aspm_disable' flag to manage disabled ASPM state more
robust way.

Acked-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 24 insertions, 17 deletions

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 0800c5146826..8f7884a8bc2e 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -43,6 +43,7 @@ struct pcie_link_state {
         u32 aspm_support:2;             /* Supported ASPM state */
         u32 aspm_enabled:2;             /* Enabled ASPM state */
         u32 aspm_default:2;             /* Default ASPM state by BIOS */
+        u32 aspm_disable:2;             /* Disabled ASPM state */
 
         /* Clock PM state */
         u32 clkpm_capable:1;            /* Clock PM capable? */
@@ -322,10 +323,9 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
         struct pci_bus *linkbus = parent->subordinate;
 
         if (blacklist) {
-                /* Set support state to 0, so we will disable ASPM later */
-                link->aspm_support = 0;
-                link->aspm_default = 0;
+                /* Set enabled/disable so that we will disable ASPM later */
                 link->aspm_enabled = PCIE_LINK_STATE_L0S | PCIE_LINK_STATE_L1;
+                link->aspm_disable = PCIE_LINK_STATE_L0S | PCIE_LINK_STATE_L1;
                 return;
         }
 
@@ -348,6 +348,17 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
 
         /* Save default state */
         link->aspm_default = link->aspm_enabled;
+        /*
+         * If the downstream component has pci bridge function, don't
+         * do ASPM for now.
+         */
+        list_for_each_entry(child, &linkbus->devices, bus_list) {
+                if (child->pcie_type == PCI_EXP_TYPE_PCI_BRIDGE) {
+                        link->aspm_disable =
+                                PCIE_LINK_STATE_L0S | PCIE_LINK_STATE_L1;
+                        break;
+                }
+        }
 
         if (!link->aspm_support)
                 return;
@@ -458,14 +469,10 @@ static void __pcie_aspm_config_link(struct pcie_link_state *link, u32 state)
         struct pci_dev *child, *parent = link->pdev;
         struct pci_bus *linkbus = parent->subordinate;
 
-        /*
-         * If the downstream component has pci bridge function, don't
-         * do ASPM now.
-         */
-        list_for_each_entry(child, &linkbus->devices, bus_list) {
-                if (child->pcie_type == PCI_EXP_TYPE_PCI_BRIDGE)
-                        return;
-        }
+        state &= ~link->aspm_disable;
+        /* Nothing to do if the link is already in the requested state */
+        if (link->aspm_enabled == state)
+                return;
         /*
          * Spec 2.0 suggests all functions should be configured the
          * same setting for ASPM. Enabling ASPM L1 should be done in
@@ -719,7 +726,7 @@ void pcie_aspm_pm_state_change(struct pci_dev *pdev)
 void pci_disable_link_state(struct pci_dev *pdev, int state)
 {
         struct pci_dev *parent = pdev->bus->self;
-        struct pcie_link_state *link_state;
+        struct pcie_link_state *link;
 
         if (aspm_disabled || !pdev->is_pcie)
                 return;
@@ -731,12 +738,12 @@ void pci_disable_link_state(struct pci_dev *pdev, int state)
 
         down_read(&pci_bus_sem);
         mutex_lock(&aspm_lock);
-        link_state = parent->link_state;
-        link_state->aspm_support &= ~state;
-        __pcie_aspm_configure_link_state(link_state, link_state->aspm_enabled);
+        link = parent->link_state;
+        link->aspm_disable |= state;
+        __pcie_aspm_configure_link_state(link, link->aspm_enabled);
         if (state & PCIE_LINK_STATE_CLKPM) {
-                link_state->clkpm_capable = 0;
-                pcie_set_clkpm(link_state, 0);
+                link->clkpm_capable = 0;
+                pcie_set_clkpm(link, 0);
         }
         mutex_unlock(&aspm_lock);
         up_read(&pci_bus_sem);