[PATCH v4 4/6] PCI: brcmstb: Do not turn off regulators if EP can wake up

[Jim Quinlan]

If any downstream device may wake up during S2/S3 suspend, we do not want
to turn off its power when suspending.

Signed-off-by: Jim Quinlan <jim2101...@gmail.com>
---
 drivers/pci/controller/pcie-brcmstb.c | 58 +++++++++++++++++++++++----
 1 file changed, 51 insertions(+), 7 deletions(-)

diff --git a/drivers/pci/controller/pcie-brcmstb.c 
b/drivers/pci/controller/pcie-brcmstb.c
index 1b0de0c7da60..4c79aff66de7 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -193,6 +193,7 @@ static inline void 
brcm_pcie_bridge_sw_init_set_generic(struct brcm_pcie *pcie,
 static inline void brcm_pcie_perst_set_4908(struct brcm_pcie *pcie, u32 val);
 static inline void brcm_pcie_perst_set_7278(struct brcm_pcie *pcie, u32 val);
 static inline void brcm_pcie_perst_set_generic(struct brcm_pcie *pcie, u32 
val);
+static bool brcm_pcie_link_up(struct brcm_pcie *pcie);
 
 static const char * const supplies[] = {
        "vpcie12v-supply",
@@ -304,22 +305,65 @@ struct brcm_pcie {
        void                    (*bridge_sw_init_set)(struct brcm_pcie *pcie, 
u32 val);
        struct regulator_bulk_data supplies[PCIE_BRCM_MAX_EP_REGULATORS];
        unsigned int            num_supplies;
+       bool                    ep_wakeup_capable;
 };
 
-static int brcm_set_regulators(struct brcm_pcie *pcie, bool on)
+static int pci_dev_may_wakeup(struct pci_dev *dev, void *data)
 {
+       bool *ret = data;
+
+       if (device_may_wakeup(&dev->dev)) {
+               *ret = true;
+               dev_dbg(&dev->dev, "disable cancelled for wake-up device\n");
+       }
+       return (int) *ret;
+}
+
+enum {
+       TURN_OFF,               /* Turn regulators off, unless an EP is 
wakeup-capable */
+       TURN_OFF_ALWAYS,        /* Turn regulators off, no exceptions */
+       TURN_ON,                /* Turn regulators on, unless 
pcie->ep_wakeup_capable */
+};
+
+static int brcm_set_regulators(struct brcm_pcie *pcie, int how)
+{
+       struct pci_host_bridge *bridge = pci_host_bridge_from_priv(pcie);
        struct device *dev = pcie->dev;
        int ret;
 
        if (!pcie->num_supplies)
                return 0;
-       if (on)
+       if (how == TURN_ON) {
+               if (pcie->ep_wakeup_capable) {
+                       /*
+                        * We are resuming from a suspend.  In the
+                        * previous suspend we did not disable the power
+                        * supplies, so there is no need to enable them
+                        * (and falsely increase their usage count).
+                        */
+                       pcie->ep_wakeup_capable = false;
+                       return 0;
+               }
+       } else if (how == TURN_OFF) {
+               /*
+                * If at least one device on this bus is enabled as a
+                * wake-up source, do not turn off regulators.
+                */
+               pcie->ep_wakeup_capable = false;
+               if (bridge->bus && brcm_pcie_link_up(pcie)) {
+                       pci_walk_bus(bridge->bus, pci_dev_may_wakeup, 
&pcie->ep_wakeup_capable);
+                       if (pcie->ep_wakeup_capable)
+                               return 0;
+               }
+       }
+
+       if (how == TURN_ON)
                ret = regulator_bulk_enable(pcie->num_supplies, pcie->supplies);
        else
                ret = regulator_bulk_disable(pcie->num_supplies, 
pcie->supplies);
        if (ret)
                dev_err(dev, "failed to %s EP regulators\n",
-                       on ? "enable" : "disable");
+                       how == TURN_ON ? "enable" : "disable");
        return ret;
 }
 
@@ -1206,7 +1250,7 @@ static int brcm_pcie_suspend(struct device *dev)
        brcm_phy_stop(pcie);
        clk_disable_unprepare(pcie->clk);
 
-       return brcm_set_regulators(pcie, false);
+       return brcm_set_regulators(pcie, TURN_OFF);
 }
 
 static int brcm_pcie_resume(struct device *dev)
@@ -1221,7 +1265,7 @@ static int brcm_pcie_resume(struct device *dev)
        if (ret)
                return ret;
 
-       ret = brcm_set_regulators(pcie, true);
+       ret = brcm_set_regulators(pcie, TURN_ON);
        if (ret)
                return ret;
 
@@ -1261,7 +1305,7 @@ static void __brcm_pcie_remove(struct brcm_pcie *pcie)
        brcm_phy_stop(pcie);
        reset_control_assert(pcie->rescal);
        clk_disable_unprepare(pcie->clk);
-       brcm_set_regulators(pcie, false);
+       brcm_set_regulators(pcie, TURN_OFF_ALWAYS);
 }
 
 static int brcm_pcie_remove(struct platform_device *pdev)
@@ -1360,7 +1404,7 @@ static int brcm_pcie_probe(struct platform_device *pdev)
                goto fail;
        }
 
-       ret = brcm_set_regulators(pcie, true);
+       ret = brcm_set_regulators(pcie, TURN_ON);
        if (ret)
                goto fail;
 
-- 
2.17.1