usb: host: xhci-tegra: Implement basic ELPG support

This implements basic engine-level powergate support which allows the
XUSB controller to be put into a low power mode on system sleep and get
it out of that low power mode again on resume.

Based on work by JC Kuo <jckuo@nvidia.com>.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20191206140653.2085561-11-thierry.reding@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/xhci-tegra.c b/drivers/usb/host/xhci-tegra.c
index 7f6657a..0b58ef3 100644 (file)
--- a/drivers/usb/host/xhci-tegra.c
+++ b/drivers/usb/host/xhci-tegra.c
@@ -1447,6 +1447,45 @@ static int tegra_xusb_remove(struct platform_device *pdev)
 }
 
 #ifdef CONFIG_PM_SLEEP
+static bool xhci_hub_ports_suspended(struct xhci_hub *hub)
+{
+       struct device *dev = hub->hcd->self.controller;
+       bool status = true;
+       unsigned int i;
+       u32 value;
+
+       for (i = 0; i < hub->num_ports; i++) {
+               value = readl(hub->ports[i]->addr);
+               if ((value & PORT_PE) == 0)
+                       continue;
+
+               if ((value & PORT_PLS_MASK) != XDEV_U3) {
+                       dev_info(dev, "%u-%u isn't suspended: %#010x\n",
+                                hub->hcd->self.busnum, i + 1, value);
+                       status = false;
+               }
+       }
+
+       return status;
+}
+
+static int tegra_xusb_check_ports(struct tegra_xusb *tegra)
+{
+       struct xhci_hcd *xhci = hcd_to_xhci(tegra->hcd);
+       unsigned long flags;
+       int err = 0;
+
+       spin_lock_irqsave(&xhci->lock, flags);
+
+       if (!xhci_hub_ports_suspended(&xhci->usb2_rhub) ||
+           !xhci_hub_ports_suspended(&xhci->usb3_rhub))
+               err = -EBUSY;
+
+       spin_unlock_irqrestore(&xhci->lock, flags);
+
+       return err;
+}
+
 static void tegra_xusb_save_context(struct tegra_xusb *tegra)
 {
        const struct tegra_xusb_context_soc *soc = tegra->soc->context;
@@ -1481,31 +1520,103 @@ static void tegra_xusb_restore_context(struct tegra_xusb *tegra)
        }
 }
 
-static int tegra_xusb_suspend(struct device *dev)
+static int tegra_xusb_enter_elpg(struct tegra_xusb *tegra, bool wakeup)
 {
-       struct tegra_xusb *tegra = dev_get_drvdata(dev);
        struct xhci_hcd *xhci = hcd_to_xhci(tegra->hcd);
-       bool wakeup = device_may_wakeup(dev);
        int err;
 
-       /* TODO: Powergate controller across suspend/resume. */
+       err = tegra_xusb_check_ports(tegra);
+       if (err < 0) {
+               dev_err(tegra->dev, "not all ports suspended: %d\n", err);
+               return err;
+       }
+
        err = xhci_suspend(xhci, wakeup);
-       if (err < 0)
+       if (err < 0) {
+               dev_err(tegra->dev, "failed to suspend XHCI: %d\n", err);
                return err;
+       }
 
        tegra_xusb_save_context(tegra);
+       tegra_xusb_phy_disable(tegra);
+       tegra_xusb_clk_disable(tegra);
 
        return 0;
 }
 
-static int tegra_xusb_resume(struct device *dev)
+static int tegra_xusb_exit_elpg(struct tegra_xusb *tegra, bool wakeup)
 {
-       struct tegra_xusb *tegra = dev_get_drvdata(dev);
        struct xhci_hcd *xhci = hcd_to_xhci(tegra->hcd);
+       int err;
 
+       err = tegra_xusb_clk_enable(tegra);
+       if (err < 0) {
+               dev_err(tegra->dev, "failed to enable clocks: %d\n", err);
+               return err;
+       }
+
+       err = tegra_xusb_phy_enable(tegra);
+       if (err < 0) {
+               dev_err(tegra->dev, "failed to enable PHYs: %d\n", err);
+               goto disable_clk;
+       }
+
+       tegra_xusb_config(tegra);
        tegra_xusb_restore_context(tegra);
 
-       return xhci_resume(xhci, false);
+       err = tegra_xusb_load_firmware(tegra);
+       if (err < 0) {
+               dev_err(tegra->dev, "failed to load firmware: %d\n", err);
+               goto disable_phy;
+       }
+
+       err = __tegra_xusb_enable_firmware_messages(tegra);
+       if (err < 0) {
+               dev_err(tegra->dev, "failed to enable messages: %d\n", err);
+               goto disable_phy;
+       }
+
+       err = xhci_resume(xhci, true);
+       if (err < 0) {
+               dev_err(tegra->dev, "failed to resume XHCI: %d\n", err);
+               goto disable_phy;
+       }
+
+       return 0;
+
+disable_phy:
+       tegra_xusb_phy_disable(tegra);
+disable_clk:
+       tegra_xusb_clk_disable(tegra);
+       return err;
+}
+
+static int tegra_xusb_suspend(struct device *dev)
+{
+       struct tegra_xusb *tegra = dev_get_drvdata(dev);
+       bool wakeup = device_may_wakeup(dev);
+       int err;
+
+       synchronize_irq(tegra->mbox_irq);
+
+       mutex_lock(&tegra->lock);
+       err = tegra_xusb_enter_elpg(tegra, wakeup);
+       mutex_unlock(&tegra->lock);
+
+       return err;
+}
+
+static int tegra_xusb_resume(struct device *dev)
+{
+       struct tegra_xusb *tegra = dev_get_drvdata(dev);
+       bool wakeup = device_may_wakeup(dev);
+       int err;
+
+       mutex_lock(&tegra->lock);
+       err = tegra_xusb_exit_elpg(tegra, wakeup);
+       mutex_unlock(&tegra->lock);
+
+       return err;
 }
 #endif