linux-kernel - [PATCH v8 6/8] PCI/portdrv: Do not turn off subdev regulators if EP can wake up

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Message-Id: <20211110221456.11977-7-jim2101024@gmail.com>
Date:   Wed, 10 Nov 2021 17:14:46 -0500
From:   Jim Quinlan <jim2101024@...il.com>
To:     linux-pci@...r.kernel.org, Bjorn Helgaas <bhelgaas@...gle.com>,
        Nicolas Saenz Julienne <nsaenz@...nel.org>,
        Rob Herring <robh@...nel.org>, Mark Brown <broonie@...nel.org>,
        bcm-kernel-feedback-list@...adcom.com, jim2101024@...il.com,
        james.quinlan@...adcom.com
Cc:     Sean V Kelley <sean.v.kelley@...el.com>,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>,
        Qiuxu Zhuo <qiuxu.zhuo@...el.com>,
        Keith Busch <kbusch@...nel.org>,
        linux-kernel@...r.kernel.org (open list)
Subject: [PATCH v8 6/8] PCI/portdrv: Do not turn off subdev regulators if EP can wake up

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 <jim2101024@...il.com>
---
 drivers/pci/pci.h              |  1 +
 drivers/pci/pcie/portdrv_pci.c | 43 +++++++++++++++++++++++++++++-----
 2 files changed, 38 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 3f6cf75b91cc..27abb977d0ec 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -746,6 +746,7 @@ extern const struct attribute_group aspm_ctrl_attr_group;
 extern const struct attribute_group pci_dev_reset_method_attr_group;
 
 struct subdev_regulators {
+	bool ep_wakeup_capable;
 	unsigned int num_supplies;
 	struct regulator_bulk_data supplies[];
 };
diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c
index 9330cfbebdc1..717e816d0fc8 100644
--- a/drivers/pci/pcie/portdrv_pci.c
+++ b/drivers/pci/pcie/portdrv_pci.c
@@ -111,24 +111,55 @@ bool pcie_is_port_dev(struct pci_dev *dev)
 }
 EXPORT_SYMBOL_GPL(pcie_is_port_dev);
 
+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;
+}
+
 static int subdev_regulator_resume(struct pci_dev *dev)
 {
 	struct subdev_regulators *sr = dev->dev.driver_data;
 
-	if (sr)
-		return regulator_bulk_enable(sr->num_supplies, sr->supplies);
+	if (!sr)
+		return 0;
 
-	return 0;
+	if (sr->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).
+		 */
+		sr->ep_wakeup_capable = false;
+		return 0;
+	}
+
+	return regulator_bulk_enable(sr->num_supplies, sr->supplies);
 }
 
 static int subdev_regulator_suspend(struct pci_dev *dev, pm_message_t state)
 {
 	struct subdev_regulators *sr = dev->dev.driver_data;
 
-	if (sr)
-		return regulator_bulk_disable(sr->num_supplies, sr->supplies);
+	if (!sr)
+		return 0;
+	/*
+	 * If at least one device on this bus is enabled as a
+	 * wake-up source, do not turn off regulators.
+	 */
+	sr->ep_wakeup_capable = false;
+	pci_walk_bus(dev->bus, pci_dev_may_wakeup,
+		     &sr->ep_wakeup_capable);
+	if (sr->ep_wakeup_capable)
+		return 0;
 
-	return 0;
+	return regulator_bulk_disable(sr->num_supplies, sr->supplies);
 }
 
 /*
-- 
2.17.1