Thread (20 messages) read the whole thread 20 messages, 4 authors, 2017-12-23

[RFC PATCH v2 1/3] PCI: rockchip: Add support for pcie wake irq

From: briannorris@chromium.org (Brian Norris)
Date: 2017-08-18 17:01:13
Also in: linux-pci, linux-rockchip, lkml

+ Tony

On Thu, Aug 17, 2017 at 08:04:29PM +0800, Jeffy Chen wrote:
quoted hunk ↗ jump to hunk
Add support for PCIE_WAKE pin in rockchip pcie driver.

Signed-off-by: Jeffy Chen <redacted>
---

Changes in v2:
Use dev_pm_set_dedicated_wake_irq
        -- Suggested by Brian Norris [off-list ref]

 drivers/pci/host/pcie-rockchip.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/pci/host/pcie-rockchip.c b/drivers/pci/host/pcie-rockchip.c
index 7bb9870f6d8c..c2b973c738fe 100644
--- a/drivers/pci/host/pcie-rockchip.c
+++ b/drivers/pci/host/pcie-rockchip.c
@@ -36,6 +36,7 @@
 #include <linux/pci_ids.h>
 #include <linux/phy/phy.h>
 #include <linux/platform_device.h>
+#include <linux/pm_wakeirq.h>
 #include <linux/reset.h>
 #include <linux/regmap.h>
 
@@ -853,7 +854,6 @@ static void rockchip_pcie_legacy_int_handler(struct irq_desc *desc)
 	chained_irq_exit(chip, desc);
 }
 
-
 /**
  * rockchip_pcie_parse_dt - Parse Device Tree
  * @rockchip: PCIe port information
@@ -1018,6 +1018,14 @@ static int rockchip_pcie_parse_dt(struct rockchip_pcie *rockchip)
 		return err;
 	}
 
+	device_init_wakeup(dev, true);
+	irq = platform_get_irq_byname(pdev, "wake");
+	if (irq >= 0) {
+		err = dev_pm_set_dedicated_wake_irq(dev, irq);
Did you test that this works out correctly as a level-triggered
interrupt? IIUC, the dummy handler won't mask the interrupt, so it might
keep firing. See:

static irqreturn_t handle_threaded_wake_irq(int irq, void *_wirq)
{
        struct wake_irq *wirq = _wirq;
        int res;

        /* Maybe abort suspend? */
        if (irqd_is_wakeup_set(irq_get_irq_data(irq))) {
                pm_wakeup_event(wirq->dev, 0);
        
                return IRQ_HANDLED; <--- We can return here, with the trigger still asserted
        }
...

This could cause some kind of an IRQ storm, including a lockup or
significant slowdown, I think.

BTW, in another context, Tony suggested we might need to fix up the IRQ flags
like this:

int dev_pm_set_dedicated_wake_irq(struct device *dev, int irq)
{
...
        err = request_threaded_irq(irq, NULL, handle_threaded_wake_irq,
-                                  IRQF_ONESHOT, dev_name(dev), wirq);
+                                  IRQF_ONESHOT | irq_get_trigger_type(irq), dev_name(dev), wirq);

But IIUC, that's not actually necessary, because __setup_irq()
automatically configures the trigger type if the driver didn't request
one explicitly.

Brian
quoted hunk ↗ jump to hunk
+		if (err)
+			dev_err(dev, "failed to setup PCIe wake IRQ\n");
+	}
+
 	rockchip->vpcie3v3 = devm_regulator_get_optional(dev, "vpcie3v3");
 	if (IS_ERR(rockchip->vpcie3v3)) {
 		if (PTR_ERR(rockchip->vpcie3v3) == -EPROBE_DEFER)
@@ -1524,6 +1532,9 @@ static int rockchip_pcie_remove(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct rockchip_pcie *rockchip = dev_get_drvdata(dev);
 
+	dev_pm_clear_wake_irq(dev);
+	device_init_wakeup(dev, false);
+
 	pci_stop_root_bus(rockchip->root_bus);
 	pci_remove_root_bus(rockchip->root_bus);
 	pci_unmap_iospace(rockchip->io);
-- 
2.11.0
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