usb: cdns3-ti: run HW init at resume() if HW was reset

At runtime_resume(), read the W1 (Wrapper Register 1) register to detect
if an hardware reset occurred. If it did, run the hardware init sequence.

This callback will be called at system-wide resume. Previously, if a
reset occurred during suspend, we would crash. The wrapper config had
not been written, leading to invalid register accesses inside cdns3.

Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Link: https://lore.kernel.org/r/20250205-s2r-cdns-v7-6-13658a271c3c@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/cdns3/cdns3-ti.c b/drivers/usb/cdns3/cdns3-ti.c
index d573a259f1ae5c4efd59a496a43b23b75e859dd8..302ebf6d8e5367c25046d8364c0b2e5b30fab4f7 100644 (file)
--- a/drivers/usb/cdns3/cdns3-ti.c
+++ b/drivers/usb/cdns3/cdns3-ti.c
@@ -186,6 +186,12 @@ static int cdns_ti_probe(struct platform_device *pdev)
        data->vbus_divider = device_property_read_bool(dev, "ti,vbus-divider");
        data->usb2_only = device_property_read_bool(dev, "ti,usb2-only");
 
+       /*
+        * The call below to pm_runtime_get_sync() MIGHT reset hardware, if it
+        * detects it as uninitialised. We want to enforce a reset at probe,
+        * and so do it manually here. This means the first runtime_resume()
+        * will be a no-op.
+        */
        cdns_ti_reset_and_init_hw(data);
 
        pm_runtime_enable(dev);
@@ -230,6 +236,24 @@ static void cdns_ti_remove(struct platform_device *pdev)
        platform_set_drvdata(pdev, NULL);
 }
 
+static int cdns_ti_runtime_resume(struct device *dev)
+{
+       const u32 mask = USBSS_W1_PWRUP_RST | USBSS_W1_MODESTRAP_SEL;
+       struct cdns_ti *data = dev_get_drvdata(dev);
+       u32 w1;
+
+       w1 = cdns_ti_readl(data, USBSS_W1);
+       if ((w1 & mask) != mask)
+               cdns_ti_reset_and_init_hw(data);
+
+       return 0;
+}
+
+static const struct dev_pm_ops cdns_ti_pm_ops = {
+       RUNTIME_PM_OPS(NULL, cdns_ti_runtime_resume, NULL)
+       SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume)
+};
+
 static const struct of_device_id cdns_ti_of_match[] = {
        { .compatible = "ti,j721e-usb", },
        { .compatible = "ti,am64-usb", },
@@ -243,6 +267,7 @@ static struct platform_driver cdns_ti_driver = {
        .driver         = {
                .name   = "cdns3-ti",
                .of_match_table = cdns_ti_of_match,
+               .pm     = pm_ptr(&cdns_ti_pm_ops),
        },
 };