On Wed, Nov 10, 2021 at 4:16 AM Abel Vesa <abelvesa@xxxxxxxxxx> wrote: > > On 21-09-28 17:07:33, Saravana Kannan wrote: > > fw_devlink could end up creating device links for bus only devices. > > However, bus only devices don't get probed and can block probe() or > > sync_state() [1] call backs of other devices. To avoid this, probe these > > devices using the simple-pm-bus driver. > > > > However, there are instances of devices that are not simple buses (they get > > probed by their specific drivers) that also list the "simple-bus" (or other > > bus only compatible strings) in their compatible property to automatically > > populate their child devices. We still want these devices to get probed by > > their specific drivers. So, we make sure this driver only probes devices > > that are only buses. > > > > [1] - https://lore.kernel.org/lkml/CAPDyKFo9Bxremkb1dDrr4OcXSpE0keVze94Cm=zrkOVxHHxBmQ@xxxxxxxxxxxxxx/ > > Fixes: c442a0d18744 ("driver core: Set fw_devlink to "permissive" behavior by default") > > Signed-off-by: Saravana Kannan <saravanak@xxxxxxxxxx> > > Tested-by: Saravana Kannan <saravanak@xxxxxxxxxx> > > Tested-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx> > > --- > > drivers/bus/simple-pm-bus.c | 42 ++++++++++++++++++++++++++++++++++--- > > 1 file changed, 39 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/bus/simple-pm-bus.c b/drivers/bus/simple-pm-bus.c > > index 01a3d0cd08ed..6b8d6257ed8a 100644 > > --- a/drivers/bus/simple-pm-bus.c > > +++ b/drivers/bus/simple-pm-bus.c > > @@ -13,11 +13,36 @@ > > #include <linux/platform_device.h> > > #include <linux/pm_runtime.h> > > > > - > > static int simple_pm_bus_probe(struct platform_device *pdev) > > { > > - const struct of_dev_auxdata *lookup = dev_get_platdata(&pdev->dev); > > - struct device_node *np = pdev->dev.of_node; > > + const struct device *dev = &pdev->dev; > > + const struct of_dev_auxdata *lookup = dev_get_platdata(dev); > > + struct device_node *np = dev->of_node; > > + const struct of_device_id *match; > > + > > + /* > > + * Allow user to use driver_override to bind this driver to a > > + * transparent bus device which has a different compatible string > > + * that's not listed in simple_pm_bus_of_match. We don't want to do any > > + * of the simple-pm-bus tasks for these devices, so return early. > > + */ > > + if (pdev->driver_override) > > + return 0; > > + > > + match = of_match_device(dev->driver->of_match_table, dev); > > + /* > > + * These are transparent bus devices (not simple-pm-bus matches) that > > + * have their child nodes populated automatically. So, don't need to > > + * do anything more. We only match with the device if this driver is > > + * the most specific match because we don't want to incorrectly bind to > > + * a device that has a more specific driver. > > + */ > > + if (match && match->data) { > > + if (of_property_match_string(np, "compatible", match->compatible) == 0) > > + return 0; > > + else > > + return -ENODEV; > > + } > > This change is breaking the expected behavior for the already existent > simple-bus nodes. All the simple-bus compatibles should be replaced now > to simple-pm-bus. In my case, on some i.MX8 platforms, without the > devlink, the devices suspend sequence changes (and even breaks). > > To avoid breaking the already existent simple-bus nodes, maybe the logic > should've been reversed: keep the simple-bus as is and add another > compatible, IDK, something like simple-trasnparent-bus, or something. The intent of this change IS to affect existing simple-bus nodes (but not in the way it's affecting you). But if it's breaking stuff, we obviously need to fix it. I have a hunch on what's going on in your case, but can you point me to the specific simple-bus node that's getting affected? I'm expecting it to be a simple-bus node that gets added AFTER this driver is registered at device_initcall (module_init gets converted to device_initcall). Also, can you try this hack patch to see if it helps your case? https://lore.kernel.org/lkml/CAGETcx9U130Oq-umrvXME4JhEpO0Wadoki3kNxx=0-YvTR6PtQ@xxxxxxxxxxxxxx/ I have some thoughts on how I could fix this, but I need to think about a few cases. -Saravana > > > > > dev_dbg(&pdev->dev, "%s\n", __func__); > > > > @@ -31,14 +56,25 @@ static int simple_pm_bus_probe(struct platform_device *pdev) > > > > static int simple_pm_bus_remove(struct platform_device *pdev) > > { > > + const void *data = of_device_get_match_data(&pdev->dev); > > + > > + if (pdev->driver_override || data) > > + return 0; > > + > > dev_dbg(&pdev->dev, "%s\n", __func__); > > > > pm_runtime_disable(&pdev->dev); > > return 0; > > } > > > > +#define ONLY_BUS ((void *) 1) /* Match if the device is only a bus. */ > > + > > static const struct of_device_id simple_pm_bus_of_match[] = { > > { .compatible = "simple-pm-bus", }, > > + { .compatible = "simple-bus", .data = ONLY_BUS }, > > + { .compatible = "simple-mfd", .data = ONLY_BUS }, > > + { .compatible = "isa", .data = ONLY_BUS }, > > + { .compatible = "arm,amba-bus", .data = ONLY_BUS }, > > { /* sentinel */ } > > }; > > MODULE_DEVICE_TABLE(of, simple_pm_bus_of_match); > > -- > > 2.33.0.685.g46640cef36-goog > >
