amba: Fix resource leak for drivers without .remove

Consider an amba driver with a .probe but without a .remove callback (e.g.
pl061_gpio_driver). The function amba_probe() is called to bind a device
and so dev_pm_domain_attach() and others are called. As there is no remove
callback amba_remove() isn't called at unbind time however and so calling
dev_pm_domain_detach() is missed and the pm domain keeps active.

To fix this always use the core driver callbacks and handle missing amba
callbacks there. For probe refuse registration as a driver without probe
doesn't make sense.

Fixes: 7cfe249475fd ("ARM: AMBA: Add pclk support to AMBA bus infrastructure")
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20210126165835.687514-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
index ecc3041..b5f5ca4 100644 (file)
--- a/drivers/amba/bus.c
+++ b/drivers/amba/bus.c
@@ -299,10 +299,11 @@ static int amba_remove(struct device *dev)
 {
        struct amba_device *pcdev = to_amba_device(dev);
        struct amba_driver *drv = to_amba_driver(dev->driver);
-       int ret;
+       int ret = 0;
 
        pm_runtime_get_sync(dev);
-       ret = drv->remove(pcdev);
+       if (drv->remove)
+               ret = drv->remove(pcdev);
        pm_runtime_put_noidle(dev);
 
        /* Undo the runtime PM settings in amba_probe() */
@@ -319,7 +320,9 @@ static int amba_remove(struct device *dev)
 static void amba_shutdown(struct device *dev)
 {
        struct amba_driver *drv = to_amba_driver(dev->driver);
-       drv->shutdown(to_amba_device(dev));
+
+       if (drv->shutdown)
+               drv->shutdown(to_amba_device(dev));
 }
 
 /**
@@ -332,12 +335,13 @@ static void amba_shutdown(struct device *dev)
  */
 int amba_driver_register(struct amba_driver *drv)
 {
-       drv->drv.bus = &amba_bustype;
+       if (!drv->probe)
+               return -EINVAL;
 
-#define SETFN(fn)      if (drv->fn) drv->drv.fn = amba_##fn
-       SETFN(probe);
-       SETFN(remove);
-       SETFN(shutdown);
+       drv->drv.bus = &amba_bustype;
+       drv->drv.probe = amba_probe;
+       drv->drv.remove = amba_remove;
+       drv->drv.shutdown = amba_shutdown;
 
        return driver_register(&drv->drv);
 }