Re: RE: RE: [PATCH v6 1/2] usb: dwc3: add Realtek DHC RTD SoC dwc3 glue layer driver

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Le 03/11/2023 à 11:54, Stanley Chang[昌育德] a écrit :
Hi Christophe,

Le 01/11/2023 à 07:27, Stanley Chang[昌育德] a écrit :
Hi CJ,

I think these functions are not needed in remove function.

In dwc3_rtk_probe_dwc3_core,
I have used
dwc3_node = of_get_compatible_child(node, "snps,dwc3"); and dwc3_pdev
= of_find_device_by_node(dwc3_node);

So, I call these put functions.
platform_device_put(dwc3_pdev);
of_node_put(dwc3_node);

Yes, but you call it only in the error handling path of the function.

I wonder if they should also be called in the remove function in order to
decrement the ref-counted reference.


Same in __get_dwc3_maximum_speed(), the reference taken by:
     dwc3_np = of_get_compatible_child(np, "snps,dwc3"); is never released.


See the comment at [1] to see what I mean.


[1]: https://elixir.bootlin.com/linux/v6.6/source/drivers/of/base.c#L681

You are right!
For dwc3_pdev, dwc3_np or dwc3_node, I should add of_node_put to release them when the function exits.
https://elixir.bootlin.com/linux/v6.5.10/source/drivers/usb/dwc3/dwc3-meson-g12a.c#L567

I will add a patch to fix this.

For example,
diff --git a/drivers/usb/dwc3/dwc3-rtk.c b/drivers/usb/dwc3/dwc3-rtk.c
index 590028e8fdcb..9d6f2a8bd6ce 100644
--- a/drivers/usb/dwc3/dwc3-rtk.c
+++ b/drivers/usb/dwc3/dwc3-rtk.c
@@ -187,6 +187,7 @@ static enum usb_device_speed __get_dwc3_maximum_speed(struct device_node *np)

         ret = match_string(speed_names, ARRAY_SIZE(speed_names), maximum_speed);

+       of_node_put(dwc3_np);
         return (ret < 0) ? USB_SPEED_UNKNOWN : ret;
  }

@@ -339,6 +340,8 @@ static int dwc3_rtk_probe_dwc3_core(struct dwc3_rtk *rtk)

         switch_usb2_role(rtk, rtk->cur_role);

+       platform_device_put(dwc3_pdev);
+       of_node_put(dwc3_node);
         return 0;

  err_pdev_put:


LGTM.

CJ


Thanks,
Stanley

CJ

Thanks,
Stanley

Hi,

Is something like
          platform_device_put(dwc3_pdev);
          of_node_put(dwc3_node);
needed in the remove function?

(as done in the error handling path of dwc3_rtk_probe_dwc3_core())

Or should it be added at the end of dwc3_rtk_probe_dwc3_core() if the
reference are nor needed anymore when we leave the function?

CJ

+     of_platform_depopulate(rtk->dev); }
+

...







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