linux-kernel - RE: [PATCH 1/2] usb: cdns3: fix cdns3_core_init

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Message-ID: <BYAPR07MB470974496C7C59FDE615E5F3DD920@BYAPR07MB4709.namprd07.prod.outlook.com>
Date:   Wed, 16 Oct 2019 04:32:29 +0000
From:   Pawel Laszczak <pawell@...ence.com>
To:     Roger Quadros <rogerq@...com>,
        "felipe.balbi@...ux.intel.com" <felipe.balbi@...ux.intel.com>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>
CC:     "peter.chen@....com" <peter.chen@....com>,
        "nsekhar@...com" <nsekhar@...com>,
        Rahul Kumar <kurahul@...ence.com>,
        "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 1/2] usb: cdns3: fix cdns3_core_init_role()

Hi Roger

>
>At startup we should trigger the HW state machine
>only if it is OTG mode. Otherwise we should just
>start the respective role.
>
>Initialize idle role by default. If we don't do this then
>cdns3_idle_role_stop() is not called when switching to
>host/device role and so lane switch mechanism
>doesn't work. This results to super-speed device not working
>in one orientation if it was plugged before driver probe.
>
>Signed-off-by: Roger Quadros <rogerq@...com>
>Signed-off-by: Sekhar Nori <nsekhar@...com>
>---
> drivers/usb/cdns3/core.c | 20 +++++++++++++++++++-
> 1 file changed, 19 insertions(+), 1 deletion(-)
>
>diff --git a/drivers/usb/cdns3/core.c b/drivers/usb/cdns3/core.c
>index 06f1e105be4e..1109dc5a4c39 100644
>--- a/drivers/usb/cdns3/core.c
>+++ b/drivers/usb/cdns3/core.c
>@@ -160,10 +160,28 @@ static int cdns3_core_init_role(struct cdns3 *cdns)
> 	if (ret)
> 		goto err;
>
>-	if (cdns->dr_mode != USB_DR_MODE_OTG) {
>+	/* Initialize idle role to start with */
>+	ret = cdns3_role_start(cdns, USB_ROLE_NONE);
>+	if (ret)
>+		goto err;
>+
>+	switch (cdns->dr_mode) {
>+	case USB_DR_MODE_UNKNOWN:

One note in this place. USB_DR_MODE_UNKNOWN is not possible in this place.
If cdns->dr_mode will be USB_DR_MODE_UNKNOWN then driver returns -EINVAL
some line before after returning form cdns3_drd_update_mode and in consequence 
it jump to err label. 

Maybe for better readability it this condition should be treated here also as error.

>+	case USB_DR_MODE_OTG:
> 		ret = cdns3_hw_role_switch(cdns);
> 		if (ret)
> 			goto err;
>+		break;
>+	case USB_DR_MODE_PERIPHERAL:
>+		ret = cdns3_role_start(cdns, USB_ROLE_DEVICE);
>+		if (ret)
>+			goto err;
>+		break;
>+	case USB_DR_MODE_HOST:
>+		ret = cdns3_role_start(cdns, USB_ROLE_HOST);
>+		if (ret)
>+			goto err;
>+		break;
> 	}
>
> 	return ret;

Reviewed-by: Pawel Laszczak <pawell@...ence.com>
Tested-by: Pawel Laszczak <pawell@...ence.com>

>--
>Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
>Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
--
Regards,
Pawel