From:   Pawel Laszczak <pawell@cadence.com>
To:     Greg KH <gregkh@linuxfoundation.org>
CC:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
        "Daisy.Barrera@siriusxm.com" <Daisy.Barrera@siriusxm.com>,
        "Cliff.Holden@siriusxm.com" <Cliff.Holden@siriusxm.com>,
        "arnd@arndb.de" <arnd@arndb.de>,
        "tony@atomide.com" <tony@atomide.com>,
        "jdelvare@suse.de" <jdelvare@suse.de>,
        "neal_liu@aspeedtech.com" <neal_liu@aspeedtech.com>,
        "linus.walleij@linaro.org" <linus.walleij@linaro.org>,
        "egtvedt@samfundet.no" <egtvedt@samfundet.no>,
        "biju.das.jz@bp.renesas.com" <biju.das.jz@bp.renesas.com>,
        "herve.codina@bootlin.com" <herve.codina@bootlin.com>
Subject: RE: [PATCH 1/4] usb: cdns2: Device side header file for CDNS2 driver
Thread-Topic: [PATCH 1/4] usb: cdns2: Device side header file for CDNS2 driver
Thread-Index: AQHZQfUsInC9rM/c9Ee1hWGZtNZxhq7RbngAgAADZnA=
Date:   Thu, 16 Feb 2023 11:53:19 +0000
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>-----Original Message-----
>From: Greg KH <gregkh@linuxfoundation.org>
>Sent: Thursday, February 16, 2023 12:24 PM
>To: Pawel Laszczak <pawell@cadence.com>
>Cc: linux-kernel@vger.kernel.org; linux-usb@vger.kernel.org;
>Daisy.Barrera@siriusxm.com; Cliff.Holden@siriusxm.com; arnd@arndb.de;
>tony@atomide.com; jdelvare@suse.de; neal_liu@aspeedtech.com;
>linus.walleij@linaro.org; egtvedt@samfundet.no; biju.das.jz@bp.renesas.com=
;
>herve.codina@bootlin.com
>Subject: Re: [PATCH 1/4] usb: cdns2: Device side header file for CDNS2 dri=
ver
>
>EXTERNAL MAIL
>
>
>On Thu, Feb 16, 2023 at 05:54:08AM -0500, Pawel Laszczak wrote:
>> Patch defines macros, registers and structures used by Device side
>> driver.
>>
>> Signed-off-by: Pawel Laszczak <pawell@cadence.com>
>> ---
>>  drivers/usb/gadget/udc/cdns2/cdns2-gadget.h | 670
>> ++++++++++++++++++++
>>  1 file changed, 670 insertions(+)
>>  create mode 100644 drivers/usb/gadget/udc/cdns2/cdns2-gadget.h
>>
>> diff --git a/drivers/usb/gadget/udc/cdns2/cdns2-gadget.h
>> b/drivers/usb/gadget/udc/cdns2/cdns2-gadget.h
>> new file mode 100644
>> index 000000000000..66cdb902163c
>> --- /dev/null
>> +++ b/drivers/usb/gadget/udc/cdns2/cdns2-gadget.h
>> @@ -0,0 +1,670 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * USBHS-DEV device controller driver header file
>> + *
>> + * Copyright (C) 2023 Cadence.
>> + *
>> + * Author: Pawel Laszczak <pawell@cadence.com>  */
>> +
>> +#ifndef __LINUX_CDNS2_GADGET
>> +#define __LINUX_CDNS2_GADGET
>> +
>> +#include <linux/usb/gadget.h>
>> +#include <linux/dma-direction.h>
>> +
>> +/*
>> + * USBHS register interface.
>> + * This corresponds to the USBHS Device Controller Interface.
>> + */
>> +
>> +/**
>> + * struct cdns2_ep0_regs - endpoint 0 related registers.
>> + * @rxbc: receive (OUT) 0 endpoint byte count register.
>> + * @txbc: transmit (IN) 0 endpoint byte count register.
>> + * @cs: 0 endpoint control and status register.
>> + * @fifo: 0 endpoint fifo register.
>> + * @setupdat: SETUP data register.
>> + * @maxpack: 0 endpoint max packet size.
>
>You didn't describe the "reserved" fields in here, so you will get a kerne=
ldoc
>warning :(
>
>> + */
>> +struct cdns2_ep0_regs {
>> +	__u8 rxbc;
>> +	__u8 txbc;
>> +	__u8 cs;
>> +	__u8 reserved1[4];
>> +	__u8 fifo;
>> +	__le32 reserved2[94];
>> +	__u8 setupdat[8];
>> +	__u8 reserved4[88];
>
>Why are these all reserved?  Should they be set to 0?  Something else?
>
>Same with the other reserved fields in this file, you need to fix up the
>kerneldoc for them too.
>

Structure describes the part of register map related with ep0 endpoint.
In the reserved space there can be other registers related with another con=
troller=20
logic.  Not all reserved field are set to 0.=20
The registers map is quite big and confusing, and I tried to split them int=
o some group
to make driver more readable.

I will add some descriptions for all reserved* field in this file.

Thanks,

Pawel Laszczak