Re: [PATCH v3 1/3] usb: gadget: ccid: add support for USB CCID Gadget Device

From: Felipe Balbi
Date: Mon Jun 18 2018 - 05:33:17 EST



Hi,

Marcus Folkesson <marcus.folkesson@xxxxxxxxx> writes:
> Hi Felipe,
>
> Should I send out v4 or what do you think?

sorry for the delay, have been busy with other tasks.

> On Wed, May 30, 2018 at 04:04:15PM +0200, Marcus Folkesson wrote:
>> Hi Filipe,
>>
>> On Wed, May 30, 2018 at 03:28:18PM +0300, Felipe Balbi wrote:
>> > Marcus Folkesson <marcus.folkesson@xxxxxxxxx> writes:
>> >
>> > > Chip Card Interface Device (CCID) protocol is a USB protocol that
>> > > allows a smartcard device to be connected to a computer via a card
>> > > reader using a standard USB interface, without the need for each manufacturer
>> > > of smartcards to provide its own reader or protocol.
>> > >
>> > > This gadget driver makes Linux show up as a CCID device to the host and let a
>> > > userspace daemon act as the smartcard.
>> > >
>> > > This is useful when the Linux gadget itself should act as a cryptographic
>> > > device or forward APDUs to an embedded smartcard device.
>> > >
>> > > Signed-off-by: Marcus Folkesson <marcus.folkesson@xxxxxxxxx>
>> >
>> > this could be done entirely in userspace with functionfs, why do we need
>> > this part in the kernel? It does very little.
>>
>> Andrzej pointed this out, and I actually do not have any good answer
>> more than that the userspace application could be kept small and the
>> important configuration of the CCID device is done with well (I hope)
>> documented configfs attributes.

can we use existing open source applications without modification by
accepting this glue layer?

--
balbi

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