From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6F1C1D535 for ; Tue, 31 Oct 2023 06:00:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Zh2A5CVZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 77CA8C433CA; Tue, 31 Oct 2023 06:00:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1698732048; bh=iB7SU7X4lCstBjTo8XyyKak/6Jb9SnOPNn+3KyJ7p0I=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Zh2A5CVZRru44YRIKIqWgBlvs+Eka4zB5nuE+V1uSdIzn+2pyUyu8fNZoXzVlJeb3 jK88r+MzXmF/B9wcDF+a0H03NTf4zlODNJbAy8VhyW48AnY9vQUFXafHtFCKMZzIt3 Q/LqauFxEy+LhgzZAEaZX3fI/h4nUR9xzrdK+h6U= Date: Tue, 31 Oct 2023 07:00:43 +0100 From: Greg Kroah-Hartman To: Manan Aurora Cc: Alan Stern , Badhri Jagan Sridharan , Francesco Dolcini , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, manugautam@google.com Subject: Re: [PATCH] usb: gadget: Support transfers from device memory Message-ID: <2023103156-clapping-shed-4626@gregkh> References: <20231031035403.661938-1-maurora@google.com> Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231031035403.661938-1-maurora@google.com> On Tue, Oct 31, 2023 at 03:54:02AM +0000, Manan Aurora wrote: > USB gadget stack only supports usb_request objects that point to buffers > located in memory. Support use cases where data is transferred from > physical addresses in device mmio regions > > Added a bit "pre_mapped" to usb_request to bypass dma_map_single and > dma_map_sg for such requests > > The caller must determine the dma address for the request before queuing > it > > Signed-off-by: Manan Aurora > --- > drivers/usb/gadget/udc/core.c | 4 ++-- > include/linux/usb/gadget.h | 1 + > 2 files changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c > index ded9531f141b..236165ba08f4 100644 > --- a/drivers/usb/gadget/udc/core.c > +++ b/drivers/usb/gadget/udc/core.c > @@ -900,7 +900,7 @@ EXPORT_SYMBOL_GPL(usb_gadget_activate); > int usb_gadget_map_request_by_dev(struct device *dev, > struct usb_request *req, int is_in) > { > - if (req->length == 0) > + if (req->pre_mapped || req->length == 0) > return 0; > > if (req->num_sgs) { > @@ -948,7 +948,7 @@ EXPORT_SYMBOL_GPL(usb_gadget_map_request); > void usb_gadget_unmap_request_by_dev(struct device *dev, > struct usb_request *req, int is_in) > { > - if (req->length == 0) > + if (req->pre_mapped || req->length == 0) > return; > > if (req->num_mapped_sgs) { > diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h > index a771ccc038ac..6bc035439098 100644 > --- a/include/linux/usb/gadget.h > +++ b/include/linux/usb/gadget.h > @@ -111,6 +111,7 @@ struct usb_request { > unsigned zero:1; > unsigned short_not_ok:1; > unsigned dma_mapped:1; > + unsigned pre_mapped:1; > > void (*complete)(struct usb_ep *ep, > struct usb_request *req); > -- > 2.42.0.820.g83a721a137-goog > > You can not add features/functionality that no in-kernel driver uses, so this can not be accepted as-is, sorry. Please submit it as part of a patch series where it is actually used, otherwise we have no idea if this is even something that we should do or not. thanks, greg k-h