linux-kernel - Re: [PATCH v2] usb: dwc3: gadget: Refine the logic for resizing Tx FIFOs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20240903221055.s4gu6actfbrkonmr@synopsys.com>
Date: Tue, 3 Sep 2024 22:11:07 +0000
From: Thinh Nguyen <Thinh.Nguyen@...opsys.com>
To: Akash Kumar <quic_akakum@...cinc.com>
CC: Thinh Nguyen <Thinh.Nguyen@...opsys.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jing Leng <jleng@...arella.com>, Felipe Balbi <balbi@...nel.org>,
        Jack Pham <quic_jackp@...cinc.com>,
        "kernel@...cinc.com" <kernel@...cinc.com>,
        Wesley Cheng <quic_wcheng@...cinc.com>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Daniel Scally <dan.scally@...asonboard.com>,
        Vijayavardhan Vennapusa <quic_vvreddy@...cinc.com>,
        Krishna Kurapati <quic_kriskura@...cinc.com>,
        "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] usb: dwc3: gadget: Refine the logic for resizing Tx
 FIFOs

On Tue, Sep 03, 2024, Akash Kumar wrote:
> The current logic is rigid, setting num_fifos to fixed values:
> 
> 3 for any maxburst greater than 1.
> tx_fifo_resize_max_num for maxburst greater than 6.
> Additionally, it did not differentiate much between bulk and
> isochronous transfers, applying similar logic to both.
> 
> The new logic is more dynamic and tailored to the specific needs of
> bulk and isochronous transfers:
> 
> Bulk Transfers: Ensures that num_fifos is optimized by considering
> both the maxburst value and the maximum allowed number of FIFOs.
> 
> Isochronous Transfers: Ensures that num_fifos is sufficient by
> considering the maxburst value and the maximum packet multiplier.
> 
> This change aims to optimize the allocation of Tx FIFOs for both bulk
> and isochronous endpoints, potentially improving data transfer
> efficiency and overall performance.
> It also enhances support for all use cases, which can be tweaked
> with DT parameters and the endpoint’s maxburst and maxpacket.
> 
> Signed-off-by: Akash Kumar <quic_akakum@...cinc.com>
> ---
> Changes for v2:
> Redefine logic for resizing tx fifos.
> 
> Changes for v1:
> Added additional condition to allocate tx fifo for hs isoc eps,
> keeping the other resize logic same.
> ---
>  drivers/usb/dwc3/gadget.c | 15 ++++++---------
>  1 file changed, 6 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 89fc690fdf34..49809a931104 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -778,15 +778,12 @@ static int dwc3_gadget_resize_tx_fifos(struct dwc3_ep *dep)
>  
>  	ram1_depth = DWC3_RAM1_DEPTH(dwc->hwparams.hwparams7);
>  
> -	if ((dep->endpoint.maxburst > 1 &&
> -	     usb_endpoint_xfer_bulk(dep->endpoint.desc)) ||
> -	    usb_endpoint_xfer_isoc(dep->endpoint.desc))
> -		num_fifos = 3;
> -
> -	if (dep->endpoint.maxburst > 6 &&
> -	    (usb_endpoint_xfer_bulk(dep->endpoint.desc) ||
> -	     usb_endpoint_xfer_isoc(dep->endpoint.desc)) && DWC3_IP_IS(DWC31))
> -		num_fifos = dwc->tx_fifo_resize_max_num;
> +	if (usb_endpoint_xfer_bulk(dep->endpoint.desc))
> +		num_fifos = min_t(unsigned int, dep->endpoint.maxburst + 1,
> +				  dwc->tx_fifo_resize_max_num);
> +	if (usb_endpoint_xfer_isoc(dep->endpoint.desc))
> +		num_fifos = max_t(unsigned int, dep->endpoint.maxburst,
> +				  usb_endpoint_maxp_mult(dep->endpoint.desc));

No. Don't mix usb_endpoint_maxp_mult with maxburst like this. Check base
on operating speed. Also, now you're ignoring tx_fifo_resize_max_num for
isoc.

BR,
Thinh