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From: Greg KH <gregkh@linuxfoundation.org>
To: Wesley Cheng <wcheng@codeaurora.org>
Cc: agross@kernel.org, bjorn.andersson@linaro.org, balbi@kernel.org,
	robh+dt@kernel.org, frowand.list@gmail.com,
	linux-arm-msm@vger.kernel.org, linux-usb@vger.kernel.org,
	linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
	jackp@codeaurora.org, fntoth@gmail.com
Subject: Re: [PATCH v12 3/6] usb: dwc3: Resize TX FIFOs to meet EP bursting requirements
Date: Tue, 6 Jul 2021 20:13:24 +0200	[thread overview]
Message-ID: <YOSdRKTy3+CdV/UF@kroah.com> (raw)
In-Reply-To: <1625218655-14180-4-git-send-email-wcheng@codeaurora.org>

On Fri, Jul 02, 2021 at 02:37:32AM -0700, Wesley Cheng wrote:
> Some devices have USB compositions which may require multiple endpoints
> that support EP bursting.  HW defined TX FIFO sizes may not always be
> sufficient for these compositions.  By utilizing flexible TX FIFO
> allocation, this allows for endpoints to request the required FIFO depth to
> achieve higher bandwidth.  With some higher bMaxBurst configurations, using
> a larger TX FIFO size results in better TX throughput.
> 
> By introducing the check_config() callback, the resizing logic can fetch
> the maximum number of endpoints used in the USB composition (can contain
> multiple configurations), which helps ensure that the resizing logic can
> fulfill the configuration(s), or return an error to the gadget layer
> otherwise during bind time.
> 
> Signed-off-by: Wesley Cheng <wcheng@codeaurora.org>
> ---
>  drivers/usb/dwc3/core.c   |   9 ++
>  drivers/usb/dwc3/core.h   |  15 ++++
>  drivers/usb/dwc3/ep0.c    |   2 +
>  drivers/usb/dwc3/gadget.c | 221 ++++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 247 insertions(+)
> 
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index e0a8e79..a7bcdb9d 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -1267,6 +1267,7 @@ static void dwc3_get_properties(struct dwc3 *dwc)
>  	u8			rx_max_burst_prd;
>  	u8			tx_thr_num_pkt_prd;
>  	u8			tx_max_burst_prd;
> +	u8			tx_fifo_resize_max_num;
>  	const char		*usb_psy_name;
>  	int			ret;
>  
> @@ -1282,6 +1283,8 @@ static void dwc3_get_properties(struct dwc3 *dwc)
>  	 */
>  	hird_threshold = 12;
>  
> +	tx_fifo_resize_max_num = 6;
> +

No comment as to why 6 was picked, like the other defaults in this
function?

Why was 6 picked?


>  	dwc->maximum_speed = usb_get_maximum_speed(dev);
>  	dwc->max_ssp_rate = usb_get_maximum_ssp_rate(dev);
>  	dwc->dr_mode = usb_get_dr_mode(dev);
> @@ -1325,6 +1328,10 @@ static void dwc3_get_properties(struct dwc3 *dwc)
>  				&tx_thr_num_pkt_prd);
>  	device_property_read_u8(dev, "snps,tx-max-burst-prd",
>  				&tx_max_burst_prd);
> +	dwc->do_fifo_resize = device_property_read_bool(dev,
> +							"tx-fifo-resize");
> +	device_property_read_u8(dev, "tx-fifo-max-num",
> +				&tx_fifo_resize_max_num);

So you overwrite the "max" with whatever is given to you?  What if
tx-fifo-resize is not enabled?

thanks,

greg k-h

  reply	other threads:[~2021-07-06 18:13 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-02  9:37 [PATCH v12 0/6] Re-introduce TX FIFO resize for larger EP bursting Wesley Cheng
2021-07-02  9:37 ` [PATCH v12 1/6] usb: gadget: udc: core: Introduce check_config to verify USB configuration Wesley Cheng
2021-07-02  9:37 ` [PATCH v12 2/6] usb: gadget: configfs: Check USB configuration before adding Wesley Cheng
2021-07-02  9:37 ` [PATCH v12 3/6] usb: dwc3: Resize TX FIFOs to meet EP bursting requirements Wesley Cheng
2021-07-06 18:13   ` Greg KH [this message]
2021-07-06 20:19     ` Wesley Cheng
2021-07-07  6:36       ` Greg KH
2021-07-02  9:37 ` [PATCH v12 4/6] of: Add stub for of_add_property() Wesley Cheng
2021-07-02  9:37 ` [PATCH v12 5/6] usb: dwc3: dwc3-qcom: Enable tx-fifo-resize property by default Wesley Cheng
2021-07-02  9:37 ` [PATCH v12 6/6] dt-bindings: usb: dwc3: Update dwc3 TX fifo properties Wesley Cheng
2021-07-06 18:14   ` Greg KH

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