Re: [PATCH v8 16/34] usb: dwc3: Specify maximum number of XHCI interrupters

[Thinh Nguyen]

On Tue, Oct 10, 2023, Wesley Cheng wrote:
> Allow for the DWC3 host driver to pass along XHCI property that defines
> how many interrupters to allocate.  This is in relation for the number of
> event rings that can be potentially used by other processors within the
> system.
> 
> Signed-off-by: Wesley Cheng <quic_wcheng@xxxxxxxxxxx>
> ---
>  drivers/usb/dwc3/core.c | 12 ++++++++++++
>  drivers/usb/dwc3/core.h |  2 ++
>  drivers/usb/dwc3/host.c |  5 ++++-
>  3 files changed, 18 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 44ee8526dc28..652171c2f244 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -1459,6 +1459,7 @@ static void dwc3_get_properties(struct dwc3 *dwc)
>  	u8			tx_thr_num_pkt_prd = 0;
>  	u8			tx_max_burst_prd = 0;
>  	u8			tx_fifo_resize_max_num;
> +	u16			num_hc_interrupters;
>  	const char		*usb_psy_name;
>  	int			ret;
>  
> @@ -1481,6 +1482,9 @@ static void dwc3_get_properties(struct dwc3 *dwc)
>  	 */
>  	tx_fifo_resize_max_num = 6;
>  
> +	/* default to a single XHCI interrupter */
> +	num_hc_interrupters = 1;
> +
>  	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);
> @@ -1532,6 +1536,12 @@ 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);
> +	device_property_read_u16(dev, "num-hc-interrupters",
> +				&num_hc_interrupters);
> +	/* DWC3 core allowed to have a max of 8 interrupters */
> +	if (num_hc_interrupters > 8)
> +		num_hc_interrupters = 8;
> +
>  	dwc->do_fifo_resize = device_property_read_bool(dev,
>  							"tx-fifo-resize");
>  	if (dwc->do_fifo_resize)
> @@ -1620,6 +1630,8 @@ static void dwc3_get_properties(struct dwc3 *dwc)
>  	dwc->imod_interval = 0;
>  
>  	dwc->tx_fifo_resize_max_num = tx_fifo_resize_max_num;
> +
> +	dwc->num_hc_interrupters = num_hc_interrupters;
>  }
>  
>  /* check whether the core supports IMOD */
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index c6c87acbd376..2ce5e1e59380 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -1060,6 +1060,7 @@ struct dwc3_scratchpad_array {
>   * @tx_max_burst_prd: max periodic ESS transmit burst size
>   * @tx_fifo_resize_max_num: max number of fifos allocated during txfifo resize
>   * @clear_stall_protocol: endpoint number that requires a delayed status phase
> + * @num_hc_interrupters: number of host controller interrupters
>   * @hsphy_interface: "utmi" or "ulpi"
>   * @connected: true when we're connected to a host, false otherwise
>   * @softconnect: true when gadget connect is called, false when disconnect runs
> @@ -1294,6 +1295,7 @@ struct dwc3 {
>  	u8			tx_max_burst_prd;
>  	u8			tx_fifo_resize_max_num;
>  	u8			clear_stall_protocol;
> +	u16			num_hc_interrupters;
>  
>  	const char		*hsphy_interface;
>  
> diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c
> index 61f57fe5bb78..79ce359c342a 100644
> --- a/drivers/usb/dwc3/host.c
> +++ b/drivers/usb/dwc3/host.c
> @@ -61,7 +61,7 @@ static int dwc3_host_get_irq(struct dwc3 *dwc)
>  
>  int dwc3_host_init(struct dwc3 *dwc)
>  {
> -	struct property_entry	props[4];
> +	struct property_entry	props[5];
>  	struct platform_device	*xhci;
>  	int			ret, irq;
>  	int			prop_idx = 0;
> @@ -107,6 +107,9 @@ int dwc3_host_init(struct dwc3 *dwc)
>  	if (DWC3_VER_IS_WITHIN(DWC3, ANY, 300A))
>  		props[prop_idx++] = PROPERTY_ENTRY_BOOL("quirk-broken-port-ped");
>  
> +	props[prop_idx++] = PROPERTY_ENTRY_U16("num-hc-interrupters",
> +						dwc->num_hc_interrupters);
> +
>  	if (prop_idx) {
>  		ret = device_create_managed_software_node(&xhci->dev, props, NULL);
>  		if (ret) {

Acked-by: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx>

Thanks,
Thinh