Re: [PATCH v36 03/31] usb: host: xhci-mem: Allow for interrupter clients to choose specific index

[Puma Hsu]

On Wed, Mar 19, 2025 at 8:59 AM Wesley Cheng <quic_wcheng@xxxxxxxxxxx> wrote:
>
> Some clients may operate only on a specific XHCI interrupter instance.
> Allow for the associated class driver to request for the interrupter that
> it requires.
>
> Signed-off-by: Wesley Cheng <quic_wcheng@xxxxxxxxxxx>

Tested-by: Puma Hsu <pumahsu@xxxxxxxxxx>

> ---
>  drivers/usb/host/xhci-mem.c       | 24 ++++++++++++++----------
>  drivers/usb/host/xhci-sideband.c  |  5 +++--
>  drivers/usb/host/xhci.h           |  2 +-
>  include/linux/usb/xhci-sideband.h |  2 +-
>  4 files changed, 19 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
> index daea0f76e844..ed36df46b140 100644
> --- a/drivers/usb/host/xhci-mem.c
> +++ b/drivers/usb/host/xhci-mem.c
> @@ -2331,14 +2331,15 @@ xhci_add_interrupter(struct xhci_hcd *xhci, struct xhci_interrupter *ir,
>
>  struct xhci_interrupter *
>  xhci_create_secondary_interrupter(struct usb_hcd *hcd, unsigned int segs,
> -                                 u32 imod_interval)
> +                                 u32 imod_interval, unsigned int intr_num)
>  {
>         struct xhci_hcd *xhci = hcd_to_xhci(hcd);
>         struct xhci_interrupter *ir;
>         unsigned int i;
>         int err = -ENOSPC;
>
> -       if (!xhci->interrupters || xhci->max_interrupters <= 1)
> +       if (!xhci->interrupters || xhci->max_interrupters <= 1 ||
> +           intr_num >= xhci->max_interrupters)
>                 return NULL;
>
>         ir = xhci_alloc_interrupter(xhci, segs, GFP_KERNEL);
> @@ -2346,15 +2347,18 @@ xhci_create_secondary_interrupter(struct usb_hcd *hcd, unsigned int segs,
>                 return NULL;
>
>         spin_lock_irq(&xhci->lock);
> -
> -       /* Find available secondary interrupter, interrupter 0 is reserved for primary */
> -       for (i = 1; i < xhci->max_interrupters; i++) {
> -               if (xhci->interrupters[i] == NULL) {
> -                       err = xhci_add_interrupter(xhci, ir, i);
> -                       break;
> +       if (!intr_num) {
> +               /* Find available secondary interrupter, interrupter 0 is reserved for primary */
> +               for (i = 1; i < xhci->max_interrupters; i++) {
> +                       if (!xhci->interrupters[i]) {
> +                               err = xhci_add_interrupter(xhci, ir, i);
> +                               break;
> +                       }
>                 }
> +       } else {
> +               if (!xhci->interrupters[intr_num])
> +                       err = xhci_add_interrupter(xhci, ir, intr_num);
>         }
> -
>         spin_unlock_irq(&xhci->lock);
>
>         if (err) {
> @@ -2370,7 +2374,7 @@ xhci_create_secondary_interrupter(struct usb_hcd *hcd, unsigned int segs,
>                           i, imod_interval);
>
>         xhci_dbg(xhci, "Add secondary interrupter %d, max interrupters %d\n",
> -                i, xhci->max_interrupters);
> +                ir->intr_num, xhci->max_interrupters);
>
>         return ir;
>  }
> diff --git a/drivers/usb/host/xhci-sideband.c b/drivers/usb/host/xhci-sideband.c
> index 19c58ae60414..742bbc6c2d9b 100644
> --- a/drivers/usb/host/xhci-sideband.c
> +++ b/drivers/usb/host/xhci-sideband.c
> @@ -259,7 +259,7 @@ EXPORT_SYMBOL_GPL(xhci_sideband_get_event_buffer);
>   */
>  int
>  xhci_sideband_create_interrupter(struct xhci_sideband *sb, int num_seg,
> -                                bool ip_autoclear, u32 imod_interval)
> +                                bool ip_autoclear, u32 imod_interval, int intr_num)
>  {
>         int ret = 0;
>
> @@ -273,7 +273,8 @@ xhci_sideband_create_interrupter(struct xhci_sideband *sb, int num_seg,
>         }
>
>         sb->ir = xhci_create_secondary_interrupter(xhci_to_hcd(sb->xhci),
> -                                                  num_seg, imod_interval);
> +                                                  num_seg, imod_interval,
> +                                                  intr_num);
>         if (!sb->ir) {
>                 ret = -ENOMEM;
>                 goto out;
> diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
> index 3fa8669e3b2d..7eaabe4f6c87 100644
> --- a/drivers/usb/host/xhci.h
> +++ b/drivers/usb/host/xhci.h
> @@ -1853,7 +1853,7 @@ void xhci_free_container_ctx(struct xhci_hcd *xhci,
>                 struct xhci_container_ctx *ctx);
>  struct xhci_interrupter *
>  xhci_create_secondary_interrupter(struct usb_hcd *hcd, unsigned int segs,
> -                                 u32 imod_interval);
> +                                 u32 imod_interval, unsigned int intr_num);
>  void xhci_remove_secondary_interrupter(struct usb_hcd
>                                        *hcd, struct xhci_interrupter *ir);
>  void xhci_skip_sec_intr_events(struct xhci_hcd *xhci,
> diff --git a/include/linux/usb/xhci-sideband.h b/include/linux/usb/xhci-sideband.h
> index 4b382af892fa..f8722afb8a2d 100644
> --- a/include/linux/usb/xhci-sideband.h
> +++ b/include/linux/usb/xhci-sideband.h
> @@ -66,7 +66,7 @@ struct sg_table *
>  xhci_sideband_get_event_buffer(struct xhci_sideband *sb);
>  int
>  xhci_sideband_create_interrupter(struct xhci_sideband *sb, int num_seg,
> -                                bool ip_autoclear, u32 imod_interval);
> +                                bool ip_autoclear, u32 imod_interval, int intr_num);
>  void
>  xhci_sideband_remove_interrupter(struct xhci_sideband *sb);
>  int
>