[RFC v4 PATCH] usb: xhci-mtk: improve bandwidth scheduling with TT
Ikjoon Jang
ikjn at chromium.org
Sun Feb 21 22:12:52 EST 2021
On Mon, Feb 8, 2021 at 11:27 AM Chunfeng Yun <chunfeng.yun at mediatek.com> wrote:
>
> When the USB headset is plug into an external hub, sometimes
> can't set config due to not enough bandwidth, so need improve
> LS/FS INT/ISOC bandwidth scheduling with TT.
>
> Fixes: 08e469de87a2 ("usb: xhci-mtk: supports bandwidth scheduling with multi-TT")
> Signed-off-by: Yaqii Wu <yaqii.wu at mediatek.com>
> Signed-off-by: Chunfeng Yun <chunfeng.yun at mediatek.com>
Tested-by: Ikjoon Jang <ikjn at chromium.org>
> ---
> drivers/usb/host/xhci-mtk-sch.c | 270 +++++++++++++++++++++++---------
> drivers/usb/host/xhci-mtk.h | 8 +-
> 2 files changed, 201 insertions(+), 77 deletions(-)
>
> diff --git a/drivers/usb/host/xhci-mtk-sch.c b/drivers/usb/host/xhci-mtk-sch.c
> index b45e5bf08997..f3cdfcf4e5bf 100644
> --- a/drivers/usb/host/xhci-mtk-sch.c
> +++ b/drivers/usb/host/xhci-mtk-sch.c
> @@ -32,6 +32,35 @@
> #define EP_BOFFSET(p) ((p) & 0x3fff)
> #define EP_BREPEAT(p) (((p) & 0x7fff) << 16)
>
> +enum mtk_sch_err_type {
> + SCH_SUCCESS = 0,
> + SCH_ERR_Y6,
> + SCH_SS_OVERLAP,
> + SCH_CS_OVERFLOW,
> + SCH_BW_OVERFLOW,
> + SCH_FIXME,
> +};
> +
> +static char *sch_error_string(enum mtk_sch_err_type error)
> +{
> + switch (error) {
> + case SCH_SUCCESS:
> + return "Success";
> + case SCH_ERR_Y6:
> + return "Can't schedule Start-Split in Y6";
> + case SCH_SS_OVERLAP:
> + return "Can't find a suitable Start-Split location";
> + case SCH_CS_OVERFLOW:
> + return "The last Complete-Split is greater than 7";
> + case SCH_BW_OVERFLOW:
> + return "Bandwidth exceeds the max limit";
> + case SCH_FIXME:
> + return "FIXME, to be resolved";
> + default:
> + return "Unknown error type";
> + }
> +}
> +
> static int is_fs_or_ls(enum usb_device_speed speed)
> {
> return speed == USB_SPEED_FULL || speed == USB_SPEED_LOW;
> @@ -81,11 +110,22 @@ static u32 get_esit(struct xhci_ep_ctx *ep_ctx)
> return esit;
> }
>
> +static u32 get_bw_boundary(enum usb_device_speed speed)
> +{
> + switch (speed) {
> + case USB_SPEED_SUPER_PLUS:
> + return SSP_BW_BOUNDARY;
> + case USB_SPEED_SUPER:
> + return SS_BW_BOUNDARY;
> + default:
> + return HS_BW_BOUNDARY;
> + }
> +}
> +
> static struct mu3h_sch_tt *find_tt(struct usb_device *udev)
> {
> struct usb_tt *utt = udev->tt;
> struct mu3h_sch_tt *tt, **tt_index, **ptt;
> - unsigned int port;
> bool allocated_index = false;
>
> if (!utt)
> @@ -107,10 +147,9 @@ static struct mu3h_sch_tt *find_tt(struct usb_device *udev)
> utt->hcpriv = tt_index;
> allocated_index = true;
> }
> - port = udev->ttport - 1;
> - ptt = &tt_index[port];
> +
> + ptt = &tt_index[udev->ttport - 1];
> } else {
> - port = 0;
> ptt = (struct mu3h_sch_tt **) &utt->hcpriv;
> }
>
> @@ -125,8 +164,7 @@ static struct mu3h_sch_tt *find_tt(struct usb_device *udev)
> return ERR_PTR(-ENOMEM);
> }
> INIT_LIST_HEAD(&tt->ep_list);
> - tt->usb_tt = utt;
> - tt->tt_port = port;
> +
> *ptt = tt;
> }
>
> @@ -206,6 +244,15 @@ static struct mu3h_sch_ep_info *create_sch_ep(struct usb_device *udev,
> return sch_ep;
> }
>
> +static void delete_sch_ep(struct usb_device *udev, struct mu3h_sch_ep_info *sch_ep)
> +{
> + if (sch_ep->sch_tt)
> + drop_tt(udev);
> +
> + list_del(&sch_ep->endpoint);
> + kfree(sch_ep);
> +}
> +
> static void setup_sch_info(struct usb_device *udev,
> struct xhci_ep_ctx *ep_ctx, struct mu3h_sch_ep_info *sch_ep)
> {
> @@ -375,21 +422,55 @@ static void update_bus_bw(struct mu3h_sch_bw_info *sch_bw,
> sch_ep->bw_budget_table[j];
> }
> }
> - sch_ep->allocated = used;
> }
>
> -static int check_sch_tt(struct usb_device *udev,
> - struct mu3h_sch_ep_info *sch_ep, u32 offset)
> +static int check_fs_bus_bw(struct mu3h_sch_ep_info *sch_ep, int offset)
> +{
> + struct mu3h_sch_tt *tt = sch_ep->sch_tt;
> + u32 num_esit, base;
> + u32 i, j;
> + u32 tmp;
> +
> + num_esit = XHCI_MTK_MAX_ESIT / sch_ep->esit;
> +
> + for (i = 0; i < num_esit; i++) {
> + base = offset + i * sch_ep->esit;
> +
> + /*
> + * Compared with hs bus, no matter what ep type
> + * The hub will always delay one uframe to send
> + * data for us. As described in the figure below.
> + */
> + if (sch_ep->ep_type == ISOC_OUT_EP) {
> + for (j = 0; j < sch_ep->num_budget_microframes; j++) {
> + tmp = tt->fs_bus_bw[base + 1 + j]
> + + sch_ep->bw_cost_per_microframe;
> +
> + if (tmp > FS_PAYLOAD_MAX)
> + return SCH_BW_OVERFLOW;
> + }
> + } else {
> + for (j = 0; j < sch_ep->cs_count; j++) {
> + tmp = tt->fs_bus_bw[base + 1 + j]
> + + sch_ep->bw_cost_per_microframe;
> +
> + if (tmp > FS_PAYLOAD_MAX)
> + return SCH_BW_OVERFLOW;
> + }
> + }
> + }
> + return SCH_SUCCESS;
> +}
> +
> +static int check_sch_tt(struct mu3h_sch_ep_info *sch_ep, int offset)
> {
> struct mu3h_sch_tt *tt = sch_ep->sch_tt;
> u32 extra_cs_count;
> - u32 fs_budget_start;
> u32 start_ss, last_ss;
> u32 start_cs, last_cs;
> - int i;
> + u32 i;
>
> start_ss = offset % 8;
> - fs_budget_start = (start_ss + 1) % 8;
>
> if (sch_ep->ep_type == ISOC_OUT_EP) {
> last_ss = start_ss + sch_ep->cs_count - 1;
> @@ -399,12 +480,12 @@ static int check_sch_tt(struct usb_device *udev,
> * must never schedule Start-Split in Y6
> */
> if (!(start_ss == 7 || last_ss < 6))
> - return -ERANGE;
> -
> - for (i = 0; i < sch_ep->cs_count; i++)
> - if (test_bit(offset + i, tt->split_bit_map))
> - return -ERANGE;
> + return SCH_ERR_Y6;
>
> + for (i = 0; i < sch_ep->cs_count; i++) {
> + if (test_bit(offset + i, tt->ss_bit_map))
> + return SCH_SS_OVERLAP;
> + }
> } else {
> u32 cs_count = DIV_ROUND_UP(sch_ep->maxpkt, FS_PAYLOAD_MAX);
>
> @@ -413,27 +494,36 @@ static int check_sch_tt(struct usb_device *udev,
> * must never schedule Start-Split in Y6
> */
> if (start_ss == 6)
> - return -ERANGE;
> + return SCH_ERR_Y6;
>
> /* one uframe for ss + one uframe for idle */
> start_cs = (start_ss + 2) % 8;
> last_cs = start_cs + cs_count - 1;
>
> if (last_cs > 7)
> - return -ERANGE;
> + return SCH_CS_OVERFLOW;
>
> + /*
> + * usb_20 spec section11.18, the bottom of page 378:
> + * For interrupt endpoints, the maximum size of the LS/FS
> + * transaction guarantees that it can never require more than
> + * two complete-split transactions.
> + */
> if (sch_ep->ep_type == ISOC_IN_EP)
> extra_cs_count = (last_cs == 7) ? 1 : 2;
> else /* ep_type : INTR IN / INTR OUT */
> - extra_cs_count = (fs_budget_start == 6) ? 1 : 2;
> + extra_cs_count = 1;
>
> cs_count += extra_cs_count;
> if (cs_count > 7)
> cs_count = 7; /* HW limit */
>
> - for (i = 0; i < cs_count + 2; i++) {
> - if (test_bit(offset + i, tt->split_bit_map))
> - return -ERANGE;
> + if (test_bit(offset, tt->ss_bit_map))
> + return SCH_SS_OVERLAP;
> +
> + if (sch_ep->ep_type == INT_OUT_EP) {
> + if (test_bit(offset, tt->idle_bit_map))
> + return SCH_FIXME;
> }
>
> sch_ep->cs_count = cs_count;
> @@ -448,41 +538,88 @@ static int check_sch_tt(struct usb_device *udev,
> sch_ep->num_budget_microframes = sch_ep->esit;
> }
>
> - return 0;
> + return check_fs_bus_bw(sch_ep, offset);
> }
>
> -static void update_sch_tt(struct usb_device *udev,
> - struct mu3h_sch_ep_info *sch_ep)
> +static void update_sch_tt(struct mu3h_sch_ep_info *sch_ep, bool used)
> {
> struct mu3h_sch_tt *tt = sch_ep->sch_tt;
> u32 base, num_esit;
> - int i, j;
> + u32 i, j;
>
> num_esit = XHCI_MTK_MAX_ESIT / sch_ep->esit;
> +
> for (i = 0; i < num_esit; i++) {
> base = sch_ep->offset + i * sch_ep->esit;
> - for (j = 0; j < sch_ep->num_budget_microframes; j++)
> - set_bit(base + j, tt->split_bit_map);
> +
> + if (sch_ep->ep_type == ISOC_OUT_EP) {
> + for (j = 0; j < sch_ep->num_budget_microframes; j++) {
> + if (used) {
> + set_bit(base + j, tt->ss_bit_map);
> + tt->fs_bus_bw[base + 1 + j] +=
> + sch_ep->bw_cost_per_microframe;
> + } else {
> + clear_bit(base + j, tt->ss_bit_map);
> + tt->fs_bus_bw[base + 1 + j] -=
> + sch_ep->bw_cost_per_microframe;
> + }
> + }
> + } else {
> + if (used)
> + set_bit(base, tt->ss_bit_map);
> + else
> + clear_bit(base, tt->ss_bit_map);
> +
> + if (sch_ep->ep_type == INT_OUT_EP) {
> + if (used)
> + set_bit(base + 1, tt->idle_bit_map);
> + else
> + clear_bit(base + 1, tt->idle_bit_map);
> + }
> +
> + for (j = 0; j < sch_ep->cs_count; j++) {
> + if (used)
> + tt->fs_bus_bw[base + 1 + j] +=
> + sch_ep->bw_cost_per_microframe;
> + else
> + tt->fs_bus_bw[base + 1 + j] -=
> + sch_ep->bw_cost_per_microframe;
> + }
> + }
> + }
> +}
> +
> +static int load_ep_bw(struct mu3h_sch_bw_info *sch_bw,
> + struct mu3h_sch_ep_info *sch_ep, bool loaded)
> +{
> + struct mu3h_sch_tt *tt = sch_ep->sch_tt;
> +
> + if (sch_ep->sch_tt) {
> + update_sch_tt(sch_ep, loaded);
> + if (loaded)
> + list_add_tail(&sch_ep->tt_endpoint, &tt->ep_list);
> + else
> + list_del(&sch_ep->tt_endpoint);
> }
>
> - list_add_tail(&sch_ep->tt_endpoint, &tt->ep_list);
> + /* update bus bandwidth info */
> + update_bus_bw(sch_bw, sch_ep, loaded);
> + sch_ep->allocated = loaded;
> + return 0;
> }
>
> static int check_sch_bw(struct usb_device *udev,
> struct mu3h_sch_bw_info *sch_bw, struct mu3h_sch_ep_info *sch_ep)
> {
> u32 offset;
> - u32 esit;
> u32 min_bw;
> u32 min_index;
> u32 worst_bw;
> u32 bw_boundary;
> + u32 boundary;
> u32 min_num_budget;
> u32 min_cs_count;
> - bool tt_offset_ok = false;
> - int ret;
> -
> - esit = sch_ep->esit;
> + int ret = 0;
>
> /*
> * Search through all possible schedule microframes.
> @@ -492,16 +629,20 @@ static int check_sch_bw(struct usb_device *udev,
> min_index = 0;
> min_cs_count = sch_ep->cs_count;
> min_num_budget = sch_ep->num_budget_microframes;
> - for (offset = 0; offset < esit; offset++) {
> - if (is_fs_or_ls(udev->speed)) {
> - ret = check_sch_tt(udev, sch_ep, offset);
> - if (ret)
> +
> + if (is_fs_or_ls(udev->speed) && sch_ep->ep_type != ISOC_OUT_EP)
> + boundary = sch_ep->esit + 1;
> + else
> + boundary = sch_ep->esit;
> +
> + for (offset = 0; offset < sch_ep->esit; offset++) {
> + if (sch_ep->sch_tt) {
> + ret = check_sch_tt(sch_ep, offset);
> + if (ret != SCH_SUCCESS)
> continue;
> - else
> - tt_offset_ok = true;
> }
>
> - if ((offset + sch_ep->num_budget_microframes) > sch_ep->esit)
> + if ((offset + sch_ep->num_budget_microframes) > boundary)
> break;
>
> worst_bw = get_max_bw(sch_bw, sch_ep, offset);
> @@ -515,33 +656,22 @@ static int check_sch_bw(struct usb_device *udev,
> break;
> }
>
> - if (udev->speed == USB_SPEED_SUPER_PLUS)
> - bw_boundary = SSP_BW_BOUNDARY;
> - else if (udev->speed == USB_SPEED_SUPER)
> - bw_boundary = SS_BW_BOUNDARY;
> - else
> - bw_boundary = HS_BW_BOUNDARY;
> -
> + bw_boundary = get_bw_boundary(udev->speed);
> /* check bandwidth */
> - if (min_bw > bw_boundary)
> + if (min_bw > bw_boundary) {
> + if (ret) {
> + dev_err(&udev->dev, "%s %s\n", __func__,
> + sch_error_string(ret));
> + return -ret;
> + }
> +
> return -ERANGE;
> + }
>
> sch_ep->offset = min_index;
> sch_ep->cs_count = min_cs_count;
> sch_ep->num_budget_microframes = min_num_budget;
> -
> - if (is_fs_or_ls(udev->speed)) {
> - /* all offset for tt is not ok*/
> - if (!tt_offset_ok)
> - return -ERANGE;
> -
> - update_sch_tt(udev, sch_ep);
> - }
> -
> - /* update bus bandwidth info */
> - update_bus_bw(sch_bw, sch_ep, 1);
> -
> - return 0;
> + return load_ep_bw(sch_bw, sch_ep, true);
> }
>
> static void destroy_sch_ep(struct usb_device *udev,
> @@ -549,23 +679,17 @@ static void destroy_sch_ep(struct usb_device *udev,
> {
> /* only release ep bw check passed by check_sch_bw() */
> if (sch_ep->allocated)
> - update_bus_bw(sch_bw, sch_ep, 0);
> + load_ep_bw(sch_bw, sch_ep, false);
>
> - list_del(&sch_ep->endpoint);
> -
> - if (sch_ep->sch_tt) {
> - list_del(&sch_ep->tt_endpoint);
> - drop_tt(udev);
> - }
> - kfree(sch_ep);
> + delete_sch_ep(udev, sch_ep);
> }
>
> static bool need_bw_sch(struct usb_host_endpoint *ep,
> enum usb_device_speed speed, int has_tt)
> {
> /* only for periodic endpoints */
> - if (usb_endpoint_xfer_control(&ep->desc)
> - || usb_endpoint_xfer_bulk(&ep->desc))
> + if (usb_endpoint_xfer_control(&ep->desc) ||
> + usb_endpoint_xfer_bulk(&ep->desc))
> return false;
>
> /*
> diff --git a/drivers/usb/host/xhci-mtk.h b/drivers/usb/host/xhci-mtk.h
> index cbb09dfea62e..81e9b56958c5 100644
> --- a/drivers/usb/host/xhci-mtk.h
> +++ b/drivers/usb/host/xhci-mtk.h
> @@ -26,10 +26,10 @@
> * @tt_port: TT port number
> */
> struct mu3h_sch_tt {
> - DECLARE_BITMAP(split_bit_map, XHCI_MTK_MAX_ESIT);
> + DECLARE_BITMAP(ss_bit_map, XHCI_MTK_MAX_ESIT);
> + DECLARE_BITMAP(idle_bit_map, XHCI_MTK_MAX_ESIT);
> + u32 fs_bus_bw[XHCI_MTK_MAX_ESIT + 1];
> struct list_head ep_list;
> - struct usb_tt *usb_tt;
> - int tt_port;
> };
>
> /**
> @@ -84,9 +84,9 @@ struct mu3h_sch_ep_info {
> struct list_head endpoint;
> struct list_head tt_endpoint;
> struct mu3h_sch_tt *sch_tt;
> + struct usb_host_endpoint *ep;
> u32 ep_type;
> u32 maxpkt;
> - void *ep;
> bool allocated;
> /*
> * mtk xHCI scheduling information put into reserved DWs
> --
> 2.18.0
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