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Message-ID: <1617179512.2752.2.camel@mhfsdcap03>
Date: Wed, 31 Mar 2021 16:31:52 +0800
From: Chunfeng Yun <chunfeng.yun@...iatek.com>
To: Ikjoon Jang <ikjn@...omium.org>, Yaqii Wu <Yaqii.Wu@...iatek.com>
CC: <linux-usb@...r.kernel.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Mathias Nyman <mathias.nyman@...el.com>,
Matthias Brugger <matthias.bgg@...il.com>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>,
<linux-mediatek@...ts.infradead.org>
Subject: Re: [PATCH 2/2] usb: xhci-mtk: relax periodic TT bandwidth checking
On Tue, 2021-03-30 at 16:06 +0800, Ikjoon Jang wrote:
> Software bandwidth checking logics used by xhci-mtk puts
> a quite heavy constraints to TT periodic endpoint allocations.
>
> This patch provides a relaxed bandwidth calculation by
> - Allowing multiple periodic transactions in a same microframe
> for a device with multiple interrupt endpoints.
> - Using best case budget instead of maximum number of
> complete-split when calculating byte budgets on lower speed bus
>
> Without this patch, a typical full speed audio headset with
> 3 periodic endpoints (audio isoc-in/out, input int-in) cannot be
> configured with xhci-mtk.
>
> Signed-off-by: Ikjoon Jang <ikjn@...omium.org>
> ---
cc Yaqii Wu <Yaqii.Wu@...iatek.com>
I'll test it, thanks
>
> drivers/usb/host/xhci-mtk-sch.c | 68 ++++++++++-----------------------
> drivers/usb/host/xhci-mtk.h | 2 -
> 2 files changed, 20 insertions(+), 50 deletions(-)
>
> diff --git a/drivers/usb/host/xhci-mtk-sch.c b/drivers/usb/host/xhci-mtk-sch.c
> index 0cb41007ec65..76827e48049a 100644
> --- a/drivers/usb/host/xhci-mtk-sch.c
> +++ b/drivers/usb/host/xhci-mtk-sch.c
> @@ -388,13 +388,17 @@ static void setup_sch_info(struct xhci_ep_ctx *ep_ctx,
> } else { /* INT_IN_EP or ISOC_IN_EP */
> bwb_table[0] = 0; /* start split */
> bwb_table[1] = 0; /* idle */
> +
> + sch_ep->num_budget_microframes += 2;
> + if (sch_ep->num_budget_microframes > sch_ep->esit)
> + sch_ep->num_budget_microframes = sch_ep->esit;
> /*
> * due to cs_count will be updated according to cs
> * position, assign all remainder budget array
> * elements as @bw_cost_per_microframe, but only first
> * @num_budget_microframes elements will be used later
> */
> - for (i = 2; i < TT_MICROFRAMES_MAX; i++)
> + for (i = 2; i < sch_ep->num_budget_microframes; i++)
> bwb_table[i] = sch_ep->bw_cost_per_microframe;
> }
> }
> @@ -449,20 +453,17 @@ static void update_bus_bw(struct mu3h_sch_bw_info *sch_bw,
> 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, tmp;
> - int base;
> int i, j;
> + const int nr_lower_uframes =
> + DIV_ROUND_UP(sch_ep->maxpkt, FS_PAYLOAD_MAX);
>
> - num_esit = XHCI_MTK_MAX_ESIT / sch_ep->esit;
> - for (i = 0; i < num_esit; i++) {
> - base = offset + i * sch_ep->esit;
> -
> + for (i = offset; i < XHCI_MTK_MAX_ESIT; i += sch_ep->esit) {
> /*
> * Compared with hs bus, no matter what ep type,
> * the hub will always delay one uframe to send data
> */
> - for (j = 0; j < sch_ep->cs_count; j++) {
> - tmp = tt->fs_bus_bw[base + j] + sch_ep->bw_cost_per_microframe;
> + for (j = 0; j < nr_lower_uframes; j++) {
> + u32 tmp = tt->fs_bus_bw[i + j + 1] + sch_ep->bw_cost_per_microframe;
> if (tmp > FS_PAYLOAD_MAX)
> return -ESCH_BW_OVERFLOW;
> }
> @@ -473,11 +474,9 @@ static int check_fs_bus_bw(struct mu3h_sch_ep_info *sch_ep, int offset)
>
> static int check_sch_tt(struct mu3h_sch_ep_info *sch_ep, u32 offset)
> {
> - struct mu3h_sch_tt *tt = sch_ep->sch_tt;
> u32 extra_cs_count;
> u32 start_ss, last_ss;
> u32 start_cs, last_cs;
> - int i;
>
> if (!sch_ep->sch_tt)
> return 0;
> @@ -494,10 +493,6 @@ static int check_sch_tt(struct mu3h_sch_ep_info *sch_ep, u32 offset)
> if (!(start_ss == 7 || last_ss < 6))
> return -ESCH_SS_Y6;
>
> - for (i = 0; i < sch_ep->cs_count; i++)
> - if (test_bit(offset + i, tt->ss_bit_map))
> - return -ESCH_SS_OVERLAP;
> -
> } else {
> u32 cs_count = DIV_ROUND_UP(sch_ep->maxpkt, FS_PAYLOAD_MAX);
>
> @@ -524,19 +519,7 @@ static int check_sch_tt(struct mu3h_sch_ep_info *sch_ep, u32 offset)
> if (cs_count > 7)
> cs_count = 7; /* HW limit */
>
> - if (test_bit(offset, tt->ss_bit_map))
> - return -ESCH_SS_OVERLAP;
> -
> sch_ep->cs_count = cs_count;
> - /* one for ss, the other for idle */
> - sch_ep->num_budget_microframes = cs_count + 2;
> -
> - /*
> - * if interval=1, maxp >752, num_budge_micoframe is larger
> - * than sch_ep->esit, will overstep boundary
> - */
> - if (sch_ep->num_budget_microframes > sch_ep->esit)
> - sch_ep->num_budget_microframes = sch_ep->esit;
> }
>
> return check_fs_bus_bw(sch_ep, offset);
> @@ -545,31 +528,18 @@ static int check_sch_tt(struct mu3h_sch_ep_info *sch_ep, u32 offset)
> 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 bw_updated;
> - int bits;
> - int i, j;
> -
> - num_esit = XHCI_MTK_MAX_ESIT / sch_ep->esit;
> - bits = (sch_ep->ep_type == ISOC_OUT_EP) ? sch_ep->cs_count : 1;
> + int i, j, bw_updated;
> + const int nr_lower_uframes =
> + DIV_ROUND_UP(sch_ep->maxpkt, FS_PAYLOAD_MAX);
>
> if (used)
> bw_updated = sch_ep->bw_cost_per_microframe;
> else
> bw_updated = -sch_ep->bw_cost_per_microframe;
>
> - for (i = 0; i < num_esit; i++) {
> - base = sch_ep->offset + i * sch_ep->esit;
> -
> - for (j = 0; j < bits; j++) {
> - if (used)
> - set_bit(base + j, tt->ss_bit_map);
> - else
> - clear_bit(base + j, tt->ss_bit_map);
> - }
> -
> - for (j = 0; j < sch_ep->cs_count; j++)
> - tt->fs_bus_bw[base + j] += bw_updated;
> + for (i = sch_ep->offset; i < XHCI_MTK_MAX_ESIT; i += sch_ep->esit) {
> + for (j = 0; j < nr_lower_uframes; j++)
> + tt->fs_bus_bw[i+ j + 1] += bw_updated;
> }
>
> if (used)
> @@ -634,9 +604,11 @@ static int check_sch_bw(struct mu3h_sch_bw_info *sch_bw,
> if (min_bw > worst_bw) {
> min_bw = worst_bw;
> found = i;
> + /* fastpath: bandwidth contributions to host is low
> + * when it's fs/ls */
> + if (sch_ep->sch_tt || min_bw == 0)
> + break;
> }
> - if (min_bw == 0)
> - break;
> }
>
> /* check bandwidth */
> diff --git a/drivers/usb/host/xhci-mtk.h b/drivers/usb/host/xhci-mtk.h
> index 621ec1a85009..8a879f99ae1c 100644
> --- a/drivers/usb/host/xhci-mtk.h
> +++ b/drivers/usb/host/xhci-mtk.h
> @@ -20,12 +20,10 @@
> #define XHCI_MTK_MAX_ESIT 64
>
> /**
> - * @ss_bit_map: used to avoid start split microframes overlay
> * @fs_bus_bw: array to keep track of bandwidth already used for FS
> * @ep_list: Endpoints using this TT
> */
> struct mu3h_sch_tt {
> - DECLARE_BITMAP(ss_bit_map, XHCI_MTK_MAX_ESIT);
> u32 fs_bus_bw[XHCI_MTK_MAX_ESIT];
> struct list_head ep_list;
> };
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