[PATCH] usb: xhci-mtk: relax TT periodic bandwidth allocation
From: Ikjoon Jang <hidden>
Date: 2021-08-05 05:40:05
Also in:
linux-mediatek, linux-usb, lkml
Subsystem:
mediatek usb3 drd ip driver, the rest, usb subsystem, usb xhci driver · Maintainers:
Chunfeng Yun, Linus Torvalds, Greg Kroah-Hartman, Mathias Nyman
Currently xhci-mtk needs software-managed bandwidth allocation for periodic endpoints, it allocates the microframe index for the first start-split packet for each endpoint. As this index allocation logic should avoid the conflicts with other full/low-speed periodic endpoints, it uses the worst case byte budgets on high-speed bus bandwidth For example, for an isochronos IN endpoint with 192 bytes budget, it will consume the whole 4 u-frames(188 * 4) while the actual full-speed bus budget should be just 192bytes. This patch changes the low/full-speed bandwidth allocation logic to use "approximate" best case budget for lower speed bandwidth management. For the same endpoint from the above example, the approximate best case budget is now reduced to (188 * 2) bytes. Without this patch, many usb audio headsets with 3 interfaces (audio input, audio output, and HID) cannot be configured on xhci-mtk. Signed-off-by: Ikjoon Jang <redacted> --- drivers/usb/host/xhci-mtk-sch.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-)
diff --git a/drivers/usb/host/xhci-mtk-sch.c b/drivers/usb/host/xhci-mtk-sch.c
index f9b4d27ce449..46cbf5d54f4f 100644
--- a/drivers/usb/host/xhci-mtk-sch.c
+++ b/drivers/usb/host/xhci-mtk-sch.c@@ -459,16 +459,17 @@ static int check_fs_bus_bw(struct mu3h_sch_ep_info *sch_ep, int offset) u32 num_esit, tmp; int base; int i, j; + u8 uframes = DIV_ROUND_UP(sch_ep->maxpkt, FS_PAYLOAD_MAX); num_esit = XHCI_MTK_MAX_ESIT / sch_ep->esit; + + if (sch_ep->ep_type == INT_IN_EP || sch_ep->ep_type == ISOC_IN_EP) + offset++; + 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 (j = 0; j < sch_ep->cs_count; j++) { + for (j = 0; j < uframes; j++) { tmp = tt->fs_bus_bw[base + j] + sch_ep->bw_cost_per_microframe; if (tmp > FS_PAYLOAD_MAX) return -ESCH_BW_OVERFLOW;
@@ -546,6 +547,8 @@ static void update_sch_tt(struct mu3h_sch_ep_info *sch_ep, bool used) u32 base, num_esit; int bw_updated; int i, j; + int offset = sch_ep->offset; + u8 uframes = DIV_ROUND_UP(sch_ep->maxpkt, FS_PAYLOAD_MAX); num_esit = XHCI_MTK_MAX_ESIT / sch_ep->esit;
@@ -554,10 +557,13 @@ static void update_sch_tt(struct mu3h_sch_ep_info *sch_ep, bool used) else bw_updated = -sch_ep->bw_cost_per_microframe; + if (sch_ep->ep_type == INT_IN_EP || sch_ep->ep_type == ISOC_IN_EP) + offset++; + for (i = 0; i < num_esit; i++) { - base = sch_ep->offset + i * sch_ep->esit; + base = offset + i * sch_ep->esit; - for (j = 0; j < sch_ep->cs_count; j++) + for (j = 0; j < uframes; j++) tt->fs_bus_bw[base + j] += bw_updated; }
--
2.32.0.554.ge1b32706d8-goog
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