Message-ID: <20210208032716.20247-1-chunfeng.yun@mediatek.com>
Date:   Mon, 8 Feb 2021 11:27:16 +0800
From:   Chunfeng Yun <chunfeng.yun@...iatek.com>
To:     Ikjoon Jang <ikjn@...omium.org>
CC:     Chunfeng Yun <chunfeng.yun@...iatek.com>,
        <linux-mediatek@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>,
        Tianping Fang <tianping.fang@...iatek.com>,
        Yaqii Wu <yaqii.wu@...iatek.com>
Subject: [RFC v4 PATCH] usb: xhci-mtk: improve bandwidth scheduling with TT

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@...iatek.com>
Signed-off-by: Chunfeng Yun <chunfeng.yun@...iatek.com>
---
 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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