From ccda8c224c0701caac007311d06a2de9543a7590 Mon Sep 17 00:00:00 2001
From: Chunfeng Yun <chunfeng.yun@mediatek.com>
Date: Mon, 8 Mar 2021 10:52:02 +0800
Subject: [PATCH] usb: xhci-mtk: add some schedule error number
Git-commit: ccda8c224c0701caac007311d06a2de9543a7590
Patch-mainline: v5.13-rc1
References: git-fixes

This is used to provide more information about which case
causes bandwidth schedule failure.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/9771f44093053b581e9c4be4b7fb68d9fcecad08.1615170625.git.chunfeng.yun@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/usb/host/xhci-mtk-sch.c |   44 +++++++++++++++++++++++++++++++---------
 1 file changed, 35 insertions(+), 9 deletions(-)

--- a/drivers/usb/host/xhci-mtk-sch.c
+++ b/drivers/usb/host/xhci-mtk-sch.c
@@ -25,6 +25,13 @@
  */
 #define TT_MICROFRAMES_MAX 9
 
+/* schedule error type */
+#define ESCH_SS_Y6		1001
+#define ESCH_SS_OVERLAP		1002
+#define ESCH_CS_OVERFLOW	1003
+#define ESCH_BW_OVERFLOW	1004
+#define ESCH_FIXME		1005
+
 /* mtk scheduler bitmasks */
 #define EP_BPKTS(p)	((p) & 0x7f)
 #define EP_BCSCOUNT(p)	(((p) & 0x7) << 8)
@@ -32,6 +39,24 @@
 #define EP_BOFFSET(p)	((p) & 0x3fff)
 #define EP_BREPEAT(p)	(((p) & 0x7fff) << 16)
 
+static char *sch_error_string(int err_num)
+{
+	switch (err_num) {
+	case ESCH_SS_Y6:
+		return "Can't schedule Start-Split in Y6";
+	case ESCH_SS_OVERLAP:
+		return "Can't find a suitable Start-Split location";
+	case ESCH_CS_OVERFLOW:
+		return "The last Complete-Split is greater than 7";
+	case ESCH_BW_OVERFLOW:
+		return "Bandwidth exceeds the maximum limit";
+	case ESCH_FIXME:
+		return "FIXME, to be resolved";
+	default:
+		return "Unknown";
+	}
+}
+
 static int is_fs_or_ls(enum usb_device_speed speed)
 {
 	return speed == USB_SPEED_FULL || speed == USB_SPEED_LOW;
@@ -395,7 +420,7 @@ static int check_fs_bus_bw(struct mu3h_s
 		for (j = 0; j < sch_ep->cs_count; j++) {
 			tmp = tt->fs_bus_bw[base + j] + sch_ep->bw_cost_per_microframe;
 			if (tmp > FS_PAYLOAD_MAX)
-				return -ERANGE;
+				return -ESCH_BW_OVERFLOW;
 		}
 	}
 
@@ -421,11 +446,11 @@ static int check_sch_tt(struct usb_devic
 		 * must never schedule Start-Split in Y6
 		 */
 		if (!(start_ss == 7 || last_ss < 6))
-			return -ERANGE;
+			return -ESCH_SS_Y6;
 
 		for (i = 0; i < sch_ep->cs_count; i++)
 			if (test_bit(offset + i, tt->ss_bit_map))
-				return -ERANGE;
+				return -ESCH_SS_OVERLAP;
 
 	} else {
 		u32 cs_count = DIV_ROUND_UP(sch_ep->maxpkt, FS_PAYLOAD_MAX);
@@ -435,14 +460,14 @@ static int check_sch_tt(struct usb_devic
 		 * must never schedule Start-Split in Y6
 		 */
 		if (start_ss == 6)
-			return -ERANGE;
+			return -ESCH_SS_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 -ESCH_CS_OVERFLOW;
 
 		if (sch_ep->ep_type == ISOC_IN_EP)
 			extra_cs_count = (last_cs == 7) ? 1 : 2;
@@ -454,7 +479,7 @@ static int check_sch_tt(struct usb_devic
 			cs_count = 7; /* HW limit */
 
 		if (test_bit(offset, tt->ss_bit_map))
-			return -ERANGE;
+			return -ESCH_SS_OVERLAP;
 
 		sch_ep->cs_count = cs_count;
 		/* one for ss, the other for idle */
@@ -547,7 +572,7 @@ static int check_sch_bw(struct usb_devic
 	u32 esit_boundary;
 	u32 min_num_budget;
 	u32 min_cs_count;
-	int ret;
+	int ret = 0;
 
 	/*
 	 * Search through all possible schedule microframes.
@@ -588,7 +613,7 @@ static int check_sch_bw(struct usb_devic
 
 	/* check bandwidth */
 	if (min_bw > bw_boundary)
-		return -ERANGE;
+		return ret ? ret : -ESCH_BW_OVERFLOW;
 
 	sch_ep->offset = min_index;
 	sch_ep->cs_count = min_cs_count;
@@ -765,7 +790,8 @@ int xhci_mtk_check_bandwidth(struct usb_
 
 		ret = check_sch_bw(udev, sch_bw, sch_ep);
 		if (ret) {
-			xhci_err(xhci, "Not enough bandwidth!\n");
+			xhci_err(xhci, "Not enough bandwidth! (%s)\n",
+				 sch_error_string(-ret));
 			return -ENOSPC;
 		}
 	}