linux-kernel - [PATCH 1/2] usb: xhci-mtk: remove unnecessary assignments in periodic TT scheduler

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Date:   Tue, 30 Mar 2021 16:06:16 +0800
From:   Ikjoon Jang <ikjn@...omium.org>
To:     linux-usb@...r.kernel.org
Cc:     Ikjoon Jang <ikjn@...omium.org>,
        Chunfeng Yun <chunfeng.yun@...iatek.com>,
        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: [PATCH 1/2] usb: xhci-mtk: remove unnecessary assignments in periodic TT scheduler

Remove unnecessary variables in check_sch_bw().
No functional changes, just for better readability.

Signed-off-by: Ikjoon Jang <ikjn@...omium.org>
---

 drivers/usb/host/xhci-mtk-sch.c | 52 +++++++++++++--------------------
 1 file changed, 21 insertions(+), 31 deletions(-)

diff --git a/drivers/usb/host/xhci-mtk-sch.c b/drivers/usb/host/xhci-mtk-sch.c
index a59d1f6d4744..0cb41007ec65 100644
--- a/drivers/usb/host/xhci-mtk-sch.c
+++ b/drivers/usb/host/xhci-mtk-sch.c
@@ -479,6 +479,9 @@ static int check_sch_tt(struct mu3h_sch_ep_info *sch_ep, u32 offset)
 	u32 start_cs, last_cs;
 	int i;
 
+	if (!sch_ep->sch_tt)
+		return 0;
+
 	start_ss = offset % 8;
 
 	if (sch_ep->ep_type == ISOC_OUT_EP) {
@@ -606,54 +609,41 @@ static u32 get_esit_boundary(struct mu3h_sch_ep_info *sch_ep)
 static int check_sch_bw(struct mu3h_sch_bw_info *sch_bw,
 			struct mu3h_sch_ep_info *sch_ep)
 {
-	u32 offset;
-	u32 min_bw;
-	u32 min_index;
-	u32 worst_bw;
-	u32 bw_boundary;
-	u32 esit_boundary;
-	u32 min_num_budget;
-	u32 min_cs_count;
-	int ret = 0;
+	int i, found = -1;
+	const u32 esit_boundary = get_esit_boundary(sch_ep);
+	const u32 bw_boundary = get_bw_boundary(sch_ep->speed);
+	u32 min_bw = ~0;
 
 	/*
 	 * Search through all possible schedule microframes.
 	 * and find a microframe where its worst bandwidth is minimum.
 	 */
-	min_bw = ~0;
-	min_index = 0;
-	min_cs_count = sch_ep->cs_count;
-	min_num_budget = sch_ep->num_budget_microframes;
-	esit_boundary = get_esit_boundary(sch_ep);
-	for (offset = 0; offset < sch_ep->esit; offset++) {
-		if (sch_ep->sch_tt) {
-			ret = check_sch_tt(sch_ep, offset);
-			if (ret)
-				continue;
-		}
+	for (i = 0; i < sch_ep->esit; i++) {
+		u32 worst_bw;
 
-		if ((offset + sch_ep->num_budget_microframes) > esit_boundary)
+		if ((i + sch_ep->num_budget_microframes) > esit_boundary)
 			break;
 
-		worst_bw = get_max_bw(sch_bw, sch_ep, offset);
+		if (check_sch_tt(sch_ep, i))
+			continue;
+
+		worst_bw = get_max_bw(sch_bw, sch_ep, i);
+		if (worst_bw > bw_boundary)
+			continue;
+
 		if (min_bw > worst_bw) {
 			min_bw = worst_bw;
-			min_index = offset;
-			min_cs_count = sch_ep->cs_count;
-			min_num_budget = sch_ep->num_budget_microframes;
+			found = i;
 		}
 		if (min_bw == 0)
 			break;
 	}
 
-	bw_boundary = get_bw_boundary(sch_ep->speed);
 	/* check bandwidth */
-	if (min_bw > bw_boundary)
-		return ret ? ret : -ESCH_BW_OVERFLOW;
+	if (found < 0)
+		return -ESCH_BW_OVERFLOW;
 
-	sch_ep->offset = min_index;
-	sch_ep->cs_count = min_cs_count;
-	sch_ep->num_budget_microframes = min_num_budget;
+	sch_ep->offset = found;
 
 	return load_ep_bw(sch_bw, sch_ep, true);
 }
-- 
2.31.0.291.g576ba9dcdaf-goog