From 95099d4622f8cb224d94e314c7a8e0df60b13f87 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Sat, 09 Dec 2023 08:38:01 +0000
Subject: [PATCH] enable docker ppp

---
 kernel/drivers/dma/amba-pl08x.c |   63 ++++++++++++-------------------
 1 files changed, 25 insertions(+), 38 deletions(-)

diff --git a/kernel/drivers/dma/amba-pl08x.c b/kernel/drivers/dma/amba-pl08x.c
index 97483df..a24882b 100644
--- a/kernel/drivers/dma/amba-pl08x.c
+++ b/kernel/drivers/dma/amba-pl08x.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Copyright (c) 2006 ARM Ltd.
  * Copyright (c) 2010 ST-Ericsson SA
@@ -5,19 +6,6 @@
  *
  * Author: Peter Pearse <peter.pearse@arm.com>
  * Author: Linus Walleij <linus.walleij@linaro.org>
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License as published by the Free
- * Software Foundation; either version 2 of the License, or (at your option)
- * any later version.
- *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
- * more details.
- *
- * The full GNU General Public License is in this distribution in the file
- * called COPYING.
  *
  * Documentation: ARM DDI 0196G == PL080
  * Documentation: ARM DDI 0218E == PL081
@@ -254,6 +242,7 @@
  * @slave: whether this channel is a device (slave) or for memcpy
  * @signal: the physical DMA request signal which this channel is using
  * @mux_use: count of descriptors using this DMA request signal setting
+ * @waiting_at: time in jiffies when this channel moved to waiting state
  */
 struct pl08x_dma_chan {
 	struct virt_dma_chan vc;
@@ -267,6 +256,7 @@
 	bool slave;
 	int signal;
 	unsigned mux_use;
+	unsigned long waiting_at;
 };
 
 /**
@@ -875,6 +865,7 @@
 	if (!ch) {
 		dev_dbg(&pl08x->adev->dev, "no physical channel available for xfer on %s\n", plchan->name);
 		plchan->state = PL08X_CHAN_WAITING;
+		plchan->waiting_at = jiffies;
 		return;
 	}
 
@@ -913,22 +904,29 @@
 {
 	struct pl08x_driver_data *pl08x = plchan->host;
 	struct pl08x_dma_chan *p, *next;
-
+	unsigned long waiting_at;
  retry:
 	next = NULL;
+	waiting_at = jiffies;
 
-	/* Find a waiting virtual channel for the next transfer. */
+	/*
+	 * Find a waiting virtual channel for the next transfer.
+	 * To be fair, time when each channel reached waiting state is compared
+	 * to select channel that is waiting for the longest time.
+	 */
 	list_for_each_entry(p, &pl08x->memcpy.channels, vc.chan.device_node)
-		if (p->state == PL08X_CHAN_WAITING) {
+		if (p->state == PL08X_CHAN_WAITING &&
+		    p->waiting_at <= waiting_at) {
 			next = p;
-			break;
+			waiting_at = p->waiting_at;
 		}
 
 	if (!next && pl08x->has_slave) {
 		list_for_each_entry(p, &pl08x->slave.channels, vc.chan.device_node)
-			if (p->state == PL08X_CHAN_WAITING) {
+			if (p->state == PL08X_CHAN_WAITING &&
+			    p->waiting_at <= waiting_at) {
 				next = p;
-				break;
+				waiting_at = p->waiting_at;
 			}
 	}
 
@@ -1769,7 +1767,7 @@
 	default:
 		dev_err(&pl08x->adev->dev,
 			"illegal burst size for memcpy, set to 1\n");
-		/* Fall through */
+		fallthrough;
 	case PL08X_BURST_SZ_1:
 		cctl |= PL080_BSIZE_1 << PL080_CONTROL_SB_SIZE_SHIFT |
 			PL080_BSIZE_1 << PL080_CONTROL_DB_SIZE_SHIFT;
@@ -1808,7 +1806,7 @@
 	default:
 		dev_err(&pl08x->adev->dev,
 			"illegal bus width for memcpy, set to 8 bits\n");
-		/* Fall through */
+		fallthrough;
 	case PL08X_BUS_WIDTH_8_BITS:
 		cctl |= PL080_WIDTH_8BIT << PL080_CONTROL_SWIDTH_SHIFT |
 			PL080_WIDTH_8BIT << PL080_CONTROL_DWIDTH_SHIFT;
@@ -1852,7 +1850,7 @@
 	default:
 		dev_err(&pl08x->adev->dev,
 			"illegal bus width for memcpy, set to 8 bits\n");
-		/* Fall through */
+		fallthrough;
 	case PL08X_BUS_WIDTH_8_BITS:
 		cctl |= PL080_WIDTH_8BIT << FTDMAC020_LLI_SRC_WIDTH_SHIFT |
 			PL080_WIDTH_8BIT << FTDMAC020_LLI_DST_WIDTH_SHIFT;
@@ -2505,24 +2503,13 @@
 	return 0;
 }
 
-static int pl08x_debugfs_open(struct inode *inode, struct file *file)
-{
-	return single_open(file, pl08x_debugfs_show, inode->i_private);
-}
-
-static const struct file_operations pl08x_debugfs_operations = {
-	.open		= pl08x_debugfs_open,
-	.read		= seq_read,
-	.llseek		= seq_lseek,
-	.release	= single_release,
-};
+DEFINE_SHOW_ATTRIBUTE(pl08x_debugfs);
 
 static void init_pl08x_debugfs(struct pl08x_driver_data *pl08x)
 {
 	/* Expose a simple debugfs interface to view all clocks */
-	(void) debugfs_create_file(dev_name(&pl08x->adev->dev),
-			S_IFREG | S_IRUGO, NULL, pl08x,
-			&pl08x_debugfs_operations);
+	debugfs_create_file(dev_name(&pl08x->adev->dev), S_IFREG | S_IRUGO,
+			    NULL, pl08x, &pl08x_debugfs_fops);
 }
 
 #else
@@ -2625,7 +2612,7 @@
 	switch (val) {
 	default:
 		dev_err(&adev->dev, "illegal burst size for memcpy, set to 1\n");
-		/* Fall through */
+		fallthrough;
 	case 1:
 		pd->memcpy_burst_size = PL08X_BURST_SZ_1;
 		break;
@@ -2660,7 +2647,7 @@
 	switch (val) {
 	default:
 		dev_err(&adev->dev, "illegal bus width for memcpy, set to 8 bits\n");
-		/* Fall through */
+		fallthrough;
 	case 8:
 		pd->memcpy_bus_width = PL08X_BUS_WIDTH_8_BITS;
 		break;

--
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