Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/gpu/ipu-v3/ipu-pre.c b/drivers/gpu/ipu-v3/ipu-pre.c
index 2f8db9d..ad82c9e 100644
--- a/drivers/gpu/ipu-v3/ipu-pre.c
+++ b/drivers/gpu/ipu-v3/ipu-pre.c
@@ -1,14 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2017 Lucas Stach, Pengutronix
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms and conditions of the GNU General Public License,
- * version 2, as published by the Free Software Foundation.
- *
- * This program is distributed in the hope 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.
  */
 
 #include <drm/drm_fourcc.h>
@@ -106,6 +98,7 @@
 	void			*buffer_virt;
 	bool			in_use;
 	unsigned int		safe_window_end;
+	unsigned int		last_bufaddr;
 };
 
 static DEFINE_MUTEX(ipu_pre_list_mutex);
@@ -185,6 +178,7 @@
 
 	writel(bufaddr, pre->regs + IPU_PRE_CUR_BUF);
 	writel(bufaddr, pre->regs + IPU_PRE_NEXT_BUF);
+	pre->last_bufaddr = bufaddr;
 
 	val = IPU_PRE_PREF_ENG_CTRL_INPUT_PIXEL_FORMAT(0) |
 	      IPU_PRE_PREF_ENG_CTRL_INPUT_ACTIVE_BPP(active_bpp) |
@@ -242,7 +236,11 @@
 	unsigned short current_yblock;
 	u32 val;
 
+	if (bufaddr == pre->last_bufaddr)
+		return;
+
 	writel(bufaddr, pre->regs + IPU_PRE_NEXT_BUF);
+	pre->last_bufaddr = bufaddr;
 
 	do {
 		if (time_after(jiffies, timeout)) {
@@ -259,6 +257,12 @@
 	writel(IPU_PRE_CTRL_SDW_UPDATE, pre->regs + IPU_PRE_CTRL_SET);
 }
 
+bool ipu_pre_update_pending(struct ipu_pre *pre)
+{
+	return !!(readl_relaxed(pre->regs + IPU_PRE_CTRL) &
+		  IPU_PRE_CTRL_SDW_UPDATE);
+}
+
 u32 ipu_pre_get_baddr(struct ipu_pre *pre)
 {
 	return (u32)pre->buffer_paddr;