From c9bbeb37416295a7e31f2fbb17e0ee2163908989 Mon Sep 17 00:00:00 2001
From: Frank Wang <frank.wang@rock-chips.com>
Date: Thu, 28 Jul 2022 11:35:54 +0800
Subject: [PATCH] mailbox: rockchip: add reading the last message support

The client can invoke rockchip_mbox_read_msg() to read the last message
in the related mailbox channel.

Signed-off-by: Frank Wang <frank.wang@rock-chips.com>
Change-Id: Ia9b78bfc04341648f98db4363ca94b66ebe2cee5
---
 drivers/mailbox/rockchip-mailbox.c      | 48 ++++++++++++++++++-------
 include/soc/rockchip/rockchip-mailbox.h | 30 ++++++++++++++++
 2 files changed, 65 insertions(+), 13 deletions(-)
 create mode 100644 include/soc/rockchip/rockchip-mailbox.h

diff --git a/drivers/mailbox/rockchip-mailbox.c b/drivers/mailbox/rockchip-mailbox.c
index 918bb0115b4a..c2ed4f510342 100644
--- a/drivers/mailbox/rockchip-mailbox.c
+++ b/drivers/mailbox/rockchip-mailbox.c
@@ -12,6 +12,7 @@
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/spinlock.h>
+#include <soc/rockchip/rockchip-mailbox.h>
 
 #define MAILBOX_A2B_INTEN		0x00
 #define MAILBOX_A2B_STATUS		0x04
@@ -23,11 +24,6 @@
 #define MAILBOX_B2A_CMD(x)		(0x30 + (x) * 8)
 #define MAILBOX_B2A_DAT(x)		(0x34 + (x) * 8)
 
-struct rockchip_mbox_msg {
-	u32 cmd;
-	u32 data;
-};
-
 struct rockchip_mbox_data {
 	int num_chans;
 };
@@ -42,6 +38,7 @@ struct rockchip_mbox {
 	struct clk *pclk;
 	void __iomem *mbox_base;
 	spinlock_t cfg_lock; /* Serialise access to the register */
+	struct rockchip_mbox_msg *msg;
 
 	struct rockchip_mbox_chan *chans;
 };
@@ -108,27 +105,47 @@ static const struct mbox_chan_ops rockchip_mbox_chan_ops = {
 	.shutdown	= rockchip_mbox_shutdown,
 };
 
+int rockchip_mbox_read_msg(struct mbox_chan *chan,
+			   struct rockchip_mbox_msg *msg)
+{
+	struct rockchip_mbox *mb;
+	struct rockchip_mbox_chan *chans;
+
+	if (!chan || !msg)
+		return -EINVAL;
+
+	mb = dev_get_drvdata(chan->mbox->dev);
+	chans = chan->con_priv;
+
+	msg->cmd  = mb->msg[chans->idx].cmd;
+	msg->data = mb->msg[chans->idx].data;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(rockchip_mbox_read_msg);
+
 static irqreturn_t rockchip_mbox_irq(int irq, void *dev_id)
 {
 	int idx;
-	struct rockchip_mbox_msg msg;
+	struct rockchip_mbox_msg *msg;
 	struct rockchip_mbox *mb = (struct rockchip_mbox *)dev_id;
 	u32 status = readl_relaxed(mb->mbox_base + MAILBOX_B2A_STATUS);
 
 	for (idx = 0; idx < mb->mbox.num_chans; idx++) {
 		if ((status & (1U << idx)) && irq == mb->chans[idx].irq) {
 			/* Get cmd/data from the channel of B2A */
-			msg.cmd = readl_relaxed(mb->mbox_base +
-						MAILBOX_B2A_CMD(idx));
-			msg.data = readl_relaxed(mb->mbox_base +
-						 MAILBOX_B2A_DAT(idx));
+			msg = &mb->msg[idx];
+			msg->cmd = readl_relaxed(mb->mbox_base +
+						 MAILBOX_B2A_CMD(idx));
+			msg->data = readl_relaxed(mb->mbox_base +
+						  MAILBOX_B2A_DAT(idx));
 
 			dev_dbg(mb->mbox.dev, "Chan[%d]: B2A message, cmd 0x%08x, data 0x%08x\n",
-				idx, msg.cmd, msg.data);
+				idx, msg->cmd, msg->data);
 
 			if (mb->mbox.chans[idx].cl)
-				mbox_chan_received_data(&mb->mbox.chans[idx],
-							&msg);
+				mbox_chan_received_data(&mb->mbox.chans[idx], msg);
+
 			/* Clear mbox interrupt */
 			writel_relaxed(1U << idx,
 				       mb->mbox_base + MAILBOX_B2A_STATUS);
@@ -166,6 +183,11 @@ static int rockchip_mbox_probe(struct platform_device *pdev)
 	if (!mb)
 		return -ENOMEM;
 
+	mb->msg = devm_kcalloc(&pdev->dev, drv_data->num_chans,
+			       sizeof(*mb->msg), GFP_KERNEL);
+	if (!mb->msg)
+		return -ENOMEM;
+
 	mb->chans = devm_kcalloc(&pdev->dev, drv_data->num_chans,
 				 sizeof(*mb->chans), GFP_KERNEL);
 	if (!mb->chans)
diff --git a/include/soc/rockchip/rockchip-mailbox.h b/include/soc/rockchip/rockchip-mailbox.h
new file mode 100644
index 000000000000..e3698b9e10fe
--- /dev/null
+++ b/include/soc/rockchip/rockchip-mailbox.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2022 Rockchip Electronics Co., Ltd
+ */
+
+#ifndef __SOC_ROCKCHIP_MAILBOX_H__
+#define __SOC_ROCKCHIP_MAILBOX_H__
+
+#include <linux/errno.h>
+#include <linux/types.h>
+
+struct mbox_chan;
+
+struct rockchip_mbox_msg {
+	u32 cmd;
+	u32 data;
+};
+
+#if IS_REACHABLE(CONFIG_ROCKCHIP_MBOX)
+int rockchip_mbox_read_msg(struct mbox_chan *chan,
+			   struct rockchip_mbox_msg *msg);
+#else
+static inline int rockchip_mbox_read_msg(struct mbox_chan *chan,
+					 struct rockchip_mbox_msg *msg)
+{
+	return -EOPNOTSUPP;
+}
+#endif
+
+#endif /* __SOC_ROCKCHIP_MAILBOX_H__ */