Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Zhiyong Tao <zhiyong.tao@mediatek.com>
To:     <timur@kernel.org>, <linux@armlinux.org.uk>, <alcooperx@gmail.com>,
        <tklauser@distanz.ch>, <sean.wang@kernel.org>
CC:     <srv_heupstream@mediatek.com>, <zhiyong.tao@mediatek.com>,
        <hui.liu@mediatek.com>, <yuchen.huang@mediatek.com>,
        <huihui.wang@mediatek.com>, <eddie.huang@mediatek.com>,
        <sean.wang@mediatek.com>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-mediatek@lists.infradead.org>,
        <linux-serial@vger.kernel.org>
Subject: [PATCH v1] serial: 8250_mtk: fix uart corruption issue when rx power off
Date:   Thu, 29 Jul 2021 09:48:17 +0800
Message-ID: <20210729014817.11879-2-zhiyong.tao@mediatek.com>
In-Reply-To: <20210729014817.11879-1-zhiyong.tao@mediatek.com>
References: <20210729014817.11879-1-zhiyong.tao@mediatek.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

Fix uart corruption issue when rx power off.
Add spin lock in mtk8250_dma_rx_complete function in APDMA mode.

Signed-off-by: Zhiyong Tao <zhiyong.tao@mediatek.com>
---
 drivers/tty/serial/8250/8250_mtk.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
index f7d3023f860f..fb65dc601b23 100644
--- a/drivers/tty/serial/8250/8250_mtk.c
+++ b/drivers/tty/serial/8250/8250_mtk.c
@@ -93,10 +93,13 @@ static void mtk8250_dma_rx_complete(void *param)
 	struct dma_tx_state state;
 	int copied, total, cnt;
 	unsigned char *ptr;
+	unsigned long flags;
 
 	if (data->rx_status == DMA_RX_SHUTDOWN)
 		return;
 
+	spin_lock_irqsave(&up->port.lock, flags);
+
 	dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state);
 	total = dma->rx_size - state.residue;
 	cnt = total;
@@ -120,6 +123,8 @@ static void mtk8250_dma_rx_complete(void *param)
 	tty_flip_buffer_push(tty_port);
 
 	mtk8250_rx_dma(up);
+
+	spin_unlock_irqrestore(&up->port.lock, flags);
 }
 
 static void mtk8250_rx_dma(struct uart_8250_port *up)
-- 
2.18.0