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FAILED: patch "[PATCH] serial: mvebu-uart: uart2 error bits clearing" failed to apply to 4.9-stable tree

PATCH [email protected] 1 participant 1 message Aug 13, 2022

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Stable branch TTY layer and serial drivers Marvell armada 3700 serial driver
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The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From a7209541239e5dd44d981289e5f9059222d40fd1 Mon Sep 17 00:00:00 2001
From: Narendra Hadke <[email protected]>
Date: Tue, 26 Jul 2022 11:12:21 +0200
Subject: [PATCH] serial: mvebu-uart: uart2 error bits clearing
MIME-Version: 1.0
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For mvebu uart2, error bits are not cleared on buffer read. This causes interrupt loop and system hang.

Cc [email protected]
Reviewed-by Yi Guo <[email protected]>
Reviewed-by Nadav Haklai <[email protected]>
Signed-off-by Narendra Hadke <[email protected]>
Signed-off-by Pali Rohár <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here
Signed-off-by Greg Kroah-Hartman <[email protected]>
drivers/tty/serial/mvebu-uart.c +11 -0
index 0429c2a54290..ff61a8d00014 100644
@@ -265,6 +265,7 @@ static void mvebu_uart_rx_chars(struct uart_port *port, unsigned int status)
 	struct tty_port *tport = &port->state->port;
 	unsigned char ch = 0;
 	char flag = 0;
+	int ret;
 
 	do {
 		if (status & STAT_RX_RDY(port)) {

@@ -277,6 +278,16 @@ static void mvebu_uart_rx_chars(struct uart_port *port, unsigned int status)
 				port->icount.parity++;
 		}
 
+		/*
+		 * For UART2, error bits are not cleared on buffer read.
+		 * This causes interrupt loop and system hang.
+		 */
+		if (IS_EXTENDED(port) && (status & STAT_BRK_ERR)) {
+			ret = readl(port->membase + UART_STAT);
+			ret |= STAT_BRK_ERR;
+			writel(ret, port->membase + UART_STAT);
+		}
+
 		if (status & STAT_BRK_DET) {
 			port->icount.brk++;
 			status &= ~(STAT_FRM_ERR | STAT_PAR_ERR);