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From:   Rasmus Villemoes <linux@rasmusvillemoes.dk>
To:     Qiang Zhao <qiang.zhao@nxp.com>, Li Yang <leoyang.li@nxp.com>,
        Christophe Leroy <christophe.leroy@c-s.fr>
Cc:     linuxppc-dev@lists.ozlabs.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Scott Wood <oss@buserror.net>, Timur Tabi <timur@kernel.org>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        linux-serial@vger.kernel.org
Subject: [PATCH v6 33/49] serial: ucc_uart: limit brg-frequency workaround to PPC32
Date:   Thu, 28 Nov 2019 15:55:38 +0100
Message-Id: <20191128145554.1297-34-linux@rasmusvillemoes.dk>
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According to Timur Tabi

    This bug in older U-Boots is definitely PowerPC-specific

So before allowing this driver to be built for platforms other than
PPC32, make sure that we don't accept malformed device trees on those
other platforms.

Suggested-by: Timur Tabi <timur@kernel.org>
Reviewed-by: Timur Tabi <timur@kernel.org>
Acked-by: Timur Tabi <timur@kernel.org>
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---
 drivers/tty/serial/ucc_uart.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/tty/serial/ucc_uart.c b/drivers/tty/serial/ucc_uart.c
index c055abf4c919..9436b93d5cfa 100644
--- a/drivers/tty/serial/ucc_uart.c
+++ b/drivers/tty/serial/ucc_uart.c
@@ -1392,6 +1392,13 @@ static int ucc_uart_probe(struct platform_device *ofdev)
 	if (val)
 		qe_port->port.uartclk = val;
 	else {
+		if (!IS_ENABLED(CONFIG_PPC32)) {
+			dev_err(&ofdev->dev,
+				"invalid brg-frequency in device tree\n");
+			ret = -EINVAL;
+			goto out_np;
+		}
+
 		/*
 		 * Older versions of U-Boot do not initialize the brg-frequency
 		 * property, so in this case we assume the BRG frequency is
-- 
2.23.0