serial: tegra: protect IER against LCR.DLAB (18a4c404) · Commits · 戴 / test

The IER and DLH registers occupy the same address space, selected by the LCR.DLAB bit. Hence, add port lock to protect IER when LCR.DLAB bit is set. Signed-off-by:

Ahung Cheng <ahcheng@nvidia.com> Signed-off-by:

Krishna Yarlagadda <kyarlagadda@nvidia.com> Acked-by:

Thierry Reding <treding@nvidia.com> Link: https://lore.kernel.org/r/1565609303-27000-5-git-send-email-kyarlagadda@nvidia.com Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/serial-tegra.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -294,6 +294,7 @@ static int tegra_set_baudrate(struct tegra_uart_port *tup, unsigned int baud)
		unsigned long rate;
		unsigned int divisor;
		unsigned long lcr;
		unsigned long flags;
		int ret;

		if (tup->current_baud == baud)
		@@ -313,6 +314,7 @@ static int tegra_set_baudrate(struct tegra_uart_port *tup, unsigned int baud)
		divisor = DIV_ROUND_CLOSEST(rate, baud * 16);
		}

		spin_lock_irqsave(&tup->uport.lock, flags);
		lcr = tup->lcr_shadow;
		lcr \|= UART_LCR_DLAB;
		tegra_uart_write(tup, lcr, UART_LCR);
		@@ -325,6 +327,7 @@ static int tegra_set_baudrate(struct tegra_uart_port *tup, unsigned int baud)

		/* Dummy read to ensure the write is posted */
		tegra_uart_read(tup, UART_SCR);
		spin_unlock_irqrestore(&tup->uport.lock, flags);

		tup->current_baud = baud;

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