[04/14] serial: tegra: protect IER against LCR.DLAB
diff mbox series

Message ID 1565609303-27000-5-git-send-email-kyarlagadda@nvidia.com
State New
Headers show
Series
  • serial: tegra: Tegra186 support and fixes
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Commit Message

Krishna Yarlagadda Aug. 12, 2019, 11:28 a.m. UTC
From: Ahung Cheng <ahcheng@nvidia.com>

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>
---
 drivers/tty/serial/serial-tegra.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

Thierry Reding Aug. 13, 2019, 9:46 a.m. UTC | #1
On Mon, Aug 12, 2019 at 04:58:13PM +0530, Krishna Yarlagadda wrote:
> From: Ahung Cheng <ahcheng@nvidia.com>
> 
> 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>
> ---
>  drivers/tty/serial/serial-tegra.c | 3 +++
>  1 file changed, 3 insertions(+)

Acked-by: Thierry Reding <treding@nvidia.com>

Patch
diff mbox series

diff --git a/drivers/tty/serial/serial-tegra.c b/drivers/tty/serial/serial-tegra.c
index d908465..ae7225c 100644
--- a/drivers/tty/serial/serial-tegra.c
+++ b/drivers/tty/serial/serial-tegra.c
@@ -296,6 +296,7 @@  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)
@@ -315,6 +316,7 @@  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);
@@ -327,6 +329,7 @@  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;