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serial: 8250_omap: Fix Errata i2310 with RX FIFO level check

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commit c128a1b052 upstream.

Errata i2310[0] says, Erroneous timeout can be triggered,
if this Erroneous interrupt is not cleared then it may leads
to storm of interrupts.

Commit 9d141c1e61 ("serial: 8250_omap: Implementation of Errata i2310")
which added the workaround but missed ensuring RX FIFO is really empty
before applying the errata workaround as recommended in the errata text.
Fix this by adding back check for UART_OMAP_RX_LVL to be 0 for
workaround to take effect.

[0] https://www.ti.com/lit/pdf/sprz536 page 23

Fixes: 9d141c1e61 ("serial: 8250_omap: Implementation of Errata i2310")
Cc: stable@vger.kernel.org
Reported-by: Vignesh Raghavendra <vigneshr@ti.com>
Closes: https://lore.kernel.org/all/e96d0c55-0b12-4cbf-9d23-48963543de49@ti.com/
Signed-off-by: Udit Kumar <u-kumar1@ti.com>
Link: https://lore.kernel.org/r/20240625160725.2102194-1-u-kumar1@ti.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Udit Kumar
2024-06-25 21:37:25 +05:30
committed by Greg Kroah-Hartman
parent f05cdbe17a
commit 8fb36f85f7
1 changed files with 2 additions and 1 deletions
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3
drivers/tty/serial/8250/8250_omap.c
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@@ -673,7 +673,8 @@ static irqreturn_t omap8250_irq(int irq, void *dev_id)
* https://www.ti.com/lit/pdf/sprz536
*/
if (priv->habit & UART_RX_TIMEOUT_QUIRK &&
(iir & UART_IIR_RX_TIMEOUT) == UART_IIR_RX_TIMEOUT) {
(iir & UART_IIR_RX_TIMEOUT) == UART_IIR_RX_TIMEOUT &&
serial_port_in(port, UART_OMAP_RX_LVL) == 0) {
unsigned char efr2, timeout_h, timeout_l;
efr2 = serial_in(up, UART_OMAP_EFR2);