From 18630d83b7708032f00b84b1733da05f0b53a1e9 Mon Sep 17 00:00:00 2001 From: Udit Kumar Date: Tue, 25 Jun 2024 21:37:25 +0530 Subject: [PATCH] serial: 8250_omap: Fix Errata i2310 with RX FIFO level check commit c128a1b0523b685c8856ddc0ac0e1caef1fdeee5 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 9d141c1e6157 ("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: 9d141c1e6157 ("serial: 8250_omap: Implementation of Errata i2310") Cc: stable@vger.kernel.org Reported-by: Vignesh Raghavendra Closes: https://lore.kernel.org/all/e96d0c55-0b12-4cbf-9d23-48963543de49@ti.com/ Signed-off-by: Udit Kumar Link: https://lore.kernel.org/r/20240625160725.2102194-1-u-kumar1@ti.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_omap.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c index 2bb4514e4956..8f472a2080ff 100644 --- a/drivers/tty/serial/8250/8250_omap.c +++ b/drivers/tty/serial/8250/8250_omap.c @@ -655,7 +655,8 @@ 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);