6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Udit Kumar <u-kumar1@xxxxxx> commit 9d141c1e615795eeb93cd35501ad144ee997a826 upstream. As per Errata i2310[0], Erroneous timeout can be triggered, if this Erroneous interrupt is not cleared then it may leads to storm of interrupts, therefore apply Errata i2310 solution. [0] https://www.ti.com/lit/pdf/sprz536 page 23 Fixes: b67e830d38fa ("serial: 8250: 8250_omap: Fix possible interrupt storm on K3 SoCs") Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Udit Kumar <u-kumar1@xxxxxx> Link: https://lore.kernel.org/r/20240619105903.165434-1-u-kumar1@xxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/tty/serial/8250/8250_omap.c | 25 ++++++++++++++++++++----- 1 file changed, 20 insertions(+), 5 deletions(-) --- a/drivers/tty/serial/8250/8250_omap.c +++ b/drivers/tty/serial/8250/8250_omap.c @@ -165,6 +165,10 @@ static u32 uart_read(struct omap8250_pri return readl(priv->membase + (reg << OMAP_UART_REGSHIFT)); } +/* Timeout low and High */ +#define UART_OMAP_TO_L 0x26 +#define UART_OMAP_TO_H 0x27 + /* * Called on runtime PM resume path from omap8250_restore_regs(), and * omap8250_set_mctrl(). @@ -646,13 +650,24 @@ static irqreturn_t omap8250_irq(int irq, /* * On K3 SoCs, it is observed that RX TIMEOUT is signalled after - * FIFO has been drained, in which case a dummy read of RX FIFO - * is required to clear RX TIMEOUT condition. + * FIFO has been drained or erroneously. + * So apply solution of Errata i2310 as mentioned in + * https://www.ti.com/lit/pdf/sprz536 */ if (priv->habit & UART_RX_TIMEOUT_QUIRK && - (iir & UART_IIR_RX_TIMEOUT) == UART_IIR_RX_TIMEOUT && - serial_port_in(port, UART_OMAP_RX_LVL) == 0) { - serial_port_in(port, UART_RX); + (iir & UART_IIR_RX_TIMEOUT) == UART_IIR_RX_TIMEOUT) { + unsigned char efr2, timeout_h, timeout_l; + + efr2 = serial_in(up, UART_OMAP_EFR2); + timeout_h = serial_in(up, UART_OMAP_TO_H); + timeout_l = serial_in(up, UART_OMAP_TO_L); + serial_out(up, UART_OMAP_TO_H, 0xFF); + serial_out(up, UART_OMAP_TO_L, 0xFF); + serial_out(up, UART_OMAP_EFR2, UART_OMAP_EFR2_TIMEOUT_BEHAVE); + serial_in(up, UART_IIR); + serial_out(up, UART_OMAP_EFR2, efr2); + serial_out(up, UART_OMAP_TO_H, timeout_h); + serial_out(up, UART_OMAP_TO_L, timeout_l); } /* Stop processing interrupts on input overrun */
