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serial: 8250_omap: Implementation of Errata i2310

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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@vger.kernel.org
Signed-off-by: Udit Kumar <u-kumar1@ti.com>
Link: https://lore.kernel.org/r/20240619105903.165434-1-u-kumar1@ti.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Udit Kumar
2024-06-19 16:29:03 +05:30
committed by Greg Kroah-Hartman
parent 75ddbf776d
commit cb87930066
1 changed files with 20 additions and 5 deletions
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25
drivers/tty/serial/8250/8250_omap.c
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@@ -164,6 +164,10 @@ static void uart_write(struct omap8250_priv *priv, u32 reg, u32 val)
writel(val, priv->membase + (reg << OMAP_UART_REGSHIFT)); writel(val, 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 * Called on runtime PM resume path from omap8250_restore_regs(), and
* omap8250_set_mctrl(). * omap8250_set_mctrl().
@@ -647,13 +651,24 @@ static irqreturn_t omap8250_irq(int irq, void *dev_id)
/* /*
* On K3 SoCs, it is observed that RX TIMEOUT is signalled after * 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 * FIFO has been drained or erroneously.
* is required to clear RX TIMEOUT condition. * So apply solution of Errata i2310 as mentioned in
* https://www.ti.com/lit/pdf/sprz536
*/ */
if (priv->habit & UART_RX_TIMEOUT_QUIRK && 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;
serial_port_in(port, UART_RX);
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 */ /* Stop processing interrupts on input overrun */