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serial: sc16is7xx: remove obsolete loop in sc16is7xx_port_irq()

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commit ed647256e8f226241ecff7baaecdb8632ffc7ec1 upstream.

Commit 8344498721 ("sc16is7xx: Fix for multi-channel stall") changed
sc16is7xx_port_irq() from looping multiple times when there was still
interrupts to serve. It simply changed the do {} while(1) loop to a
do {} while(0) loop, which makes the loop itself now obsolete.

Clean the code by removing this obsolete do {} while(0) loop.

Fixes: 8344498721 ("sc16is7xx: Fix for multi-channel stall")
Cc:  <stable@vger.kernel.org>
Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20231221231823.2327894-5-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Hugo Villeneuve
2023-12-21 18:18:11 -05:00
committed by Greg Kroah-Hartman
parent de8e41f78f
commit 80beb4424d
1 changed files with 39 additions and 42 deletions
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81
drivers/tty/serial/sc16is7xx.c
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@@ -726,58 +726,55 @@ static void sc16is7xx_update_mlines(struct sc16is7xx_one *one)
static bool sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno) static bool sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno)
{ {
bool rc = true; bool rc = true;
unsigned int iir, rxlen;
struct uart_port *port = &s->p[portno].port; struct uart_port *port = &s->p[portno].port;
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port); struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
mutex_lock(&one->efr_lock); mutex_lock(&one->efr_lock);
do { iir = sc16is7xx_port_read(port, SC16IS7XX_IIR_REG);
unsigned int iir, rxlen; if (iir & SC16IS7XX_IIR_NO_INT_BIT) {
rc = false;
goto out_port_irq;
}
iir = sc16is7xx_port_read(port, SC16IS7XX_IIR_REG); iir &= SC16IS7XX_IIR_ID_MASK;
if (iir & SC16IS7XX_IIR_NO_INT_BIT) {
rc = false;
goto out_port_irq;
}
iir &= SC16IS7XX_IIR_ID_MASK; switch (iir) {
case SC16IS7XX_IIR_RDI_SRC:
case SC16IS7XX_IIR_RLSE_SRC:
case SC16IS7XX_IIR_RTOI_SRC:
case SC16IS7XX_IIR_XOFFI_SRC:
rxlen = sc16is7xx_port_read(port, SC16IS7XX_RXLVL_REG);
switch (iir) { /*
case SC16IS7XX_IIR_RDI_SRC: * There is a silicon bug that makes the chip report a
case SC16IS7XX_IIR_RLSE_SRC: * time-out interrupt but no data in the FIFO. This is
case SC16IS7XX_IIR_RTOI_SRC: * described in errata section 18.1.4.
case SC16IS7XX_IIR_XOFFI_SRC: *
rxlen = sc16is7xx_port_read(port, SC16IS7XX_RXLVL_REG); * When this happens, read one byte from the FIFO to
* clear the interrupt.
*/
if (iir == SC16IS7XX_IIR_RTOI_SRC && !rxlen)
rxlen = 1;
/* if (rxlen)
* There is a silicon bug that makes the chip report a sc16is7xx_handle_rx(port, rxlen, iir);
* time-out interrupt but no data in the FIFO. This is break;
* described in errata section 18.1.4.
*
* When this happens, read one byte from the FIFO to
* clear the interrupt.
*/
if (iir == SC16IS7XX_IIR_RTOI_SRC && !rxlen)
rxlen = 1;
if (rxlen)
sc16is7xx_handle_rx(port, rxlen, iir);
break;
/* CTSRTS interrupt comes only when CTS goes inactive */ /* CTSRTS interrupt comes only when CTS goes inactive */
case SC16IS7XX_IIR_CTSRTS_SRC: case SC16IS7XX_IIR_CTSRTS_SRC:
case SC16IS7XX_IIR_MSI_SRC: case SC16IS7XX_IIR_MSI_SRC:
sc16is7xx_update_mlines(one); sc16is7xx_update_mlines(one);
break; break;
case SC16IS7XX_IIR_THRI_SRC: case SC16IS7XX_IIR_THRI_SRC:
sc16is7xx_handle_tx(port); sc16is7xx_handle_tx(port);
break; break;
default: default:
dev_err_ratelimited(port->dev, dev_err_ratelimited(port->dev,
"ttySC%i: Unexpected interrupt: %x", "ttySC%i: Unexpected interrupt: %x",
port->line, iir); port->line, iir);
break; break;
} }
} while (0);
out_port_irq: out_port_irq:
mutex_unlock(&one->efr_lock); mutex_unlock(&one->efr_lock);