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serial: sc16is7xx: remove obsolete loop in sc16is7xx_port_irq() 

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 3ef79cd141
commit ed647256e8
1 changed files with 39 additions and 42 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

81
drivers/tty/serial/sc16is7xx.c
View File

@ -725,58 +725,55 @@ static void sc16is7xx_update_mlines(struct sc16is7xx_one *one)
static bool sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno)
{
bool rc = true;
unsigned int iir, rxlen;
struct uart_port *port = &s->p[portno].port;
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
mutex_lock(&one->efr_lock);
do {
unsigned int iir, rxlen;
iir = sc16is7xx_port_read(port, SC16IS7XX_IIR_REG);
if (iir & SC16IS7XX_IIR_NO_INT_BIT) {
rc = false;
goto out_port_irq;
}
iir = sc16is7xx_port_read(port, SC16IS7XX_IIR_REG);
if (iir & SC16IS7XX_IIR_NO_INT_BIT) {
rc = false;
goto out_port_irq;
}
iir &= SC16IS7XX_IIR_ID_MASK;
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:
case SC16IS7XX_IIR_RLSE_SRC:
case SC16IS7XX_IIR_RTOI_SRC:
case SC16IS7XX_IIR_XOFFI_SRC:
rxlen = sc16is7xx_port_read(port, SC16IS7XX_RXLVL_REG);
/*
* There is a silicon bug that makes the chip report a
* time-out interrupt but no data in the FIFO. This is
* 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;
/*
* There is a silicon bug that makes the chip report a
* time-out interrupt but no data in the FIFO. This is
* 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;
if (rxlen)
sc16is7xx_handle_rx(port, rxlen, iir);
break;
/* CTSRTS interrupt comes only when CTS goes inactive */
case SC16IS7XX_IIR_CTSRTS_SRC:
case SC16IS7XX_IIR_MSI_SRC:
sc16is7xx_update_mlines(one);
break;
case SC16IS7XX_IIR_THRI_SRC:
sc16is7xx_handle_tx(port);
break;
default:
dev_err_ratelimited(port->dev,
"ttySC%i: Unexpected interrupt: %x",
port->line, iir);
break;
}
} while (0);
case SC16IS7XX_IIR_CTSRTS_SRC:
case SC16IS7XX_IIR_MSI_SRC:
sc16is7xx_update_mlines(one);
break;
case SC16IS7XX_IIR_THRI_SRC:
sc16is7xx_handle_tx(port);
break;
default:
dev_err_ratelimited(port->dev,
"ttySC%i: Unexpected interrupt: %x",
port->line, iir);
break;
}
out_port_irq:
mutex_unlock(&one->efr_lock);