| Message ID | 20230113184334.287130-7-sorganov@gmail.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | serial: imx: work-around for hardware RX flood, and then isr improvements | expand |
On Fri, 13 Jan 2023, Sergey Organov wrote: > The chip provides all the needed bits in the URXD0 register that we read > anyway for data, so get rid of reading USR2 and use only URXD0 bits > instead. > > Signed-off-by: Sergey Organov <sorganov@gmail.com> > --- > drivers/tty/serial/imx.c | 18 ++++++------------ > 1 file changed, 6 insertions(+), 12 deletions(-) > > diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c > index c44a7293c013..be00362b8b67 100644 > --- a/drivers/tty/serial/imx.c > +++ b/drivers/tty/serial/imx.c > @@ -892,27 +892,21 @@ static irqreturn_t __imx_uart_rxint(int irq, void *dev_id) > struct tty_port *port = &sport->port.state->port; > u32 usr2; > > - usr2 = imx_uart_readl(sport, USR2); > - > /* If we received something, check for 0xff flood */ > + usr2 = imx_uart_readl(sport, USR2); Please just place the read into the correct place in 2/8 rather than moving it needlessly here again.
Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> writes: > On Fri, 13 Jan 2023, Sergey Organov wrote: > >> The chip provides all the needed bits in the URXD0 register that we read >> anyway for data, so get rid of reading USR2 and use only URXD0 bits >> instead. >> >> Signed-off-by: Sergey Organov <sorganov@gmail.com> >> --- >> drivers/tty/serial/imx.c | 18 ++++++------------ >> 1 file changed, 6 insertions(+), 12 deletions(-) >> >> diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c >> index c44a7293c013..be00362b8b67 100644 >> --- a/drivers/tty/serial/imx.c >> +++ b/drivers/tty/serial/imx.c >> @@ -892,27 +892,21 @@ static irqreturn_t __imx_uart_rxint(int irq, void *dev_id) >> struct tty_port *port = &sport->port.state->port; >> u32 usr2; >> >> - usr2 = imx_uart_readl(sport, USR2); >> - >> /* If we received something, check for 0xff flood */ >> + usr2 = imx_uart_readl(sport, USR2); > > Please just place the read into the correct place in 2/8 rather than > moving it needlessly here again. Well, this I considered and rejected already, before publishing the patches. In 2/8 this read was an initialization for the entire FIFO reading loop, the value being re-used for flood check at the beginning as well, and with this patch it becomes just a local read for subsequent 2 lines of code that perform flood check, not used in the FIFO loop anymore, so I moved it in this patch to where it now belongs. Thanks, -- Sergey Organov
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index c44a7293c013..be00362b8b67 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -892,27 +892,21 @@ static irqreturn_t __imx_uart_rxint(int irq, void *dev_id) struct tty_port *port = &sport->port.state->port; u32 usr2; - usr2 = imx_uart_readl(sport, USR2); - /* If we received something, check for 0xff flood */ + usr2 = imx_uart_readl(sport, USR2); if (usr2 & USR2_RDR) imx_uart_check_flood(sport, usr2); - for ( ; usr2 & USR2_RDR; usr2 = imx_uart_readl(sport, USR2)) { + while ((rx = imx_uart_readl(sport, URXD0)) & URXD_CHARRDY) { flg = TTY_NORMAL; sport->port.icount.rx++; - rx = imx_uart_readl(sport, URXD0); - - if (usr2 & USR2_BRCD) { - imx_uart_writel(sport, USR2_BRCD, USR2); - if (uart_handle_break(&sport->port)) - continue; - } - if (unlikely(rx & URXD_ERR)) { - if (rx & URXD_BRK) + if (rx & URXD_BRK) { sport->port.icount.brk++; + if (uart_handle_break(&sport->port)) + continue; + } else if (rx & URXD_PRERR) sport->port.icount.parity++; else if (rx & URXD_FRMERR)
The chip provides all the needed bits in the URXD0 register that we read anyway for data, so get rid of reading USR2 and use only URXD0 bits instead. Signed-off-by: Sergey Organov <sorganov@gmail.com> --- drivers/tty/serial/imx.c | 18 ++++++------------ 1 file changed, 6 insertions(+), 12 deletions(-)