| Message ID | 20150212192333.GA18882@linutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 02/12/2015 02:23 PM, Sebastian Andrzej Siewior wrote: > * Peter Hurley | 2015-02-12 11:32:04 [-0500]: > >> That said, I don't think serial8250_do_startup() is really doing that much >> for OMAP h/w startup; open-coding what omap_8250 really needs is probably >> < 10 loc. > > 10 loc? I have a few more. :) > serial8250_clear_fifos(), > serial_link_irq_chain() aren't exported. serial8250_set_mctrl() can > maybe accessed via uart_ops->set_mctrl(). Maybe I'm not removing the > obvious not required code but here it looks better to just a BUG flag for > the Omap. Ok. FWIW, > --- a/drivers/tty/serial/8250/8250_omap.c > +++ b/drivers/tty/serial/8250/8250_omap.c > @@ -557,9 +557,74 @@ static int omap_8250_startup(struct uart_port *port) > > pm_runtime_get_sync(port->dev); > > - ret = serial8250_do_startup(port); > - if (ret) > - goto err; > + up->mcr = 0; > + > + /* > + * Clear the FIFO buffers and disable them. > + * (they will be reenabled in set_termios()) > + */ > + serial8250_clear_fifos(up); For omap this would just be: serial_out(up, UART_FCR, UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT); In any event, the fifo enable/disable is probably not happening since FIFO_EN is ignored unless the divisor == 0. > + > + /* > + * Clear the interrupt registers. > + */ > + if (serial_port_in(port, UART_LSR) & UART_LSR_DR) > + serial_port_in(port, UART_RX); > + serial_port_in(port, UART_IIR); > + serial_port_in(port, UART_MSR); > + > + retval = serial_link_irq_chain(up); > + if (retval) > + goto out; omap doesn't really need the legacy irq chain handling; this could just be request_irq(). In the 8250 split I'll be posting soon, all the irq chaining and polling-via-timeout workarounds stays in the universal/legacy driver so other 8250 drivers can opt-out. > + > + /* > + * Now, initialize the UART > + */ > + serial_port_out(port, UART_LCR, UART_LCR_WLEN8); > + --- >% --- > + spin_lock_irqsave(&port->lock, flags); > + /* > + * Most PC uarts need OUT2 raised to enable interrupts. > + */ > + if (port->irq) > + up->port.mctrl |= TIOCM_OUT2; > + > + serial8250_set_mctrl(port, port->mctrl); > + > + spin_unlock_irqrestore(&port->lock, flags); > + None of this is required because there is no OUT2 on omap. --------- --- >% ---- > + /* > + * Clear the interrupt registers again for luck, and clear the > + * saved flags to avoid getting false values from polling > + * routines or the previous session. > + */ > + if (serial_port_in(port, UART_LSR) & UART_LSR_DR) > + serial_port_in(port, UART_RX); > + serial_port_in(port, UART_IIR); > + serial_port_in(port, UART_MSR); None of this is required because none of the probing is taking place. ------------ > + up->lsr_saved_flags = 0; > + up->msr_saved_flags = 0; > + > + /* > + * Request DMA channels for both RX and TX. > + */ > + if (up->dma) { > + retval = serial8250_request_dma(up); > + if (retval) { > + pr_warn_ratelimited("ttyS%d - failed to request DMA\n", > + serial_index(port)); > + up->dma = NULL; > + } > + } > + > + /* > + * Finally, enable interrupts. Note: Modem status interrupts > + * are set via set_termios(), which will be occurring imminently > + * anyway, so we don't enable them here. > + */ > + up->ier = UART_IER_RLSI | UART_IER_RDI; > + serial_port_out(port, UART_IER, up->ier); > + > > #ifdef CONFIG_PM > up->capabilities |= UART_CAP_RPM; > > Sebastian >
On 02/12/2015 08:55 PM, Peter Hurley wrote: > On 02/12/2015 02:23 PM, Sebastian Andrzej Siewior wrote: >> * Peter Hurley | 2015-02-12 11:32:04 [-0500]: >> >>> That said, I don't think serial8250_do_startup() is really doing that much >>> for OMAP h/w startup; open-coding what omap_8250 really needs is probably >>> < 10 loc. >> >> 10 loc? I have a few more. > > :) > >> serial8250_clear_fifos(), >> serial_link_irq_chain() aren't exported. serial8250_set_mctrl() can >> maybe accessed via uart_ops->set_mctrl(). Maybe I'm not removing the >> obvious not required code but here it looks better to just a BUG flag for >> the Omap. > > Ok. Okay. I will try to post something tomorrow. >> --- a/drivers/tty/serial/8250/8250_omap.c >> +++ b/drivers/tty/serial/8250/8250_omap.c >> + >> + /* >> + * Clear the interrupt registers. >> + */ >> + if (serial_port_in(port, UART_LSR) & UART_LSR_DR) >> + serial_port_in(port, UART_RX); >> + serial_port_in(port, UART_IIR); >> + serial_port_in(port, UART_MSR); >> + >> + retval = serial_link_irq_chain(up); >> + if (retval) >> + goto out; > > omap doesn't really need the legacy irq chain handling; this could just be > request_irq(). > > In the 8250 split I'll be posting soon, all the irq chaining and > polling-via-timeout workarounds stays in the universal/legacy driver so > other 8250 drivers can opt-out. Ah. This sounds interesting. Sebastian
--- a/drivers/tty/serial/8250/8250_omap.c +++ b/drivers/tty/serial/8250/8250_omap.c @@ -557,9 +557,74 @@ static int omap_8250_startup(struct uart_port *port) pm_runtime_get_sync(port->dev); - ret = serial8250_do_startup(port); - if (ret) - goto err; + up->mcr = 0; + + /* + * Clear the FIFO buffers and disable them. + * (they will be reenabled in set_termios()) + */ + serial8250_clear_fifos(up); + + /* + * Clear the interrupt registers. + */ + if (serial_port_in(port, UART_LSR) & UART_LSR_DR) + serial_port_in(port, UART_RX); + serial_port_in(port, UART_IIR); + serial_port_in(port, UART_MSR); + + retval = serial_link_irq_chain(up); + if (retval) + goto out; + + /* + * Now, initialize the UART + */ + serial_port_out(port, UART_LCR, UART_LCR_WLEN8); + + spin_lock_irqsave(&port->lock, flags); + /* + * Most PC uarts need OUT2 raised to enable interrupts. + */ + if (port->irq) + up->port.mctrl |= TIOCM_OUT2; + + serial8250_set_mctrl(port, port->mctrl); + + spin_unlock_irqrestore(&port->lock, flags); + + /* + * Clear the interrupt registers again for luck, and clear the + * saved flags to avoid getting false values from polling + * routines or the previous session. + */ + if (serial_port_in(port, UART_LSR) & UART_LSR_DR) + serial_port_in(port, UART_RX); + serial_port_in(port, UART_IIR); + serial_port_in(port, UART_MSR); + up->lsr_saved_flags = 0; + up->msr_saved_flags = 0; + + /* + * Request DMA channels for both RX and TX. + */ + if (up->dma) { + retval = serial8250_request_dma(up); + if (retval) { + pr_warn_ratelimited("ttyS%d - failed to request DMA\n", + serial_index(port)); + up->dma = NULL; + } + } + + /* + * Finally, enable interrupts. Note: Modem status interrupts + * are set via set_termios(), which will be occurring imminently + * anyway, so we don't enable them here. + */ + up->ier = UART_IER_RLSI | UART_IER_RDI; + serial_port_out(port, UART_IER, up->ier); + #ifdef CONFIG_PM up->capabilities |= UART_CAP_RPM;