| Message ID | 1400853478-5824-11-git-send-email-daniel.thompson@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Dan, On 23/05/14 14:57, Daniel Thompson wrote: > If the platform bus has provided the st-asc with a FIQ resource (i.e. a > second IRQ) then speculatively register it with KGDB when the polling > driver is initialized. > > By providing this information to KGDB the serial driver offers > "permission" for KGDB to route the UART interrupt signal from the > drivers own handler to KGDBs FIQ handler (which will eventually use the > UART's polled I/O callbacks to interact with the user). This permission > also implies the st-asc driver has already unmasked RX interrupts > (otherwise the FIQ handler will never trigger). This unmask is copied > from similar code in amba-pl011.c . > > Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> > Cc: Srinivas Kandagatla <srinivas.kandagatla@gmail.com> > Cc: Maxime Coquelin <maxime.coquelin@st.com> > Cc: Patrice Chotard <patrice.chotard@st.com> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Cc: Jiri Slaby <jslaby@suse.cz> > Cc: kernel@stlinux.com > Cc: linux-serial@vger.kernel.org > --- > drivers/tty/serial/st-asc.c | 27 +++++++++++++++++++++++++++ > 1 file changed, 27 insertions(+) > Also this new entry should be documented in the st-asc dt bindings. > diff --git a/drivers/tty/serial/st-asc.c b/drivers/tty/serial/st-asc.c > index c7f61ac..328720f 100644 > --- a/drivers/tty/serial/st-asc.c > +++ b/drivers/tty/serial/st-asc.c > @@ -30,6 +30,7 @@ > #include <linux/of_platform.h> > #include <linux/serial_core.h> > #include <linux/clk.h> > +#include <linux/kgdb.h> > > #define DRIVER_NAME "st-asc" > #define ASC_SERIAL_NAME "ttyAS" > @@ -39,6 +40,7 @@ > struct asc_port { > struct uart_port port; > struct clk *clk; > + int fiq; > unsigned int hw_flow_control:1; > unsigned int force_m1:1; > }; ... > #ifdef CONFIG_CONSOLE_POLL > +#ifdef CONFIG_KGDB_FIQ > + .poll_init = asc_poll_init, > +#endif /* CONFIG_KGDB_FIQ */ > .poll_get_char = asc_get_poll_char, > .poll_put_char = asc_put_poll_char, > #endif /* CONFIG_CONSOLE_POLL */ > }; > > + no need of extra new line here. > static int asc_init_port(struct asc_port *ascport, > struct platform_device *pdev) > { > @@ -673,6 +699,7 @@ static int asc_init_port(struct asc_port *ascport, > port->fifosize = ASC_FIFO_SIZE; > port->dev = &pdev->dev; > port->irq = platform_get_irq(pdev, 0); > + ascport->fiq = platform_get_irq(pdev, 1); > Probably its better to give names to the irq resources and get them. As forcing the order in DT is always tricky highly possible for an error. Thanks, srini > res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > port->membase = devm_ioremap_resource(&pdev->dev, res); >
diff --git a/drivers/tty/serial/st-asc.c b/drivers/tty/serial/st-asc.c index c7f61ac..328720f 100644 --- a/drivers/tty/serial/st-asc.c +++ b/drivers/tty/serial/st-asc.c @@ -30,6 +30,7 @@ #include <linux/of_platform.h> #include <linux/serial_core.h> #include <linux/clk.h> +#include <linux/kgdb.h> #define DRIVER_NAME "st-asc" #define ASC_SERIAL_NAME "ttyAS" @@ -39,6 +40,7 @@ struct asc_port { struct uart_port port; struct clk *clk; + int fiq; unsigned int hw_flow_control:1; unsigned int force_m1:1; }; @@ -613,6 +615,26 @@ asc_verify_port(struct uart_port *port, struct serial_struct *ser) } #ifdef CONFIG_CONSOLE_POLL + +#ifdef CONFIG_KGDB_FIQ +/* + * Prepare the UART to be used from kgdb's NMI support. + */ +static int asc_poll_init(struct uart_port *port) +{ + struct asc_port *ascport = container_of(port, struct asc_port, port); + + /* register the FIQ with kgdb */ + if (ascport->fiq >= 0) + kgdb_register_fiq(ascport->fiq); + + /* enable RX interrupts in case the interrupt is used for NMI entry. */ + asc_enable_rx_interrupts(port); + + return 0; +} +#endif /* CONFIG_KGDB_FIQ */ + /* * Console polling routines for writing and reading from the uart while * in an interrupt or debug context (i.e. kgdb). @@ -656,11 +678,15 @@ static struct uart_ops asc_uart_ops = { .verify_port = asc_verify_port, .pm = asc_pm, #ifdef CONFIG_CONSOLE_POLL +#ifdef CONFIG_KGDB_FIQ + .poll_init = asc_poll_init, +#endif /* CONFIG_KGDB_FIQ */ .poll_get_char = asc_get_poll_char, .poll_put_char = asc_put_poll_char, #endif /* CONFIG_CONSOLE_POLL */ }; + static int asc_init_port(struct asc_port *ascport, struct platform_device *pdev) { @@ -673,6 +699,7 @@ static int asc_init_port(struct asc_port *ascport, port->fifosize = ASC_FIFO_SIZE; port->dev = &pdev->dev; port->irq = platform_get_irq(pdev, 0); + ascport->fiq = platform_get_irq(pdev, 1); res = platform_get_resource(pdev, IORESOURCE_MEM, 0); port->membase = devm_ioremap_resource(&pdev->dev, res);
If the platform bus has provided the st-asc with a FIQ resource (i.e. a second IRQ) then speculatively register it with KGDB when the polling driver is initialized. By providing this information to KGDB the serial driver offers "permission" for KGDB to route the UART interrupt signal from the drivers own handler to KGDBs FIQ handler (which will eventually use the UART's polled I/O callbacks to interact with the user). This permission also implies the st-asc driver has already unmasked RX interrupts (otherwise the FIQ handler will never trigger). This unmask is copied from similar code in amba-pl011.c . Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Cc: Srinivas Kandagatla <srinivas.kandagatla@gmail.com> Cc: Maxime Coquelin <maxime.coquelin@st.com> Cc: Patrice Chotard <patrice.chotard@st.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jslaby@suse.cz> Cc: kernel@stlinux.com Cc: linux-serial@vger.kernel.org --- drivers/tty/serial/st-asc.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+)