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Message-ID: <53F24660.2030404@hurleysoftware.com>
Date: Mon, 18 Aug 2014 14:30:56 -0400
From: Peter Hurley <peter@...leysoftware.com>
To: Daniel Thompson <daniel.thompson@...aro.org>,
Russell King <linux@....linux.org.uk>
CC: linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
kgdb-bugreport@...ts.sourceforge.net, patches@...aro.org,
linaro-kernel@...ts.linaro.org,
John Stultz <john.stultz@...aro.org>,
Anton Vorontsov <anton.vorontsov@...aro.org>,
Colin Cross <ccross@...roid.com>, kernel-team@...roid.com,
Rob Herring <robherring2@...il.com>,
Linus Walleij <linus.walleij@...aro.org>,
Ben Dooks <ben.dooks@...ethink.co.uk>,
Catalin Marinas <catalin.marinas@....com>,
Dave Martin <Dave.Martin@....com>,
Fabio Estevam <festevam@...il.com>,
Frederic Weisbecker <fweisbec@...il.com>,
Nicolas Pitre <nico@...aro.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Jiri Slaby <jslaby@...e.cz>, linux-serial@...r.kernel.org
Subject: Re: [PATCH v9 12/16] serial: amba-pl011: Pass FIQ information to
KGDB.
Hi Daniel,
On 08/18/2014 10:28 AM, Daniel Thompson wrote:
> Speculatively register a FIQ resource with KGDB. KGDB will only
> accept it if the kgdb/fiq feature is enabled (both with compile time and
> runtime switches) and the interrupt controller supports FIQ.
>
> 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 amba-pl011 driver has already unmasked RX interrupts
> (otherwise the FIQ handler will never trigger).
>
> Signed-off-by: Daniel Thompson <daniel.thompson@...aro.org>
> Cc: Russell King <linux@....linux.org.uk>
> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> Cc: Jiri Slaby <jslaby@...e.cz>
> Cc: linux-serial@...r.kernel.org
> ---
> drivers/tty/serial/amba-pl011.c | 94 ++++++++++++++++++++++++-----------------
> 1 file changed, 55 insertions(+), 39 deletions(-)
>
> diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
> index 8572f2a..ec8ddc7 100644
> --- a/drivers/tty/serial/amba-pl011.c
> +++ b/drivers/tty/serial/amba-pl011.c
> @@ -58,6 +58,7 @@
> #include <linux/pinctrl/consumer.h>
> #include <linux/sizes.h>
> #include <linux/io.h>
> +#include <linux/kgdb.h>
>
> #define UART_NR 14
>
> @@ -1416,8 +1417,61 @@ static void pl011_break_ctl(struct uart_port *port, int break_state)
> spin_unlock_irqrestore(&uap->port.lock, flags);
> }
>
Is pl011_hwinit() just being relocated in source to avoid the forward
declaration? If so, this is usually split into its own commit.
> +static int pl011_hwinit(struct uart_port *port)
> +{
> + struct uart_amba_port *uap = (struct uart_amba_port *)port;
> + int retval;
> +
> + /* Optionaly enable pins to be muxed in and configured */
> + pinctrl_pm_select_default_state(port->dev);
> +
> + /*
> + * Try to enable the clock producer.
> + */
> + retval = clk_prepare_enable(uap->clk);
> + if (retval)
> + return retval;
> +
> + uap->port.uartclk = clk_get_rate(uap->clk);
> +
> + /* Clear pending error and receive interrupts */
> + writew(UART011_OEIS | UART011_BEIS | UART011_PEIS | UART011_FEIS |
> + UART011_RTIS | UART011_RXIS, uap->port.membase + UART011_ICR);
> +
> + /*
> + * Save interrupts enable mask, and enable RX interrupts in case if
> + * the interrupt is used for NMI entry.
> + */
> + uap->im = readw(uap->port.membase + UART011_IMSC);
> + writew(UART011_RTIM | UART011_RXIM, uap->port.membase + UART011_IMSC);
> +
> + if (dev_get_platdata(uap->port.dev)) {
> + struct amba_pl011_data *plat;
> +
> + plat = dev_get_platdata(uap->port.dev);
> + if (plat->init)
> + plat->init();
> + }
> + return 0;
> +}
> +
> #ifdef CONFIG_CONSOLE_POLL
>
> +static int pl011_poll_init(struct uart_port *port)
> +{
> + struct uart_amba_port *uap = (struct uart_amba_port *)port;
Please use container_of() in new code.
> + int retval;
> +
> + retval = pl011_hwinit(port);
> +
> +#ifdef CONFIG_KGDB_FIQ
> + if (retval == 0)
> + kgdb_register_fiq(uap->port.irq);
The uap->port dereference is unnecessary since the port parameter
is the same thing.
kgdb_register_fiq(port->irq);
Regards,
Peter Hurley
> +#endif
> +
> + return retval;
> +}
> +
> static void pl011_quiesce_irqs(struct uart_port *port)
> {
> struct uart_amba_port *uap = (struct uart_amba_port *)port;
> @@ -1471,44 +1525,6 @@ static void pl011_put_poll_char(struct uart_port *port,
>
> #endif /* CONFIG_CONSOLE_POLL */
>
> -static int pl011_hwinit(struct uart_port *port)
> -{
> - struct uart_amba_port *uap = (struct uart_amba_port *)port;
> - int retval;
> -
> - /* Optionaly enable pins to be muxed in and configured */
> - pinctrl_pm_select_default_state(port->dev);
> -
> - /*
> - * Try to enable the clock producer.
> - */
> - retval = clk_prepare_enable(uap->clk);
> - if (retval)
> - return retval;
> -
> - uap->port.uartclk = clk_get_rate(uap->clk);
> -
> - /* Clear pending error and receive interrupts */
> - writew(UART011_OEIS | UART011_BEIS | UART011_PEIS | UART011_FEIS |
> - UART011_RTIS | UART011_RXIS, uap->port.membase + UART011_ICR);
> -
> - /*
> - * Save interrupts enable mask, and enable RX interrupts in case if
> - * the interrupt is used for NMI entry.
> - */
> - uap->im = readw(uap->port.membase + UART011_IMSC);
> - writew(UART011_RTIM | UART011_RXIM, uap->port.membase + UART011_IMSC);
> -
> - if (dev_get_platdata(uap->port.dev)) {
> - struct amba_pl011_data *plat;
> -
> - plat = dev_get_platdata(uap->port.dev);
> - if (plat->init)
> - plat->init();
> - }
> - return 0;
> -}
> -
> static void pl011_write_lcr_h(struct uart_amba_port *uap, unsigned int lcr_h)
> {
> writew(lcr_h, uap->port.membase + uap->lcrh_rx);
> @@ -1888,7 +1904,7 @@ static struct uart_ops amba_pl011_pops = {
> .config_port = pl011_config_port,
> .verify_port = pl011_verify_port,
> #ifdef CONFIG_CONSOLE_POLL
> - .poll_init = pl011_hwinit,
> + .poll_init = pl011_poll_init,
> .poll_get_char = pl011_get_poll_char,
> .poll_put_char = pl011_put_poll_char,
> #endif
>
--
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