From: Anton Vorontsov <anton.vorontsov@linaro.org>
To: Andrew Morton <akpm@linux-foundation.org>,
Russell King <linux@arm.linux.org.uk>,
Jason Wessel <jason.wessel@windriver.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Alan Cox <alan@linux.intel.com>
Cc: "Arve Hjønnevåg" <arve@android.com>,
"Colin Cross" <ccross@android.com>,
"Brian Swetland" <swetland@google.com>,
"John Stultz" <john.stultz@linaro.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linaro-kernel@lists.linaro.org, patches@linaro.org,
kernel-team@android.com, kgdb-bugreport@lists.sourceforge.net,
linux-serial@vger.kernel.org
Subject: [PATCH 04/11] tty/serial/core: Introduce poll_init callback
Date: Wed, 19 Sep 2012 16:41:55 -0700 [thread overview]
Message-ID: <1348098122-11041-4-git-send-email-anton.vorontsov@linaro.org> (raw)
In-Reply-To: <20120919234003.GA24143@lizard>
It was noticed that polling drivers (like KGDB) are not able to use
serial ports if the ports were not previously initialized via console.
I.e. when booting with console=ttyAMA0 kgdboc=ttyAMA0, everything works
fine, but with console=ttyFOO kgdboc=ttyAMA0, the kgdboc doesn't work.
This is because we don't initialize the hardware. Calling ->startup() is
not an option, because drivers request interrupts there, and drivers
fail to handle situations when tty isn't opened with interrupts enabled.
So, we have to implement a new callback (actually, tty_ops already have
a similar callback), which does everything needed to initialize just the
hardware.
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Acked-by: Alan Cox <alan@linux.intel.com>
---
drivers/tty/serial/serial_core.c | 17 +++++++++++++++++
include/linux/serial_core.h | 1 +
2 files changed, 18 insertions(+)
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 046279c..dcb2d5a 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -2129,6 +2129,7 @@ static int uart_poll_init(struct tty_driver *driver, int line, char *options)
int bits = 8;
int parity = 'n';
int flow = 'n';
+ int ret;
if (!state || !state->uart_port)
return -1;
@@ -2137,6 +2138,22 @@ static int uart_poll_init(struct tty_driver *driver, int line, char *options)
if (!(port->ops->poll_get_char && port->ops->poll_put_char))
return -1;
+ if (port->ops->poll_init) {
+ struct tty_port *tport = &state->port;
+
+ ret = 0;
+ mutex_lock(&tport->mutex);
+ /*
+ * We don't set ASYNCB_INITIALIZED as we only initialized the
+ * hw, e.g. state->xmit is still uninitialized.
+ */
+ if (!test_bit(ASYNCB_INITIALIZED, &tport->flags))
+ ret = port->ops->poll_init(port);
+ mutex_unlock(&tport->mutex);
+ if (ret)
+ return ret;
+ }
+
if (options) {
uart_parse_options(options, &baud, &parity, &bits, &flow);
return uart_set_options(port, NULL, baud, parity, bits, flow);
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 7cf0b68..822c887 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -274,6 +274,7 @@ struct uart_ops {
int (*verify_port)(struct uart_port *, struct serial_struct *);
int (*ioctl)(struct uart_port *, unsigned int, unsigned long);
#ifdef CONFIG_CONSOLE_POLL
+ int (*poll_init)(struct uart_port *);
void (*poll_put_char)(struct uart_port *, unsigned char);
int (*poll_get_char)(struct uart_port *);
#endif
--
1.7.11.5
next prev parent reply other threads:[~2012-09-19 23:46 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-19 23:40 [PATCH v8 0/11] KGDB/KDB FIQ (NMI) debugger Anton Vorontsov
2012-09-19 23:41 ` [PATCH 01/11] kernel/debug: Mask KGDB NMI upon entry Anton Vorontsov
2012-09-19 23:41 ` [PATCH 02/11] kdb: Implement disable_nmi command Anton Vorontsov
2012-09-19 23:41 ` [PATCH 03/11] kdb: Turn KGDB_KDB=n stubs into static inlines Anton Vorontsov
2012-09-19 23:41 ` Anton Vorontsov [this message]
2012-09-19 23:41 ` [PATCH 05/11] tty/serial/amba-pl011: Implement poll_init callback Anton Vorontsov
2012-09-19 23:41 ` [PATCH 06/11] tty/serial/amba-pl011: Quiesce interrupts in poll_get_char Anton Vorontsov
2012-09-19 23:41 ` [PATCH 07/11] tty/serial: Add kgdb_nmi driver Anton Vorontsov
2012-09-20 13:57 ` Jason Wessel
2012-09-20 18:30 ` [PATCH updated " Anton Vorontsov
2012-09-19 23:41 ` [PATCH 08/11] ARM: Move some macros from entry-armv to entry-header Anton Vorontsov
2012-09-19 23:42 ` [PATCH 09/11] ARM: Add KGDB/KDB FIQ debugger generic code Anton Vorontsov
2012-09-19 23:42 ` [PATCH 10/11] ARM: VIC: Add a couple of low-level FIQ management helpers Anton Vorontsov
2012-09-19 23:42 ` [PATCH 11/11] ARM: versatile: Make able to use UART ports for KGDB FIQ debugger Anton Vorontsov
2012-09-20 13:40 ` [PATCH v8 0/11] KGDB/KDB FIQ (NMI) debugger Jason Wessel
2012-09-24 10:46 ` Jason Wessel
2012-09-24 21:25 ` Anton Vorontsov
-- strict thread matches above, loose matches on Subject: below --
2012-09-24 21:26 [PATCH v9 " Anton Vorontsov
2012-09-24 21:27 ` [PATCH 04/11] tty/serial/core: Introduce poll_init callback Anton Vorontsov
2012-09-13 15:01 [PATCH v7 0/11] KGDB/KDB FIQ (NMI) debugger Anton Vorontsov
2012-09-13 15:03 ` [PATCH 04/11] tty/serial/core: Introduce poll_init callback Anton Vorontsov
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