Thread (262 messages) 262 messages, 17 authors, 2014-09-14

[RFC v2 10/10] serial: asc: Add support for KGDB's FIQ/NMI mode

From: Srinivas Kandagatla <hidden>
Date: 2014-05-23 14:50:37
Also in: linux-devicetree, linux-serial

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 <redacted>
Cc: Srinivas Kandagatla <redacted>
Cc: Maxime Coquelin <redacted>
Cc: Patrice Chotard <redacted>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <redacted>
Cc: kernel at stlinux.com
Cc: linux-serial at 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.

quoted hunk ↗ jump to hunk
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.
quoted hunk ↗ jump to hunk
  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);
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