From: Mikhail Zolotaryov <lebon@faust.net.ua>
To: mporter@kernel.crashing.org
Cc: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] PPC4xx UART0 (8250) problem
Date: Sat, 07 Apr 2007 07:21:36 +0300 [thread overview]
Message-ID: <46171C50.3020104@faust.net.ua> (raw)
On PPC4xx embedded we often have UART0 on IRQ0 but 8250 UART driver
uses IRQ0 as "no irq" hack. It's suggested that platforms with UART
on IRQ0 will redefine is_real_interrupt(irq) macro but 8250 code
anyway overrides that. As the result, serial line on UART0 works
on polling-way and we have character loss on high baud rates.
In patch I added check if UART0 is on IRQ0, if so we define
is_real_interrupt macro to be 1 (true). Also, check if
is_real_interrupt macro is already defined added to 8250 UART
driver.
-------------------------------------------------------------------
--- linux.orig/include/asm-ppc/ibm4xx.h 2007-03-23 21:52:51.000000000 +0200
+++ linux/include/asm-ppc/ibm4xx.h 2007-04-06 17:37:22.000000000 +0300
@@ -54,6 +54,12 @@
#include <platforms/4xx/xilinx_ml403.h>
#endif
+#ifdef UART0_INT
+#if (UART0_INT == 0)
+#define is_real_interrupt(irq) (1)
+#endif
+#endif
+
#ifndef __ASSEMBLY__
#ifdef CONFIG_40x
--- linux.orig/drivers/serial/8250.c 2007-03-23 21:52:51.000000000 +0200
+++ linux/drivers/serial/8250.c 2007-04-06 16:44:32.000000000 +0300
@@ -77,7 +77,9 @@
* machine types want others as well - they're free
* to redefine this in their header file.
*/
+#ifndef is_real_interrupt(irq)
#define is_real_interrupt(irq) ((irq) != 0)
+#endif
#ifdef CONFIG_SERIAL_8250_DETECT_IRQ
#define CONFIG_SERIAL_DETECT_IRQ 1
next reply other threads:[~2007-04-07 4:16 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-07 4:21 Mikhail Zolotaryov [this message]
2007-04-07 5:12 ` [PATCH] PPC4xx UART0 (8250) problem Benjamin Herrenschmidt
2007-04-07 8:41 ` Mikhail Zolotaryov
-- strict thread matches above, loose matches on Subject: below --
2007-04-06 15:11 Mikhail Zolotaryov
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