cleanup early console setup

This patch cleans up our early console hacks so that we use the "approved" way of doing things. I've only tested this on a J6k... looking for testers on other systems.

Especially interesting would be something that uses non-8250 consoles, such as E/K class systems that use the serial mux console. I suspect some changes are needed there. If you can test on such a system, and see some problems [*], please let me know. likely we will need to move the register_console() call from mux_probe() into a separate initcall.

[*] during startup, the console print messages should show up regularly, and only once. symptoms of problems are if your console prints pause for a long time, or if you start seeing each line printed twice.

randolph

Index: arch/parisc/Kconfig
===================================================================
RCS file: /var/cvs/linux-2.6/arch/parisc/Kconfig,v retrieving revision 1.25

diff -u -p -r1.25 Kconfig
@@ -19,6 +19,9 @@ config MMU
 config STACK_GROWSUP
 	def_bool y
 
+config EARLY_PRINTK
+	def_bool y
+
 config UID16
 	bool
 

Index: arch/parisc/kernel/pdc_cons.c
===================================================================
RCS file: /var/cvs/linux-2.6/arch/parisc/kernel/pdc_cons.c,v retrieving revision 1.7

diff -u -p -r1.7 pdc_cons.c
@@ -39,11 +39,6 @@
  *  can or will be a fully functional linux console.
  */
 
-/* Define EARLY_BOOTUP_DEBUG to debug kernel related boot problems. 
- * On production kernels EARLY_BOOTUP_DEBUG should be undefined. */
-#undef EARLY_BOOTUP_DEBUG
-
-
 #include <linux/config.h>
 #include <linux/kernel.h>
 #include <linux/console.h>

@@ -81,8 +76,11 @@ void pdc_printf(const char *fmt, ...)
 	len = vscnprintf(buf, sizeof(buf), fmt, args);
 	va_end(args);
 
-	for (i = 0; i < len; i++)
+	for (i = 0; i < len; i++) {
+		if (buf[i] == '\n')
+			pdc_iodc_outc('\r');
 		pdc_iodc_outc(buf[i]);
+	}
 }
 
 int pdc_console_poll_key(struct console *co)

@@ -112,14 +110,11 @@ static struct console pdc_cons = {
 	.write =	pdc_console_write,
 	.device =	PDC_CONSOLE_DEVICE,
 	.setup =	pdc_console_setup,
-	.flags =	CON_BOOT|CON_PRINTBUFFER|CON_ENABLED,
+	.flags =	CON_PRINTBUFFER,
 	.index =	-1,
 };
 
 static int pdc_console_initialized;
-extern unsigned long con_start;	/* kernel/printk.c */
-extern unsigned long log_end;	/* kernel/printk.c */
-
 
 static void pdc_console_init_force(void)
 {

@@ -135,14 +130,10 @@ static void pdc_console_init_force(void)
 	register_console(&pdc_cons);
 }
 
-void __init pdc_console_init(void)
+void __init 
+pdc_console_init(void)
 {
-#if defined(EARLY_BOOTUP_DEBUG) || defined(CONFIG_PDC_CONSOLE)
 	pdc_console_init_force();
-#endif
-#ifdef EARLY_BOOTUP_DEBUG
-	printk(KERN_INFO "Initialized PDC Console for debugging.\n");
-#endif
 }
 
 

@@ -155,12 +146,17 @@ void pdc_console_die(void)
 
 	printk(KERN_INFO "Switching from PDC console\n");
 
-	/* Don't repeat what we've already printed */
-	con_start = log_end;
-
 	unregister_console(&pdc_cons);
 }
 
+void __init 
+disable_early_printk(void)
+{
+#ifndef CONFIG_PDC_CONSOLE
+	pdc_console_die();
+#endif
+}
+
 
 /*
  * Used for emergencies. Currently only used if an HPMC occurs. If an

@@ -180,9 +176,6 @@ void pdc_console_restart(void)
 	while ((console = console_drivers) != NULL)
 		unregister_console(console_drivers);
 
-	/* Don't repeat what we've already printed */
-	con_start = log_end;
-	
 	/* force registering the pdc console */
 	pdc_console_init_force();
 }

Index: arch/parisc/kernel/setup.c
===================================================================
RCS file: /var/cvs/linux-2.6/arch/parisc/kernel/setup.c,v retrieving revision 1.12

diff -u -p -r1.12 setup.c
@@ -157,7 +157,8 @@ void __init setup_arch(char **cmdline_p)
 #endif
 
 #if defined(CONFIG_VT) && defined(CONFIG_DUMMY_CONSOLE)
-	conswitchp = &dummy_con;	/* we use take_over_console() later ! */
+	if (!conswitchp)
+		conswitchp = &dummy_con;	/* we use take_over_console() later ! */
 #endif
 
 }

Index: kernel/printk.c
===================================================================
RCS file: /var/cvs/linux-2.6/kernel/printk.c,v
retrieving revision 1.26

diff -u -p -r1.26 printk.c
@@ -92,8 +92,8 @@ static int log_buf_len = __LOG_BUF_LEN;
  * must be masked before subscripting
  */
 static unsigned long log_start;	/* Index into log_buf: next char to be read by syslog() */
-unsigned long con_start;	/* Index into log_buf: next char to be sent to consoles */
-unsigned long log_end;	/* Index into log_buf: most-recently-written-char + 1 */
+static unsigned long con_start;	/* Index into log_buf: next char to be sent to consoles */
+static unsigned long log_end;	/* Index into log_buf: most-recently-written-char + 1 */
 static unsigned long logged_chars; /* Number of chars produced since last read+clear operation */
 
 /*

@@ -793,11 +793,6 @@ void register_console(struct console * c
 
 	if (!(console->flags & CON_ENABLED))
 		return;

My comments in >>> <<<, this is the boot log from Knapps

Linux version 2.6.11-rc3-pa5 (willy@palinux) (gcc version 3.3.5 (Debian 1:3.3.5-5)) #9 Sun Feb 13 18:53:41 MST 2005 FP[0] enabled: Rev 0 Model 14
The 32-bit Kernel has started...
Determining PDC firmware type: System Map.
model 000058f0 00000491 00000000 00000002 53ad0a91 100000f1 00000008 000000b2 000000b2
vers 00000201
CPUID vers 14 rev 5 (0x000001c5)
model 9000/889/K460
Total Memory: 1920 Mb
Built 1 zonelists
Kernel command line: HOME=/ root=/dev/sda3 console=ttyB0 TERM=vt102 palo_kernel=0/vmlinux
PID hash table entries: 4096 (order: 12, 65536 bytes)
Switching from PDC console

Linux version 2.6.11-rc3-pa5 (willy@palinux) (gcc version 3.3.5 (Debian 1:3.3.5-5)) #9 Sun Feb 13 18:53:41 MST 2005 FP[0] enabled: Rev 0 Model 14
The 32-bit Kernel has started...
Determining PDC firmware type: System Map.
model 000058f0 00000491 00000000 00000002 53ad0a91 100000f1 00000008 000000b2 000000b2
vers 00000201
CPUID vers 14 rev 5 (0x000001c5)
model 9000/889/K460
Total Memory: 1920 Mb
Built 1 zonelists
Kernel command line: HOME=/ root=/dev/sda3 console=ttyB0 TERM=vt102 palo_kernel=0/vmlinux
PID hash table entries: 4096 (order: 12, 65536 bytes)
Switching from PDC console
Console: colour dummy device 160x64
Dentry cache hash table entries: 262144 (order: 8, 1048576 bytes)
Inode-cache hash table entries: 131072 (order: 7, 524288 bytes)
Memory: 1966080k available
Mount-cache hash table entries: 512 (order: 0, 4096 bytes)
NET: Registered protocol family 16

Serial mux driver (8 ports) Revision: 0.3
ttyB0 at MMIO 0xf1900800 (polled) is a Mux

Debian GNU/Linux 3.1 knapps ttyB0

knapps login: root
Password:
Last login: Mon Feb 14 01:56:30 2005 on ttyB0
Linux knapps 2.6.11-rc3-pa5 #9 Sun Feb 13 18:53:41 MST 2005 parisc GNU/Linux

"Next the statesmen will invent cheap lies, putting the blame upon 
the nation that is attacked, and every man will be glad of those
conscience-soothing falsities, and will diligently study them, and refuse
to examine any refutations of them; and thus he will by and by convince 
himself that the war is just, and will thank God for the better sleep 
he enjoys after this process of grotesque self-deception." -- Mark Twain
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I'm not sure we can avoid the long pauses. Look at what happens:

The console starts up and disables the early console, using the dummy driver. Then we wait while we do a buswalk ...

... and eventually the mux driver gets registered and starts spewing everything out.

So there's still a long period of time during which we have no console driver registered and it's frequently the most interesting part from the point of view of drivers or devices having trouble ;-(

Based on this, CON_BOOT seems like a superior solution. That's annoying.

"Next the statesmen will invent cheap lies, putting the blame upon 
the nation that is attacked, and every man will be glad of those
conscience-soothing falsities, and will diligently study them, and refuse
to examine any refutations of them; and thus he will by and by convince 
himself that the war is just, and will thank God for the better sleep 
he enjoys after this process of grotesque self-deception." -- Mark Twain
_______________________________________________
parisc-linux mailing list
[email protected]
http://lists.parisc-linux.org/mailman/listinfo/parisc-linux