serial: allow 8250 to be used on sparc

This requires three changes:

1) Remove !SPARC restriction in Kconfig.

2) Move Sparc specific serial drivers before 8250, so that serial
   console devices don't change names on us, even if 8250 finds
   devices.

3) Since the Sparc specific serial drivers try to use the
   same major/minor device namespace as 8250, some coordination
   is necessary.  Use the sunserial_*() layer routines to allocate
   minor number space within TTY_MAJOR when CONFIG_SPARC.

   This has no effect on other platforms.

Thanks to Josip Rodin for bringing up this issue and testing
plus debugging various revisions of this patch.

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 17 insertions, 4 deletions

diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index ed593c4..db2cdc1 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -44,6 +44,10 @@
 
 #include "8250.h"
 
+#ifdef CONFIG_SPARC
+#include "suncore.h"
+#endif
+
 /*
  * Configuration:
  *   share_irqs - whether we pass IRQF_SHARED to request_irq().  This option
@@ -2676,7 +2680,6 @@ static struct uart_driver serial8250_reg = {
 	.dev_name		= "ttyS",
 	.major			= TTY_MAJOR,
 	.minor			= 64,
-	.nr			= UART_NR,
 	.cons			= SERIAL8250_CONSOLE,
 };
 
@@ -2958,10 +2961,12 @@ static int __init serial8250_init(void)
 		"%d ports, IRQ sharing %sabled\n", nr_uarts,
 		share_irqs ? "en" : "dis");
 
-	for (i = 0; i < NR_IRQS; i++)
-		spin_lock_init(&irq_lists[i].lock);
-
+#ifdef CONFIG_SPARC
+	ret = sunserial_register_minors(&serial8250_reg, UART_NR);
+#else
+	serial8250_reg.nr = UART_NR;
 	ret = uart_register_driver(&serial8250_reg);
+#endif
 	if (ret)
 		goto out;
 
@@ -2986,7 +2991,11 @@ static int __init serial8250_init(void)
  put_dev:
 	platform_device_put(serial8250_isa_devs);
  unreg_uart_drv:
+#ifdef CONFIG_SPARC
+	sunserial_unregister_minors(&serial8250_reg, UART_NR);
+#else
 	uart_unregister_driver(&serial8250_reg);
+#endif
  out:
 	return ret;
 }
@@ -3005,7 +3014,11 @@ static void __exit serial8250_exit(void)
 	platform_driver_unregister(&serial8250_isa_driver);
 	platform_device_unregister(isa_dev);
 
+#ifdef CONFIG_SPARC
+	sunserial_unregister_minors(&serial8250_reg, UART_NR);
+#else
 	uart_unregister_driver(&serial8250_reg);
+#endif
 }
 
 module_init(serial8250_init);