[Linux-ia64] runtime platform detection in GENERIC kernels

Martin Hicks
2003-05-14T15:03:46Z

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Hello,

In the process of trying to get a GENERIC kernel running on SGI SN2
hardware we've run into a few instances where knowing what type of
machine we are running on is useful. Would it be acceptable to make a
macro such as is_sgi_sn2() to check this?

One of the specific situations is in console_init()
(drivers/char/tty_io.c) where SN2 machines must use the sgi-l1_protocol
driver and the rest of the IA64 machines just use the normal serial
driver. A small check was added:

mac_scc_console_init();
#elif defined(CONFIG_PARISC)
pdc_console_init();
+#elif defined(CONFIG_IA64_GENERIC)
+ if (is_sgi_sn2())
+ sgi_l1_serial_console_init();
+ else
+ serial_console_init();
#elif defined(CONFIG_SERIAL)
serial_console_init();
#endif /* CONFIG_8xx */

The current patch is attached. It's a first draft. I'm looking
comments on whether this (or something like it) has any chance
of being accepted, and if so, any comments on the design of
the facility.

mh

--
Wild Open Source Inc. mort@wildopensource.com

===========================================================================
Index: linux/arch/ia64/kernel/setup.c
===========================================================================

--- /usr/tmp/TmpDir.30939-0/linux/arch/ia64/kernel/setup.c_1.33 Tue May 13 14:41:50 2003
+++ linux/arch/ia64/kernel/setup.c Tue May 13 14:38:08 2003
@@ -63,6 +63,8 @@
struct cpuinfo_ia64 _cpu_data[NR_CPUS] __attribute__ ((section ("__special_page_section")));
#endif

+int machine_is_sgi_sn2;
+
unsigned long ia64_cycles_per_usec;
struct ia64_boot_param *ia64_boot_param;
struct screen_info screen_info;
@@ -446,7 +448,11 @@
ia64_sal_init(efi.sal_systab);

#ifdef CONFIG_IA64_GENERIC
- machvec_init(acpi_get_sysname());
+ {
+ char *str = acpi_get_sysname();
+ machvec_init(str);
+ init_is_sgi_sn2(str);
+ }
#endif

/*

===========================================================================
Index: linux/include/asm-ia64/system.h
===========================================================================

--- /usr/tmp/TmpDir.30939-0/linux/include/asm-ia64/system.h_1.25 Tue May 13 14:41:50 2003
+++ linux/include/asm-ia64/system.h Tue May 13 14:40:26 2003
@@ -445,6 +445,20 @@
#define task_running(rq, p) (((rq)->curr == (p)) || spin_is_locked(&(p)->switch_lock))
#define idle_needs_wakeup 0

+#ifdef CONFIG_IA64_GENERIC
+extern int machine_is_sgi_sn2;
+#define init_is_sgi_sn2(str) do { \
+ if (!strcmp(str,"sn2")) \
+ machine_is_sgi_sn2=1; \
+ } while (0)
+
+#define is_sgi_sn2() (machine_is_sgi_sn2)
+#elif CONFIG_IA64_SGI_SN
+#define is_sgi_sn2() 1
+#else
+#define is_sgi_sn2() 0
+#endif /* CONFIG_IA64_GENERIC */
+
#endif /* __KERNEL__ */

#endif /* __ASSEMBLY__ */

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