ARM: Defer lookup of machine_type to setup.c

Since the debug macros no longer depend on the machine type information,
the machine type lookup can be deferred to setup_arch() in setup.c which
simplifies the code somewhat.

We also move the __error_a functionality into setup.c for displaying a
message when a bad machine ID is passed to the kernel via the LL debug
code.  We also log this into the kernel ring buffer which makes it
possible to retrieve the message via a debugger.

Original idea from Grant Likely.

Acked-by: Grant Likely <grant.likely@secretlab.ca>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 38 insertions, 1 deletions

diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 420b8d6485d6..78678b07901c 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -308,7 +308,44 @@ static void __init cacheid_init(void)
  * already provide the required functionality.
  */
 extern struct proc_info_list *lookup_processor_type(unsigned int);
-extern struct machine_desc *lookup_machine_type(unsigned int);
+
+static void __init early_print(const char *str, ...)
+{
+        extern void printascii(const char *);
+        char buf[256];
+        va_list ap;
+
+        va_start(ap, str);
+        vsnprintf(buf, sizeof(buf), str, ap);
+        va_end(ap);
+
+#ifdef CONFIG_DEBUG_LL
+        printascii(buf);
+#endif
+        printk("%s", buf);
+}
+
+static struct machine_desc * __init lookup_machine_type(unsigned int type)
+{
+        extern struct machine_desc __arch_info_begin[], __arch_info_end[];
+        struct machine_desc *p;
+
+        for (p = __arch_info_begin; p < __arch_info_end; p++)
+                if (type == p->nr)
+                        return p;
+
+        early_print("\n"
+                "Error: unrecognized/unsupported machine ID (r1 = 0x%08x).\n\n"
+                "Available machine support:\n\nID (hex)\tNAME\n", type);
+
+        for (p = __arch_info_begin; p < __arch_info_end; p++)
+                early_print("%08x\t%s\n", p->nr, p->name);
+
+        early_print("\nPlease check your kernel config and/or bootloader.\n");
+
+        while (true)
+                /* can't use cpu_relax() here as it may require MMU setup */;
+}
 
 static void __init feat_v6_fixup(void)
 {