MIPS: CFE: Add cfe_die()

Add a cfe_die() implementation which is useful when the kernel does an
early panic and no console is registered. This allows us to print
useful diagnostics such as an invalid DTB having been
configured/selected.

Since the BMIPS_GENERIC kernel can be built with support for multiple
processors, we need to do a runtime determination of the type of CPU
that we are executing on to perform the appropriate XKS01 disabling.

Since cfe_init() + cfe_die() could be conceivably called at very early
stages of the kernel boot, before cpu_probe(), we do not rely on the
structure(s) populated by cpu_probe().

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

diff --git a/arch/mips/fw/cfe/cfe_api.c b/arch/mips/fw/cfe/cfe_api.c
index 0c9c97ab291e7a0e2c3b7879307d5f35f430d988..dcdfd962dbdee351bdb2e79d02582f6c91a8220c 100644 (file)
--- a/arch/mips/fw/cfe/cfe_api.c
+++ b/arch/mips/fw/cfe/cfe_api.c
@@ -13,10 +13,15 @@
  *
  * Authors:  Mitch Lichtenberg, Chris Demetriou
  */
-
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/printk.h>
+#include <asm/mipsregs.h>
 #include <asm/fw/cfe/cfe_api.h>
 #include "cfe_api_int.h"
 
+unsigned long __initdata cfe_seal;
+
 /* Cast from a native pointer to a cfe_xptr_t and back.         */
 #define XPTR_FROM_NATIVE(n)    ((cfe_xptr_t) (intptr_t) (n))
 #define NATIVE_FROM_XPTR(x)    ((void *) (intptr_t) (x))
@@ -412,3 +417,64 @@ int cfe_writeblk(int handle, s64 offset, const char *buffer, int length)
                return xiocb.xiocb_status;
        return xiocb.plist.xiocb_buffer.buf_retlen;
 }
+
+void __init cfe_die(char *fmt, ...)
+{
+       unsigned int prid, __maybe_unused rev;
+       char msg[128];
+       va_list ap;
+       int handle;
+       unsigned int count;
+
+       va_start(ap, fmt);
+       vsprintf(msg, fmt, ap);
+       strcat(msg, "\r\n");
+
+       if (cfe_seal != CFE_EPTSEAL)
+               goto no_cfe;
+
+       prid = read_c0_prid();
+       if ((prid & PRID_COMP_MASK) != PRID_COMP_BROADCOM)
+               goto no_cfe;
+
+       rev = prid & PRID_REV_MASK;
+
+       /* disable XKS01 so that CFE can access the registers */
+       switch (prid & PRID_IMP_MASK) {
+#ifdef CONFIG_CPU_BMIPS4380
+       case PRID_IMP_BMIPS43XX:
+               if (rev >= PRID_REV_BMIPS4380_LO &&
+                   rev <= PRID_REV_BMIPS4380_HI)
+                       __write_32bit_c0_register($22, 3,
+                               __read_32bit_c0_register($22, 3) & ~BIT(12));
+               break;
+#endif
+#ifdef CONFIG_CPU_BMIPS5000
+       case PRID_IMP_BMIPS5000:
+       case PRID_IMP_BMIPS5200:
+               __write_32bit_c0_register($22, 5,
+                       __read_32bit_c0_register($22, 5) & ~BIT(8));
+               break;
+#endif
+       default:
+               break;
+       }
+
+       handle = cfe_getstdhandle(CFE_STDHANDLE_CONSOLE);
+       if (handle < 0)
+               goto no_cfe;
+
+       cfe_write(handle, msg, strlen(msg));
+
+       for (count = 0; count < 0x7fffffff; count++)
+               mb();
+       cfe_exit(0, 1);
+       while (1)
+               ;
+
+no_cfe:
+       /* probably won't print anywhere useful */
+       panic("%s", msg);
+
+       va_end(ap);
+}

diff --git a/arch/mips/include/asm/fw/cfe/cfe_api.h b/arch/mips/include/asm/fw/cfe/cfe_api.h
index 6457f36897a241dfe9eb56b85fc32a20f85f115a..25df2f4deb31f1ef612d4141c877916c68fb12ba 100644 (file)
--- a/arch/mips/include/asm/fw/cfe/cfe_api.h
+++ b/arch/mips/include/asm/fw/cfe/cfe_api.h
@@ -105,5 +105,7 @@ int cfe_setenv(char *name, char *val);
 int cfe_write(int handle, const char *buffer, int length);
 int cfe_writeblk(int handle, int64_t offset, const char *buffer,
                 int length);
+extern unsigned long cfe_seal;
+__printf(1, 2) void cfe_die(char *fmt, ...);
 
 #endif                         /* CFE_API_H */