powerpc/85xx: Workaroudn e500 CPU erratum A005

[cascardo/linux.git] / arch / powerpc / math-emu / math_efp.c

diff --git a/arch/powerpc/math-emu/math_efp.c b/arch/powerpc/math-emu/math_efp.c
index 41f4ef3..634830b 100644 (file)
--- a/arch/powerpc/math-emu/math_efp.c
+++ b/arch/powerpc/math-emu/math_efp.c
@@ -1,7 +1,7 @@
 /*
  * arch/powerpc/math-emu/math_efp.c
  *
- * Copyright (C) 2006-2008 Freescale Semiconductor, Inc. All rights reserved.
+ * Copyright (C) 2006-2008, 2010 Freescale Semiconductor, Inc.
  *
  * Author: Ebony Zhu,  <ebony.zhu@freescale.com>
  *         Yu Liu,     <yu.liu@freescale.com>
@@ -104,6 +104,8 @@
 #define FP_EX_MASK     (FP_EX_INEXACT | FP_EX_INVALID | FP_EX_DIVZERO | \
                        FP_EX_UNDERFLOW | FP_EX_OVERFLOW)
 
+static int have_e500_cpu_a005_erratum;
+
 union dw_union {
        u64 dp[1];
        u32 wp[2];
@@ -652,6 +654,15 @@ update_regs:
        return 0;
 
 illegal:
+       if (have_e500_cpu_a005_erratum) {
+               /* according to e500 cpu a005 erratum, reissue efp inst */
+               regs->nip -= 4;
+#ifdef DEBUG
+               printk(KERN_DEBUG "re-issue efp inst: %08lx\n", speinsn);
+#endif
+               return 0;
+       }
+
        printk(KERN_ERR "\nOoops! IEEE-754 compliance handler encountered un-supported instruction.\ninst code: %08lx\n", speinsn);
        return -ENOSYS;
 }
@@ -718,3 +729,43 @@ int speround_handler(struct pt_regs *regs)
 
        return 0;
 }
+
+int __init spe_mathemu_init(void)
+{
+       u32 pvr, maj, min;
+
+       pvr = mfspr(SPRN_PVR);
+
+       if ((PVR_VER(pvr) == PVR_VER_E500V1) ||
+           (PVR_VER(pvr) == PVR_VER_E500V2)) {
+               maj = PVR_MAJ(pvr);
+               min = PVR_MIN(pvr);
+
+               /*
+                * E500 revision below 1.1, 2.3, 3.1, 4.1, 5.1
+                * need cpu a005 errata workaround
+                */
+               switch (maj) {
+               case 1:
+                       if (min < 1)
+                               have_e500_cpu_a005_erratum = 1;
+                       break;
+               case 2:
+                       if (min < 3)
+                               have_e500_cpu_a005_erratum = 1;
+                       break;
+               case 3:
+               case 4:
+               case 5:
+                       if (min < 1)
+                               have_e500_cpu_a005_erratum = 1;
+                       break;
+               default:
+                       break;
+               }
+       }
+
+       return 0;
+}
+
+module_init(spe_mathemu_init);