diff options
| -rw-r--r-- | arch/powerpc/cpu/mpc85xx/start.S | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/arch/powerpc/cpu/mpc85xx/start.S b/arch/powerpc/cpu/mpc85xx/start.S index d494528..7bd5cc0 100644 --- a/arch/powerpc/cpu/mpc85xx/start.S +++ b/arch/powerpc/cpu/mpc85xx/start.S @@ -319,6 +319,55 @@ l2_disabled: #endif /* CONFIG_MPC8569 */ /* + * Search for the TLB that covers the code we're executing, and shrink it + * so that it covers only this 4K page. That will ensure that any other + * TLB we create won't interfere with it. We assume that the TLB exists, + * which is why we don't check the Valid bit of MAS1. + * + * This is necessary, for example, when booting from the on-chip ROM, + * which (oddly) creates a single 4GB TLB that covers CCSR and DDR. + * If we don't shrink this TLB now, then we'll accidentally delete it + * in "purge_old_ccsr_tlb" below. + */ + bl nexti /* Find our address */ +nexti: mflr r1 /* R1 = our PC */ + li r2, 0 + mtspr MAS6, r2 /* Assume the current PID and AS are 0 */ + isync + msync + tlbsx 0, r1 /* This must succeed */ + + /* Set the size of the TLB to 4KB */ + mfspr r3, MAS1 + li r2, 0xF00 + andc r3, r3, r2 /* Clear the TSIZE bits */ + ori r3, r3, MAS1_TSIZE(BOOKE_PAGESZ_4K)@l + mtspr MAS1, r3 + + /* + * Set the base address of the TLB to our PC. We assume that + * virtual == physical. We also assume that MAS2_EPN == MAS3_RPN. + */ + lis r3, MAS2_EPN@h + ori r3, r3, MAS2_EPN@l /* R3 = MAS2_EPN */ + + and r1, r1, r3 /* Our PC, rounded down to the nearest page */ + + mfspr r2, MAS2 + andc r2, r2, r3 + or r2, r2, r1 + mtspr MAS2, r2 /* Set the EPN to our PC base address */ + + mfspr r2, MAS3 + andc r2, r2, r3 + or r2, r2, r1 + mtspr MAS3, r2 /* Set the RPN to our PC base address */ + + isync + msync + tlbwe + +/* * Relocate CCSR, if necessary. We relocate CCSR if (obviously) the default * location is not where we want it. This typically happens on a 36-bit * system, where we want to move CCSR to near the top of 36-bit address space. |