MIPS: Netlogic: Enable access to more than 64GB

The ELPA bit needs to be set in the PAGEGRAIN register to enable
access to >64GB physical address. Update reset.S to do this from
every hardware thread.

Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6866/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 15 insertions, 0 deletions

diff --git a/arch/mips/netlogic/common/reset.S b/arch/mips/netlogic/common/reset.S
index fda772a8595b..13c1bc5b5988 100644
--- a/arch/mips/netlogic/common/reset.S
+++ b/arch/mips/netlogic/common/reset.S
@@ -74,6 +74,18 @@
 .endm
 
 /*
+ * Allow access to physical mem >64G by enabling ELPA in PAGEGRAIN
+ * register. This is needed before going to C code since the SP can
+ * in this region. Called from all HW threads.
+ */
+.macro xlp_early_mmu_init
+        mfc0    t0, CP0_PAGEMASK, 1
+        li      t1, (1 << 29)           /* ELPA bit */
+        or      t0, t1
+        mtc0    t0, CP0_PAGEMASK, 1
+.endm
+
+/*
  * L1D cache has to be flushed before enabling threads in XLP.
  * On XLP8xx/XLP3xx, we do a low level flush using processor control
  * registers. On XLPII CPUs, usual cache instructions work.
@@ -228,6 +240,8 @@ EXPORT(nlm_boot_siblings)
 #endif
         mtc0    t1, CP0_STATUS
 
+        xlp_early_mmu_init
+
         /* mark CPU ready */
         li      t3, CKSEG1ADDR(RESET_DATA_PHYS)
         ADDIU   t1, t3, BOOT_CPU_READY
@@ -254,6 +268,7 @@ EXPORT(nlm_reset_entry_end)
 LEAF(nlm_init_boot_cpu)
 #ifdef CONFIG_CPU_XLP
         xlp_config_lsu
+        xlp_early_mmu_init
 #endif
         jr      ra
         nop