powerpc: Add early debug for WSP platforms

Signed-off-by: Jack Miller <jack@codezen.org>
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S
index c98e9d260621..4d0abb4930a1 100644
--- a/arch/powerpc/kernel/exceptions-64e.S
+++ b/arch/powerpc/kernel/exceptions-64e.S
@@ -17,6 +17,7 @@
 #include <asm/cputable.h>
 #include <asm/setup.h>
 #include <asm/thread_info.h>
+#include <asm/reg_a2.h>
 #include <asm/exception-64e.h>
 #include <asm/bug.h>
 #include <asm/irqflags.h>
@@ -951,6 +952,22 @@ a2_tlbinit_after_linear_map:
         .globl  a2_tlbinit_after_iprot_flush
 a2_tlbinit_after_iprot_flush:
 
+#ifdef CONFIG_PPC_EARLY_DEBUG_WSP
+        /* Now establish early debug mappings if applicable */
+        /* Restore the MAS0 we used for linear mapping load */
+        mtspr   SPRN_MAS0,r11
+
+        lis     r3,(MAS1_VALID | MAS1_IPROT)@h
+        ori     r3,r3,(BOOK3E_PAGESZ_4K << MAS1_TSIZE_SHIFT)
+        mtspr   SPRN_MAS1,r3
+        LOAD_REG_IMMEDIATE(r3, WSP_UART_VIRT | MAS2_I | MAS2_G)
+        mtspr   SPRN_MAS2,r3
+        LOAD_REG_IMMEDIATE(r3, WSP_UART_PHYS | MAS3_SR | MAS3_SW)
+        mtspr   SPRN_MAS7_MAS3,r3
+        /* re-use the MAS8 value from the linear mapping */
+        tlbwe
+#endif /* CONFIG_PPC_EARLY_DEBUG_WSP */
+
         PPC_TLBILX(0,0,0)
         sync
         isync