[PATCH v2 21/34] ARM: mmu: alloc 64k for early page tables

[Sascha Hauer <s.hauer@pengutronix.de>]

This is a preparation for using two level page tables in the PBL.
To do that we need a way to allocate page tables in PBL. As malloc
is not available in PBL, increase the area we use for the TTB to
make some space available for page tables.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 arch/arm/cpu/mmu_32.c              | 6 ++++++
 arch/arm/include/asm/barebox-arm.h | 8 ++------
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/arch/arm/cpu/mmu_32.c b/arch/arm/cpu/mmu_32.c
index 12fe892400..4050d96846 100644
--- a/arch/arm/cpu/mmu_32.c
+++ b/arch/arm/cpu/mmu_32.c
@@ -24,6 +24,12 @@
 #define PTRS_PER_PTE		(PGDIR_SIZE / PAGE_SIZE)
 #define ARCH_MAP_WRITECOMBINE	((unsigned)-1)
 
+/*
+ * We have a 4GiB address space split into 1MiB sections, with each
+ * section header taking 4 bytes
+ */
+#define ARM_TTB_SIZE	(SZ_4G / SZ_1M * sizeof(u32))
+
 static uint32_t *ttb;
 
 /*
diff --git a/arch/arm/include/asm/barebox-arm.h b/arch/arm/include/asm/barebox-arm.h
index f5a74b4746..eb31ca2788 100644
--- a/arch/arm/include/asm/barebox-arm.h
+++ b/arch/arm/include/asm/barebox-arm.h
@@ -23,11 +23,7 @@
 #include <asm/reloc.h>
 #include <linux/stringify.h>
 
-/*
- * We have a 4GiB address space split into 1MiB sections, with each
- * section header taking 4 bytes
- */
-#define ARM_TTB_SIZE	(SZ_4G / SZ_1M * sizeof(u32))
+#define ARM_EARLY_PAGETABLE_SIZE	SZ_64K
 
 void __noreturn barebox_arm_entry(unsigned long membase, unsigned long memsize, void *boarddata);
 
@@ -89,7 +85,7 @@ static inline unsigned long arm_mem_stack(unsigned long endmem)
 static inline unsigned long arm_mem_ttb(unsigned long endmem)
 {
 	endmem = arm_mem_stack(endmem);
-	endmem = ALIGN_DOWN(endmem, ARM_TTB_SIZE) - ARM_TTB_SIZE;
+	endmem = ALIGN_DOWN(endmem, ARM_EARLY_PAGETABLE_SIZE) - ARM_EARLY_PAGETABLE_SIZE;
 
 	return endmem;
 }
-- 
2.39.2