arm: armv8: mmu: export mmu_setup

The mmu_setup function configures the page tables based on the board
supplied mem_map struct array. It is called implicitly as part of
dcache_enable but this limits us to only be able to use APIs such as
mmu_change_region_attr only after caches are enabled.

This might lead to speculative accesses before we can unmap a region
that is marked as cacheable in the static memory map.

Therefore this patch exports the mmu_setup function in mmu.h allowing
users to have more control over when the mmu is configured.

For K3 specifically this allows for the following configuration sequence
as part of enable_caches:

static mem_map fixups (TODO) -> mmu_setup -> carveouts using
mmu_change_region_attr (TODO) -> icache/dcache enable

Reviewed-by: Dhruva Gole <d-gole@ti.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Anshul Dalal <anshuld@ti.com>
Tested-by: Wadim Egorov <w.egorov@phytec.de>

arch/arm/include/asm/armv8/mmu.h

@@ -197,6 +197,11 @@ struct mm_region {
 extern struct mm_region *mem_map;
 void setup_pgtables(void);
 u64 get_tcr(u64 *pips, u64 *pva_bits);
+
+/**
+ * mmu_setup() - Sets up the mmu page tables as per mem_map
+ */
+void mmu_setup(void);
 #endif
 
 #endif /* _ASM_ARMV8_MMU_H_ */

arch/arm/mach-k3/common.c

@@ -30,6 +30,7 @@
 #include <soc.h>
 #include <dm/uclass-internal.h>
 #include <dm/device-internal.h>
+#include <asm/armv8/mmu.h>
 
 #define PROC_BOOT_CTRL_FLAG_R5_CORE_HALT	0x00000001
 #define PROC_BOOT_STATUS_FLAG_R5_WFI		0x00000002
@@ -261,6 +262,8 @@ void board_prep_linux(struct bootm_headers *images)
 
 void enable_caches(void)
 {
+	mmu_setup();
+
 	icache_enable();
 	dcache_enable();
 }