From afff8cbdd816ca9b0d71ab54882ce70b21ed84e1 Mon Sep 17 00:00:00 2001
From: Achin Gupta <achin.gupta@arm.com>
Date: Thu, 26 Jun 2014 08:59:07 +0100
Subject: [PATCH] Make enablement of the MMU more flexible

This patch adds a 'flags' parameter to each exception level specific function
responsible for enabling the MMU. At present only a single flag which indicates
whether the data cache should also be enabled is implemented. Subsequent patches
will use this flag when enabling the MMU in the warm boot paths.

Change-Id: I0eafae1e678c9ecc604e680851093f1680e9cefa
---
 include/lib/aarch64/xlat_tables.h      | 13 +++++++++++--
 include/plat/common/platform.h         |  4 ++--
 lib/aarch64/xlat_tables.c              | 10 ++++++++--
 plat/common/aarch64/plat_common.c      |  8 ++++----
 plat/fvp/aarch64/fvp_common.c          |  2 +-
 services/std_svc/psci/psci_afflvl_on.c |  2 +-
 6 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/include/lib/aarch64/xlat_tables.h b/include/lib/aarch64/xlat_tables.h
index 8e0adc7fa..2d4a211b9 100644
--- a/include/lib/aarch64/xlat_tables.h
+++ b/include/lib/aarch64/xlat_tables.h
@@ -31,6 +31,14 @@
 #ifndef __XLAT_TABLES_H__
 #define __XLAT_TABLES_H__
 
+
+/*
+ * Flags to override default values used to program system registers while
+ * enabling the MMU.
+ */
+#define DISABLE_DCACHE		(1 << 0)
+
+#ifndef __ASSEMBLY__
 #include <stdint.h>
 
 /*
@@ -67,7 +75,8 @@ void mmap_add(const mmap_region_t *mm);
 
 void init_xlat_tables(void);
 
-void enable_mmu_el1(void);
-void enable_mmu_el3(void);
+void enable_mmu_el1(uint32_t flags);
+void enable_mmu_el3(uint32_t flags);
 
+#endif /*__ASSEMBLY__*/
 #endif /* __XLAT_TABLES_H__ */
diff --git a/include/plat/common/platform.h b/include/plat/common/platform.h
index 1eeaac278..4b73a0971 100644
--- a/include/plat/common/platform.h
+++ b/include/plat/common/platform.h
@@ -180,7 +180,7 @@ unsigned int plat_get_aff_state(unsigned int, unsigned long);
 /*******************************************************************************
  * Optional BL3-1 functions (may be overridden)
  ******************************************************************************/
-void bl31_plat_enable_mmu(void);
+void bl31_plat_enable_mmu(uint32_t flags);
 
 /*******************************************************************************
  * Mandatory BL3-2 functions (only if platform contains a BL3-2)
@@ -190,6 +190,6 @@ void bl32_platform_setup(void);
 /*******************************************************************************
  * Optional BL3-2 functions (may be overridden)
  ******************************************************************************/
-void bl32_plat_enable_mmu(void);
+void bl32_plat_enable_mmu(uint32_t flags);
 
 #endif /* __PLATFORM_H__ */
diff --git a/lib/aarch64/xlat_tables.c b/lib/aarch64/xlat_tables.c
index f1d658d52..d49411297 100644
--- a/lib/aarch64/xlat_tables.c
+++ b/lib/aarch64/xlat_tables.c
@@ -292,7 +292,7 @@ void init_xlat_tables(void)
  *			exception level
  ******************************************************************************/
 #define DEFINE_ENABLE_MMU_EL(_el, _tcr_extra, _tlbi_fct)		\
-	void enable_mmu_el##_el(void)					\
+	void enable_mmu_el##_el(uint32_t flags)				\
 	{								\
 		uint64_t mair, tcr, ttbr;				\
 		uint32_t sctlr;						\
@@ -330,7 +330,13 @@ void init_xlat_tables(void)
 									\
 		sctlr = read_sctlr_el##_el();				\
 		sctlr |= SCTLR_WXN_BIT | SCTLR_M_BIT | SCTLR_I_BIT;	\
-		sctlr |= SCTLR_A_BIT | SCTLR_C_BIT;			\
+		sctlr |= SCTLR_A_BIT;					\
+									\
+		if (flags & DISABLE_DCACHE)				\
+			sctlr &= ~SCTLR_C_BIT;				\
+		else							\
+			sctlr |= SCTLR_C_BIT;				\
+									\
 		write_sctlr_el##_el(sctlr);				\
 									\
 		/* Ensure the MMU enable takes effect immediately */	\
diff --git a/plat/common/aarch64/plat_common.c b/plat/common/aarch64/plat_common.c
index 94b9dfdf0..90574fd66 100644
--- a/plat/common/aarch64/plat_common.c
+++ b/plat/common/aarch64/plat_common.c
@@ -38,12 +38,12 @@
 #pragma weak bl31_plat_enable_mmu
 #pragma weak bl32_plat_enable_mmu
 
-void bl31_plat_enable_mmu(void)
+void bl31_plat_enable_mmu(uint32_t flags)
 {
-	enable_mmu_el3();
+	enable_mmu_el3(flags);
 }
 
-void bl32_plat_enable_mmu(void)
+void bl32_plat_enable_mmu(uint32_t flags)
 {
-	enable_mmu_el1();
+	enable_mmu_el1(flags);
 }
diff --git a/plat/fvp/aarch64/fvp_common.c b/plat/fvp/aarch64/fvp_common.c
index 3fe3a218f..392623971 100644
--- a/plat/fvp/aarch64/fvp_common.c
+++ b/plat/fvp/aarch64/fvp_common.c
@@ -119,7 +119,7 @@ const unsigned int num_sec_irqs = sizeof(irq_sec_array) /
 		mmap_add(fvp_mmap);					\
 		init_xlat_tables();					\
 									\
-		enable_mmu_el##_el();					\
+		enable_mmu_el##_el(0);					\
 	}
 
 /* Define EL1 and EL3 variants of the function initialising the MMU */
diff --git a/services/std_svc/psci/psci_afflvl_on.c b/services/std_svc/psci/psci_afflvl_on.c
index d62017245..1551cfe82 100644
--- a/services/std_svc/psci/psci_afflvl_on.c
+++ b/services/std_svc/psci/psci_afflvl_on.c
@@ -361,7 +361,7 @@ static unsigned int psci_afflvl0_on_finish(aff_map_node_t *cpu_node)
 	/*
 	 * Arch. management: Turn on mmu & restore architectural state
 	 */
-	bl31_plat_enable_mmu();
+	bl31_plat_enable_mmu(0);
 
 	/*
 	 * All the platform specific actions for turning this cpu