Remove useless copies of meminfo structures

Platform setup code has to reserve some memory for storing the
memory layout information.  It is populated in early platform setup
code.

blx_get_sec_mem_layout() functions used to return a copy of this
structure.  This patch modifies blx_get_sec_mem_layout() functions
so that they now directly return a pointer to their memory layout
structure.  It ensures that the memory layout returned by
blx_get_sec_mem_layout() is always up-to-date and also avoids a
useless copy of the meminfo structure.

Also rename blx_get_sec_mem_layout() to blx_plat_sec_mem_layout()
to make it clear those functions are platform specific.

Change-Id: Ic7a6f9d6b6236b14865ab48a9f5eff545ce56551

10 files changed, 49 insertions, 40 deletions

diff --git a/bl1/bl1_main.c b/bl1/bl1_main.c
index ab9fa8c..5dfb564 100644
--- a/bl1/bl1_main.c
+++ b/bl1/bl1_main.c
@@ -50,7 +50,8 @@ void bl1_main(void)
 	unsigned long sctlr_el3 = read_sctlr();
 	unsigned long bl2_base;
 	unsigned int load_type = TOP_LOAD, spsr;
-	meminfo bl1_tzram_layout, *bl2_tzram_layout = 0x0;
+	meminfo *bl1_tzram_layout;
+	meminfo *bl2_tzram_layout = 0x0;
 
 	/*
 	 * Ensure that MMU/Caches and coherency are turned on
@@ -73,8 +74,8 @@ void bl1_main(void)
 	 * Find out how much free trusted ram remains after BL1 load
 	 * & load the BL2 image at its top
 	 */
-	bl1_tzram_layout = bl1_get_sec_mem_layout();
-	bl2_base = load_image(&bl1_tzram_layout,
+	bl1_tzram_layout = bl1_plat_sec_mem_layout();
+	bl2_base = load_image(bl1_tzram_layout,
 			      (const char *) BL2_IMAGE_NAME,
 			      load_type, BL2_BASE);
 
@@ -85,8 +86,8 @@ void bl1_main(void)
 	 * to BL2. BL2 will read the memory layout before using its
 	 * memory for other purposes.
 	 */
-	bl2_tzram_layout = (meminfo *) bl1_tzram_layout.free_base;
-	init_bl2_mem_layout(&bl1_tzram_layout,
+	bl2_tzram_layout = (meminfo *) bl1_tzram_layout->free_base;
+	init_bl2_mem_layout(bl1_tzram_layout,
 			    bl2_tzram_layout,
 			    load_type,
 			    bl2_base);
diff --git a/bl2/bl2_main.c b/bl2/bl2_main.c
index c738677..2d976fc 100644
--- a/bl2/bl2_main.c
+++ b/bl2/bl2_main.c
@@ -46,7 +46,8 @@
  ******************************************************************************/
 void bl2_main(void)
 {
-	meminfo bl2_tzram_layout, *bl31_tzram_layout;
+	meminfo *bl2_tzram_layout;
+	meminfo *bl31_tzram_layout;
 	el_change_info *ns_image_info;
 	unsigned long bl31_base, el_status;
 	unsigned int bl2_load, bl31_load, mode;
@@ -62,7 +63,7 @@ void bl2_main(void)
 #endif
 
 	/* Find out how much free trusted ram remains after BL2 load */
-	bl2_tzram_layout = bl2_get_sec_mem_layout();
+	bl2_tzram_layout = bl2_plat_sec_mem_layout();
 
 	/*
 	 * Load BL31. BL1 tells BL2 whether it has been TOP or BOTTOM loaded.
@@ -70,10 +71,10 @@ void bl2_main(void)
 	 * loaded opposite to BL2. This allows BL31 to reclaim BL2 memory
 	 * while maintaining its free space in one contiguous chunk.
 	 */
-	bl2_load = bl2_tzram_layout.attr & LOAD_MASK;
+	bl2_load = bl2_tzram_layout->attr & LOAD_MASK;
 	assert((bl2_load == TOP_LOAD) || (bl2_load == BOT_LOAD));
 	bl31_load = (bl2_load == TOP_LOAD) ? BOT_LOAD : TOP_LOAD;
-	bl31_base = load_image(&bl2_tzram_layout, BL31_IMAGE_NAME,
+	bl31_base = load_image(bl2_tzram_layout, BL31_IMAGE_NAME,
 	                       bl31_load, BL31_BASE);
 
 	/* Assert if it has not been possible to load BL31 */
@@ -84,7 +85,7 @@ void bl2_main(void)
 	 * will gobble up all the BL2 memory.
 	 */
 	bl31_tzram_layout = (meminfo *) get_el_change_mem_ptr();
-	init_bl31_mem_layout(&bl2_tzram_layout, bl31_tzram_layout, bl31_load);
+	init_bl31_mem_layout(bl2_tzram_layout, bl31_tzram_layout, bl31_load);
 
 	/*
 	 * BL2 also needs to tell BL31 where the non-trusted software image
diff --git a/docs/change-log.md b/docs/change-log.md
index 4e5b9aa..e813cb1 100644
--- a/docs/change-log.md
+++ b/docs/change-log.md
@@ -73,6 +73,11 @@ Detailed changes since last release
     CPU_SUSPEND and CPU_OFF apis simultaneously across cpus & clusters should
     not result in unexpected behaviour.
 
+*   The API to return the memory layout structures for each bootloader stage has
+    undergone change. A pointer to these structures is returned instead of their
+    copy.
+
+
 ARM Trusted Firmware - version 0.2
 ==================================
 
diff --git a/docs/porting-guide.md b/docs/porting-guide.md
index c0e6ace..aa1451f 100644
--- a/docs/porting-guide.md
+++ b/docs/porting-guide.md
@@ -436,14 +436,15 @@ implementation of the generic timer counter and initializes the console.
 This function helps fulfill requirement 5 above.
 
 
-### Function : bl1_get_sec_mem_layout() [mandatory]
+### Function : bl1_plat_sec_mem_layout() [mandatory]
 
     Argument : void
-    Return   : meminfo
+    Return   : meminfo *
 
-This function executes with the MMU and data caches enabled. The `meminfo`
-structure returned by this function must contain the extents and availability of
-secure RAM for the BL1 stage.
+This function should only be called on the cold boot path. It executes with the
+MMU and data caches enabled. The pointer returned by this function must point to
+a `meminfo` structure containing the extents and availability of secure RAM for
+the BL1 stage.
 
     meminfo.total_base = Base address of secure RAM visible to BL1
     meminfo.total_size = Size of secure RAM visible to BL1
@@ -533,7 +534,7 @@ by the primary CPU. The arguments to this function are:
 The platform must copy the contents of the `meminfo` structure into a private
 variable as the original memory may be subsequently overwritten by BL2. The
 copied structure is made available to all BL2 code through the
-`bl2_get_sec_mem_layout()` function.
+`bl2_plat_sec_mem_layout()` function.
 
 
 ### Function : bl2_plat_arch_setup() [mandatory]
@@ -576,17 +577,17 @@ initialized by the platform to point to memory where an `el_change_info`
 structure can be populated.
 
 
-### Function : bl2_get_sec_mem_layout() [mandatory]
+### Function : bl2_plat_sec_mem_layout() [mandatory]
 
     Argument : void
-    Return   : meminfo
+    Return   : meminfo *
 
-This function may execute with the MMU and data caches enabled if the platform
-port does the necessary initialization in `bl2_plat_arch_setup()`. It is only
-called by the primary CPU.
+This function should only be called on the cold boot path. It may execute with
+the MMU and data caches enabled if the platform port does the necessary
+initialization in `bl2_plat_arch_setup()`. It is only called by the primary CPU.
 
-The purpose of this function is to return a `meminfo` structure populated with
-the extents of secure RAM available for BL2 to use. See
+The purpose of this function is to return a pointer to a `meminfo` structure
+populated with the extents of secure RAM available for BL2 to use. See
 `bl2_early_platform_setup()` above.
 
 
@@ -663,7 +664,7 @@ by the primary CPU. The arguments to this function are:
 The platform must copy the contents of the `meminfo` structure into a private
 variable as the original memory may be subsequently overwritten by BL3-1. The
 copied structure is made available to all BL3-1 code through the
-`bl31_get_sec_mem_layout()` function.
+`bl31_plat_sec_mem_layout()` function.
 
 
 ### Function : bl31_plat_arch_setup() [mandatory]
@@ -713,17 +714,18 @@ function must return a pointer to the `el_change_info` structure (that was
 copied during `bl31_early_platform_setup()`).
 
 
-### Function : bl31_get_sec_mem_layout() [mandatory]
+### Function : bl31_plat_sec_mem_layout() [mandatory]
 
     Argument : void
-    Return   : meminfo
+    Return   : meminfo *
 
-This function may execute with the MMU and data caches enabled if the platform
-port does the necessary initializations in `bl31_plat_arch_setup()`. It is only
-called by the primary CPU.
+This function should only be called on the cold boot path. This function may
+execute with the MMU and data caches enabled if the platform port does the
+necessary initializations in `bl31_plat_arch_setup()`. It is only called by the
+primary CPU.
 
-The purpose of this function is to return a `meminfo` structure populated with
-the extents of secure RAM available for BL3-1 to use. See
+The purpose of this function is to return a pointer to a `meminfo` structure
+populated with the extents of secure RAM available for BL3-1 to use. See
 `bl31_early_platform_setup()` above.
 
 
diff --git a/include/bl1.h b/include/bl1.h
index 81b5bc4..9920cb8 100644
--- a/include/bl1.h
+++ b/include/bl1.h
@@ -45,7 +45,7 @@
  * Function prototypes
  *****************************************/
 extern void bl1_platform_setup(void);
-extern meminfo bl1_get_sec_mem_layout(void);
+extern meminfo *bl1_plat_sec_mem_layout(void);
 
 #endif /*__ASSEMBLY__*/
 
diff --git a/include/bl2.h b/include/bl2.h
index 3981a86..e105641 100644
--- a/include/bl2.h
+++ b/include/bl2.h
@@ -42,7 +42,7 @@ extern unsigned long long bl2_entrypoint;
  * Function prototypes
  *****************************************/
 extern void bl2_platform_setup(void);
-extern meminfo bl2_get_sec_mem_layout(void);
+extern meminfo *bl2_plat_sec_mem_layout(void);
 extern meminfo bl2_get_ns_mem_layout(void);
 
 #endif /* __BL2_H__ */
diff --git a/include/bl31.h b/include/bl31.h
index dbf7e5a..acb1229 100644
--- a/include/bl31.h
+++ b/include/bl31.h
@@ -42,7 +42,7 @@ extern unsigned long bl31_entrypoint;
  * Function prototypes
  ******************************************************************************/
 extern void bl31_platform_setup(void);
-extern meminfo bl31_get_sec_mem_layout(void);
+extern meminfo *bl31_plat_sec_mem_layout(void);
 extern el_change_info* bl31_get_next_image_info(unsigned long);
 extern void gic_cpuif_deactivate(unsigned int);
 extern void gic_cpuif_setup(unsigned int);
diff --git a/plat/fvp/bl1_plat_setup.c b/plat/fvp/bl1_plat_setup.c
index 9d19bb8..8fe4c95 100644
--- a/plat/fvp/bl1_plat_setup.c
+++ b/plat/fvp/bl1_plat_setup.c
@@ -63,9 +63,9 @@ extern unsigned long __BL1_RAM_END__;
 /* Data structure which holds the extents of the trusted SRAM for BL1*/
 static meminfo bl1_tzram_layout;
 
-meminfo bl1_get_sec_mem_layout(void)
+meminfo *bl1_plat_sec_mem_layout(void)
 {
-	return bl1_tzram_layout;
+	return &bl1_tzram_layout;
 }
 
 /*******************************************************************************
diff --git a/plat/fvp/bl2_plat_setup.c b/plat/fvp/bl2_plat_setup.c
index 7212df1..978cc9b 100644
--- a/plat/fvp/bl2_plat_setup.c
+++ b/plat/fvp/bl2_plat_setup.c
@@ -72,9 +72,9 @@ static meminfo bl2_tzram_layout
 __attribute__ ((aligned(PLATFORM_CACHE_LINE_SIZE),
 		section("tzfw_coherent_mem")));
 
-meminfo bl2_get_sec_mem_layout(void)
+meminfo *bl2_plat_sec_mem_layout(void)
 {
-	return bl2_tzram_layout;
+	return &bl2_tzram_layout;
 }
 
 /*******************************************************************************
diff --git a/plat/fvp/bl31_plat_setup.c b/plat/fvp/bl31_plat_setup.c
index ab8e378..221b85a 100644
--- a/plat/fvp/bl31_plat_setup.c
+++ b/plat/fvp/bl31_plat_setup.c
@@ -85,9 +85,9 @@ static meminfo bl31_tzram_layout
 __attribute__ ((aligned(PLATFORM_CACHE_LINE_SIZE),
 		section("tzfw_coherent_mem")));
 
-meminfo bl31_get_sec_mem_layout(void)
+meminfo *bl31_plat_sec_mem_layout(void)
 {
-	return bl31_tzram_layout;
+	return &bl31_tzram_layout;
 }
 
 /*******************************************************************************