Remove the concept of coherent stacks

This patch removes the allocation of memory for coherent stacks, associated
accessor function and some dead code which called the accessor function. It also
updates the porting guide to remove the concept and the motivation behind using
stacks allocated in coherent memory.

Fixes ARM-software/tf-issues#198

Change-Id: I00ff9a04f693a03df3627ba39727e3497263fc38

2 files changed, 2 insertions, 57 deletions

diff --git a/plat/common/aarch64/platform_mp_stack.S b/plat/common/aarch64/platform_mp_stack.S
index 801ec7fa..8eb1aa68 100644
--- a/plat/common/aarch64/platform_mp_stack.S
+++ b/plat/common/aarch64/platform_mp_stack.S
@@ -33,29 +33,12 @@
 #include <platform_def.h>
 
 
-	.local	pcpu_dv_mem_stack
 	.local	platform_normal_stacks
 	.weak	platform_set_stack
 	.weak	platform_get_stack
-	.weak	platform_set_coherent_stack
 
 
 	/* -----------------------------------------------------
-	 * void platform_set_coherent_stack (unsigned long mpidr)
-	 *
-	 * For a given CPU, this function sets the stack pointer
-	 * to a stack allocated in device memory. This stack can
-	 * be used by C code which enables/disables the SCTLR.M
-	 * SCTLR.C bit e.g. while powering down a cpu
-	 * -----------------------------------------------------
-	 */
-func platform_set_coherent_stack
-	mov x5, x30 // lr
-	get_mp_stack pcpu_dv_mem_stack, PCPU_DV_MEM_STACK_SIZE
-	mov sp, x0
-	ret x5
-
-	/* -----------------------------------------------------
 	 * unsigned long platform_get_stack (unsigned long mpidr)
 	 *
 	 * For a given CPU, this function returns the stack
@@ -81,22 +64,9 @@ func platform_set_stack
 	ret x9
 
 	/* -----------------------------------------------------
-	 * Per-cpu stacks in normal memory.
-	 * Used for C code during runtime execution (when coherent
-	 * stacks are not required).
-	 * Each cpu gets a stack of PLATFORM_STACK_SIZE bytes.
+	 * Per-cpu stacks in normal memory. Each cpu gets a
+	 * stack of PLATFORM_STACK_SIZE bytes.
 	 * -----------------------------------------------------
 	 */
 declare_stack platform_normal_stacks, tzfw_normal_stacks, \
 		PLATFORM_STACK_SIZE, PLATFORM_CORE_COUNT
-
-	/* -----------------------------------------------------
-	 * Per-cpu stacks in device memory.
-	 * Used for C code just before power down or right after
-	 * power up when the MMU or caches need to be turned on
-	 * or off.
-	 * Each cpu gets a stack of PCPU_DV_MEM_STACK_SIZE bytes.
-	 * -----------------------------------------------------
-	 */
-declare_stack pcpu_dv_mem_stack, tzfw_coherent_mem, \
-		PCPU_DV_MEM_STACK_SIZE, PLATFORM_CORE_COUNT
diff --git a/plat/common/aarch64/platform_up_stack.S b/plat/common/aarch64/platform_up_stack.S
index 45a96a64..73b74b2e 100644
--- a/plat/common/aarch64/platform_up_stack.S
+++ b/plat/common/aarch64/platform_up_stack.S
@@ -33,26 +33,9 @@
 #include <platform_def.h>
 
 
-	.local	pcpu_dv_mem_stack
 	.local	platform_normal_stacks
 	.globl	platform_set_stack
 	.globl	platform_get_stack
-	.globl	platform_set_coherent_stack
-
-
-	/* -----------------------------------------------------
-	 * void platform_set_coherent_stack (unsigned long)
-	 *
-	 * For cold-boot BL images, only the primary CPU needs a
-	 * stack. This function sets the stack pointer to a stack
-	 * allocated in device memory.
-	 * -----------------------------------------------------
-	 */
-func platform_set_coherent_stack
-	get_up_stack pcpu_dv_mem_stack, PCPU_DV_MEM_STACK_SIZE
-	mov sp, x0
-	ret
-
 
 	/* -----------------------------------------------------
 	 * unsigned long platform_get_stack (unsigned long)
@@ -87,11 +70,3 @@ func platform_set_stack
 	 */
 declare_stack platform_normal_stacks, tzfw_normal_stacks, \
 		PLATFORM_STACK_SIZE, 1
-
-	/* -----------------------------------------------------
-	 * Single cpu stack in device/coherent memory.
-	 * PCPU_DV_MEM_STACK_SIZE bytes are allocated.
-	 * -----------------------------------------------------
-	 */
-declare_stack pcpu_dv_mem_stack, tzfw_coherent_mem, \
-		PCPU_DV_MEM_STACK_SIZE, 1