Cosmetic changes to suspend_private.h
Reword some comments, express offsets relative to one another, move the
compile-time assertions closer to the structure they depend on.
Change-Id: Id3d61ca704321844d12c9bb25e2e6eb303a7a579
Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>
diff --git a/lib/power_management/suspend/suspend_private.h b/lib/power_management/suspend/suspend_private.h
index 9949dc6..b67bbab 100644
--- a/lib/power_management/suspend/suspend_private.h
+++ b/lib/power_management/suspend/suspend_private.h
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2018, Arm Limited. All rights reserved.
+ * Copyright (c) 2018-2019, Arm Limited. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
@@ -7,9 +7,21 @@
#ifndef __SUSPEND_PRIV_H__
#define __SUSPEND_PRIV_H__
-#define SUSPEND_CTX_SZ 64
-#define SUSPEND_CTX_SP_OFFSET 48
-#define SUSPEND_CTX_SAVE_SYSTEM_CTX_OFFSET 56
+/*
+ * Number of system registers we need to save/restore across a CPU suspend:
+ * MAIR, CPACR_EL1/HCR_EL2, TTBR0, TCR, VBAR and SCTLR.
+ */
+#define NR_CTX_REGS 6
+
+/* Offsets of the fields in the context structure. Needed by asm code. */
+#define SUSPEND_CTX_SP_OFFSET (8 * NR_CTX_REGS)
+#define SUSPEND_CTX_SAVE_SYSTEM_CTX_OFFSET (SUSPEND_CTX_SP_OFFSET + 8)
+
+/*
+ * Size of the context structure.
+ * +8 because of the padding bytes inserted for alignment constraint.
+ */
+#define SUSPEND_CTX_SZ (SUSPEND_CTX_SAVE_SYSTEM_CTX_OFFSET + 8)
#ifndef __ASSEMBLY__
#include <cassert.h>
@@ -17,11 +29,10 @@
#include <stdint.h>
#include <string.h>
-#define NR_CTX_REGS 6
-
/*
- * struct tftf_suspend_ctx represents the architecture context to
- * be saved and restored while entering suspend and coming out.
+ * Architectural context to be saved/restored when entering/exiting suspend
+ * mode.
+ *
* It must be 16-byte aligned since it is allocated on the stack, which must be
* 16-byte aligned on ARMv8 (AArch64). Even though the alignment requirement
* is not present in AArch32, we use the same alignment and register width as
@@ -30,6 +41,7 @@
typedef struct tftf_suspend_context {
uint64_t arch_ctx_regs[NR_CTX_REGS];
uint64_t stack_pointer;
+
/*
* Whether the system context is saved and and needs to be restored.
* Note that the system context itself is not saved in this structure.
@@ -38,6 +50,21 @@
} __aligned(16) tftf_suspend_ctx_t;
/*
+ * Ensure consistent view of the context structure layout across asm and C
+ * code.
+ */
+CASSERT(SUSPEND_CTX_SZ == sizeof(tftf_suspend_ctx_t),
+ assert_suspend_context_size_mismatch);
+
+CASSERT(SUSPEND_CTX_SP_OFFSET ==
+ __builtin_offsetof(tftf_suspend_ctx_t, stack_pointer),
+ assert_stack_pointer_location_mismatch_in_suspend_ctx);
+
+CASSERT(SUSPEND_CTX_SAVE_SYSTEM_CTX_OFFSET ==
+ __builtin_offsetof(tftf_suspend_ctx_t, save_system_context),
+ assert_save_sys_ctx_mismatch_in_suspend_ctx);
+
+/*
* Saves callee save registers on the stack
* Allocate space on stack for CPU context regs
* Enters suspend by calling tftf_enter_suspend.
@@ -82,14 +109,6 @@
*/
unsigned int __tftf_cpu_resume_ep(void);
-/* Assembler asserts to verify #defines of offsets match as seen by compiler */
-CASSERT(SUSPEND_CTX_SZ == sizeof(tftf_suspend_ctx_t),
- assert_suspend_context_size_mismatch);
-CASSERT(SUSPEND_CTX_SP_OFFSET == __builtin_offsetof(tftf_suspend_ctx_t, stack_pointer),
- assert_stack_pointer_location_mismatch_in_suspend_ctx);
-CASSERT(SUSPEND_CTX_SAVE_SYSTEM_CTX_OFFSET ==
- __builtin_offsetof(tftf_suspend_ctx_t, save_system_context),
- assert_save_sys_ctx_mismatch_in_suspend_ctx);
#endif /* __ASSEMBLY__ */
#endif /* __SUSPEND_PRIV_H__ */