Introduce the new BL handover interface

This patch introduces a new BL handover interface. It essentially allows
passing 4 arguments between the different BL stages. Effort has been made
so as to be compatible with the previous handover interface. The previous
blx_early_platform_setup() platform API is now deprecated and the new
blx_early_platform_setup2() variant is introduced. The weak compatiblity
implementation for the new API is done in the `plat_bl_common.c` file.
Some of the new arguments in the new API will be reserved for generic
code use when dynamic configuration support is implemented. Otherwise
the other registers are available for platform use.

Change-Id: Ifddfe2ea8e32497fe1beb565cac155ad9d50d404
Signed-off-by: Soby Mathew <soby.mathew@arm.com>

bl2/aarch32/bl2_entrypoint.S

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2016-2018, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -26,12 +26,14 @@ vector_base bl2_vector_table
 
 func bl2_entrypoint
 	/*---------------------------------------------
-	 * Save from r1 the extents of the trusted ram
-	 * available to BL2 for future use.
-	 * r0 is not currently used.
+	 * Save arguments x0 - x3 from BL1 for future
+	 * use.
 	 * ---------------------------------------------
 	 */
- 	mov	r11, r1
+	mov	r9, r0
+	mov	r10, r1
+	mov	r11, r2
+	mov	r12, r3
 
 	/* ---------------------------------------------
 	 * Set the exception vector to something sane.
@@ -111,8 +113,11 @@ func bl2_entrypoint
 	 * specific early arch. setup e.g. mmu setup
 	 * ---------------------------------------------
 	 */
-	mov	r0, r11
-	bl	bl2_early_platform_setup
+	mov	r0, r9
+	mov	r1, r10
+	mov	r2, r11
+	mov	r3, r12
+	bl	bl2_early_platform_setup2
 	bl	bl2_plat_arch_setup
 
 	/* ---------------------------------------------

bl2/aarch64/bl2_entrypoint.S

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2018, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -15,12 +15,14 @@
 
 func bl2_entrypoint
 	/*---------------------------------------------
-	 * Save from x1 the extents of the tzram
-	 * available to BL2 for future use.
-	 * x0 is not currently used.
+	 * Save arguments x0 - x3 from BL1 for future
+	 * use.
 	 * ---------------------------------------------
 	 */
-	mov	x20, x1
+	mov	x20, x0
+	mov	x21, x1
+	mov	x22, x2
+	mov	x23, x3
 
 	/* ---------------------------------------------
 	 * Set the exception vector to something sane.
@@ -103,7 +105,11 @@ func bl2_entrypoint
 	 * ---------------------------------------------
 	 */
 	mov	x0, x20
-	bl	bl2_early_platform_setup
+	mov	x1, x21
+	mov	x2, x22
+	mov	x3, x23
+	bl	bl2_early_platform_setup2
+
 	bl	bl2_plat_arch_setup
 
 	/* ---------------------------------------------

bl31/aarch64/bl31_entrypoint.S

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2018, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -23,13 +23,13 @@
 func bl31_entrypoint
 #if !RESET_TO_BL31
 	/* ---------------------------------------------------------------
-	 * Preceding bootloader has populated x0 with a pointer to a
-	 * 'bl31_params' structure & x1 with a pointer to platform
-	 * specific structure
+	 * Stash the previous bootloader arguments x0 - x3 for later use.
 	 * ---------------------------------------------------------------
 	 */
 	mov	x20, x0
 	mov	x21, x1
+	mov	x22, x2
+	mov	x23, x3
 
 	/* ---------------------------------------------------------------------
 	 * For !RESET_TO_BL31 systems, only the primary CPU ever reaches
@@ -47,13 +47,6 @@ func bl31_entrypoint
 		_init_memory=0					\
 		_init_c_runtime=1				\
 		_exception_vectors=runtime_exceptions
-
-	/* ---------------------------------------------------------------------
-	 * Relay the previous bootloader's arguments to the platform layer
-	 * ---------------------------------------------------------------------
-	 */
-	mov	x0, x20
-	mov	x1, x21
 #else
 	/* ---------------------------------------------------------------------
 	 * For RESET_TO_BL31 systems which have a programmable reset address,
@@ -75,15 +68,20 @@ func bl31_entrypoint
 	 * arguments passed to the platform layer to reflect that.
 	 * ---------------------------------------------------------------------
 	 */
-	mov	x0, 0
-	mov	x1, 0
+	mov	x20, 0
+	mov	x21, 0
+	mov	x22, 0
+	mov	x23, 0
 #endif /* RESET_TO_BL31 */
-
 	/* ---------------------------------------------
 	 * Perform platform specific early arch. setup
 	 * ---------------------------------------------
 	 */
-	bl	bl31_early_platform_setup
+	mov	x0, x20
+	mov	x1, x21
+	mov	x2, x22
+	mov	x3, x23
+	bl	bl31_early_platform_setup2
 	bl	bl31_plat_arch_setup
 
 	/* ---------------------------------------------

bl32/sp_min/aarch32/entrypoint.S

@@ -64,8 +64,10 @@ func sp_min_entrypoint
 	 * specific structure
 	 * ---------------------------------------------------------------
 	 */
-	mov	r11, r0
-	mov	r12, r1
+	mov	r9, r0
+	mov	r10, r1
+	mov	r11, r2
+	mov	r12, r3
 
 	/* ---------------------------------------------------------------------
 	 * For !RESET_TO_SP_MIN systems, only the primary CPU ever reaches
@@ -88,8 +90,6 @@ func sp_min_entrypoint
 	 * Relay the previous bootloader's arguments to the platform layer
 	 * ---------------------------------------------------------------------
 	 */
-	mov	r0, r11
-	mov	r1, r12
 #else
 	/* ---------------------------------------------------------------------
 	 * For RESET_TO_SP_MIN systems which have a programmable reset address,
@@ -111,15 +111,22 @@ func sp_min_entrypoint
 	 * Zero the arguments passed to the platform layer to reflect that.
 	 * ---------------------------------------------------------------------
 	 */
-	mov	r0, #0
-	mov	r1, #0
+	mov	r9, #0
+	mov	r10, #0
+	mov	r11, #0
+	mov	r12, #0
+
 #endif /* RESET_TO_SP_MIN */
 
 #if SP_MIN_WITH_SECURE_FIQ
 	route_fiq_to_sp_min r4
 #endif
 
-	bl	sp_min_early_platform_setup
+	mov	r0, r9
+	mov	r1, r10
+	mov	r2, r11
+	mov	r3, r12
+	bl	sp_min_early_platform_setup2
 	bl	sp_min_plat_arch_setup
 
 	/* Jump to the main function */

include/bl32/sp_min/platform_sp_min.h

@@ -10,8 +10,12 @@
 /*******************************************************************************
  * Mandatory SP_MIN functions
  ******************************************************************************/
+#if !ERROR_DEPRECATED
 void sp_min_early_platform_setup(void *from_bl2,
 		void *plat_params_from_bl2);
+#endif
+void sp_min_early_platform_setup2(u_register_t arg0, u_register_t arg1,
+		u_register_t arg2, u_register_t arg3);
 void sp_min_platform_setup(void);
 void sp_min_plat_runtime_setup(void);
 void sp_min_plat_arch_setup(void);

include/plat/common/platform.h

@@ -165,7 +165,10 @@ int bl1_plat_handle_post_image_load(unsigned int image_id);
 /*******************************************************************************
  * Mandatory BL2 functions
  ******************************************************************************/
+void bl2_early_platform_setup2(u_register_t arg0, u_register_t arg1, u_register_t arg2, u_register_t arg3);
+#if !ERROR_DEPRECATED
 void bl2_early_platform_setup(struct meminfo *mem_layout);
+#endif
 void bl2_plat_arch_setup(void);
 void bl2_platform_setup(void);
 struct meminfo *bl2_plat_sec_mem_layout(void);
@@ -277,6 +280,7 @@ int bl2u_plat_handle_scp_bl2u(void);
 /*******************************************************************************
  * Mandatory BL31 functions
  ******************************************************************************/
+#if !ERROR_DEPRECATED
 #if LOAD_IMAGE_V2
 void bl31_early_platform_setup(void *from_bl2,
 				void *plat_params_from_bl2);
@@ -284,6 +288,9 @@ void bl31_early_platform_setup(void *from_bl2,
 void bl31_early_platform_setup(struct bl31_params *from_bl2,
 				void *plat_params_from_bl2);
 #endif
+#endif /* ERROR_DEPRECATED */
+void bl31_early_platform_setup2(u_register_t arg0, u_register_t arg1,
+		u_register_t arg2, u_register_t arg3);
 void bl31_plat_arch_setup(void);
 void bl31_platform_setup(void);
 void bl31_plat_runtime_setup(void);

plat/common/aarch32/plat_common.c

@@ -1,11 +1,12 @@
 /*
- * Copyright (c) 2016-2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2016-2018, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
 #include <console.h>
 #include <platform.h>
+#include <platform_sp_min.h>
 #include <xlat_mmu_helpers.h>
 
 /*
@@ -29,3 +30,14 @@ void sp_min_plat_runtime_setup(void)
 	 */
 	console_uninit();
 }
+
+#if !ERROR_DEPRECATED
+
+#pragma weak sp_min_early_platform_setup2
+
+void sp_min_early_platform_setup2(u_register_t arg0, u_register_t arg1,
+			u_register_t arg2, u_register_t arg3)
+{
+	sp_min_early_platform_setup((void *) arg0, (void *)arg1);
+}
+#endif

plat/common/aarch64/plat_common.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014-2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2014-2018, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -20,6 +20,7 @@
 #pragma weak bl31_plat_runtime_setup
 #if !ERROR_DEPRECATED
 #pragma weak plat_get_syscnt_freq2
+#pragma weak bl31_early_platform_setup2
 #endif /* ERROR_DEPRECATED */
 
 #if SDEI_SUPPORT
@@ -70,6 +71,12 @@ unsigned int plat_get_syscnt_freq2(void)
 
 	return (unsigned int)freq;
 }
+
+void bl31_early_platform_setup2(u_register_t arg0, u_register_t arg1,
+			u_register_t arg2, u_register_t arg3)
+{
+	bl31_early_platform_setup((void *) arg0, (void *)arg1);
+}
 #endif /* ERROR_DEPRECATED */
 
 #if SDEI_SUPPORT

plat/common/plat_bl_common.c

@@ -9,6 +9,7 @@
 #include <bl_common.h>
 #include <debug.h>
 #include <errno.h>
+#include <platform.h>
 
 /*
  * The following platform functions are weakly defined. The Platforms
@@ -49,3 +50,17 @@ int plat_try_next_boot_source(void)
 {
 	return 0;
 }
+
+#if !ERROR_DEPRECATED
+#pragma weak bl2_early_platform_setup2
+
+/*
+ * The following platform API implementation that allow compatibility for
+ * the older platform APIs.
+ */
+void bl2_early_platform_setup2(u_register_t arg0, u_register_t arg1,
+			u_register_t arg2, u_register_t arg3)
+{
+	bl2_early_platform_setup((void *)arg1);
+}
+#endif