Enable use of FIQs and IRQs as TSP interrupts

On a GICv2 system, interrupts that should be handled in the secure world are
typically signalled as FIQs. On a GICv3 system, these interrupts are signalled
as IRQs instead. The mechanism for handling both types of interrupts is the same
in both cases. This patch enables the TSP to run on a GICv3 system by:

1. adding support for handling IRQs in the exception handling code.
2. removing use of "fiq" in the names of data structures, macros and functions.

The build option TSPD_ROUTE_IRQ_TO_EL3 is deprecated and is replaced with a
new build flag TSP_NS_INTR_ASYNC_PREEMPT. For compatibility reasons, if the
former build flag is defined, it will be used to define the value for the
new build flag. The documentation is also updated accordingly.

Change-Id: I1807d371f41c3656322dd259340a57649833065e
diff --git a/bl32/tsp/aarch64/tsp_entrypoint.S b/bl32/tsp/aarch64/tsp_entrypoint.S
index 9732ff2..d183dff 100644
--- a/bl32/tsp/aarch64/tsp_entrypoint.S
+++ b/bl32/tsp/aarch64/tsp_entrypoint.S
@@ -177,7 +177,7 @@
 	b	tsp_cpu_off_entry
 	b	tsp_cpu_resume_entry
 	b	tsp_cpu_suspend_entry
-	b	tsp_fiq_entry
+	b	tsp_sel1_intr_entry
 	b	tsp_system_off_entry
 	b	tsp_system_reset_entry
 endfunc tsp_vector_table
@@ -325,13 +325,13 @@
 	restore_args_call_smc
 endfunc tsp_cpu_suspend_entry
 
-	/*---------------------------------------------
+	/*-------------------------------------------------
 	 * This entrypoint is used by the TSPD to pass
-	 * control for handling a pending S-EL1 FIQ.
+	 * control for handling a pending S-EL1 Interrupt.
 	 * 'x0' contains a magic number which indicates
 	 * this. TSPD expects control to be handed back
-	 * at the end of FIQ processing. This is done
-	 * through an SMC. The handover agreement is:
+	 * at the end of interrupt processing. This is
+	 * done through an SMC. The handover agreement is:
 	 *
 	 * 1. PSTATE.DAIF are set upon entry. 'x1' has
 	 *    the ELR_EL3 from the non-secure state.
@@ -343,40 +343,41 @@
 	 * 4. TSP can use 'x0-x18' to enable its C
 	 *    runtime.
 	 * 5. TSP returns to TSPD using an SMC with
-	 *    'x0' = TSP_HANDLED_S_EL1_FIQ
-	 * ---------------------------------------------
+	 *    'x0' = TSP_HANDLED_S_EL1_INTR
+	 * ------------------------------------------------
 	 */
-func	tsp_fiq_entry
+func	tsp_sel1_intr_entry
 #if DEBUG
-	mov	x2, #(TSP_HANDLE_FIQ_AND_RETURN & ~0xffff)
-	movk	x2, #(TSP_HANDLE_FIQ_AND_RETURN &  0xffff)
+	mov	x2, #(TSP_HANDLE_SEL1_INTR_AND_RETURN & ~0xffff)
+	movk	x2, #(TSP_HANDLE_SEL1_INTR_AND_RETURN &  0xffff)
 	cmp	x0, x2
-	b.ne	tsp_fiq_entry_panic
+	b.ne	tsp_sel1_int_entry_panic
 #endif
-	/*---------------------------------------------
+	/*-------------------------------------------------
 	 * Save any previous context needed to perform
 	 * an exception return from S-EL1 e.g. context
-	 * from a previous IRQ. Update statistics and
-	 * handle the FIQ before returning to the TSPD.
+	 * from a previous Non secure Interrupt.
+	 * Update statistics and handle the S-EL1
+	 * interrupt before returning to the TSPD.
 	 * IRQ/FIQs are not enabled since that will
 	 * complicate the implementation. Execution
 	 * will be transferred back to the normal world
 	 * in any case. A non-zero return value from the
-	 * fiq handler is an error.
-	 * ---------------------------------------------
+	 * interrupt handler is an error.
+	 * ------------------------------------------------
 	 */
 	save_eret_context x2 x3
-	bl	tsp_update_sync_fiq_stats
-	bl	tsp_fiq_handler
-	cbnz	x0, tsp_fiq_entry_panic
+	bl	tsp_update_sync_sel1_intr_stats
+	bl	tsp_common_int_handler
+	cbnz	x0, tsp_sel1_int_entry_panic
 	restore_eret_context x2 x3
-	mov	x0, #(TSP_HANDLED_S_EL1_FIQ & ~0xffff)
-	movk	x0, #(TSP_HANDLED_S_EL1_FIQ &  0xffff)
+	mov	x0, #(TSP_HANDLED_S_EL1_INTR & ~0xffff)
+	movk	x0, #(TSP_HANDLED_S_EL1_INTR &  0xffff)
 	smc	#0
 
-tsp_fiq_entry_panic:
-	b	tsp_fiq_entry_panic
-endfunc tsp_fiq_entry
+tsp_sel1_int_entry_panic:
+	b	tsp_sel1_int_entry_panic
+endfunc tsp_sel1_intr_entry
 
 	/*---------------------------------------------
 	 * This entrypoint is used by the TSPD when this
diff --git a/bl32/tsp/aarch64/tsp_exceptions.S b/bl32/tsp/aarch64/tsp_exceptions.S
index 272d94b..d5e089f 100644
--- a/bl32/tsp/aarch64/tsp_exceptions.S
+++ b/bl32/tsp/aarch64/tsp_exceptions.S
@@ -70,6 +70,28 @@
 	add	sp, sp, SCRATCH_REG_SIZE
 	.endm
 
+	/* ----------------------------------------------------
+	 * Common TSP interrupt handling routine
+	 * ----------------------------------------------------
+	 */
+	.macro	handle_tsp_interrupt label
+	/* Enable the SError interrupt */
+	msr	daifclr, #DAIF_ABT_BIT
+
+	save_caller_regs_and_lr
+	bl	tsp_common_int_handler
+	cbz	x0, interrupt_exit_\label
+
+	/*
+	 * This interrupt was not targetted to S-EL1 so send it to
+	 * the monitor and wait for execution to resume.
+	 */
+	smc	#0
+interrupt_exit_\label:
+	restore_caller_regs_and_lr
+	eret
+	.endm
+
 	.globl	tsp_exceptions
 
 	/* -----------------------------------------------------
@@ -120,36 +142,12 @@
 
 	.align	7
 irq_sp_elx:
-	/* Enable the SError interrupt */
-	msr	daifclr, #DAIF_ABT_BIT
-
-	save_caller_regs_and_lr
-	/* We just update some statistics in the handler */
-	bl	tsp_handle_preemption
-	/* Hand over control to the normal world to handle the IRQ */
-	smc	#0
-	/* The resume std smc starts from here */
-	restore_caller_regs_and_lr
-	eret
+	handle_tsp_interrupt irq_sp_elx
 	check_vector_size irq_sp_elx
 
 	.align	7
 fiq_sp_elx:
-	/* Enable the SError interrupt */
-	msr	daifclr, #DAIF_ABT_BIT
-
-	save_caller_regs_and_lr
-	bl	tsp_fiq_handler
-	cbz	x0, fiq_sp_elx_done
-
-	/*
-	 * This FIQ was not targetted to S-EL1 so send it to
-	 * the monitor and wait for execution to resume.
-	 */
-	smc	#0
-fiq_sp_elx_done:
-	restore_caller_regs_and_lr
-	eret
+	handle_tsp_interrupt fiq_sp_elx
 	check_vector_size fiq_sp_elx
 
 	.align	7
diff --git a/bl32/tsp/tsp_interrupt.c b/bl32/tsp/tsp_interrupt.c
index d5379cd..7654d2e 100644
--- a/bl32/tsp/tsp_interrupt.c
+++ b/bl32/tsp/tsp_interrupt.c
@@ -31,38 +31,39 @@
 #include <arch_helpers.h>
 #include <assert.h>
 #include <debug.h>
-#include <gic_v2.h>
 #include <platform.h>
 #include <platform_def.h>
 #include <tsp.h>
 #include "tsp_private.h"
 
 /*******************************************************************************
- * This function updates the TSP statistics for FIQs handled synchronously i.e
- * the ones that have been handed over by the TSPD. It also keeps count of the
- * number of times control was passed back to the TSPD after handling an FIQ.
- * In the future it will be possible that the TSPD hands over an FIQ to the TSP
- * but does not expect it to return execution. This statistic will be useful to
- * distinguish between these two models of synchronous FIQ handling.
- * The 'elr_el3' parameter contains the address of the instruction in normal
- * world where this FIQ was generated.
+ * This function updates the TSP statistics for S-EL1 interrupts handled
+ * synchronously i.e the ones that have been handed over by the TSPD. It also
+ * keeps count of the number of times control was passed back to the TSPD
+ * after handling the interrupt. In the future it will be possible that the
+ * TSPD hands over an S-EL1 interrupt to the TSP but does not expect it to
+ * return execution. This statistic will be useful to distinguish between these
+ * two models of synchronous S-EL1 interrupt handling. The 'elr_el3' parameter
+ * contains the address of the instruction in normal world where this S-EL1
+ * interrupt was generated.
  ******************************************************************************/
-void tsp_update_sync_fiq_stats(uint32_t type, uint64_t elr_el3)
+void tsp_update_sync_sel1_intr_stats(uint32_t type, uint64_t elr_el3)
 {
 	uint32_t linear_id = plat_my_core_pos();
 
-	tsp_stats[linear_id].sync_fiq_count++;
-	if (type == TSP_HANDLE_FIQ_AND_RETURN)
-		tsp_stats[linear_id].sync_fiq_ret_count++;
+	tsp_stats[linear_id].sync_sel1_intr_count++;
+	if (type == TSP_HANDLE_SEL1_INTR_AND_RETURN)
+		tsp_stats[linear_id].sync_sel1_intr_ret_count++;
 
 #if LOG_LEVEL >= LOG_LEVEL_VERBOSE
 	spin_lock(&console_lock);
-	VERBOSE("TSP: cpu 0x%lx sync fiq request from 0x%lx\n",
+	VERBOSE("TSP: cpu 0x%lx sync s-el1 interrupt request from 0x%lx\n",
 		read_mpidr(), elr_el3);
-	VERBOSE("TSP: cpu 0x%lx: %d sync fiq requests, %d sync fiq returns\n",
+	VERBOSE("TSP: cpu 0x%lx: %d sync s-el1 interrupt requests,"
+		" %d sync s-el1 interrupt returns\n",
 		read_mpidr(),
-		tsp_stats[linear_id].sync_fiq_count,
-		tsp_stats[linear_id].sync_fiq_ret_count);
+		tsp_stats[linear_id].sync_sel1_intr_count,
+		tsp_stats[linear_id].sync_sel1_intr_ret_count);
 	spin_unlock(&console_lock);
 #endif
 }
@@ -87,13 +88,13 @@
 }
 
 /*******************************************************************************
- * TSP FIQ handler called as a part of both synchronous and asynchronous
- * handling of FIQ interrupts. It returns 0 upon successfully handling a S-EL1
- * FIQ and treats all other FIQs as EL3 interrupts. It assumes that the GIC
- * architecture version in v2.0 and the secure physical timer interrupt is the
- * only S-EL1 interrupt that it needs to handle.
+ * TSP interrupt handler is called as a part of both synchronous and
+ * asynchronous handling of TSP interrupts. Currently the physical timer
+ * interrupt is the only S-EL1 interrupt that this handler expects. It returns
+ * 0 upon successfully handling the expected interrupt and all other
+ * interrupts are treated as normal world or EL3 interrupts.
  ******************************************************************************/
-int32_t tsp_fiq_handler(void)
+int32_t tsp_common_int_handler(void)
 {
 	uint32_t linear_id = plat_my_core_pos(), id;
 
@@ -123,13 +124,13 @@
 	plat_ic_end_of_interrupt(id);
 
 	/* Update the statistics and print some messages */
-	tsp_stats[linear_id].fiq_count++;
+	tsp_stats[linear_id].sel1_intr_count++;
 #if LOG_LEVEL >= LOG_LEVEL_VERBOSE
 	spin_lock(&console_lock);
-	VERBOSE("TSP: cpu 0x%lx handled fiq %d\n",
+	VERBOSE("TSP: cpu 0x%lx handled S-EL1 interrupt %d\n",
 	       read_mpidr(), id);
-	VERBOSE("TSP: cpu 0x%lx: %d fiq requests\n",
-	     read_mpidr(), tsp_stats[linear_id].fiq_count);
+	VERBOSE("TSP: cpu 0x%lx: %d S-EL1 requests\n",
+	     read_mpidr(), tsp_stats[linear_id].sel1_intr_count);
 	spin_unlock(&console_lock);
 #endif
 	return 0;
diff --git a/bl32/tsp/tsp_private.h b/bl32/tsp/tsp_private.h
index 346351c..e341cfd 100644
--- a/bl32/tsp/tsp_private.h
+++ b/bl32/tsp/tsp_private.h
@@ -54,11 +54,14 @@
 
 
 typedef struct work_statistics {
-	uint32_t fiq_count;		/* Number of FIQs on this cpu */
-	uint32_t sync_fiq_count;	/* Number of sync. fiqs on this cpu */
-	uint32_t sync_fiq_ret_count;	/* Number of fiq returns on this cpu */
+	/* Number of s-el1 interrupts on this cpu */
+	uint32_t sel1_intr_count;
 	/* Number of non s-el1 interrupts on this cpu which preempted TSP */
 	uint32_t preempt_intr_count;
+	/* Number of sync s-el1 interrupts on this cpu */
+	uint32_t sync_sel1_intr_count;
+	/* Number of s-el1 interrupts returns on this cpu */
+	uint32_t sync_sel1_intr_ret_count;
 	uint32_t smc_count;		/* Number of returns on this cpu */
 	uint32_t eret_count;		/* Number of entries on this cpu */
 	uint32_t cpu_on_count;		/* Number of cpu on requests */
@@ -116,8 +119,8 @@
 void tsp_generic_timer_save(void);
 void tsp_generic_timer_restore(void);
 
-/* FIQ management functions */
-void tsp_update_sync_fiq_stats(uint32_t type, uint64_t elr_el3);
+/* S-EL1 interrupt management functions */
+void tsp_update_sync_sel1_intr_stats(uint32_t type, uint64_t elr_el3);
 
 
 /* Data structure to keep track of TSP statistics */
diff --git a/docs/interrupt-framework-design.md b/docs/interrupt-framework-design.md
index 53707ae..271cd92 100644
--- a/docs/interrupt-framework-design.md
+++ b/docs/interrupt-framework-design.md
@@ -399,12 +399,12 @@
 1.  It passes control to the Test Secure Payload to perform its
     initialisation. The TSP provides the address of the vector table
     `tsp_vectors` in the SP which also includes the handler for Secure-EL1
-    interrupts in the `fiq_entry` field. The TSPD passes control to the TSP at
+    interrupts in the `sel1_intr_entry` field. The TSPD passes control to the TSP at
     this address when it receives a Secure-EL1 interrupt.
 
     The handover agreement between the TSP and the TSPD requires that the TSPD
     masks all interrupts (`PSTATE.DAIF` bits) when it calls
-    `tsp_fiq_entry()`. The TSP has to preserve the callee saved general
+    `tsp_sel1_intr_entry()`. The TSP has to preserve the callee saved general
     purpose, SP_EL1/Secure-EL0, LR, VFP and system registers. It can use
     `x0-x18` to enable its C runtime.
 
@@ -514,7 +514,7 @@
 The routing model for Secure-EL1 and non-secure interrupts chosen by the TSP is
 described in Section 2.2.2. It is known to the TSPD service at build time.
 
-The TSP implements an entrypoint (`tsp_fiq_entry()`) for handling Secure-EL1
+The TSP implements an entrypoint (`tsp_sel1_intr_entry()`) for handling Secure-EL1
 interrupts taken in non-secure state and routed through the TSPD service
 (synchronous handling model). It passes the reference to this entrypoint via
 `tsp_vectors` to the TSPD service.
@@ -700,9 +700,9 @@
 3.  It saves the system register context for the non-secure state by calling
     `cm_el1_sysregs_context_save(NON_SECURE);`.
 
-4.  It sets the `ELR_EL3` system register to `tsp_fiq_entry` and sets the
+4.  It sets the `ELR_EL3` system register to `tsp_sel1_intr_entry` and sets the
     `SPSR_EL3.DAIF` bits in the secure CPU context. It sets `x0` to
-    `TSP_HANDLE_FIQ_AND_RETURN`. If the TSP was in the middle of handling a
+    `TSP_HANDLE_SEL1_INTR_AND_RETURN`. If the TSP was in the middle of handling a
     standard SMC, then the `ELR_EL3` and `SPSR_EL3` registers in the secure CPU
     context are saved first.
 
@@ -723,20 +723,20 @@
 
 ![Image 1](diagrams/sec-int-handling.png?raw=true)
 
-The TSP issues an SMC with `TSP_HANDLED_S_EL1_FIQ` as the function identifier to
+The TSP issues an SMC with `TSP_HANDLED_S_EL1_INTR` as the function identifier to
 signal completion of interrupt handling.
 
 The TSP issues an SMC with `TSP_PREEMPTED` as the function identifier to signal
 generation of a non-secure interrupt in Secure-EL1.
 
 The TSPD service takes the following actions in `tspd_smc_handler()` function
-upon receiving an SMC with `TSP_HANDLED_S_EL1_FIQ` and `TSP_PREEMPTED` as the
+upon receiving an SMC with `TSP_HANDLED_S_EL1_INTR` and `TSP_PREEMPTED` as the
 function identifiers:
 
 1.  It ensures that the call originated from the secure state otherwise
     execution returns to the non-secure state with `SMC_UNK` in `x0`.
 
-2.  If the function identifier is `TSP_HANDLED_S_EL1_FIQ`, it restores the
+2.  If the function identifier is `TSP_HANDLED_S_EL1_INTR`, it restores the
     saved `ELR_EL3` and `SPSR_EL3` system registers back to the secure CPU
     context (see step 4 above) in case the TSP had been preempted by a non
     secure interrupt earlier.  It does not save the secure context since the
@@ -811,7 +811,7 @@
 
 ##### 2.3.3.1 Test secure payload behavior
 The TSPD hands control of a Secure-EL1 interrupt to the TSP at the
-`tsp_fiq_entry()`.  The TSP handles the interrupt while ensuring that the
+`tsp_sel1_intr_entry()`.  The TSP handles the interrupt while ensuring that the
 handover agreement described in Section 2.2.2.1 is maintained. It updates some
 statistics by calling `tsp_update_sync_fiq_stats()`. It then calls
 `tsp_fiq_handler()` which.
@@ -827,7 +827,7 @@
     end of interrupt processing.
 
 The TSP passes control back to the TSPD by issuing an SMC64 with
-`TSP_HANDLED_S_EL1_FIQ` as the function identifier.
+`TSP_HANDLED_S_EL1_INTR` as the function identifier.
 
 The TSP handles interrupts under the asynchronous model as follows.
 
diff --git a/docs/user-guide.md b/docs/user-guide.md
index bcdc645..716ed7d 100644
--- a/docs/user-guide.md
+++ b/docs/user-guide.md
@@ -278,10 +278,13 @@
     (Coherent memory region is included) or 0 (Coherent memory region is
     excluded). Default is 1.
 
-*   `TSPD_ROUTE_IRQ_TO_EL3`: A non zero value enables the routing model
-    for non-secure interrupts in which they are routed to EL3 (TSPD). The
-    default model (when the value is 0) is to route non-secure interrupts
-    to S-EL1 (TSP).
+*   `TSP_NS_INTR_ASYNC_PREEMPT`: A non zero value enables the interrupt
+    routing model which routes non-secure interrupts asynchronously from TSP
+    to EL3 causing immediate preemption of TSP. The EL3 is responsible
+    for saving and restoring the TSP context in this routing model. The
+    default routing model (when the value is 0) is to route non-secure
+    interrupts to TSP allowing it to save its context and hand over
+    synchronously to EL3 via an SMC.
 
 *   `TRUSTED_BOARD_BOOT`: Boolean flag to include support for the Trusted Board
     Boot feature. When set to '1', BL1 and BL2 images include support to load
diff --git a/include/bl32/tsp/tsp.h b/include/bl32/tsp/tsp.h
index 2286b3f..fd43fd3 100644
--- a/include/bl32/tsp/tsp.h
+++ b/include/bl32/tsp/tsp.h
@@ -45,11 +45,12 @@
 #define TSP_SYSTEM_RESET_DONE	0xf2000009
 
 /*
- * Function identifiers to handle FIQs through the synchronous handling model.
- * If the TSP was previously interrupted then control has to be returned to
- * the TSPD after handling the interrupt else execution can remain in the TSP.
+ * Function identifiers to handle S-El1 interrupt through the synchronous
+ * handling model. If the TSP was previously interrupted then control has to
+ * be returned to the TSPD after handling the interrupt else execution can
+ * remain in the TSP.
  */
-#define TSP_HANDLED_S_EL1_FIQ		0xf2000006
+#define TSP_HANDLED_S_EL1_INTR		0xf2000006
 
 /* SMC function ID that TSP uses to request service from secure monitor */
 #define TSP_GET_ARGS		0xf2001000
@@ -62,7 +63,7 @@
 #define TSP_SUB		0x2001
 #define TSP_MUL		0x2002
 #define TSP_DIV		0x2003
-#define TSP_HANDLE_FIQ_AND_RETURN	0x2004
+#define TSP_HANDLE_SEL1_INTR_AND_RETURN	0x2004
 
 /*
  * Generate function IDs for TSP services to be used in SMC calls, by
@@ -114,7 +115,7 @@
 	tsp_vector_isn_t cpu_off_entry;
 	tsp_vector_isn_t cpu_resume_entry;
 	tsp_vector_isn_t cpu_suspend_entry;
-	tsp_vector_isn_t fiq_entry;
+	tsp_vector_isn_t sel1_intr_entry;
 	tsp_vector_isn_t system_off_entry;
 	tsp_vector_isn_t system_reset_entry;
 } tsp_vectors_t;
diff --git a/services/spd/tspd/tspd.mk b/services/spd/tspd/tspd.mk
index 139c7d7..ede2504 100644
--- a/services/spd/tspd/tspd.mk
+++ b/services/spd/tspd/tspd.mk
@@ -55,7 +55,17 @@
 
 # Flag used to enable routing of non-secure interrupts to EL3 when they are
 # generated while the code is executing in S-EL1/0.
-TSPD_ROUTE_IRQ_TO_EL3	:=	0
+TSP_NS_INTR_ASYNC_PREEMPT	:=	0
+
+# If TSPD_ROUTE_IRQ_TO_EL3 build flag is defined, use it to define value for
+# TSP_NS_INTR_ASYNC_PREEMPT for backward compatibility.
+ifdef TSPD_ROUTE_IRQ_TO_EL3
+ifeq (${ERROR_DEPRECATED},1)
+$(error "TSPD_ROUTE_IRQ_TO_EL3 is deprecated. Please use the new build flag TSP_NS_INTR_ASYNC_PREEMPT")
+endif
+$(warning "TSPD_ROUTE_IRQ_TO_EL3 is deprecated. Please use the new build flag TSP_NS_INTR_ASYNC_PREEMPT")
+TSP_NS_INTR_ASYNC_PREEMPT	:= ${TSPD_ROUTE_IRQ_TO_EL3}
+endif
 
-$(eval $(call assert_boolean,TSPD_ROUTE_IRQ_TO_EL3))
-$(eval $(call add_define,TSPD_ROUTE_IRQ_TO_EL3))
+$(eval $(call assert_boolean,TSP_NS_INTR_ASYNC_PREEMPT))
+$(eval $(call add_define,TSP_NS_INTR_ASYNC_PREEMPT))
diff --git a/services/spd/tspd/tspd_main.c b/services/spd/tspd/tspd_main.c
index 0d6e0d2..4c4861d 100644
--- a/services/spd/tspd/tspd_main.c
+++ b/services/spd/tspd/tspd_main.c
@@ -108,7 +108,7 @@
 /*******************************************************************************
  * This function is the handler registered for S-EL1 interrupts by the TSPD. It
  * validates the interrupt and upon success arranges entry into the TSP at
- * 'tsp_fiq_entry()' for handling the interrupt.
+ * 'tsp_sel1_intr_entry()' for handling the interrupt.
  ******************************************************************************/
 static uint64_t tspd_sel1_interrupt_handler(uint32_t id,
 					    uint32_t flags,
@@ -136,44 +136,44 @@
 	 * Determine if the TSP was previously preempted. Its last known
 	 * context has to be preserved in this case.
 	 * The TSP should return control to the TSPD after handling this
-	 * FIQ. Preserve essential EL3 context to allow entry into the
-	 * TSP at the FIQ entry point using the 'cpu_context' structure.
-	 * There is no need to save the secure system register context
-	 * since the TSP is supposed to preserve it during S-EL1 interrupt
-	 * handling.
+	 * S-EL1 interrupt. Preserve essential EL3 context to allow entry into
+	 * the TSP at the S-EL1 interrupt entry point using the 'cpu_context'
+	 * structure. There is no need to save the secure system register
+	 * context since the TSP is supposed to preserve it during S-EL1
+	 * interrupt handling.
 	 */
 	if (get_std_smc_active_flag(tsp_ctx->state)) {
 		tsp_ctx->saved_spsr_el3 = SMC_GET_EL3(&tsp_ctx->cpu_ctx,
 						      CTX_SPSR_EL3);
 		tsp_ctx->saved_elr_el3 = SMC_GET_EL3(&tsp_ctx->cpu_ctx,
 						     CTX_ELR_EL3);
-#if TSPD_ROUTE_IRQ_TO_EL3
+#if TSP_NS_INTR_ASYNC_PREEMPT
 		/*Need to save the previously interrupted secure context */
 		memcpy(&tsp_ctx->sp_ctx, &tsp_ctx->cpu_ctx, TSPD_SP_CTX_SIZE);
 #endif
 	}
 
 	cm_el1_sysregs_context_restore(SECURE);
-	cm_set_elr_spsr_el3(SECURE, (uint64_t) &tsp_vectors->fiq_entry,
+	cm_set_elr_spsr_el3(SECURE, (uint64_t) &tsp_vectors->sel1_intr_entry,
 		    SPSR_64(MODE_EL1, MODE_SP_ELX, DISABLE_ALL_EXCEPTIONS));
 
 	cm_set_next_eret_context(SECURE);
 
 	/*
-	 * Tell the TSP that it has to handle an FIQ synchronously. Also the
-	 * instruction in normal world where the interrupt was generated is
-	 * passed for debugging purposes. It is safe to retrieve this address
-	 * from ELR_EL3 as the secure context will not take effect until
-	 * el3_exit().
+	 * Tell the TSP that it has to handle a S-EL1 interrupt synchronously.
+	 * Also the instruction in normal world where the interrupt was
+	 * generated is passed for debugging purposes. It is safe to retrieve
+	 * this address from ELR_EL3 as the secure context will not take effect
+	 * until el3_exit().
 	 */
-	SMC_RET2(&tsp_ctx->cpu_ctx, TSP_HANDLE_FIQ_AND_RETURN, read_elr_el3());
+	SMC_RET2(&tsp_ctx->cpu_ctx, TSP_HANDLE_SEL1_INTR_AND_RETURN, read_elr_el3());
 }
 
-#if TSPD_ROUTE_IRQ_TO_EL3
+#if TSP_NS_INTR_ASYNC_PREEMPT
 /*******************************************************************************
- * This function is the handler registered for S-EL1 interrupts by the TSPD. It
- * validates the interrupt and upon success arranges entry into the TSP at
- * 'tsp_fiq_entry()' for handling the interrupt.
+ * This function is the handler registered for Non secure interrupts by the
+ * TSPD. It validates the interrupt and upon success arranges entry into the
+ * normal world for handling the interrupt.
  ******************************************************************************/
 static uint64_t tspd_ns_interrupt_handler(uint32_t id,
 					    uint32_t flags,
@@ -327,10 +327,10 @@
 
 	/*
 	 * This function ID is used only by the TSP to indicate that it has
-	 * finished handling a S-EL1 FIQ interrupt. Execution should resume
+	 * finished handling a S-EL1 interrupt. Execution should resume
 	 * in the normal world.
 	 */
-	case TSP_HANDLED_S_EL1_FIQ:
+	case TSP_HANDLED_S_EL1_INTR:
 		if (ns)
 			SMC_RET1(handle, SMC_UNK);
 
@@ -347,7 +347,7 @@
 			SMC_SET_EL3(&tsp_ctx->cpu_ctx,
 				    CTX_ELR_EL3,
 				    tsp_ctx->saved_elr_el3);
-#if TSPD_ROUTE_IRQ_TO_EL3
+#if TSP_NS_INTR_ASYNC_PREEMPT
 			/*
 			 * Need to restore the previously interrupted
 			 * secure context.
@@ -408,7 +408,7 @@
 			if (rc)
 				panic();
 
-#if TSPD_ROUTE_IRQ_TO_EL3
+#if TSP_NS_INTR_ASYNC_PREEMPT
 			/*
 			 * Register an interrupt handler for NS interrupts when
 			 * generated during code executing in secure state are
@@ -546,7 +546,7 @@
 				set_std_smc_active_flag(tsp_ctx->state);
 				cm_set_elr_el3(SECURE, (uint64_t)
 						&tsp_vectors->std_smc_entry);
-#if TSPD_ROUTE_IRQ_TO_EL3
+#if TSP_NS_INTR_ASYNC_PREEMPT
 				/*
 				 * Enable the routing of NS interrupts to EL3
 				 * during STD SMC processing on this core.
@@ -577,7 +577,7 @@
 			cm_set_next_eret_context(NON_SECURE);
 			if (GET_SMC_TYPE(smc_fid) == SMC_TYPE_STD) {
 				clr_std_smc_active_flag(tsp_ctx->state);
-#if TSPD_ROUTE_IRQ_TO_EL3
+#if TSP_NS_INTR_ASYNC_PREEMPT
 				/*
 				 * Disable the routing of NS interrupts to EL3
 				 * after STD SMC processing is finished on this
@@ -620,7 +620,7 @@
 		 * We are done stashing the non-secure context. Ask the
 		 * secure payload to do the work now.
 		 */
-#if TSPD_ROUTE_IRQ_TO_EL3
+#if TSP_NS_INTR_ASYNC_PREEMPT
 		/*
 		 * Enable the routing of NS interrupts to EL3 during resumption
 		 * of STD SMC call on this core.
diff --git a/services/spd/tspd/tspd_pm.c b/services/spd/tspd/tspd_pm.c
index 5089420..55562ba 100644
--- a/services/spd/tspd/tspd_pm.c
+++ b/services/spd/tspd/tspd_pm.c
@@ -130,7 +130,7 @@
 	/* Initialise this cpu's secure context */
 	cm_init_my_context(&tsp_on_entrypoint);
 
-#if TSPD_ROUTE_IRQ_TO_EL3
+#if TSP_NS_INTR_ASYNC_PREEMPT
 	/*
 	 * Disable the NS interrupt locally since it will be enabled globally
 	 * within cm_init_my_context.
diff --git a/services/spd/tspd/tspd_private.h b/services/spd/tspd/tspd_private.h
index 5f6fb2b..cadc6aa 100644
--- a/services/spd/tspd/tspd_private.h
+++ b/services/spd/tspd/tspd_private.h
@@ -183,10 +183,10 @@
 
 /*******************************************************************************
  * Structure which helps the SPD to maintain the per-cpu state of the SP.
- * 'saved_spsr_el3' - temporary copy to allow FIQ handling when the TSP has been
- *                    preempted.
- * 'saved_elr_el3'  - temporary copy to allow FIQ handling when the TSP has been
- *                    preempted.
+ * 'saved_spsr_el3' - temporary copy to allow S-EL1 interrupt handling when
+ *                    the TSP has been preempted.
+ * 'saved_elr_el3'  - temporary copy to allow S-EL1 interrupt handling when
+ *                    the TSP has been preempted.
  * 'state'          - collection of flags to track SP state e.g. on/off
  * 'mpidr'          - mpidr to associate a context with a cpu
  * 'c_rt_ctx'       - stack address to restore C runtime context from after
@@ -207,7 +207,7 @@
 	uint64_t c_rt_ctx;
 	cpu_context_t cpu_ctx;
 	uint64_t saved_tsp_args[TSP_NUM_ARGS];
-#if TSPD_ROUTE_IRQ_TO_EL3
+#if TSP_NS_INTR_ASYNC_PREEMPT
 	sp_ctx_regs_t sp_ctx;
 #endif
 } tsp_context_t;