diff --git a/include/bl31/services/psci.h b/include/bl31/services/psci.h
index f6fd4872c..004dd6146 100644
--- a/include/bl31/services/psci.h
+++ b/include/bl31/services/psci.h
@@ -167,7 +167,7 @@
 #define PSCI_E_DISABLED		-8
 #define PSCI_E_INVALID_ADDRESS	-9
 
-#define PSCI_INVALID_MPIDR	~(0ULL)
+#define PSCI_INVALID_MPIDR	~((u_register_t)0)
 
 #ifndef __ASSEMBLY__
 
@@ -188,7 +188,7 @@ typedef enum {
 /*
  * Macro to represent invalid affinity level within PSCI.
  */
-#define PSCI_INVALID_DATA -1
+#define PSCI_INVALID_PWR_LVL	(PLAT_MAX_PWR_LVL + 1)
 
 /*
  * Type for representing the local power state at a particular level.
@@ -242,11 +242,13 @@ typedef struct psci_power_state {
 typedef struct psci_cpu_data {
 	/* State as seen by PSCI Affinity Info API */
 	aff_info_state_t aff_info_state;
+
 	/*
 	 * Highest power level which takes part in a power management
 	 * operation.
 	 */
-	int8_t target_pwrlvl;
+	unsigned char target_pwrlvl;
+
 	/* The local power state of this CPU */
 	plat_local_state_t local_state;
 #if !USE_COHERENT_MEM
@@ -270,7 +272,7 @@ typedef struct plat_psci_ops {
 	void (*system_reset)(void) __dead2;
 	int (*validate_power_state)(unsigned int power_state,
 				    psci_power_state_t *req_state);
-	int (*validate_ns_entrypoint)(unsigned long ns_entrypoint);
+	int (*validate_ns_entrypoint)(uintptr_t ns_entrypoint);
 	void (*get_sys_suspend_power_state)(
 				    psci_power_state_t *req_state);
 } plat_psci_ops_t;
@@ -297,17 +299,23 @@ typedef struct spd_pm_ops {
  * Function & Data prototypes
  ******************************************************************************/
 unsigned int psci_version(void);
-int psci_affinity_info(unsigned long, unsigned int);
-int psci_migrate(unsigned long);
+int psci_cpu_on(u_register_t target_cpu,
+		uintptr_t entrypoint,
+		u_register_t context_id);
+int psci_cpu_suspend(unsigned int power_state,
+		     uintptr_t entrypoint,
+		     u_register_t context_id);
+int psci_system_suspend(uintptr_t entrypoint, u_register_t context_id);
+int psci_cpu_off(void);
+int psci_affinity_info(u_register_t target_affinity,
+		       unsigned int lowest_affinity_level);
+int psci_migrate(u_register_t target_cpu);
 int psci_migrate_info_type(void);
 long psci_migrate_info_up_cpu(void);
-int psci_cpu_on(unsigned long,
-		unsigned long,
-		unsigned long);
+int psci_features(unsigned int psci_fid);
 void __dead2 psci_power_down_wfi(void);
 void psci_entrypoint(void);
 void psci_register_spd_pm_hook(const spd_pm_ops_t *);
-
 uint64_t psci_smc_handler(uint32_t smc_fid,
 			  uint64_t x1,
 			  uint64_t x2,
@@ -318,7 +326,7 @@ uint64_t psci_smc_handler(uint32_t smc_fid,
 			  uint64_t flags);
 
 /* PSCI setup function */
-int32_t psci_setup(void);
+int psci_setup(void);
 
 #endif /*__ASSEMBLY__*/
 
diff --git a/include/bl31/services/psci_compat.h b/include/bl31/services/psci_compat.h
index cc80ae303..24bd8dcca 100644
--- a/include/bl31/services/psci_compat.h
+++ b/include/bl31/services/psci_compat.h
@@ -65,6 +65,10 @@
 #define PLAT_MAX_RET_STATE	1
 #define PLAT_MAX_OFF_STATE	2
 
+/*
+ * Macro to represent invalid affinity level within PSCI.
+ */
+#define PSCI_INVALID_DATA -1
 
 #define psci_get_pstate_afflvl(pstate)		psci_get_pstate_pwrlvl(pstate)
 
diff --git a/services/std_svc/psci/psci_common.c b/services/std_svc/psci/psci_common.c
index f810ddfac..e12df04b4 100644
--- a/services/std_svc/psci/psci_common.c
+++ b/services/std_svc/psci/psci_common.c
@@ -189,9 +189,9 @@ unsigned int psci_is_last_on_cpu(void)
  * been physically powered up. It is expected to be called immediately after
  * reset from assembler code.
  ******************************************************************************/
-static int get_power_on_target_pwrlvl(void)
+static unsigned int get_power_on_target_pwrlvl(void)
 {
-	int pwrlvl;
+	unsigned int pwrlvl;
 
 	/*
 	 * Assume that this cpu was suspended and retrieve its target power
@@ -200,7 +200,7 @@ static int get_power_on_target_pwrlvl(void)
 	 * cpu can be turned off to.
 	 */
 	pwrlvl = psci_get_suspend_pwrlvl();
-	if (pwrlvl == PSCI_INVALID_DATA)
+	if (pwrlvl == PSCI_INVALID_PWR_LVL)
 		pwrlvl = PLAT_MAX_PWR_LVL;
 	return pwrlvl;
 }
@@ -236,8 +236,8 @@ void psci_init_req_local_pwr_states(void)
  * target state for this power domain during psci state coordination. An
  * assertion is added to prevent us from accessing the CPU power level.
  *****************************************************************************/
-static plat_local_state_t *psci_get_req_local_pwr_states(int pwrlvl,
-							 int cpu_idx)
+static plat_local_state_t *psci_get_req_local_pwr_states(unsigned int pwrlvl,
+							 unsigned int cpu_idx)
 {
 	assert(pwrlvl > PSCI_CPU_PWR_LVL);
 
@@ -250,11 +250,10 @@ static plat_local_state_t *psci_get_req_local_pwr_states(int pwrlvl,
  * function will be called after a cpu is powered on to find the local state
  * each power domain has emerged from.
  *****************************************************************************/
-static void psci_get_target_local_pwr_states(uint32_t end_pwrlvl,
+static void psci_get_target_local_pwr_states(unsigned int end_pwrlvl,
 					     psci_power_state_t *target_state)
 {
-	int lvl;
-	unsigned int parent_idx;
+	unsigned int parent_idx, lvl;
 	plat_local_state_t *pd_state = target_state->pwr_domain_state;
 
 	pd_state[PSCI_CPU_PWR_LVL] = psci_get_cpu_local_state();
@@ -270,7 +269,7 @@ static void psci_get_target_local_pwr_states(uint32_t end_pwrlvl,
 		 * code runs before caches are enabled.
 		 */
 		flush_dcache_range(
-			(uint64_t)&psci_non_cpu_pd_nodes[parent_idx],
+				(uintptr_t) &psci_non_cpu_pd_nodes[parent_idx],
 				sizeof(psci_non_cpu_pd_nodes[parent_idx]));
 #endif
 		pd_state[lvl] =	psci_non_cpu_pd_nodes[parent_idx].local_state;
@@ -288,11 +287,10 @@ static void psci_get_target_local_pwr_states(uint32_t end_pwrlvl,
  * enter. This function will be called after coordination of requested power
  * states has been done for each power level.
  *****************************************************************************/
-static void psci_set_target_local_pwr_states(uint32_t end_pwrlvl,
+static void psci_set_target_local_pwr_states(unsigned int end_pwrlvl,
 					const psci_power_state_t *target_state)
 {
-	int lvl;
-	unsigned int parent_idx;
+	unsigned int parent_idx, lvl;
 	const plat_local_state_t *pd_state = target_state->pwr_domain_state;
 
 	psci_set_cpu_local_state(pd_state[PSCI_CPU_PWR_LVL]);
@@ -310,8 +308,8 @@ static void psci_set_target_local_pwr_states(uint32_t end_pwrlvl,
 		psci_non_cpu_pd_nodes[parent_idx].local_state =	pd_state[lvl];
 #if !USE_COHERENT_MEM
 		flush_dcache_range(
-			(uint64_t)&psci_non_cpu_pd_nodes[parent_idx],
-			sizeof(psci_non_cpu_pd_nodes[parent_idx]));
+				(uintptr_t)&psci_non_cpu_pd_nodes[parent_idx],
+				sizeof(psci_non_cpu_pd_nodes[parent_idx]));
 #endif
 		parent_idx = psci_non_cpu_pd_nodes[parent_idx].parent_node;
 	}
@@ -322,7 +320,7 @@ static void psci_set_target_local_pwr_states(uint32_t end_pwrlvl,
  * PSCI helper function to get the parent nodes corresponding to a cpu_index.
  ******************************************************************************/
 void psci_get_parent_pwr_domain_nodes(unsigned int cpu_idx,
-				      int end_lvl,
+				      unsigned int end_lvl,
 				      unsigned int node_index[])
 {
 	unsigned int parent_node = psci_cpu_pd_nodes[cpu_idx].parent_node;
@@ -339,10 +337,9 @@ void psci_get_parent_pwr_domain_nodes(unsigned int cpu_idx,
  * affinity info state, target power state and requested power state for the
  * current CPU and all its ancestor power domains to RUN.
  *****************************************************************************/
-void psci_set_pwr_domains_to_run(uint32_t end_pwrlvl)
+void psci_set_pwr_domains_to_run(unsigned int end_pwrlvl)
 {
-	int lvl;
-	unsigned int parent_idx, cpu_idx = plat_my_core_pos();
+	unsigned int parent_idx, cpu_idx = plat_my_core_pos(), lvl;
 	parent_idx = psci_cpu_pd_nodes[cpu_idx].parent_node;
 
 	/* Reset the local_state to RUN for the non cpu power domains. */
@@ -351,7 +348,7 @@ void psci_set_pwr_domains_to_run(uint32_t end_pwrlvl)
 				PSCI_LOCAL_STATE_RUN;
 #if !USE_COHERENT_MEM
 		flush_dcache_range(
-				(uint64_t)&psci_non_cpu_pd_nodes[parent_idx],
+				(uintptr_t) &psci_non_cpu_pd_nodes[parent_idx],
 				sizeof(psci_non_cpu_pd_nodes[parent_idx]));
 #endif
 		psci_set_req_local_pwr_state(lvl,
@@ -387,7 +384,8 @@ void psci_set_pwr_domains_to_run(uint32_t end_pwrlvl)
  * This function will only be invoked with data cache enabled and while
  * powering down a core.
  *****************************************************************************/
-void psci_do_state_coordination(int end_pwrlvl, psci_power_state_t *state_info)
+void psci_do_state_coordination(unsigned int end_pwrlvl,
+				psci_power_state_t *state_info)
 {
 	unsigned int lvl, parent_idx, cpu_idx = plat_my_core_pos();
 	unsigned int start_idx, ncpus;
@@ -463,7 +461,7 @@ int psci_validate_suspend_req(const psci_power_state_t *state_info,
 
 	/* Find the target suspend power level */
 	target_lvl = psci_find_target_suspend_lvl(state_info);
-	if (target_lvl == PSCI_INVALID_DATA)
+	if (target_lvl == PSCI_INVALID_PWR_LVL)
 		return PSCI_E_INVALID_PARAMS;
 
 	/* All power domain levels are in a RUN state to begin with */
@@ -489,7 +487,7 @@ int psci_validate_suspend_req(const psci_power_state_t *state_info,
 	max_off_lvl = psci_find_max_off_lvl(state_info);
 
 	/* The target_lvl is either equal to the max_off_lvl or max_retn_lvl */
-	max_retn_lvl = PSCI_INVALID_DATA;
+	max_retn_lvl = PSCI_INVALID_PWR_LVL;
 	if (target_lvl != max_off_lvl)
 		max_retn_lvl = target_lvl;
 
@@ -498,8 +496,8 @@ int psci_validate_suspend_req(const psci_power_state_t *state_info,
 	 * has to be invalid and max retention level has to be a valid power
 	 * level.
 	 */
-	if (!is_power_down_state && (max_off_lvl != PSCI_INVALID_DATA ||
-				    max_retn_lvl == PSCI_INVALID_DATA))
+	if (!is_power_down_state && (max_off_lvl != PSCI_INVALID_PWR_LVL ||
+				    max_retn_lvl == PSCI_INVALID_PWR_LVL))
 		return PSCI_E_INVALID_PARAMS;
 
 	return PSCI_E_SUCCESS;
@@ -518,7 +516,7 @@ unsigned int psci_find_max_off_lvl(const psci_power_state_t *state_info)
 			return i;
 	}
 
-	return PSCI_INVALID_DATA;
+	return PSCI_INVALID_PWR_LVL;
 }
 
 /******************************************************************************
@@ -534,7 +532,7 @@ unsigned int psci_find_target_suspend_lvl(const psci_power_state_t *state_info)
 			return i;
 	}
 
-	return PSCI_INVALID_DATA;
+	return PSCI_INVALID_PWR_LVL;
 }
 
 /*******************************************************************************
@@ -542,10 +540,11 @@ unsigned int psci_find_target_suspend_lvl(const psci_power_state_t *state_info)
  * tree that the operation should be applied to. It picks up locks in order of
  * increasing power domain level in the range specified.
  ******************************************************************************/
-void psci_acquire_pwr_domain_locks(int end_pwrlvl, unsigned int cpu_idx)
+void psci_acquire_pwr_domain_locks(unsigned int end_pwrlvl,
+				   unsigned int cpu_idx)
 {
 	unsigned int parent_idx = psci_cpu_pd_nodes[cpu_idx].parent_node;
-	int level;
+	unsigned int level;
 
 	/* No locking required for level 0. Hence start locking from level 1 */
 	for (level = PSCI_CPU_PWR_LVL + 1; level <= end_pwrlvl; level++) {
@@ -559,7 +558,8 @@ void psci_acquire_pwr_domain_locks(int end_pwrlvl, unsigned int cpu_idx)
  * tree that the operation should be applied to. It releases the locks in order
  * of decreasing power domain level in the range specified.
  ******************************************************************************/
-void psci_release_pwr_domain_locks(int end_pwrlvl, unsigned int cpu_idx)
+void psci_release_pwr_domain_locks(unsigned int end_pwrlvl,
+				   unsigned int cpu_idx)
 {
 	unsigned int parent_idx, parent_nodes[PLAT_MAX_PWR_LVL] = {0};
 	int level;
@@ -577,7 +577,7 @@ void psci_release_pwr_domain_locks(int end_pwrlvl, unsigned int cpu_idx)
 /*******************************************************************************
  * Simple routine to determine whether a mpidr is valid or not.
  ******************************************************************************/
-int psci_validate_mpidr(unsigned long mpidr)
+int psci_validate_mpidr(u_register_t mpidr)
 {
 	if (plat_core_pos_by_mpidr(mpidr) < 0)
 		return PSCI_E_INVALID_PARAMS;
@@ -590,11 +590,13 @@ int psci_validate_mpidr(unsigned long mpidr)
  * PSCI entrypoint on power on/resume and returns it.
  ******************************************************************************/
 static int psci_get_ns_ep_info(entry_point_info_t *ep,
-		       uint64_t entrypoint, uint64_t context_id)
+			       uintptr_t entrypoint,
+			       u_register_t context_id)
 {
-	uint32_t ep_attr, mode, sctlr, daif, ee;
-	uint32_t ns_scr_el3 = read_scr_el3();
-	uint32_t ns_sctlr_el1 = read_sctlr_el1();
+	unsigned long ep_attr, sctlr;
+	unsigned int daif, ee, mode;
+	unsigned long ns_scr_el3 = read_scr_el3();
+	unsigned long ns_sctlr_el1 = read_sctlr_el1();
 
 	sctlr = ns_scr_el3 & SCR_HCE_BIT ? read_sctlr_el2() : ns_sctlr_el1;
 	ee = 0;
@@ -648,7 +650,8 @@ static int psci_get_ns_ep_info(entry_point_info_t *ep,
  * 'entry_point_info'.
  ******************************************************************************/
 int psci_validate_entry_point(entry_point_info_t *ep,
-		       uint64_t entrypoint, uint64_t context_id)
+			      uintptr_t entrypoint,
+			      u_register_t context_id)
 {
 	int rc;
 
@@ -679,9 +682,8 @@ int psci_validate_entry_point(entry_point_info_t *ep,
  ******************************************************************************/
 void psci_power_up_finish(void)
 {
-	unsigned int cpu_idx = plat_my_core_pos();
+	unsigned int end_pwrlvl, cpu_idx = plat_my_core_pos();
 	psci_power_state_t state_info = { {PSCI_LOCAL_STATE_RUN} };
-	int end_pwrlvl;
 
 	/*
 	 * Verify that we have been explicitly turned ON or resumed from
@@ -764,7 +766,7 @@ void psci_register_spd_pm_hook(const spd_pm_ops_t *pm)
  * is resident through the mpidr parameter. Else the value of the parameter on
  * return is undefined.
  ******************************************************************************/
-int psci_spd_migrate_info(uint64_t *mpidr)
+int psci_spd_migrate_info(u_register_t *mpidr)
 {
 	int rc;
 
diff --git a/services/std_svc/psci/psci_helpers.S b/services/std_svc/psci/psci_helpers.S
index bbfa5d5d7..6ccf943c0 100644
--- a/services/std_svc/psci/psci_helpers.S
+++ b/services/std_svc/psci/psci_helpers.S
@@ -37,7 +37,7 @@
 	.globl	psci_do_pwrup_cache_maintenance
 
 /* -----------------------------------------------------------------------
- * void psci_do_pwrdown_cache_maintenance(uint32_t power level);
+ * void psci_do_pwrdown_cache_maintenance(unsigned int power level);
  *
  * This function performs cache maintenance for the specified power
  * level. The levels of cache affected are determined by the power
@@ -66,7 +66,7 @@ func psci_do_pwrdown_cache_maintenance
 	 * platform.
 	 * ---------------------------------------------
 	 */
-	cmp	x0, #PSCI_CPU_PWR_LVL
+	cmp	w0, #PSCI_CPU_PWR_LVL
 	b.eq	do_core_pwr_dwn
 	bl	prepare_cluster_pwr_dwn
 	b	do_stack_maintenance
diff --git a/services/std_svc/psci/psci_main.c b/services/std_svc/psci/psci_main.c
index 6d3af2048..e6cd3a3a4 100644
--- a/services/std_svc/psci/psci_main.c
+++ b/services/std_svc/psci/psci_main.c
@@ -41,9 +41,9 @@
 /*******************************************************************************
  * PSCI frontend api for servicing SMCs. Described in the PSCI spec.
  ******************************************************************************/
-int psci_cpu_on(unsigned long target_cpu,
-		unsigned long entrypoint,
-		unsigned long context_id)
+int psci_cpu_on(u_register_t target_cpu,
+		uintptr_t entrypoint,
+		u_register_t context_id)
 
 {
 	int rc;
@@ -77,8 +77,8 @@ unsigned int psci_version(void)
 }
 
 int psci_cpu_suspend(unsigned int power_state,
-		     unsigned long entrypoint,
-		     unsigned long context_id)
+		     uintptr_t entrypoint,
+		     u_register_t context_id)
 {
 	int rc;
 	unsigned int target_pwrlvl, is_power_down_state;
@@ -147,8 +147,8 @@ int psci_cpu_suspend(unsigned int power_state,
 	return PSCI_E_SUCCESS;
 }
 
-int psci_system_suspend(unsigned long entrypoint,
-			unsigned long context_id)
+
+int psci_system_suspend(uintptr_t entrypoint, u_register_t context_id)
 {
 	int rc;
 	psci_power_state_t state_info;
@@ -188,7 +188,7 @@ int psci_system_suspend(unsigned long entrypoint,
 int psci_cpu_off(void)
 {
 	int rc;
-	int target_pwrlvl = PLAT_MAX_PWR_LVL;
+	unsigned int target_pwrlvl = PLAT_MAX_PWR_LVL;
 
 	/*
 	 * Do what is needed to power off this CPU and possible higher power
@@ -206,7 +206,7 @@ int psci_cpu_off(void)
 	return rc;
 }
 
-int psci_affinity_info(unsigned long target_affinity,
+int psci_affinity_info(u_register_t target_affinity,
 		       unsigned int lowest_affinity_level)
 {
 	unsigned int target_idx;
@@ -223,10 +223,10 @@ int psci_affinity_info(unsigned long target_affinity,
 	return psci_get_aff_info_state_by_idx(target_idx);
 }
 
-int psci_migrate(unsigned long target_cpu)
+int psci_migrate(u_register_t target_cpu)
 {
 	int rc;
-	unsigned long resident_cpu_mpidr;
+	u_register_t resident_cpu_mpidr;
 
 	rc = psci_spd_migrate_info(&resident_cpu_mpidr);
 	if (rc != PSCI_TOS_UP_MIG_CAP)
@@ -255,14 +255,14 @@ int psci_migrate(unsigned long target_cpu)
 
 int psci_migrate_info_type(void)
 {
-	unsigned long resident_cpu_mpidr;
+	u_register_t resident_cpu_mpidr;
 
 	return psci_spd_migrate_info(&resident_cpu_mpidr);
 }
 
 long psci_migrate_info_up_cpu(void)
 {
-	unsigned long resident_cpu_mpidr;
+	u_register_t resident_cpu_mpidr;
 	int rc;
 
 	/*
@@ -278,7 +278,7 @@ long psci_migrate_info_up_cpu(void)
 
 int psci_features(unsigned int psci_fid)
 {
-	uint32_t local_caps = psci_caps;
+	unsigned int local_caps = psci_caps;
 
 	/* Check if it is a 64 bit function */
 	if (((psci_fid >> FUNCID_CC_SHIFT) & FUNCID_CC_MASK) == SMC_64)
diff --git a/services/std_svc/psci/psci_off.c b/services/std_svc/psci/psci_off.c
index 28fa52c03..f565ffb7e 100644
--- a/services/std_svc/psci/psci_off.c
+++ b/services/std_svc/psci/psci_off.c
@@ -60,7 +60,7 @@ static void psci_set_power_off_state(psci_power_state_t *state_info)
  * interconnect level if the cpu is the last in the cluster and also the
  * program the power controller.
  ******************************************************************************/
-int psci_do_cpu_off(int end_pwrlvl)
+int psci_do_cpu_off(unsigned int end_pwrlvl)
 {
 	int rc, idx = plat_my_core_pos();
 	psci_power_state_t state_info;
diff --git a/services/std_svc/psci/psci_on.c b/services/std_svc/psci/psci_on.c
index d68198f2e..cf1a782a5 100644
--- a/services/std_svc/psci/psci_on.c
+++ b/services/std_svc/psci/psci_on.c
@@ -84,9 +84,9 @@ static void psci_set_aff_info_state_by_idx(unsigned int cpu_idx,
  * The state of all the relevant power domains are changed after calling the
  * platform handler as it can return error.
  ******************************************************************************/
-int psci_cpu_on_start(unsigned long target_cpu,
+int psci_cpu_on_start(u_register_t target_cpu,
 		      entry_point_info_t *ep,
-		      int end_pwrlvl)
+		      unsigned int end_pwrlvl)
 {
 	int rc;
 	unsigned int target_idx = plat_core_pos_by_mpidr(target_cpu);
@@ -130,7 +130,7 @@ int psci_cpu_on_start(unsigned long target_cpu,
 	 * of the target cpu to allow it to perform the necessary
 	 * steps to power on.
 	 */
-	rc = psci_plat_pm_ops->pwr_domain_on((u_register_t)target_cpu);
+	rc = psci_plat_pm_ops->pwr_domain_on(target_cpu);
 	assert(rc == PSCI_E_SUCCESS || rc == PSCI_E_INTERN_FAIL);
 
 	if (rc == PSCI_E_SUCCESS)
diff --git a/services/std_svc/psci/psci_private.h b/services/std_svc/psci/psci_private.h
index 5345ee30f..9b55d9f39 100644
--- a/services/std_svc/psci/psci_private.h
+++ b/services/std_svc/psci/psci_private.h
@@ -149,7 +149,7 @@ typedef struct non_cpu_pwr_domain_node {
 } non_cpu_pd_node_t;
 
 typedef struct cpu_pwr_domain_node {
-	unsigned long mpidr;
+	u_register_t mpidr;
 
 	/*
 	 * Index of the parent power domain node.
@@ -172,7 +172,7 @@ typedef struct cpu_pwr_domain_node {
 extern const plat_psci_ops_t *psci_plat_pm_ops;
 extern non_cpu_pd_node_t psci_non_cpu_pd_nodes[PSCI_NUM_NON_CPU_PWR_DOMAINS];
 extern cpu_pd_node_t psci_cpu_pd_nodes[PLATFORM_CORE_COUNT];
-extern uint32_t psci_caps;
+extern unsigned int psci_caps;
 
 /*******************************************************************************
  * SPD's power management hooks registered with PSCI
@@ -186,43 +186,43 @@ extern const spd_pm_ops_t *psci_spd_pm;
 int psci_validate_power_state(unsigned int power_state,
 			      psci_power_state_t *state_info);
 void psci_query_sys_suspend_pwrstate(psci_power_state_t *state_info);
-int psci_validate_mpidr(unsigned long mpidr);
+int psci_validate_mpidr(u_register_t mpidr);
 void psci_init_req_local_pwr_states(void);
 void psci_power_up_finish(void);
 int psci_validate_entry_point(entry_point_info_t *ep,
-		       uint64_t entrypoint, uint64_t context_id);
+			uintptr_t entrypoint, u_register_t context_id);
 void psci_get_parent_pwr_domain_nodes(unsigned int cpu_idx,
-				      int end_lvl,
+				      unsigned int end_lvl,
 				      unsigned int node_index[]);
-void psci_do_state_coordination(int end_pwrlvl,
+void psci_do_state_coordination(unsigned int end_pwrlvl,
 				psci_power_state_t *state_info);
-void psci_acquire_pwr_domain_locks(int end_pwrlvl,
+void psci_acquire_pwr_domain_locks(unsigned int end_pwrlvl,
 				   unsigned int cpu_idx);
-void psci_release_pwr_domain_locks(int end_pwrlvl,
+void psci_release_pwr_domain_locks(unsigned int end_pwrlvl,
 				   unsigned int cpu_idx);
 int psci_validate_suspend_req(const psci_power_state_t *state_info,
 			      unsigned int is_power_down_state_req);
 unsigned int psci_find_max_off_lvl(const psci_power_state_t *state_info);
 unsigned int psci_find_target_suspend_lvl(const psci_power_state_t *state_info);
-void psci_set_pwr_domains_to_run(uint32_t end_pwrlvl);
+void psci_set_pwr_domains_to_run(unsigned int end_pwrlvl);
 void psci_print_power_domain_map(void);
 unsigned int psci_is_last_on_cpu(void);
-int psci_spd_migrate_info(uint64_t *mpidr);
+int psci_spd_migrate_info(u_register_t *mpidr);
 
 /* Private exported functions from psci_on.c */
 int psci_cpu_on_start(unsigned long target_cpu,
 		      entry_point_info_t *ep,
-		      int end_pwrlvl);
+		      unsigned int end_pwrlvl);
 
 void psci_cpu_on_finish(unsigned int cpu_idx,
 			psci_power_state_t *state_info);
 
 /* Private exported functions from psci_cpu_off.c */
-int psci_do_cpu_off(int end_pwrlvl);
+int psci_do_cpu_off(unsigned int end_pwrlvl);
 
 /* Private exported functions from psci_pwrlvl_suspend.c */
 void psci_cpu_suspend_start(entry_point_info_t *ep,
-			int end_pwrlvl,
+			unsigned int end_pwrlvl,
 			psci_power_state_t *state_info,
 			unsigned int is_power_down_state_req);
 
@@ -230,7 +230,7 @@ void psci_cpu_suspend_finish(unsigned int cpu_idx,
 			psci_power_state_t *state_info);
 
 /* Private exported functions from psci_helpers.S */
-void psci_do_pwrdown_cache_maintenance(uint32_t pwr_level);
+void psci_do_pwrdown_cache_maintenance(unsigned int pwr_level);
 void psci_do_pwrup_cache_maintenance(void);
 
 /* Private exported functions from psci_system_off.c */
diff --git a/services/std_svc/psci/psci_setup.c b/services/std_svc/psci/psci_setup.c
index ce4da9599..94fe630c9 100644
--- a/services/std_svc/psci/psci_setup.c
+++ b/services/std_svc/psci/psci_setup.c
@@ -49,13 +49,15 @@ static cpu_context_t psci_ns_context[PLATFORM_CORE_COUNT];
 /******************************************************************************
  * Define the psci capability variable.
  *****************************************************************************/
-uint32_t psci_caps;
+unsigned int psci_caps;
 
 /*******************************************************************************
  * Function which initializes the 'psci_non_cpu_pd_nodes' or the
  * 'psci_cpu_pd_nodes' corresponding to the power level.
  ******************************************************************************/
-static void psci_init_pwr_domain_node(int node_idx, int parent_idx, int level)
+static void psci_init_pwr_domain_node(unsigned int node_idx,
+					unsigned int parent_idx,
+					unsigned int level)
 {
 	if (level > PSCI_CPU_PWR_LVL) {
 		psci_non_cpu_pd_nodes[node_idx].level = level;
@@ -78,12 +80,12 @@ static void psci_init_pwr_domain_node(int node_idx, int parent_idx, int level)
 		svc_cpu_data->aff_info_state = AFF_STATE_OFF;
 
 		/* Invalidate the suspend level for the cpu */
-		svc_cpu_data->target_pwrlvl = PSCI_INVALID_DATA;
+		svc_cpu_data->target_pwrlvl = PSCI_INVALID_PWR_LVL;
 
 		/* Set the power state to OFF state */
 		svc_cpu_data->local_state = PLAT_MAX_OFF_STATE;
 
-		flush_dcache_range((uint64_t)svc_cpu_data,
+		flush_dcache_range((uintptr_t)svc_cpu_data,
 						 sizeof(*svc_cpu_data));
 
 		cm_set_context_by_index(node_idx,
@@ -103,9 +105,9 @@ static void psci_init_pwr_domain_node(int node_idx, int parent_idx, int level)
  *******************************************************************************/
 static void psci_update_pwrlvl_limits(void)
 {
-	int cpu_idx, j;
+	int j;
 	unsigned int nodes_idx[PLAT_MAX_PWR_LVL] = {0};
-	unsigned int temp_index[PLAT_MAX_PWR_LVL];
+	unsigned int temp_index[PLAT_MAX_PWR_LVL], cpu_idx;
 
 	for (cpu_idx = 0; cpu_idx < PLATFORM_CORE_COUNT; cpu_idx++) {
 		psci_get_parent_pwr_domain_nodes(cpu_idx,
@@ -182,7 +184,7 @@ static void populate_power_domain_tree(const unsigned char *topology)
 
 #if !USE_COHERENT_MEM
 	/* Flush the non CPU power domain data to memory */
-	flush_dcache_range((uint64_t) &psci_non_cpu_pd_nodes,
+	flush_dcache_range((uintptr_t) &psci_non_cpu_pd_nodes,
 			   sizeof(psci_non_cpu_pd_nodes));
 #endif
 }
@@ -208,7 +210,7 @@ static void populate_power_domain_tree(const unsigned char *topology)
  * |   CPU 0   |   CPU 1   |   CPU 2   |   CPU 3  |
  * ------------------------------------------------
  ******************************************************************************/
-int32_t psci_setup(void)
+int psci_setup(void)
 {
 	const unsigned char *topology_tree;
 
@@ -230,11 +232,11 @@ int32_t psci_setup(void)
 	 * The psci_non_cpu_pd_nodes only needs flushing when it's not allocated in
 	 * coherent memory.
 	 */
-	flush_dcache_range((uint64_t) &psci_non_cpu_pd_nodes,
+	flush_dcache_range((uintptr_t) &psci_non_cpu_pd_nodes,
 			   sizeof(psci_non_cpu_pd_nodes));
 #endif
 
-	flush_dcache_range((uint64_t) &psci_cpu_pd_nodes,
+	flush_dcache_range((uintptr_t) &psci_cpu_pd_nodes,
 			   sizeof(psci_cpu_pd_nodes));
 
 	psci_init_req_local_pwr_states();
diff --git a/services/std_svc/psci/psci_suspend.c b/services/std_svc/psci/psci_suspend.c
index 71e477842..a158e36f6 100644
--- a/services/std_svc/psci/psci_suspend.c
+++ b/services/std_svc/psci/psci_suspend.c
@@ -72,7 +72,7 @@ static void psci_suspend_to_standby_finisher(unsigned int cpu_idx,
  * This function does generic and platform specific suspend to power down
  * operations.
  ******************************************************************************/
-static void psci_suspend_to_pwrdown_start(int end_pwrlvl,
+static void psci_suspend_to_pwrdown_start(unsigned int end_pwrlvl,
 					  entry_point_info_t *ep,
 					  psci_power_state_t *state_info)
 {
@@ -127,7 +127,7 @@ static void psci_suspend_to_pwrdown_start(int end_pwrlvl,
  * not possible to undo any of the actions taken beyond that point.
  ******************************************************************************/
 void psci_cpu_suspend_start(entry_point_info_t *ep,
-			    int end_pwrlvl,
+			    unsigned int end_pwrlvl,
 			    psci_power_state_t *state_info,
 			    unsigned int is_power_down_state)
 {
@@ -212,8 +212,8 @@ exit:
 void psci_cpu_suspend_finish(unsigned int cpu_idx,
 			     psci_power_state_t *state_info)
 {
-	int32_t suspend_level;
-	uint64_t counter_freq;
+	unsigned long long counter_freq;
+	unsigned int suspend_level;
 
 	/* Ensure we have been woken up from a suspended state */
 	assert(psci_get_aff_info_state() == AFF_STATE_ON && is_local_state_off(\
@@ -246,12 +246,12 @@ void psci_cpu_suspend_finish(unsigned int cpu_idx,
 	 */
 	if (psci_spd_pm && psci_spd_pm->svc_suspend) {
 		suspend_level = psci_get_suspend_pwrlvl();
-		assert (suspend_level != PSCI_INVALID_DATA);
+		assert (suspend_level != PSCI_INVALID_PWR_LVL);
 		psci_spd_pm->svc_suspend_finish(suspend_level);
 	}
 
 	/* Invalidate the suspend level for the cpu */
-	psci_set_suspend_pwrlvl(PSCI_INVALID_DATA);
+	psci_set_suspend_pwrlvl(PSCI_INVALID_PWR_LVL);
 
 	/*
 	 * Generic management: Now we just need to retrieve the