diff --git a/drivers/auth/auth_mod.c b/drivers/auth/auth_mod.c
index a6538c4..3fb2d1a 100644
--- a/drivers/auth/auth_mod.c
+++ b/drivers/auth/auth_mod.c
@@ -30,9 +30,6 @@
 
 #pragma weak plat_set_nv_ctr2
 
-/* Pointer to CoT */
-extern const auth_img_desc_t *const *const cot_desc_ptr;
-extern unsigned int auth_img_flags[MAX_NUMBER_IDS];
 
 static int cmp_auth_param_type_desc(const auth_param_type_desc_t *a,
 		const auth_param_type_desc_t *b)
diff --git a/drivers/renesas/rcar/io/io_rcar.c b/drivers/renesas/rcar/io/io_rcar.c
index 650931b..b82c510 100644
--- a/drivers/renesas/rcar/io/io_rcar.c
+++ b/drivers/renesas/rcar/io/io_rcar.c
@@ -28,9 +28,6 @@
 extern int32_t plat_get_drv_source(uint32_t id, uintptr_t *dev,
 				   uintptr_t *image_spec);
 
-extern int auth_mod_verify_img(unsigned int img_id, void *ptr,
-				unsigned int len);
-
 static int32_t rcar_dev_open(const uintptr_t dev_spec __attribute__ ((unused)),
 			     io_dev_info_t **dev_info);
 static int32_t rcar_dev_close(io_dev_info_t *dev_info);
diff --git a/plat/imx/imx8m/include/imx8m_psci.h b/plat/imx/imx8m/include/imx8m_psci.h
index 4966403..c33d25e 100644
--- a/plat/imx/imx8m/include/imx8m_psci.h
+++ b/plat/imx/imx8m/include/imx8m_psci.h
@@ -15,13 +15,9 @@
 void imx_pwr_domain_on_finish(const psci_power_state_t *target_state);
 void imx_pwr_domain_off(const psci_power_state_t *target_state);
 int imx_validate_ns_entrypoint(uintptr_t ns_entrypoint);
-int imx_validate_power_state(unsigned int power_state, psci_power_state_t *rq_state);
 void imx_cpu_standby(plat_local_state_t cpu_state);
 void imx_domain_suspend(const psci_power_state_t *target_state);
 void imx_domain_suspend_finish(const psci_power_state_t *target_state);
-void imx_get_sys_suspend_power_state(psci_power_state_t *req_state);
-void __dead2 imx_system_reset(void);
-void __dead2 imx_system_off(void);
 void __dead2 imx_pwr_domain_pwr_down_wfi(const psci_power_state_t *target_state);
 
 #endif /* IMX8M_PSCI_H */
diff --git a/plat/intel/soc/agilex/include/agilex_system_manager.h b/plat/intel/soc/agilex/include/agilex_system_manager.h
index 381c2d3..be29536 100644
--- a/plat/intel/soc/agilex/include/agilex_system_manager.h
+++ b/plat/intel/soc/agilex/include/agilex_system_manager.h
@@ -73,7 +73,6 @@
 #define DISABLE_BRIDGE_FIREWALL			0x0ffe0101
 #define DISABLE_L4_FIREWALL	(BIT(0) | BIT(16) | BIT(24))
 
-void enable_nonsecure_access(void);
 void enable_ns_bridge_access(void);
 
 #endif
diff --git a/plat/intel/soc/stratix10/include/s10_system_manager.h b/plat/intel/soc/stratix10/include/s10_system_manager.h
index a67d689..4abfedb 100644
--- a/plat/intel/soc/stratix10/include/s10_system_manager.h
+++ b/plat/intel/soc/stratix10/include/s10_system_manager.h
@@ -69,5 +69,3 @@
 
 #define DISABLE_L4_FIREWALL	(BIT(0) | BIT(16) | BIT(24))
 
-void enable_nonsecure_access(void);
-
diff --git a/plat/mediatek/mt8173/drivers/spm/spm.h b/plat/mediatek/mt8173/drivers/spm/spm.h
index 403303a..0c05410 100644
--- a/plat/mediatek/mt8173/drivers/spm/spm.h
+++ b/plat/mediatek/mt8173/drivers/spm/spm.h
@@ -320,7 +320,6 @@
 void spm_go_to_hotplug(void);
 void spm_init_event_vector(const struct pcm_desc *pcmdesc);
 void spm_kick_im_to_fetch(const struct pcm_desc *pcmdesc);
-void spm_set_sysclk_settle(void);
 int is_mcdi_ready(void);
 int is_hotplug_ready(void);
 int is_suspend_ready(void);
diff --git a/plat/nvidia/tegra/include/tegra_private.h b/plat/nvidia/tegra/include/tegra_private.h
index cd2f773..761acde 100644
--- a/plat/nvidia/tegra/include/tegra_private.h
+++ b/plat/nvidia/tegra/include/tegra_private.h
@@ -137,7 +137,6 @@
 void tegra_delay_timer_init(void);
 
 void tegra_secure_entrypoint(void);
-void tegra186_cpu_reset_handler(void);
 
 /* Declarations for tegra_sip_calls.c */
 uintptr_t tegra_sip_handler(uint32_t smc_fid,
diff --git a/plat/nvidia/tegra/soc/t194/drivers/include/mce_private.h b/plat/nvidia/tegra/soc/t194/drivers/include/mce_private.h
index 3994b2d..7dcfd84 100644
--- a/plat/nvidia/tegra/soc/t194/drivers/include/mce_private.h
+++ b/plat/nvidia/tegra/soc/t194/drivers/include/mce_private.h
@@ -66,7 +66,6 @@
 uint64_t nvg_cache_clean(void);
 uint64_t nvg_cache_clean_inval(void);
 uint64_t nvg_cache_inval_all(void);
-int32_t nvg_roc_clean_cache_trbits(void);
 void nvg_enable_strict_checking_mode(void);
 
 /* MCE helper functions */
diff --git a/plat/nvidia/tegra/soc/t194/plat_psci_handlers.c b/plat/nvidia/tegra/soc/t194/plat_psci_handlers.c
index 1188a3b..fa5ba62 100644
--- a/plat/nvidia/tegra/soc/t194/plat_psci_handlers.c
+++ b/plat/nvidia/tegra/soc/t194/plat_psci_handlers.c
@@ -26,7 +26,6 @@
 #include <tegra_platform.h>
 #include <tegra_private.h>
 
-extern void tegra194_cpu_reset_handler(void);
 extern uint32_t __tegra194_cpu_reset_handler_data,
 		__tegra194_cpu_reset_handler_end;
 
diff --git a/plat/rockchip/rk3328/drivers/soc/soc.h b/plat/rockchip/rk3328/drivers/soc/soc.h
index a1f35b2..e8cbc09 100644
--- a/plat/rockchip/rk3328/drivers/soc/soc.h
+++ b/plat/rockchip/rk3328/drivers/soc/soc.h
@@ -16,8 +16,6 @@
 #define TIMER_INTSTATUS		0x18
 #define TIMER_EN		0x1
 
-extern const unsigned char rockchip_power_domain_tree_desc[];
-
 /**************************** read/write **************************************/
 #ifndef BITS_WMSK
 #define BITS_WMSK(msk, shift)	((msk) << (shift + REG_MSK_SHIFT))