PSCI: Unify warm reset entry points

There used to be 2 warm reset entry points:

 - the "on finisher", for when the core has been turned on using a
   PSCI CPU_ON call;

 - the "suspend finisher", entered upon resumption from a previous
   PSCI CPU_SUSPEND call.

The appropriate warm reset entry point used to be programmed into the
mailboxes by the power management hooks.

However, it is not required to provide this information to the PSCI
entry point code, as it can figure it out by itself. By querying affinity
info state, a core is able to determine on which execution path it is.
If the state is ON_PENDING then it means it's been turned on else
it is resuming from suspend.

This patch unifies the 2 warm reset entry points into a single one:
psci_entrypoint(). The patch also implements the necessary logic
to distinguish between the 2 types of warm resets in the power up
finisher.

The plat_setup_psci_ops() API now takes the
secure entry point as an additional parameter to enable the platforms
to configure their mailbox. The platform hooks `pwr_domain_on`
and `pwr_domain_suspend` no longer take secure entry point as
a parameter.

Change-Id: I7d1c93787b54213aefdbc046b8cd66a555dfbfd9

include/bl31/services/psci1.0/psci.h

@@ -256,13 +256,12 @@ typedef struct psci_cpu_data {
  ******************************************************************************/
 typedef struct plat_psci_ops {
 	void (*cpu_standby)(plat_local_state_t cpu_state);
-	int (*pwr_domain_on)(u_register_t mpidr,
-			  unsigned long sec_entrypoint);
+	int (*pwr_domain_on)(u_register_t mpidr);
 	void (*pwr_domain_off)(const psci_power_state_t *target_state);
-	void (*pwr_domain_suspend)(unsigned long sec_entrypoint,
-			       const psci_power_state_t *target_state);
+	void (*pwr_domain_suspend)(const psci_power_state_t *target_state);
 	void (*pwr_domain_on_finish)(const psci_power_state_t *target_state);
-	void (*pwr_domain_suspend_finish)(const psci_power_state_t *target_state);
+	void (*pwr_domain_suspend_finish)(
+				const psci_power_state_t *target_state);
 	void (*system_off)(void) __dead2;
 	void (*system_reset)(void) __dead2;
 	int (*validate_power_state)(unsigned int power_state,
@@ -302,8 +301,7 @@ int psci_cpu_on(unsigned long,
 		unsigned long,
 		unsigned long);
 void __dead2 psci_power_down_wfi(void);
-void psci_cpu_on_finish_entry(void);
-void psci_cpu_suspend_finish_entry(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,

include/plat/common/psci1.0/platform.h

@@ -181,7 +181,8 @@ struct entry_point_info *bl31_plat_get_next_image_ep_info(uint32_t type);
 /*******************************************************************************
  * Mandatory PSCI functions (BL3-1)
  ******************************************************************************/
-int plat_setup_psci_ops(const struct plat_psci_ops **);
+int plat_setup_psci_ops(uintptr_t sec_entrypoint,
+			const struct plat_psci_ops **);
 const unsigned char *plat_get_power_domain_tree_desc(void);
 
 /*******************************************************************************

services/std_svc/psci1.0/psci_common.c

@@ -189,7 +189,7 @@ unsigned int psci_is_last_on_cpu(void)
  * been physically powered up. It is expected to be called immediately after
  * reset from assembler code.
  ******************************************************************************/
-int get_power_on_target_pwrlvl(void)
+static int get_power_on_target_pwrlvl(void)
 {
 	int pwrlvl;
 
@@ -651,11 +651,26 @@ int psci_get_ns_ep_info(entry_point_info_t *ep,
  * code to enable the gic cpu interface and for a cluster it will enable
  * coherency at the interconnect level in addition to gic cpu interface.
  ******************************************************************************/
-void psci_power_up_finish(int end_pwrlvl,
-			  pwrlvl_power_on_finisher_t power_on_handler)
+void psci_power_up_finish(void)
 {
 	unsigned int 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
+	 * suspend.
+	 */
+	if (psci_get_aff_info_state() == AFF_STATE_OFF) {
+		ERROR("Unexpected affinity info state");
+		panic();
+	}
+
+	/*
+	 * Get the maximum power domain level to traverse to after this cpu
+	 * has been physically powered up.
+	 */
+	end_pwrlvl = get_power_on_target_pwrlvl();
 
 	/*
 	 * This function acquires the lock corresponding to each power level so
@@ -668,9 +683,21 @@ void psci_power_up_finish(int end_pwrlvl,
 	psci_get_target_local_pwr_states(end_pwrlvl, &state_info);
 
 	/*
-	 * Perform generic, architecture and platform specific handling.
+	 * This CPU could be resuming from suspend or it could have just been
+	 * turned on. To distinguish between these 2 cases, we examine the
+	 * affinity state of the CPU:
+	 *  - If the affinity state is ON_PENDING then it has just been
+	 *    turned on.
+	 *  - Else it is resuming from suspend.
+	 *
+	 * Depending on the type of warm reset identified, choose the right set
+	 * of power management handler and perform the generic, architecture
+	 * and platform specific handling.
 	 */
-	power_on_handler(cpu_idx, &state_info);
+	if (psci_get_aff_info_state() == AFF_STATE_ON_PENDING)
+		psci_cpu_on_finish(cpu_idx, &state_info);
+	else
+		psci_cpu_suspend_finish(cpu_idx, &state_info);
 
 	/*
 	 * Set the requested and target state of this CPU and all the higher

services/std_svc/psci1.0/psci_entry.S

@@ -34,25 +34,16 @@
 #include <psci.h>
 #include <xlat_tables.h>
 
-	.globl	psci_cpu_on_finish_entry
-	.globl	psci_cpu_suspend_finish_entry
+	.globl	psci_entrypoint
 	.globl	psci_power_down_wfi
 
-	/* -----------------------------------------------------
-	 * This cpu has been physically powered up. Depending
-	 * upon whether it was resumed from suspend or simply
-	 * turned on, call the common power on finisher with
-	 * the handlers (chosen depending upon original state).
-	 * -----------------------------------------------------
+	/* --------------------------------------------------------------------
+	 * This CPU has been physically powered up. It is either resuming from
+	 * suspend or has simply been turned on. In both cases, call the power
+	 * on finisher.
+	 * --------------------------------------------------------------------
 	 */
-func psci_cpu_on_finish_entry
-	adr	x23, psci_cpu_on_finish
-	b	psci_power_up_entry
-
-psci_cpu_suspend_finish_entry:
-	adr	x23, psci_cpu_suspend_finish
-
-psci_power_up_entry:
+func psci_entrypoint
 	/*
 	 * On the warm boot path, most of the EL3 initialisations performed by
 	 * 'el3_entrypoint_common' must be skipped:
@@ -98,12 +89,10 @@ psci_power_up_entry:
 	mov	x0, #DISABLE_DCACHE
 	bl	bl31_plat_enable_mmu
 
-	bl	get_power_on_target_pwrlvl
-	mov	x1, x23
 	bl	psci_power_up_finish
 
 	b	el3_exit
-endfunc psci_cpu_on_finish_entry
+endfunc psci_entrypoint
 
 	/* --------------------------------------------
 	 * This function is called to indicate to the

services/std_svc/psci1.0/psci_on.c

@@ -89,7 +89,6 @@ int psci_cpu_on_start(unsigned long target_cpu,
 		      int end_pwrlvl)
 {
 	int rc;
-	unsigned long psci_entrypoint;
 	unsigned int target_idx = plat_core_pos_by_mpidr(target_cpu);
 
 	/*
@@ -126,16 +125,12 @@ int psci_cpu_on_start(unsigned long target_cpu,
 	/*
 	 * Perform generic, architecture and platform specific handling.
 	 */
-	/* Set the secure world (EL3) re-entry point after BL1 */
-	psci_entrypoint = (unsigned long) psci_cpu_on_finish_entry;
-
 	/*
 	 * Plat. management: Give the platform the current state
 	 * 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,
-				    psci_entrypoint);
+	rc = psci_plat_pm_ops->pwr_domain_on((u_register_t)target_cpu);
 	assert(rc == PSCI_E_SUCCESS || rc == PSCI_E_INTERN_FAIL);
 
 	if (rc == PSCI_E_SUCCESS)

services/std_svc/psci1.0/psci_private.h

@@ -166,9 +166,6 @@ typedef struct cpu_pwr_domain_node {
 	spinlock_t cpu_lock;
 } cpu_pd_node_t;
 
-typedef void (*pwrlvl_power_on_finisher_t)(unsigned int cpu_idx,
-					   psci_power_state_t *state_info);
-
 /*******************************************************************************
  * Data prototypes
  ******************************************************************************/
@@ -190,10 +187,8 @@ 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 get_power_on_target_pwrlvl(void);
 void psci_init_req_local_pwr_states(void);
-void psci_power_up_finish(int end_pwrlvl,
-				 pwrlvl_power_on_finisher_t power_on_handler);
+void psci_power_up_finish(void);
 int psci_get_ns_ep_info(entry_point_info_t *ep,
 		       uint64_t entrypoint, uint64_t context_id);
 void psci_get_parent_pwr_domain_nodes(unsigned int cpu_idx,

services/std_svc/psci1.0/psci_setup.c

@@ -245,7 +245,8 @@ int32_t psci_setup(void)
 	 */
 	psci_set_pwr_domains_to_run(PLAT_MAX_PWR_LVL);
 
-	plat_setup_psci_ops(&psci_plat_pm_ops);
+	plat_setup_psci_ops((uintptr_t)psci_entrypoint,
+					&psci_plat_pm_ops);
 	assert(psci_plat_pm_ops);
 
 	/* Initialize the psci capability */

services/std_svc/psci1.0/psci_suspend.c

@@ -133,7 +133,6 @@ void psci_cpu_suspend_start(entry_point_info_t *ep,
 {
 	int skip_wfi = 0;
 	unsigned int idx = plat_my_core_pos();
-	unsigned long psci_entrypoint;
 
 	/*
 	 * This function must only be called on platforms where the
@@ -167,22 +166,16 @@ void psci_cpu_suspend_start(entry_point_info_t *ep,
 	 */
 	psci_do_state_coordination(end_pwrlvl, state_info);
 
-	psci_entrypoint = 0;
-	if (is_power_down_state) {
+	if (is_power_down_state)
 		psci_suspend_to_pwrdown_start(end_pwrlvl, ep, state_info);
 
-		/* Set the secure world (EL3) re-entry point after BL1. */
-		psci_entrypoint =
-			(unsigned long) psci_cpu_suspend_finish_entry;
-	}
-
 	/*
 	 * Plat. management: Allow the platform to perform the
 	 * necessary actions to turn off this cpu e.g. set the
 	 * platform defined mailbox with the psci entrypoint,
 	 * program the power controller etc.
 	 */
-	psci_plat_pm_ops->pwr_domain_suspend(psci_entrypoint, state_info);
+	psci_plat_pm_ops->pwr_domain_suspend(state_info);
 
 exit:
 	/*