feat(allwinner): simplify CPU_SUSPEND power state encoding

Use the encoding recommended by the PSCI specification: four bits for
the power state at each power level.

SCPI provides no way to handshake an exit from a standby state, so the
only possible standby state is the architectural WFI state. Since WFI
can be used outside of PSCI, we do not allow passing in standby states.

Change-Id: I4b3b84e5c255ee58a25255a0cab5d7623425086e
Signed-off-by: Samuel Holland <samuel@sholland.org>

diff --git a/plat/allwinner/common/sunxi_scpi_pm.c b/plat/allwinner/common/sunxi_scpi_pm.c
index ed1363537e26a5a31b899a39f43cfef90e38838e..41dc56397a01ad8e1bec031510a74bc6f32403e5 100644 (file)
--- a/plat/allwinner/common/sunxi_scpi_pm.c
+++ b/plat/allwinner/common/sunxi_scpi_pm.c
@@ -33,6 +33,9 @@
  */
 #define SCP_FIRMWARE_MAGIC             0xb4400012
 
+#define PLAT_LOCAL_PSTATE_WIDTH                U(4)
+#define PLAT_LOCAL_PSTATE_MASK         ((U(1) << PLAT_LOCAL_PSTATE_WIDTH) - 1)
+
 #define CPU_PWR_LVL                    MPIDR_AFFLVL0
 #define CLUSTER_PWR_LVL                        MPIDR_AFFLVL1
 #define SYSTEM_PWR_LVL                 MPIDR_AFFLVL2
@@ -126,7 +129,9 @@ static int sunxi_validate_power_state(unsigned int power_state,
                                      psci_power_state_t *req_state)
 {
        unsigned int power_level = psci_get_pstate_pwrlvl(power_state);
+       unsigned int state_id = psci_get_pstate_id(power_state);
        unsigned int type = psci_get_pstate_type(power_state);
+       unsigned int i;
 
        assert(req_state != NULL);
 
@@ -135,28 +140,19 @@ static int sunxi_validate_power_state(unsigned int power_state,
        }
 
        if (type == PSTATE_TYPE_STANDBY) {
-               /* Only one retention power state is supported. */
-               if (psci_get_pstate_id(power_state) > 0) {
-                       return PSCI_E_INVALID_PARAMS;
-               }
-               /* The SoC cannot be suspended without losing state */
-               if (power_level == SYSTEM_PWR_LVL) {
-                       return PSCI_E_INVALID_PARAMS;
-               }
-               for (unsigned int i = 0; i <= power_level; ++i) {
-                       req_state->pwr_domain_state[i] = PLAT_MAX_RET_STATE;
-               }
-       } else {
-               /* Only one off power state is supported. */
-               if (psci_get_pstate_id(power_state) > 0) {
-                       return PSCI_E_INVALID_PARAMS;
-               }
-               for (unsigned int i = 0; i <= power_level; ++i) {
-                       req_state->pwr_domain_state[i] = PLAT_MAX_OFF_STATE;
-               }
+               return PSCI_E_INVALID_PARAMS;
+       }
+
+       /* Pass through the requested PSCI state as-is. */
+       for (i = 0; i <= power_level; ++i) {
+               unsigned int local_pstate = state_id & PLAT_LOCAL_PSTATE_MASK;
+
+               req_state->pwr_domain_state[i] = local_pstate;
+               state_id >>= PLAT_LOCAL_PSTATE_WIDTH;
        }
+
        /* Higher power domain levels should all remain running */
-       for (unsigned int i = power_level + 1; i <= PLAT_MAX_PWR_LVL; ++i) {
+       for (; i <= PLAT_MAX_PWR_LVL; ++i) {
                req_state->pwr_domain_state[i] = PSCI_LOCAL_STATE_RUN;
        }