Tegra186: fix programming sequence for SC7/SC8 entry

This patch fixes the programming sequence for 'System Suspend' and
'Quasi power down' state entry. The device needs to update the
required power state before querying the MCE firmware to see the
entry to that power state is allowed.

Original change by Allen Yu <alleny@nvidia.com>

Change-Id: I65e03754322188af913fabf41f29d1c3595afd85
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>

diff --git a/plat/nvidia/tegra/soc/t186/plat_psci_handlers.c b/plat/nvidia/tegra/soc/t186/plat_psci_handlers.c
index 536ecbf04fea449ecea5311fb1b69fc288301f3b..8911e8f617cbe2507c1c6f5ed3fe95be547a0431 100644 (file)
--- a/plat/nvidia/tegra/soc/t186/plat_psci_handlers.c
+++ b/plat/nvidia/tegra/soc/t186/plat_psci_handlers.c
@@ -150,14 +150,6 @@ int tegra_soc_pwr_domain_suspend(const psci_power_state_t *target_state)
 
        } else if (stateid_afflvl2 == PSTATE_ID_SOC_POWERDN) {
 
-               /* loop until SC7 is allowed */
-               do {
-                       val = mce_command_handler(MCE_CMD_IS_SC7_ALLOWED,
-                                       TEGRA_ARI_CORE_C7,
-                                       MCE_CORE_SLEEP_TIME_INFINITE,
-                                       0);
-               } while (val == 0);
-
                /* save SE registers */
                se_regs[0] = mmio_read_32(TEGRA_SE0_BASE +
                                SE_MUTEX_WATCHDOG_NS_LIMIT);
@@ -184,6 +176,14 @@ int tegra_soc_pwr_domain_suspend(const psci_power_state_t *target_state)
                (void)mce_command_handler(MCE_CMD_UPDATE_CSTATE_INFO,
                        TEGRA_ARI_CLUSTER_CC7, 0, TEGRA_ARI_SYSTEM_SC7);
 
+               /* Loop until system suspend is allowed */
+               do {
+                       val = mce_command_handler(MCE_CMD_IS_SC7_ALLOWED,
+                                       TEGRA_ARI_CORE_C7,
+                                       MCE_CORE_SLEEP_TIME_INFINITE,
+                                       0);
+               } while (val == 0);
+
                /* Instruct the MCE to enter system suspend state */
                (void)mce_command_handler(MCE_CMD_ENTER_CSTATE,
                        TEGRA_ARI_CORE_C7, MCE_CORE_SLEEP_TIME_INFINITE, 0);
@@ -314,6 +314,13 @@ __dead2 void tegra_soc_prepare_system_off(void)
 
        } else if (tegra186_system_powerdn_state == TEGRA_ARI_SYSTEM_SC8) {
 
+               /* Prepare for quasi power down */
+               write_ctx_reg(gp_regs, CTX_GPREG_X4, 1);
+               write_ctx_reg(gp_regs, CTX_GPREG_X5, 0);
+               write_ctx_reg(gp_regs, CTX_GPREG_X6, 1);
+               (void)mce_command_handler(MCE_CMD_UPDATE_CSTATE_INFO,
+                       TEGRA_ARI_CLUSTER_CC7, 0, TEGRA_ARI_SYSTEM_SC8);
+
                /* loop until other CPUs power down */
                do {
                        val = mce_command_handler(MCE_CMD_IS_SC7_ALLOWED,
@@ -322,13 +329,6 @@ __dead2 void tegra_soc_prepare_system_off(void)
                                        0);
                } while (val == 0);
 
-               /* Prepare for quasi power down */
-               write_ctx_reg(gp_regs, CTX_GPREG_X4, 1);
-               write_ctx_reg(gp_regs, CTX_GPREG_X5, 0);
-               write_ctx_reg(gp_regs, CTX_GPREG_X6, 1);
-               (void)mce_command_handler(MCE_CMD_UPDATE_CSTATE_INFO,
-                       TEGRA_ARI_CLUSTER_CC7, 0, TEGRA_ARI_SYSTEM_SC8);
-
                /* Enter quasi power down state */
                (void)mce_command_handler(MCE_CMD_ENTER_CSTATE,
                        TEGRA_ARI_CORE_C7, MCE_CORE_SLEEP_TIME_INFINITE, 0);