Tegra210: toggle ring oscillator across cluster idle
This patch toggles the ring oscillator state across cluster idle
as DFLL loses its state. We dont want garbage values being written
to the pmic when we enter cluster idle state, so enable "open loop"
when we enter CC6 and restore the state to "closed loop" on exit.
Change-Id: I56f4649f57bcc651d6c415a6dcdc978e9444c97b
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>
diff --git a/plat/nvidia/tegra/soc/t210/plat_psci_handlers.c b/plat/nvidia/tegra/soc/t210/plat_psci_handlers.c
index 7907e46..7e176e6 100644
--- a/plat/nvidia/tegra/soc/t210/plat_psci_handlers.c
+++ b/plat/nvidia/tegra/soc/t210/plat_psci_handlers.c
@@ -119,6 +119,13 @@
ret = tegra_bpmp_init();
if (ret != 0U) {
+ /*
+ * flag to indicate that BPMP firmware is not
+ * available and the CPU has to handle entry/exit
+ * for all power states
+ */
+ tegra_bpmp_available = false;
+
/* Cluster idle not allowed */
target = PSCI_LOCAL_STATE_RUN;
@@ -131,13 +138,6 @@
val = mmio_read_32(TEGRA_CL_DVFS_BASE + DVFS_DFLL_CTRL);
if (val == ENABLE_CLOSED_LOOP) {
/*
- * flag to indicate that BPMP firmware is not
- * available and the CPU has to handle entry/exit
- * for all power states
- */
- tegra_bpmp_available = false;
-
- /*
* Acquire the cluster idle lock to stop
* other CPUs from powering up.
*/
@@ -217,6 +217,15 @@
if (!tegra_bpmp_available) {
+ /*
+ * When disabled, DFLL loses its state. Enable
+ * open loop state for the DFLL as we dont want
+ * garbage values being written to the pmic
+ * when we enter cluster idle state.
+ */
+ mmio_write_32(TEGRA_CL_DVFS_BASE + DVFS_DFLL_CTRL,
+ ENABLE_OPEN_LOOP);
+
/* Find if the platform uses OVR2/MAX77621 PMIC */
cfg = mmio_read_32(TEGRA_CL_DVFS_BASE + DVFS_DFLL_OUTPUT_CFG);
if (cfg & DFLL_OUTPUT_CFG_CLK_EN_BIT) {
@@ -481,8 +490,19 @@
val = mmio_read_32(TEGRA_MISC_BASE + PINMUX_AUX_DVFS_PWM);
val &= ~PINMUX_PWM_TRISTATE;
mmio_write_32(TEGRA_MISC_BASE + PINMUX_AUX_DVFS_PWM, val);
+
+ /* make sure the setting took effect */
+ val = mmio_read_32(TEGRA_MISC_BASE + PINMUX_AUX_DVFS_PWM);
+ assert((val & PINMUX_PWM_TRISTATE) == 0U);
}
+ /*
+ * Restore operation mode for the DFLL ring
+ * oscillator
+ */
+ mmio_write_32(TEGRA_CL_DVFS_BASE + DVFS_DFLL_CTRL,
+ ENABLE_CLOSED_LOOP);
+
/* release cluster idle lock */
tegra_fc_ccplex_pgexit_unlock();
}