[PATCH v5 6/6] firmware: ti_sci: Introduce prepare system suspend call

[Georgi Vlaev <g-vlaev@ti.com>]

From: Dave Gerlach <d-gerlach@ti.com>

Introduce a ti_sci_prepare_system_suspend call to be used in the driver
suspend handler to allow the system to identify the low power mode being
entered and if necessary, send TISCI_MSG_PREPARE_SLEEP with information
about the mode is being entered and the address for allocated memory for
storing the context during Deep Sleep.

We're using "pm_suspend_target_state" to map the kernel's target suspend
state to SysFW low power mode. Make sure this is available only when
CONFIG_SUSPEND is enabled.

Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
Signed-off-by: Vibhore Vardhan <vibhore@ti.com>
Signed-off-by: Georgi Vlaev <g-vlaev@ti.com>
Tested-by: Roger Quadros <rogerq@kernel.org>
---
 drivers/firmware/ti_sci.c | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/drivers/firmware/ti_sci.c b/drivers/firmware/ti_sci.c
index 09bca1a15d74..681f2ebb3fe4 100644
--- a/drivers/firmware/ti_sci.c
+++ b/drivers/firmware/ti_sci.c
@@ -3568,9 +3568,46 @@ static void ti_sci_set_is_suspending(struct ti_sci_info *info, bool is_suspendin
 	info->is_suspending = is_suspending;
 }
 
+static int ti_sci_prepare_system_suspend(struct ti_sci_info *info)
+{
+#if IS_ENABLED(CONFIG_SUSPEND)
+	u8 mode;
+
+	/* Map and validate the target Linux suspend state to TISCI LPM. */
+	switch (pm_suspend_target_state) {
+	case PM_SUSPEND_MEM:
+		/* S2MEM is not supported by the firmware. */
+		if (!(info->fw_caps & MSG_FLAG_CAPS_LPM_DEEP_SLEEP))
+			return 0;
+		/* S2MEM can't continue if the LPM firmware is not loaded. */
+		if (!info->lpm_firmware_loaded)
+			return -EINVAL;
+		mode = TISCI_MSG_VALUE_SLEEP_MODE_DEEP_SLEEP;
+		break;
+	default:
+		/*
+		 * Do not fail if we don't have action to take for a
+		 * specific suspend mode.
+		 */
+		return 0;
+	}
+
+	return ti_sci_cmd_prepare_sleep(&info->handle, mode,
+					(u32)(info->ctx_mem_addr & 0xffffffff),
+					(u32)((u64)info->ctx_mem_addr >> 32), 0);
+#else
+	return 0;
+#endif
+}
+
 static int ti_sci_suspend(struct device *dev)
 {
 	struct ti_sci_info *info = dev_get_drvdata(dev);
+	int ret;
+
+	ret = ti_sci_prepare_system_suspend(info);
+	if (ret)
+		return ret;
 	/*
 	 * We must switch operation to polled mode now as drivers and the genpd
 	 * layer may make late TI SCI calls to change clock and device states
-- 
2.30.2