[PATCH v3 2/4] cpuidle: psci: Allow skipping the suspend mode switch

[Reza Kurniawan]

From: Alejandro Tafalla <atafalla at dnyon.com>

On some SoCs (e.g. Qualcomm MSM8917 and MSM8937), PSCI reports that OSI
mode is supported but rejects any PSCI_SET_SUSPEND_MODE call with
NOT_SUPPORTED. psci_set_osi_mode() then fails with -EOPNOTSUPP and the
probe is aborted:

  psci-cpuidle-domain psci: probe with driver psci-cpuidle-domain failed
  with error -95

Add support for the "skip-suspend-mode-switch" property. When present,
do not call psci_set_osi_mode() and continue with the topology that was
already built.

Signed-off-by: Alejandro Tafalla <atafalla at dnyon.com>
[Reza Kurniawan: split out the patch, added log message for skip case, renamed
 the property, added property check at PSCI initialization]
Co-developed-by: Reza Kurniawan <imkyufie at gmail.com>
Signed-off-by: Reza Kurniawan <imkyufie at gmail.com>
---
 drivers/cpuidle/cpuidle-psci-domain.c | 16 ++++++++++------
 drivers/firmware/psci/psci.c          |  6 ++++--
 2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/cpuidle/cpuidle-psci-domain.c b/drivers/cpuidle/cpuidle-psci-domain.c
index 5722365b94..cc9f14769b 100644
--- a/drivers/cpuidle/cpuidle-psci-domain.c
+++ b/drivers/cpuidle/cpuidle-psci-domain.c
@@ -159,13 +159,17 @@ static int psci_cpuidle_domain_probe(struct platform_device *pdev)
 	if (ret)
 		goto remove_pd;
 
-	/* let's try to enable OSI. */
-	ret = psci_set_osi_mode(use_osi);
-	if (ret)
-		goto remove_pd;
+	if (of_property_read_bool(np, "skip-suspend-mode-switch")) {
+		pr_info("Initialized CPU PM domain topology, keeping firmware-set mode\n");
+	} else {
+		ret = psci_set_osi_mode(use_osi);
+		if (ret)
+			goto remove_pd;
+
+		pr_info("Initialized CPU PM domain topology using %s mode\n",
+			use_osi ? "OSI" : "PC");
+	}
 
-	pr_info("Initialized CPU PM domain topology using %s mode\n",
-		use_osi ? "OSI" : "PC");
 	return 0;
 
 remove_pd:
diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
index e73bae6cb2..3226af6d89 100644
--- a/drivers/firmware/psci/psci.c
+++ b/drivers/firmware/psci/psci.c
@@ -791,8 +791,10 @@ static int __init psci_1_0_init(const struct device_node *np)
 	if (psci_has_osi_support()) {
 		pr_info("OSI mode supported.\n");
 
-		/* Default to PC mode. */
-		psci_set_osi_mode(false);
+		if (!of_property_read_bool(np, "skip-suspend-mode-switch")) {
+			/* Default to PC mode. */
+			psci_set_osi_mode(false);
+		}
 	}
 
 	return 0;

-- 
2.56.0