[PATCH 4/5] firmware: ti-sci: for j7200 before suspend check the reserved memory for lpm

[Thomas Richard]

On j7200, a reserved memory region is needed for TF-A to save its context
during suspend to ram.
In ti-sci suspend, check if the region was defined, if not return an
error.

Signed-off-by: Thomas Richard <thomas.richard at bootlin.com>
---
 drivers/firmware/ti_sci.c | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/drivers/firmware/ti_sci.c b/drivers/firmware/ti_sci.c
index c26ec86a5ff2..deaca17322df 100644
--- a/drivers/firmware/ti_sci.c
+++ b/drivers/firmware/ti_sci.c
@@ -77,6 +77,8 @@ struct ti_sci_xfers_info {
  *		  simultaneously in the system
  * @max_msg_size: Maximum size of data per message that can be handled.
  * @restore_irqs: Set to true if allocated irqs shall be restored at resume
+ * @lpm_region: Set to true if a reserved memory region is needed for suspend to
+ *		ram
  */
 struct ti_sci_desc {
 	u8 default_host_id;
@@ -84,6 +86,7 @@ struct ti_sci_desc {
 	int max_msgs;
 	int max_msg_size;
 	bool restore_irqs;
+	bool lpm_region;
 };
 
 /**
@@ -3359,6 +3362,32 @@ static int tisci_reboot_handler(struct notifier_block *nb, unsigned long mode,
 	return NOTIFY_BAD;
 }
 
+static bool ti_sci_check_lpm_region(void)
+{
+	struct device_node *parent, *node;
+
+	parent = of_find_node_by_path("/reserved-memory");
+	for_each_child_of_node(parent, node) {
+		if (of_node_name_eq(node, "lpm-memory"))
+			return true;
+	}
+
+	return false;
+}
+
+static int __maybe_unused ti_sci_suspend(struct device *dev)
+{
+	const struct ti_sci_desc *desc = device_get_match_data(dev);
+
+	if (pm_suspend_target_state == PM_SUSPEND_MEM &&
+	    desc->lpm_region && !ti_sci_check_lpm_region()) {
+		dev_err(dev, "lpm region is required for suspend to ram but is not provided\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static int __maybe_unused ti_sci_resume_noirq(struct device *dev)
 {
 	const struct ti_sci_desc *desc = device_get_match_data(dev);
@@ -3387,6 +3416,7 @@ static int __maybe_unused ti_sci_resume_noirq(struct device *dev)
 }
 
 static const struct dev_pm_ops ti_sci_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(ti_sci_suspend, NULL)
 	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(NULL, ti_sci_resume_noirq)
 };
 
@@ -3419,6 +3449,7 @@ static const struct ti_sci_desc ti_sci_pmmc_j7200_desc = {
 	.max_msgs = 20,
 	.max_msg_size = 64,
 	.restore_irqs = true,
+	.lpm_region = true,
 };
 
 static const struct of_device_id ti_sci_of_match[] = {
@@ -3546,6 +3577,11 @@ static int ti_sci_probe(struct platform_device *pdev)
 		}
 	}
 
+#ifdef CONFIG_PM_SLEEP
+	if (desc->lpm_region && !ti_sci_check_lpm_region())
+		dev_warn(dev, "lpm region is required for suspend to ram but is not provided\n");
+#endif
+
 	dev_info(dev, "ABI: %d.%d (firmware rev 0x%04x '%s')\n",
 		 info->handle.version.abi_major, info->handle.version.abi_minor,
 		 info->handle.version.firmware_revision,

-- 
2.39.2