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From:   Rajan Vaja <rajan.vaja@xilinx.com>
To:     sre@kernel.org, robh+dt@kernel.org, mark.rutland@arm.com,
        michal.simek@xilinx.com, jollys@xilinx.com, tejas.patel@xilinx.com
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        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Rajan Vaja <rajan.vaja@xilinx.com>
Subject: [PATCH 2/2] drivers: soc: xilinx: Use mailbox IPI callback
Date:   Tue, 12 Nov 2019 05:20:51 -0800
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From: Tejas Patel <tejas.patel@xilinx.com>

Add support for init suspend callback through mailbox IPI callback.

Signed-off-by: Tejas Patel <tejas.patel@xilinx.com>
Signed-off-by: Rajan Vaja <rajan.vaja@xilinx.com>
---
 drivers/soc/xilinx/zynqmp_power.c | 119 +++++++++++++++++++++++++++++++++-----
 1 file changed, 106 insertions(+), 13 deletions(-)

diff --git a/drivers/soc/xilinx/zynqmp_power.c b/drivers/soc/xilinx/zynqmp_power.c
index 1b9d144..d572d2e 100644
--- a/drivers/soc/xilinx/zynqmp_power.c
+++ b/drivers/soc/xilinx/zynqmp_power.c
@@ -2,7 +2,7 @@
 /*
  * Xilinx Zynq MPSoC Power Management
  *
- *  Copyright (C) 2014-2018 Xilinx, Inc.
+ *  Copyright (C) 2014-2019 Xilinx, Inc.
  *
  *  Davorin Mista <davorin.mista@aggios.com>
  *  Jolly Shah <jollys@xilinx.com>
@@ -16,6 +16,20 @@
 #include <linux/suspend.h>
 
 #include <linux/firmware/xlnx-zynqmp.h>
+#include <linux/mailbox/zynqmp-ipi-message.h>
+
+/**
+ * struct zynqmp_pm_work_struct - Wrapper for struct work_struct
+ * @callback_work:	Work structure
+ * @args:		Callback arguments
+ */
+struct zynqmp_pm_work_struct {
+	struct work_struct callback_work;
+	u32 args[CB_ARG_CNT];
+};
+static struct zynqmp_pm_work_struct *zynqmp_pm_init_suspend_work;
+static struct mbox_chan *rx_chan;
+static const struct zynqmp_eemi_ops *eemi_ops;
 
 enum pm_suspend_mode {
 	PM_SUSPEND_MODE_FIRST = 0,
@@ -31,7 +45,6 @@ static const char *const suspend_modes[] = {
 };
 
 static enum pm_suspend_mode suspend_mode = PM_SUSPEND_MODE_STD;
-static const struct zynqmp_eemi_ops *eemi_ops;
 
 enum pm_api_cb_id {
 	PM_INIT_SUSPEND_CB = 30,
@@ -68,6 +81,53 @@ static irqreturn_t zynqmp_pm_isr(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
+static void ipi_receive_callback(struct mbox_client *cl, void *data)
+{
+	struct zynqmp_ipi_message *msg = (struct zynqmp_ipi_message *)data;
+	u32 payload[CB_PAYLOAD_SIZE];
+	int ret;
+
+	memcpy(payload, msg->data, sizeof(msg->len));
+	/* First element is callback API ID, others are callback arguments */
+	if (payload[0] == PM_INIT_SUSPEND_CB) {
+		if (work_pending(&zynqmp_pm_init_suspend_work->callback_work))
+			return;
+
+		/* Copy callback arguments into work's structure */
+		memcpy(zynqmp_pm_init_suspend_work->args, &payload[1],
+		       sizeof(zynqmp_pm_init_suspend_work->args));
+
+		queue_work(system_unbound_wq,
+			   &zynqmp_pm_init_suspend_work->callback_work);
+
+		/* Send NULL message to mbox controller to ack the message */
+		ret = mbox_send_message(rx_chan, NULL);
+		if (ret)
+			pr_err("IPI ack failed. Error %d\n", ret);
+	}
+}
+
+/**
+ * zynqmp_pm_init_suspend_work_fn - Initialize suspend
+ * @work:	Pointer to work_struct
+ *
+ * Bottom-half of PM callback IRQ handler.
+ */
+static void zynqmp_pm_init_suspend_work_fn(struct work_struct *work)
+{
+	struct zynqmp_pm_work_struct *pm_work =
+		container_of(work, struct zynqmp_pm_work_struct, callback_work);
+
+	if (pm_work->args[0] == SUSPEND_SYSTEM_SHUTDOWN) {
+		orderly_poweroff(true);
+	} else if (pm_work->args[0] == SUSPEND_POWER_REQUEST) {
+		pm_suspend(PM_SUSPEND_MEM);
+	} else {
+		pr_err("%s Unsupported InitSuspendCb reason code %d.\n",
+		       __func__, pm_work->args[0]);
+	}
+}
+
 static ssize_t suspend_mode_show(struct device *dev,
 				 struct device_attribute *attr, char *buf)
 {
@@ -119,6 +179,7 @@ static int zynqmp_pm_probe(struct platform_device *pdev)
 {
 	int ret, irq;
 	u32 pm_api_version;
+	struct mbox_client *client;
 
 	eemi_ops = zynqmp_pm_get_eemi_ops();
 	if (IS_ERR(eemi_ops))
@@ -134,17 +195,46 @@ static int zynqmp_pm_probe(struct platform_device *pdev)
 	if (pm_api_version < ZYNQMP_PM_VERSION)
 		return -ENODEV;
 
-	irq = platform_get_irq(pdev, 0);
-	if (irq <= 0)
-		return -ENXIO;
-
-	ret = devm_request_threaded_irq(&pdev->dev, irq, NULL, zynqmp_pm_isr,
-					IRQF_NO_SUSPEND | IRQF_ONESHOT,
-					dev_name(&pdev->dev), &pdev->dev);
-	if (ret) {
-		dev_err(&pdev->dev, "devm_request_threaded_irq '%d' failed "
-			"with %d\n", irq, ret);
-		return ret;
+	if (of_find_property(pdev->dev.of_node, "mboxes", NULL)) {
+		zynqmp_pm_init_suspend_work =
+			devm_kzalloc(&pdev->dev,
+				     sizeof(struct zynqmp_pm_work_struct),
+				     GFP_KERNEL);
+		if (!zynqmp_pm_init_suspend_work)
+			return -ENOMEM;
+
+		INIT_WORK(&zynqmp_pm_init_suspend_work->callback_work,
+			  zynqmp_pm_init_suspend_work_fn);
+		client = devm_kzalloc(&pdev->dev, sizeof(*client), GFP_KERNEL);
+		if (!client)
+			return -ENOMEM;
+
+		client->dev = &pdev->dev;
+		client->rx_callback = ipi_receive_callback;
+
+		rx_chan = mbox_request_channel_byname(client, "rx");
+		if (IS_ERR(rx_chan)) {
+			dev_err(&pdev->dev, "Failed to request rx channel\n");
+			return IS_ERR(rx_chan);
+		}
+	} else if (of_find_property(pdev->dev.of_node, "interrupts", NULL)) {
+		irq = platform_get_irq(pdev, 0);
+		if (irq <= 0)
+			return -ENXIO;
+
+		ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
+						zynqmp_pm_isr,
+						IRQF_NO_SUSPEND | IRQF_ONESHOT,
+						dev_name(&pdev->dev),
+						&pdev->dev);
+		if (ret) {
+			dev_err(&pdev->dev, "devm_request_threaded_irq '%d' "
+					    "failed with %d\n", irq, ret);
+			return ret;
+		}
+	} else {
+		dev_err(&pdev->dev, "Required property not found in DT node\n");
+		return -ENOENT;
 	}
 
 	ret = sysfs_create_file(&pdev->dev.kobj, &dev_attr_suspend_mode.attr);
@@ -160,6 +250,9 @@ static int zynqmp_pm_remove(struct platform_device *pdev)
 {
 	sysfs_remove_file(&pdev->dev.kobj, &dev_attr_suspend_mode.attr);
 
+	if (!rx_chan)
+		mbox_free_channel(rx_chan);
+
 	return 0;
 }
 
-- 
2.7.4