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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, jolly.shah@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 v3 2/2] drivers: soc: xilinx: Use mailbox IPI callback
Date:   Mon,  2 Dec 2019 02:38:51 -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>
---
Changes in v3:
 - select MAILBOX and ZYNQMP_IPI_MBOX as it is required in zynqmp
   power driver.
---
 drivers/soc/xilinx/Kconfig        |   6 +-
 drivers/soc/xilinx/zynqmp_power.c | 119 +++++++++++++++++++++++++++++++++-----
 2 files changed, 111 insertions(+), 14 deletions(-)

diff --git a/drivers/soc/xilinx/Kconfig b/drivers/soc/xilinx/Kconfig
index 01e76b5..223f1f9 100644
--- a/drivers/soc/xilinx/Kconfig
+++ b/drivers/soc/xilinx/Kconfig
@@ -21,11 +21,15 @@ config ZYNQMP_POWER
 	bool "Enable Xilinx Zynq MPSoC Power Management driver"
 	depends on PM && ARCH_ZYNQMP
 	default y
+	select MAILBOX
+	select ZYNQMP_IPI_MBOX
 	help
 	  Say yes to enable power management support for ZyqnMP SoC.
 	  This driver uses firmware driver as an interface for power
 	  management request to firmware. It registers isr to handle
-	  power management callbacks from firmware.
+	  power management callbacks from firmware. It registers mailbox client
+	  to handle power management callbacks from firmware.
+
 	  If in doubt, say N.
 
 config ZYNQMP_PM_DOMAINS
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