mailbox: Add support for Phytium SoC mailbox driver

Documentation/devicetree/bindings/mailbox/phytium,mbox.yaml

@@ -0,0 +1,48 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mailbox/phytium,mbox.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Phytium Mailbox Driver
+
+maintainers:
+  - Chen Baozi <[email protected]>
+
+description: |
+  The Phytium mailbox controller that has a channel/link to communicate
+  with the remote end. A link raises interrupt for any received data. However,
+  there is no specified way of knowing if the sent data has been read by the
+  remote. This driver assumes the sender polls STAT register and the remote
+  clears it after having read the data.
+
+properties:
+  compatible:
+    const: phytium,mbox
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  '#mbox-cells':
+    const: 1
+    description: the index of the channel needed
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - '#mbox-cells'
+
+additionalProperties: false
+
+examples:
+  - |
+    mbox: mailbox@2a000000 {
+      compatible = "phytium,mbox";
+      reg = <0x0 0x2a000000 0x0 0x1000>;
+      #mbox-cells = <1>;
+      interrupts = <0 48 4>;
+    };

drivers/firmware/arm_scmi/mailbox.c

@@ -167,6 +167,7 @@ static int mailbox_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
 	struct mbox_client *cl;
 	resource_size_t size;
 	struct resource res;
+	struct of_phandle_args args;
 
 	ret = mailbox_chan_validate(cdev, &a2p_rx_chan, &p2a_chan);
 	if (ret)
@@ -226,6 +227,16 @@ static int mailbox_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
 		}
 	}
 
+	ret = of_parse_phandle_with_args(cdev->of_node, "mboxes",
+					 "#mbox-cells", 1, &args);
+	if (ret) {
+		dev_err(cdev, "failed to get SCMI %s mailbox\n", desc);
+		return ret;
+	}
+
+	if (of_device_is_compatible(args.np, "phytium,mbox"))
+		cinfo->no_completion_irq = true;
+
 	cinfo->transport_info = smbox;
 	smbox->cinfo = cinfo;
 

drivers/mailbox/Kconfig

@@ -41,6 +41,15 @@ config IMX_MBOX
 	help
 	  Mailbox implementation for i.MX Messaging Unit (MU).
 
+config PHYTIUM_MBOX
+	tristate "Phytium SoC Mailbox Support"
+	depends on ARCH_PHYTIUM || COMPILE_TEST
+	help
+	  Mailbox driver implementation for the Phytium platform. It is used
+	  to send message between application processors and on-chip management
+	  firmware. Say Y here if you want to build this mailbox controller
+	  driver.
+
 config PLATFORM_MHU
 	tristate "Platform MHU Mailbox"
 	depends on OF

drivers/mailbox/Makefile

@@ -62,3 +62,5 @@ obj-$(CONFIG_SPRD_MBOX)		+= sprd-mailbox.o
 obj-$(CONFIG_QCOM_IPCC)		+= qcom-ipcc.o
 
 obj-$(CONFIG_APPLE_MAILBOX)	+= apple-mailbox.o
+
+obj-$(CONFIG_PHYTIUM_MBOX)	+= phytium_mailbox.o

drivers/mailbox/phytium_mailbox.c

@@ -0,0 +1,196 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Phytium SoC mailbox driver
+ *
+ * Copyright (c) 2020-2023, Phytium Technology Co., Ltd.
+ *
+ * Derived from drivers/mailbox/arm_mhu.c
+ *   Copyright (C) 2013-2015 Fujitsu Semiconductor Ltd.
+ *   Copyright (C) 2015 Linaro Ltd.
+ */
+
+#include <linux/acpi.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/mailbox_controller.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+
+#define INTR_STAT	0x0
+#define INTR_SET	0x8
+#define INTR_CLR	0x10
+
+#define TX_REG		0x100
+
+#define NR_CHANS	1
+
+struct phytium_mbox_link {
+	unsigned int irq;
+	void __iomem *tx_reg;
+	void __iomem *rx_reg;
+};
+
+struct phytium_mbox {
+	void __iomem *base;
+	struct phytium_mbox_link mlink;
+	struct mbox_chan chan;
+	struct mbox_controller mbox;
+};
+
+static irqreturn_t phytium_mbox_rx_irq(int irq, void *ch)
+{
+	struct mbox_chan *chan = ch;
+	struct phytium_mbox_link *mlink = chan->con_priv;
+	u32 val;
+
+	val = readl_relaxed(mlink->rx_reg + INTR_STAT);
+	if (!val)
+		return IRQ_NONE;
+
+	mbox_chan_received_data(chan, (void *)&val);
+
+	writel_relaxed(val, mlink->rx_reg + INTR_CLR);
+
+	return IRQ_HANDLED;
+}
+
+static int phytium_mbox_send_data(struct mbox_chan *chan, void *data)
+{
+	struct phytium_mbox_link *mlink = chan->con_priv;
+	u32 *arg = data;
+
+	writel_relaxed(*arg, mlink->tx_reg + INTR_SET);
+
+	return 0;
+}
+
+static int phytium_mbox_startup(struct mbox_chan *chan)
+{
+	struct phytium_mbox_link *mlink = chan->con_priv;
+	u32 val;
+	int ret;
+
+	val = readl_relaxed(mlink->tx_reg + INTR_STAT);
+	writel_relaxed(val, mlink->tx_reg + INTR_CLR);
+
+	ret = request_irq(mlink->irq, phytium_mbox_rx_irq,
+			  IRQF_SHARED, "phytium_mbox_link", chan);
+	if (ret) {
+		dev_err(chan->mbox->dev,
+			"Unable to acquire IRQ %d\n", mlink->irq);
+	}
+
+	return ret;
+}
+
+static void phytium_mbox_shutdown(struct mbox_chan *chan)
+{
+	struct phytium_mbox_link *mlink = chan->con_priv;
+
+	free_irq(mlink->irq, chan);
+}
+
+static bool phytium_mbox_last_tx_done(struct mbox_chan *chan)
+{
+	struct phytium_mbox_link *mlink = chan->con_priv;
+	u32 val = readl_relaxed(mlink->tx_reg + INTR_STAT);
+
+	return (val == (u32)(1U << 31));
+}
+
+static const struct mbox_chan_ops phytium_mbox_ops = {
+	.send_data = phytium_mbox_send_data,
+	.startup = phytium_mbox_startup,
+	.shutdown = phytium_mbox_shutdown,
+	.last_tx_done = phytium_mbox_last_tx_done,
+};
+
+static const struct acpi_device_id phytium_mbox_acpi_match[] = {
+	{ "PHYT0009", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, phytium_mbox_acpi_match);
+
+static const struct of_device_id phytium_mbox_of_match[] = {
+	{ .compatible = "phytium,mbox", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, phytium_mbox_of_match);
+
+static int phytium_mbox_probe(struct platform_device *pdev)
+{
+	struct phytium_mbox *mbox;
+	struct resource *res;
+	int err, irq;
+
+	/* Allocate memory for device */
+	mbox = devm_kzalloc(&pdev->dev, sizeof(*mbox), GFP_KERNEL);
+	if (!mbox)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	mbox->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(mbox->base)) {
+		dev_err(&pdev->dev, "ioremap base failed\n");
+		return PTR_ERR(mbox->base);
+	}
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(&pdev->dev, "cannot obtain irq\n");
+		return irq;
+	}
+
+	mbox->chan.con_priv = &mbox->mlink;
+	mbox->mlink.irq = irq;
+	mbox->mlink.rx_reg = mbox->base;
+	mbox->mlink.tx_reg = mbox->mlink.rx_reg + TX_REG;
+
+	mbox->mbox.dev = &pdev->dev;
+	mbox->mbox.chans = &mbox->chan;
+	mbox->mbox.num_chans = NR_CHANS;
+	mbox->mbox.ops = &phytium_mbox_ops;
+	mbox->mbox.txdone_irq = false;
+	mbox->mbox.txdone_poll = true;
+	mbox->mbox.txpoll_period = 1;
+
+	platform_set_drvdata(pdev, mbox);
+
+	err = mbox_controller_register(&mbox->mbox);
+	if (err) {
+		dev_err(&pdev->dev, "Failed to register mailboxes %d\n", err);
+		goto fail;
+	}
+
+	dev_info(&pdev->dev, "Phytium SoC Mailbox registered\n");
+fail:
+	return err;
+}
+
+static int phytium_mbox_remove(struct platform_device *pdev)
+{
+	struct phytium_mbox *mbox = platform_get_drvdata(pdev);
+
+	mbox_controller_unregister(&mbox->mbox);
+
+	return 0;
+}
+
+static struct platform_driver phytium_mbox_driver = {
+	.probe = phytium_mbox_probe,
+	.remove = phytium_mbox_remove,
+	.driver = {
+		.name = "phytium-mbox",
+		.of_match_table = of_match_ptr(phytium_mbox_of_match),
+		.acpi_match_table = ACPI_PTR(phytium_mbox_acpi_match),
+	},
+};
+
+module_platform_driver(phytium_mbox_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Phytium SoC Mailbox Driver");
+MODULE_AUTHOR("Chen Baozi <[email protected]>");