1 files changed, 231 insertions, 0 deletions
diff --git a/drivers/mailbox/qcom-cpucp-mbox.c b/drivers/mailbox/qcom-cpucp-mbox.c
new file mode 100644
index 000000000..515d2d12c
--- /dev/null
+++ b/drivers/mailbox/qcom-cpucp-mbox.c
@@ -0,0 +1,231 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2024, Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/bitops.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/mailbox_controller.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#define APSS_CPUCP_MBOX_CMD_OFF			0x4
+
+/* Tx Registers */
+#define APSS_CPUCP_TX_MBOX_CMD(i)		(0x100 + ((i) * 8))
+
+/* Rx Registers */
+#define APSS_CPUCP_RX_MBOX_CMD(i)		(0x100 + ((i) * 8))
+#define APSS_CPUCP_RX_MBOX_MAP			0x4000
+#define APSS_CPUCP_RX_MBOX_STAT			0x4400
+#define APSS_CPUCP_RX_MBOX_CLEAR		0x4800
+#define APSS_CPUCP_RX_MBOX_EN			0x4c00
+#define APSS_CPUCP_RX_MBOX_CMD_MASK		GENMASK_ULL(63, 0)
+
+/**
+ * struct qcom_cpucp_mbox_data - Per-hardware mailbox configuration data
+ * @num_chans:			Number of IPC channels supported by this hardware
+ */
+struct qcom_cpucp_mbox_data {
+	int num_chans;
+};
+
+/**
+ * struct qcom_cpucp_mbox - Holder for the mailbox driver
+ * @chans:			The mailbox channel
+ * @mbox:			The mailbox controller
+ * @tx_base:			Base address of the CPUCP tx registers
+ * @rx_base:			Base address of the CPUCP rx registers
+ */
+struct qcom_cpucp_mbox {
+	struct mbox_chan *chans;
+	struct mbox_controller mbox;
+	void __iomem *tx_base;
+	void __iomem *rx_base;
+};
+
+static inline int channel_number(struct mbox_chan *chan)
+{
+	return chan - chan->mbox->chans;
+}
+
+static irqreturn_t qcom_cpucp_mbox_irq_fn(int irq, void *data)
+{
+	struct qcom_cpucp_mbox *cpucp = data;
+	u64 status;
+	int i;
+
+	status = readq(cpucp->rx_base + APSS_CPUCP_RX_MBOX_STAT);
+
+	for_each_set_bit(i, (unsigned long *)&status, cpucp->mbox.num_chans) {
+		u32 val = readl(cpucp->rx_base + APSS_CPUCP_RX_MBOX_CMD(i) + APSS_CPUCP_MBOX_CMD_OFF);
+		struct mbox_chan *chan = &cpucp->chans[i];
+		struct mbox_client *cl;
+		unsigned long flags;
+
+		/*
+		 * Provide mutual exclusion with changes to chan->cl.
+		 * Save cl locally and clear the HW interrupt inside the lock,
+		 * then invoke mbox_chan_received_data() outside the lock to
+		 * avoid a PREEMPT_RT self-deadlock: mbox_chan_received_data()
+		 * can call back into mbox_send_message() via scmi_rx_callback()
+		 * -> mailbox_clear_channel(), which re-acquires chan->lock
+		 * (converted to an rt_spinlock under PREEMPT_RT).
+		 */
+		spin_lock_irqsave(&chan->lock, flags);
+		cl = chan->cl;
+		writeq(BIT(i), cpucp->rx_base + APSS_CPUCP_RX_MBOX_CLEAR);
+		spin_unlock_irqrestore(&chan->lock, flags);
+
+		if (cl)
+			mbox_chan_received_data(chan, &val);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int qcom_cpucp_mbox_startup(struct mbox_chan *chan)
+{
+	struct qcom_cpucp_mbox *cpucp = container_of(chan->mbox, struct qcom_cpucp_mbox, mbox);
+	unsigned long chan_id = channel_number(chan);
+	u64 val;
+
+	val = readq(cpucp->rx_base + APSS_CPUCP_RX_MBOX_EN);
+	val |= BIT(chan_id);
+	writeq(val, cpucp->rx_base + APSS_CPUCP_RX_MBOX_EN);
+
+	return 0;
+}
+
+static void qcom_cpucp_mbox_shutdown(struct mbox_chan *chan)
+{
+	struct qcom_cpucp_mbox *cpucp = container_of(chan->mbox, struct qcom_cpucp_mbox, mbox);
+	unsigned long chan_id = channel_number(chan);
+	u64 val;
+
+	val = readq(cpucp->rx_base + APSS_CPUCP_RX_MBOX_EN);
+	val &= ~BIT(chan_id);
+	writeq(val, cpucp->rx_base + APSS_CPUCP_RX_MBOX_EN);
+}
+
+static int qcom_cpucp_mbox_send_data(struct mbox_chan *chan, void *data)
+{
+	struct qcom_cpucp_mbox *cpucp = container_of(chan->mbox, struct qcom_cpucp_mbox, mbox);
+	unsigned long chan_id = channel_number(chan);
+	u32 *val = data;
+
+	/*
+	 * mailbox_clear_channel() calls mbox_send_message() with NULL data to
+	 * signal the remote side that the channel has been cleared.  Nothing
+	 * needs to be written to the TX register in that case, so just return.
+	 */
+	if (!val)
+		return 0;
+
+	writel(*val, cpucp->tx_base + APSS_CPUCP_TX_MBOX_CMD(chan_id) + APSS_CPUCP_MBOX_CMD_OFF);
+
+	return 0;
+}
+
+static const struct mbox_chan_ops qcom_cpucp_mbox_chan_ops = {
+	.startup = qcom_cpucp_mbox_startup,
+	.send_data = qcom_cpucp_mbox_send_data,
+	.shutdown = qcom_cpucp_mbox_shutdown
+};
+
+static int qcom_cpucp_mbox_probe(struct platform_device *pdev)
+{
+	const struct qcom_cpucp_mbox_data *data;
+	struct device *dev = &pdev->dev;
+	struct qcom_cpucp_mbox *cpucp;
+	struct mbox_controller *mbox;
+	int irq, ret;
+
+	data = of_device_get_match_data(dev);
+	if (!data)
+		return dev_err_probe(dev, -EINVAL, "No match data found\n");
+
+	cpucp = devm_kzalloc(dev, sizeof(*cpucp), GFP_KERNEL);
+	if (!cpucp)
+		return -ENOMEM;
+
+	cpucp->chans = devm_kcalloc(dev, data->num_chans, sizeof(*cpucp->chans), GFP_KERNEL);
+	if (!cpucp->chans)
+		return -ENOMEM;
+
+	cpucp->rx_base = devm_of_iomap(dev, dev->of_node, 0, NULL);
+	if (IS_ERR(cpucp->rx_base))
+		return PTR_ERR(cpucp->rx_base);
+
+	cpucp->tx_base = devm_of_iomap(dev, dev->of_node, 1, NULL);
+	if (IS_ERR(cpucp->tx_base))
+		return PTR_ERR(cpucp->tx_base);
+
+	writeq(0, cpucp->rx_base + APSS_CPUCP_RX_MBOX_EN);
+	writeq(0, cpucp->rx_base + APSS_CPUCP_RX_MBOX_CLEAR);
+	writeq(0, cpucp->rx_base + APSS_CPUCP_RX_MBOX_MAP);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	ret = devm_request_irq(dev, irq, qcom_cpucp_mbox_irq_fn,
+			       IRQF_TRIGGER_HIGH | IRQF_NO_SUSPEND, "apss_cpucp_mbox", cpucp);
+	if (ret < 0)
+		return ret;
+
+	writeq(APSS_CPUCP_RX_MBOX_CMD_MASK, cpucp->rx_base + APSS_CPUCP_RX_MBOX_MAP);
+
+	mbox = &cpucp->mbox;
+	mbox->dev = dev;
+	mbox->num_chans = data->num_chans;
+	mbox->chans = cpucp->chans;
+	mbox->ops = &qcom_cpucp_mbox_chan_ops;
+
+	ret = devm_mbox_controller_register(dev, mbox);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to create mailbox\n");
+
+	return 0;
+}
+
+static const struct qcom_cpucp_mbox_data qcom_x1e80100_mbox_data = {
+	.num_chans = 3,
+};
+
+static const struct qcom_cpucp_mbox_data qcom_nord_mbox_data = {
+	.num_chans = 16,
+};
+
+static const struct of_device_id qcom_cpucp_mbox_of_match[] = {
+	{ .compatible = "qcom,nord-cpucp-mbox", .data = &qcom_nord_mbox_data },
+	{ .compatible = "qcom,x1e80100-cpucp-mbox", .data = &qcom_x1e80100_mbox_data },
+	{}
+};
+MODULE_DEVICE_TABLE(of, qcom_cpucp_mbox_of_match);
+
+static struct platform_driver qcom_cpucp_mbox_driver = {
+	.probe = qcom_cpucp_mbox_probe,
+	.driver = {
+		.name = "qcom_cpucp_mbox",
+		.of_match_table = qcom_cpucp_mbox_of_match,
+	},
+};
+
+static int __init qcom_cpucp_mbox_init(void)
+{
+	return platform_driver_register(&qcom_cpucp_mbox_driver);
+}
+core_initcall(qcom_cpucp_mbox_init);
+
+static void __exit qcom_cpucp_mbox_exit(void)
+{
+	platform_driver_unregister(&qcom_cpucp_mbox_driver);
+}
+module_exit(qcom_cpucp_mbox_exit);
+
+MODULE_DESCRIPTION("QTI CPUCP MBOX Driver");
+MODULE_LICENSE("GPL");