--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2017-2018 Hisilicon Limited.
+// Copyright (c) 2017-2018 Linaro Limited.
+
+#include <linux/bitops.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/mailbox_controller.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include "mailbox.h"
+
+#define MBOX_CHAN_MAX 32
+
+#define MBOX_RX 0x0
+#define MBOX_TX 0x1
+
+#define MBOX_BASE(mbox, ch) ((mbox)->base + ((ch) * 0x40))
+#define MBOX_SRC_REG 0x00
+#define MBOX_DST_REG 0x04
+#define MBOX_DCLR_REG 0x08
+#define MBOX_DSTAT_REG 0x0c
+#define MBOX_MODE_REG 0x10
+#define MBOX_IMASK_REG 0x14
+#define MBOX_ICLR_REG 0x18
+#define MBOX_SEND_REG 0x1c
+#define MBOX_DATA_REG 0x20
+
+#define MBOX_IPC_LOCK_REG 0xa00
+#define MBOX_IPC_UNLOCK 0x1acce551
+
+#define MBOX_AUTOMATIC_ACK 1
+
+#define MBOX_STATE_IDLE BIT(4)
+#define MBOX_STATE_ACK BIT(7)
+
+#define MBOX_MSG_LEN 8
+
+/**
+ * Hi3660 mailbox channel information
+ *
+ * A channel can be used for TX or RX, it can trigger remote
+ * processor interrupt to notify remote processor and can receive
+ * interrupt if has incoming message.
+ *
+ * @dst_irq: Interrupt vector for remote processor
+ * @ack_irq: Interrupt vector for local processor
+ */
+struct hi3660_chan_info {
+ unsigned int dst_irq;
+ unsigned int ack_irq;
+};
+
+/**
+ * Hi3660 mailbox controller data
+ *
+ * Mailbox controller includes 32 channels and can allocate
+ * channel for message transferring.
+ *
+ * @dev: Device to which it is attached
+ * @base: Base address of the register mapping region
+ * @chan: Representation of channels in mailbox controller
+ * @mchan: Representation of channel info
+ * @controller: Representation of a communication channel controller
+ */
+struct hi3660_mbox {
+ struct device *dev;
+ void __iomem *base;
+ struct mbox_chan chan[MBOX_CHAN_MAX];
+ struct hi3660_chan_info mchan[MBOX_CHAN_MAX];
+ struct mbox_controller controller;
+};
+
+static struct hi3660_mbox *to_hi3660_mbox(struct mbox_controller *mbox)
+{
+ return container_of(mbox, struct hi3660_mbox, controller);
+}
+
+static int hi3660_mbox_check_state(struct mbox_chan *chan)
+{
+ unsigned long ch = (unsigned long)chan->con_priv;
+ struct hi3660_mbox *mbox = to_hi3660_mbox(chan->mbox);
+ struct hi3660_chan_info *mchan = &mbox->mchan[ch];
+ void __iomem *base = MBOX_BASE(mbox, ch);
+ unsigned long val;
+ unsigned int ret;
+
+ /* Mailbox is idle so directly bail out */
+ if (readl(base + MBOX_MODE_REG) & MBOX_STATE_IDLE)
+ return 0;
+
+ /* Wait for acknowledge from remote */
+ ret = readx_poll_timeout_atomic(readl, base + MBOX_MODE_REG,
+ val, (val & MBOX_STATE_ACK), 1000, 300000);
+ if (ret) {
+ dev_err(mbox->dev, "%s: timeout for receiving ack\n", __func__);
+ return ret;
+ }
+
+ /* Ensure channel is released */
+ writel(0xffffffff, base + MBOX_IMASK_REG);
+ writel(BIT(mchan->ack_irq), base + MBOX_SRC_REG);
+ return 0;
+}
+
+static int hi3660_mbox_unlock(struct mbox_chan *chan)
+{
+ struct hi3660_mbox *mbox = to_hi3660_mbox(chan->mbox);
+ unsigned int val, retry = 3;
+
+ do {
+ writel(MBOX_IPC_UNLOCK, mbox->base + MBOX_IPC_LOCK_REG);
+
+ val = readl(mbox->base + MBOX_IPC_LOCK_REG);
+ if (!val)
+ break;
+
+ udelay(10);
+ } while (retry--);
+
+ if (val)
+ dev_err(mbox->dev, "%s: failed to unlock mailbox\n", __func__);
+
+ return (!val) ? 0 : -ETIMEDOUT;
+}
+
+static int hi3660_mbox_acquire_channel(struct mbox_chan *chan)
+{
+ unsigned long ch = (unsigned long)chan->con_priv;
+ struct hi3660_mbox *mbox = to_hi3660_mbox(chan->mbox);
+ struct hi3660_chan_info *mchan = &mbox->mchan[ch];
+ void __iomem *base = MBOX_BASE(mbox, ch);
+ unsigned int val, retry;
+
+ for (retry = 10; retry; retry--) {
+ /* Check if channel is in idle state */
+ if (readl(base + MBOX_MODE_REG) & MBOX_STATE_IDLE) {
+ writel(BIT(mchan->ack_irq), base + MBOX_SRC_REG);
+
+ /* Check ack bit has been set successfully */
+ val = readl(base + MBOX_SRC_REG);
+ if (val & BIT(mchan->ack_irq))
+ break;
+ }
+ }
+
+ if (!retry)
+ dev_err(mbox->dev, "%s: failed to acquire channel\n", __func__);
+
+ return retry ? 0 : -ETIMEDOUT;
+}
+
+static int hi3660_mbox_startup(struct mbox_chan *chan)
+{
+ int ret;
+
+ ret = hi3660_mbox_check_state(chan);
+ if (ret)
+ return ret;
+
+ ret = hi3660_mbox_unlock(chan);
+ if (ret)
+ return ret;
+
+ ret = hi3660_mbox_acquire_channel(chan);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static int hi3660_mbox_send_data(struct mbox_chan *chan, void *msg)
+{
+ unsigned long ch = (unsigned long)chan->con_priv;
+ struct hi3660_mbox *mbox = to_hi3660_mbox(chan->mbox);
+ struct hi3660_chan_info *mchan = &mbox->mchan[ch];
+ void __iomem *base = MBOX_BASE(mbox, ch);
+ u32 *buf = msg;
+ unsigned int i;
+
+ /* Ensure channel is released */
+ writel_relaxed(0xffffffff, base + MBOX_IMASK_REG);
+ writel_relaxed(BIT(mchan->ack_irq), base + MBOX_SRC_REG);
+
+ /* Clear mask for destination interrupt */
+ writel_relaxed(~BIT(mchan->dst_irq), base + MBOX_IMASK_REG);
+
+ /* Config destination for interrupt vector */
+ writel_relaxed(BIT(mchan->dst_irq), base + MBOX_DST_REG);
+
+ /* Automatic acknowledge mode */
+ writel_relaxed(MBOX_AUTOMATIC_ACK, base + MBOX_MODE_REG);
+
+ /* Fill message data */
+ for (i = 0; i < MBOX_MSG_LEN; i++)
+ writel_relaxed(buf[i], base + MBOX_DATA_REG + i * 4);
+
+ /* Trigger data transferring */
+ writel(BIT(mchan->ack_irq), base + MBOX_SEND_REG);
+ return 0;
+}
+
+static struct mbox_chan_ops hi3660_mbox_ops = {
+ .startup = hi3660_mbox_startup,
+ .send_data = hi3660_mbox_send_data,
+};
+
+static struct mbox_chan *hi3660_mbox_xlate(struct mbox_controller *controller,
+ const struct of_phandle_args *spec)
+{
+ struct hi3660_mbox *mbox = to_hi3660_mbox(controller);
+ struct hi3660_chan_info *mchan;
+ unsigned int ch = spec->args[0];
+
+ if (ch >= MBOX_CHAN_MAX) {
+ dev_err(mbox->dev, "Invalid channel idx %d\n", ch);
+ return ERR_PTR(-EINVAL);
+ }
+
+ mchan = &mbox->mchan[ch];
+ mchan->dst_irq = spec->args[1];
+ mchan->ack_irq = spec->args[2];
+
+ return &mbox->chan[ch];
+}
+
+static const struct of_device_id hi3660_mbox_of_match[] = {
+ { .compatible = "hisilicon,hi3660-mbox", },
+ {},
+};
+
+MODULE_DEVICE_TABLE(of, hi3660_mbox_of_match);
+
+static int hi3660_mbox_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct hi3660_mbox *mbox;
+ struct mbox_chan *chan;
+ struct resource *res;
+ unsigned long ch;
+ int err;
+
+ mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL);
+ if (!mbox)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ mbox->base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(mbox->base))
+ return PTR_ERR(mbox->base);
+
+ mbox->dev = dev;
+ mbox->controller.dev = dev;
+ mbox->controller.chans = mbox->chan;
+ mbox->controller.num_chans = MBOX_CHAN_MAX;
+ mbox->controller.ops = &hi3660_mbox_ops;
+ mbox->controller.of_xlate = hi3660_mbox_xlate;
+
+ /* Initialize mailbox channel data */
+ chan = mbox->chan;
+ for (ch = 0; ch < MBOX_CHAN_MAX; ch++)
+ chan[ch].con_priv = (void *)ch;
+
+ err = mbox_controller_register(&mbox->controller);
+ if (err) {
+ dev_err(dev, "Failed to register mailbox %d\n", err);
+ return err;
+ }
+
+ platform_set_drvdata(pdev, mbox);
+ dev_info(dev, "Mailbox enabled\n");
+ return 0;
+}
+
+static int hi3660_mbox_remove(struct platform_device *pdev)
+{
+ struct hi3660_mbox *mbox = platform_get_drvdata(pdev);
+
+ mbox_controller_unregister(&mbox->controller);
+ return 0;
+}
+
+static struct platform_driver hi3660_mbox_driver = {
+ .probe = hi3660_mbox_probe,
+ .remove = hi3660_mbox_remove,
+ .driver = {
+ .name = "hi3660-mbox",
+ .of_match_table = hi3660_mbox_of_match,
+ },
+};
+
+static int __init hi3660_mbox_init(void)
+{
+ return platform_driver_register(&hi3660_mbox_driver);
+}
+core_initcall(hi3660_mbox_init);
+
+static void __exit hi3660_mbox_exit(void)
+{
+ platform_driver_unregister(&hi3660_mbox_driver);
+}
+module_exit(hi3660_mbox_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Hisilicon Hi3660 Mailbox Controller");
+MODULE_AUTHOR("Leo Yan <leo.yan@linaro.org>");