[PATCH v1 2/3] mailbox: Hi6220: add mailbox driver

[Leo Yan]

Add driver for Hi6220 mailbox, the mailbox communicates with MCU; for
sending data, it can support two methods for low level implementation:
one is to use interrupt as acknowledge, another is automatic mode which
without any acknowledge. These two methods have been supported in the
driver. For receiving data, it will depend on the interrupt to notify
the channel has incoming message; enhance rx channel's message queue,
which is based on the code in drivers/mailbox/omap-mailbox.c.

Now mailbox driver is used to send message to MCU to control dynamic
voltage and frequency scaling for CPU, GPU and DDR.

Signed-off-by: Leo Yan <leo.yan@xxxxxxxxxx>
---
 drivers/mailbox/Kconfig          |   8 +
 drivers/mailbox/Makefile         |   2 +
 drivers/mailbox/hi6220-mailbox.c | 513 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 523 insertions(+)
 create mode 100644 drivers/mailbox/hi6220-mailbox.c

diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index e269f08..21b71dd 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -70,4 +70,12 @@ config BCM2835_MBOX
 	  the services of the Videocore. Say Y here if you want to use the
 	  BCM2835 Mailbox.
 
+config HI6220_MBOX
+	tristate "Hi6220 Mailbox"
+	depends on ARCH_HISI
+	help
+	  An implementation of the hi6220 mailbox. It is used to send message
+	  between application processors and MCU. Say Y here if you want to build
+	  the Hi6220 mailbox controller driver.
+
 endif
diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
index 8e6d822..4ba9f5f 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -13,3 +13,5 @@ obj-$(CONFIG_PCC)		+= pcc.o
 obj-$(CONFIG_ALTERA_MBOX)	+= mailbox-altera.o
 
 obj-$(CONFIG_BCM2835_MBOX)	+= bcm2835-mailbox.o
+
+obj-$(CONFIG_HI6220_MBOX)	+= hi6220-mailbox.o
diff --git a/drivers/mailbox/hi6220-mailbox.c b/drivers/mailbox/hi6220-mailbox.c
new file mode 100644
index 0000000..1b2dc5b
--- /dev/null
+++ b/drivers/mailbox/hi6220-mailbox.c
@@ -0,0 +1,513 @@
+/*
+ * Hisilicon's Hi6220 mailbox driver
+ *
+ * RX channel's message queue is based on the code written in
+ * drivers/mailbox/omap-mailbox.c.
+ *
+ * Copyright (c) 2015 Hisilicon Limited.
+ * Copyright (c) 2015 Linaro Limited.
+ *
+ * Author: Leo Yan <leo.yan@xxxxxxxxxx>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kfifo.h>
+#include <linux/mailbox_controller.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+
+#define HI6220_MBOX_CHAN_MAX		32
+#define HI6220_MBOX_CHAN_NUM		2
+#define HI6220_MBOX_CHAN_SLOT_SIZE	64
+
+#define HI6220_MBOX_RX			0x0
+#define HI6220_MBOX_TX			0x1
+
+/* Mailbox message length: 32 bytes */
+#define HI6220_MBOX_MSG_LEN		32
+
+/* Mailbox kfifo size */
+#define HI6220_MBOX_MSG_FIFO_SIZE	512
+
+/* Status & Mode Register */
+#define HI6220_MBOX_MODE_REG		0x0
+
+#define HI6220_MBOX_STATUS_MASK		(0xF << 4)
+#define HI6220_MBOX_STATUS_IDLE		(0x1 << 4)
+#define HI6220_MBOX_STATUS_TX		(0x2 << 4)
+#define HI6220_MBOX_STATUS_RX		(0x4 << 4)
+#define HI6220_MBOX_STATUS_ACK		(0x8 << 4)
+#define HI6220_MBOX_ACK_CONFIG_MASK	(0x1 << 0)
+#define HI6220_MBOX_ACK_AUTOMATIC	(0x1 << 0)
+#define HI6220_MBOX_ACK_IRQ		(0x0 << 0)
+
+/* Data Registers */
+#define HI6220_MBOX_DATA_REG(i)		(0x4 + (i << 2))
+
+/* ACPU Interrupt Register */
+#define HI6220_MBOX_ACPU_INT_RAW_REG	0x400
+#define HI6220_MBOX_ACPU_INT_MSK_REG	0x404
+#define HI6220_MBOX_ACPU_INT_STAT_REG	0x408
+#define HI6220_MBOX_ACPU_INT_CLR_REG	0x40c
+#define HI6220_MBOX_ACPU_INT_ENA_REG	0x500
+#define HI6220_MBOX_ACPU_INT_DIS_REG	0x504
+
+/* MCU Interrupt Register */
+#define HI6220_MBOX_MCU_INT_RAW_REG	0x420
+
+/* Core Id */
+#define HI6220_CORE_ACPU		0x0
+#define HI6220_CORE_MCU			0x2
+
+struct hi6220_mbox_queue {
+	struct kfifo fifo;
+	struct work_struct work;
+	struct mbox_chan *chan;
+	bool full;
+};
+
+struct hi6220_mbox_chan {
+
+	/*
+	 * Description for channel's hardware info:
+	 *  - direction;
+	 *  - peer core id for communication;
+	 *  - local irq vector or number;
+	 *  - remoted irq vector or number for peer core;
+	 */
+	unsigned int dir;
+	unsigned int peer_core;
+	unsigned int remote_irq;
+	unsigned int local_irq;
+
+	/*
+	 * Slot address is cached value derived from index
+	 * within buffer for every channel
+	 */
+	void __iomem *slot;
+
+	/* For rx's fifo operations */
+	struct hi6220_mbox_queue *mq;
+
+	struct hi6220_mbox *parent;
+};
+
+struct hi6220_mbox {
+	struct device *dev;
+
+	spinlock_t lock;
+
+	unsigned int irq;
+
+	/* flag of enabling tx's irq mode */
+	bool tx_irq_mode;
+
+	/* region for ipc event */
+	void __iomem *ipc;
+
+	/* region for share mem */
+	void __iomem *buf;
+
+	unsigned int chan_num;
+	struct hi6220_mbox_chan *mchan;
+
+	void *irq_map_chan[HI6220_MBOX_CHAN_MAX];
+	struct mbox_chan *chan;
+	struct mbox_controller controller;
+};
+
+static void hi6220_mbox_set_status(struct hi6220_mbox_chan *mchan, u32 val)
+{
+	u32 status;
+
+	status = readl(mchan->slot + HI6220_MBOX_MODE_REG);
+	status &= ~HI6220_MBOX_STATUS_MASK;
+	status |= val;
+	writel(status, mchan->slot + HI6220_MBOX_MODE_REG);
+}
+
+static void hi6220_mbox_set_mode(struct hi6220_mbox_chan *mchan, u32 val)
+{
+	u32 mode;
+
+	mode = readl(mchan->slot + HI6220_MBOX_MODE_REG);
+	mode &= ~HI6220_MBOX_ACK_CONFIG_MASK;
+	mode |= val;
+	writel(mode, mchan->slot + HI6220_MBOX_MODE_REG);
+}
+
+static bool hi6220_mbox_last_tx_done(struct mbox_chan *chan)
+{
+	struct hi6220_mbox_chan *mchan = chan->con_priv;
+	struct hi6220_mbox *mbox = mchan->parent;
+	u32 status;
+
+	/* Only set idle state for polling mode */
+	BUG_ON(mbox->tx_irq_mode);
+
+	status = readl(mchan->slot + HI6220_MBOX_MODE_REG);
+	status = status & HI6220_MBOX_STATUS_MASK;
+	return (status == HI6220_MBOX_STATUS_IDLE);
+}
+
+static int hi6220_mbox_send_data(struct mbox_chan *chan, void *msg)
+{
+	struct hi6220_mbox_chan *mchan = chan->con_priv;
+	struct hi6220_mbox *mbox = mchan->parent;
+	int irq = mchan->remote_irq;
+	u32 *buf = msg;
+	unsigned long flags;
+	int i;
+
+	hi6220_mbox_set_status(mchan, HI6220_MBOX_STATUS_TX);
+
+	if (mbox->tx_irq_mode)
+		hi6220_mbox_set_mode(mchan, HI6220_MBOX_ACK_IRQ);
+	else
+		hi6220_mbox_set_mode(mchan, HI6220_MBOX_ACK_AUTOMATIC);
+
+	for (i = 0; i < (HI6220_MBOX_MSG_LEN >> 2); i++)
+		writel(buf[i], mchan->slot + HI6220_MBOX_DATA_REG(i));
+
+	/* trigger remote request */
+	spin_lock_irqsave(&mbox->lock, flags);
+	writel(1 << irq, mbox->ipc + HI6220_MBOX_MCU_INT_RAW_REG);
+	spin_unlock_irqrestore(&mbox->lock, flags);
+	return 0;
+}
+
+static void hi6220_mbox_rx_work(struct work_struct *work)
+{
+	struct hi6220_mbox_queue *mq =
+			container_of(work, struct hi6220_mbox_queue, work);
+	struct mbox_chan *chan = mq->chan;
+	struct hi6220_mbox_chan *mchan = chan->con_priv;
+	struct hi6220_mbox *mbox = mchan->parent;
+	int irq = mchan->local_irq, len;
+	u32 msg[HI6220_MBOX_MSG_LEN >> 2];
+
+	while (kfifo_len(&mq->fifo) >= sizeof(msg)) {
+		len = kfifo_out(&mq->fifo, (unsigned char *)&msg, sizeof(msg));
+		WARN_ON(len != sizeof(msg));
+
+		mbox_chan_received_data(chan, (void *)msg);
+		spin_lock_irq(&mbox->lock);
+		if (mq->full) {
+			mq->full = false;
+			writel(1 << irq,
+				mbox->ipc + HI6220_MBOX_ACPU_INT_ENA_REG);
+		}
+		spin_unlock_irq(&mbox->lock);
+	}
+}
+
+static void hi6220_mbox_tx_interrupt(struct mbox_chan *chan)
+{
+	struct hi6220_mbox_chan *mchan = chan->con_priv;
+	struct hi6220_mbox *mbox = mchan->parent;
+	int irq = mchan->local_irq;
+
+	writel(1 << irq, mbox->ipc + HI6220_MBOX_ACPU_INT_CLR_REG);
+	hi6220_mbox_set_status(mchan, HI6220_MBOX_STATUS_IDLE);
+
+	mbox_chan_txdone(chan, 0);
+}
+
+static void hi6220_mbox_rx_interrupt(struct mbox_chan *chan)
+{
+	struct hi6220_mbox_chan *mchan = chan->con_priv;
+	struct hi6220_mbox_queue *mq = mchan->mq;
+	struct hi6220_mbox *mbox = mchan->parent;
+	int irq = mchan->local_irq;
+	int msg[HI6220_MBOX_MSG_LEN >> 2];
+	int i, len;
+
+	if (unlikely(kfifo_avail(&mq->fifo) < sizeof(msg))) {
+		writel(1 << irq, mbox->ipc + HI6220_MBOX_ACPU_INT_DIS_REG);
+		mq->full = true;
+		goto nomem;
+	}
+
+	for (i = 0; i < (HI6220_MBOX_MSG_LEN >> 2); i++)
+		msg[i] = readl(mchan->slot + HI6220_MBOX_DATA_REG(i));
+
+	/* clear IRQ source */
+	writel(1 << irq, mbox->ipc + HI6220_MBOX_ACPU_INT_CLR_REG);
+
+	hi6220_mbox_set_status(mchan, HI6220_MBOX_STATUS_IDLE);
+
+	len = kfifo_in(&mq->fifo, (unsigned char *)&msg, sizeof(msg));
+	WARN_ON(len != sizeof(msg));
+
+nomem:
+	schedule_work(&mq->work);
+}
+
+static irqreturn_t hi6220_mbox_interrupt(int irq, void *p)
+{
+	struct hi6220_mbox *mbox = p;
+	struct hi6220_mbox_chan *mchan;
+	struct mbox_chan *chan;
+	unsigned int state;
+	unsigned int intr_bit;
+
+	state = readl(mbox->ipc + HI6220_MBOX_ACPU_INT_STAT_REG);
+	if (!state) {
+		dev_warn(mbox->dev, "%s: spurious interrupt\n",
+			 __func__);
+		return IRQ_HANDLED;
+	}
+
+	while (state) {
+		intr_bit = __ffs(state);
+		state &= (state - 1);
+
+		chan = mbox->irq_map_chan[intr_bit];
+		if (!chan) {
+			dev_warn(mbox->dev, "%s: unexpected irq vector %d\n",
+				 __func__, intr_bit);
+			continue;
+		}
+
+		mchan = chan->con_priv;
+		if (mchan->dir == HI6220_MBOX_TX)
+			hi6220_mbox_tx_interrupt(chan);
+		else
+			hi6220_mbox_rx_interrupt(chan);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static struct hi6220_mbox_queue *hi6220_mbox_queue_alloc(
+		struct mbox_chan *chan,
+		void (*work)(struct work_struct *))
+{
+	struct hi6220_mbox_queue *mq;
+
+	mq = kzalloc(sizeof(struct hi6220_mbox_queue), GFP_KERNEL);
+	if (!mq)
+		return NULL;
+
+	if (kfifo_alloc(&mq->fifo, HI6220_MBOX_MSG_FIFO_SIZE, GFP_KERNEL))
+		goto error;
+
+	mq->chan = chan;
+	INIT_WORK(&mq->work, work);
+	return mq;
+
+error:
+	kfree(mq);
+	return NULL;
+}
+
+static void hi6220_mbox_queue_free(struct hi6220_mbox_queue *mq)
+{
+	kfifo_free(&mq->fifo);
+	kfree(mq);
+}
+
+static int hi6220_mbox_startup(struct mbox_chan *chan)
+{
+	struct hi6220_mbox_chan *mchan = chan->con_priv;
+	struct hi6220_mbox *mbox = mchan->parent;
+	unsigned int irq = mchan->local_irq;
+	struct hi6220_mbox_queue *mq;
+	unsigned long flags;
+
+	mq = hi6220_mbox_queue_alloc(chan, hi6220_mbox_rx_work);
+	if (!mq)
+		return -ENOMEM;
+	mchan->mq = mq;
+	mbox->irq_map_chan[irq] = (void *)chan;
+
+	/* enable interrupt */
+	spin_lock_irqsave(&mbox->lock, flags);
+	writel(1 << irq, mbox->ipc + HI6220_MBOX_ACPU_INT_ENA_REG);
+	spin_unlock_irqrestore(&mbox->lock, flags);
+	return 0;
+}
+
+static void hi6220_mbox_shutdown(struct mbox_chan *chan)
+{
+	struct hi6220_mbox_chan *mchan = chan->con_priv;
+	struct hi6220_mbox *mbox = mchan->parent;
+	unsigned int irq = mchan->local_irq;
+	unsigned long flags;
+
+	/* disable interrupt */
+	spin_lock_irqsave(&mbox->lock, flags);
+	writel(1 << irq, mbox->ipc + HI6220_MBOX_ACPU_INT_DIS_REG);
+	spin_unlock_irqrestore(&mbox->lock, flags);
+
+	mbox->irq_map_chan[irq] = NULL;
+	flush_work(&mchan->mq->work);
+	hi6220_mbox_queue_free(mchan->mq);
+}
+
+static struct mbox_chan_ops hi6220_mbox_chan_ops = {
+	.send_data    = hi6220_mbox_send_data,
+	.startup      = hi6220_mbox_startup,
+	.shutdown     = hi6220_mbox_shutdown,
+	.last_tx_done = hi6220_mbox_last_tx_done,
+};
+
+static void hi6220_mbox_init_hw(struct hi6220_mbox *mbox)
+{
+	struct hi6220_mbox_chan init_data[HI6220_MBOX_CHAN_NUM] = {
+		{ HI6220_MBOX_RX, HI6220_CORE_MCU, 1, 10 },
+		{ HI6220_MBOX_TX, HI6220_CORE_MCU, 0, 11 },
+	};
+	struct hi6220_mbox_chan *mchan = mbox->mchan;
+	int i;
+
+	for (i = 0; i < HI6220_MBOX_CHAN_NUM; i++) {
+		memcpy(&mchan[i], &init_data[i], sizeof(*mchan));
+		mchan[i].slot = mbox->buf + HI6220_MBOX_CHAN_SLOT_SIZE * i;
+		mchan[i].parent = mbox;
+	}
+
+	/* mask and clear all interrupt vectors */
+	writel(0x0,  mbox->ipc + HI6220_MBOX_ACPU_INT_MSK_REG);
+	writel(~0x0, mbox->ipc + HI6220_MBOX_ACPU_INT_CLR_REG);
+
+	/* use interrupt for tx's ack */
+	mbox->tx_irq_mode = true;
+}
+
+static const struct of_device_id hi6220_mbox_of_match[] = {
+	{ .compatible = "hisilicon,hi6220-mbox", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, hi6220_mbox_of_match);
+
+static int hi6220_mbox_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct hi6220_mbox *mbox;
+	struct resource *res;
+	int i, err;
+
+	mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL);
+	if (!mbox)
+		return -ENOMEM;
+
+	mbox->dev = dev;
+	mbox->chan_num = HI6220_MBOX_CHAN_NUM;
+	mbox->mchan = devm_kzalloc(dev,
+		mbox->chan_num * sizeof(*mbox->mchan), GFP_KERNEL);
+	if (!mbox->mchan)
+		return -ENOMEM;
+
+	mbox->chan = devm_kzalloc(dev,
+		mbox->chan_num * sizeof(*mbox->chan), GFP_KERNEL);
+	if (!mbox->chan)
+		return -ENOMEM;
+
+	mbox->irq = platform_get_irq(pdev, 0);
+	if (mbox->irq < 0)
+		return mbox->irq;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	mbox->ipc = devm_ioremap_resource(dev, res);
+	if (IS_ERR(mbox->ipc)) {
+		dev_err(dev, "ioremap ipc failed\n");
+		return PTR_ERR(mbox->ipc);
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	mbox->buf = devm_ioremap_resource(dev, res);
+	if (IS_ERR(mbox->buf)) {
+		dev_err(dev, "ioremap buffer failed\n");
+		return PTR_ERR(mbox->buf);
+	}
+
+	err = devm_request_irq(dev, mbox->irq, hi6220_mbox_interrupt, 0,
+			dev_name(dev), mbox);
+	if (err) {
+		dev_err(dev, "Failed to register a mailbox IRQ handler: %d\n",
+			err);
+		return -ENODEV;
+	}
+
+	/* init hardware parameters */
+	hi6220_mbox_init_hw(mbox);
+
+	spin_lock_init(&mbox->lock);
+
+	for (i = 0; i < mbox->chan_num; i++) {
+		mbox->chan[i].con_priv = &mbox->mchan[i];
+		mbox->irq_map_chan[i] = NULL;
+	}
+
+	mbox->controller.dev = dev;
+	mbox->controller.chans = &mbox->chan[0];
+	mbox->controller.num_chans = mbox->chan_num;
+	mbox->controller.ops = &hi6220_mbox_chan_ops;
+
+	if (mbox->tx_irq_mode)
+		mbox->controller.txdone_irq = true;
+	else {
+		mbox->controller.txdone_poll = true;
+		mbox->controller.txpoll_period = 5;
+	}
+
+	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 hi6220_mbox_remove(struct platform_device *pdev)
+{
+	struct hi6220_mbox *mbox = platform_get_drvdata(pdev);
+
+	mbox_controller_unregister(&mbox->controller);
+	return 0;
+}
+
+static struct platform_driver hi6220_mbox_driver = {
+	.driver = {
+		.name = "hi6220-mbox",
+		.owner = THIS_MODULE,
+		.of_match_table = hi6220_mbox_of_match,
+	},
+	.probe	= hi6220_mbox_probe,
+	.remove	= hi6220_mbox_remove,
+};
+
+static int __init hi6220_mbox_init(void)
+{
+	return platform_driver_register(&hi6220_mbox_driver);
+}
+core_initcall(hi6220_mbox_init);
+
+static void __exit hi6220_mbox_exit(void)
+{
+	platform_driver_unregister(&hi6220_mbox_driver);
+}
+module_exit(hi6220_mbox_exit);
+
+MODULE_AUTHOR("Leo Yan <leo.yan@xxxxxxxxxx>");
+MODULE_DESCRIPTION("Hi6220 mailbox driver");
+MODULE_LICENSE("GPL v2");
-- 
1.9.1

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