Re: [PATCH v2 2/3] mailbox: Hi6220: add mailbox driver

YiPing Xu
2015-08-20T05:50:20Z

On 2015/8/20 10:53, Leo Yan wrote:
> 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@linaro.org>
> ---
> drivers/mailbox/Kconfig | 8 +
> drivers/mailbox/Makefile | 2 +
> drivers/mailbox/hi6220-mailbox.c | 519 +++++++++++++++++++++++++++++++++++++++
> 3 files changed, 529 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..8f63d0d
> --- /dev/null
> +++ b/drivers/mailbox/hi6220-mailbox.c
> @@ -0,0 +1,519 @@
> +/*
> + * 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@linaro.org>
> + *
> + * 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;
> +
> + 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);

hi6220_mbox_set_status is called in send_data context, and it is also
called in hi6220_mbox_rx_interrupt and hi6220_mbox_tx_interrupt.

no race condition here?

> + 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;
> +
> + spin_lock(&mbox->lock);
> + writel(1 << irq, mbox->ipc + HI6220_MBOX_ACPU_INT_CLR_REG);
> + spin_unlock(&mbox->lock);
> +
> + 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))) {
> + spin_lock(&mbox->lock);
> + writel(1 << irq, mbox->ipc + HI6220_MBOX_ACPU_INT_DIS_REG);
> + mq->full = true;
> + spin_unlock(&mbox->lock);
> + 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 */
> + spin_lock(&mbox->lock);
> + writel(1 << irq, mbox->ipc + HI6220_MBOX_ACPU_INT_CLR_REG);
> + spin_unlock(&mbox->lock);
> +
> + 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@linaro.org>");
> +MODULE_DESCRIPTION("Hi6220 mailbox driver");
> +MODULE_LICENSE("GPL v2");
>