Re: [PATCH v3 2/3] mailbox: Add support for Hi3660 mailbox

[Leo Yan <leo.yan@linaro.org>]

On Tue, Dec 05, 2017 at 08:58:05AM +0530, Jassi Brar wrote:
> On Fri, Nov 17, 2017 at 2:54 PM, Xu YiPing <xuyiping@hisilicon.com> wrote:
> > From: Kaihua Zhong <zhongkaihua@huawei.com>
> >
> > Hi3660 mailbox controller is used to send message within multiple
> > processors, MCU, HIFI, etc.  It supports 32 mailbox channels and every
> > channel can only be used for single transferring direction.  Once the
> > channel is enabled, it needs to specify the destination interrupt and
> > acknowledge interrupt, these two interrupt vectors are used to create
> > the connection between the mailbox and interrupt controllers.
> >
> > The data transferring supports two modes, one is named as "automatic
> > acknowledge" mode so after send message the kernel doesn't need to wait
> > for acknowledge from remote and directly return; there have another mode
> > is to rely on handling interrupt for acknowledge.
> >
> > This commit is for initial version driver, which only supports
> > "automatic acknowledge" mode to support CPU clock, which is the only
> > one consumer to use mailbox and has been verified.  Later may enhance
> > this driver for interrupt mode (e.g. for supporting HIFI).
> >
> > Signed-off-by: Leo Yan <leo.yan@linaro.org>
> > Signed-off-by: Ruyi Wang <wangruyi@huawei.com>
> > Signed-off-by: Kaihua Zhong <zhongkaihua@huawei.com>
> > ---
> >  drivers/mailbox/Kconfig          |   8 +
> >  drivers/mailbox/Makefile         |   2 +
> >  drivers/mailbox/hi3660-mailbox.c | 322 +++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 332 insertions(+)
> >  create mode 100644 drivers/mailbox/hi3660-mailbox.c
> >
> > diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
> > index c5731e5..4b5d6e9 100644
> > --- a/drivers/mailbox/Kconfig
> > +++ b/drivers/mailbox/Kconfig
> > @@ -108,6 +108,14 @@ config TI_MESSAGE_MANAGER
> >           multiple processors within the SoC. Select this driver if your
> >           platform has support for the hardware block.
> >
> > +config HI3660_MBOX
> > +       tristate "Hi3660 Mailbox"
> > +       depends on ARCH_HISI && OF
> > +       help
> > +         An implementation of the hi3660 mailbox. It is used to send message
> > +         between application processors and other processors/MCU/DSP. Select
> > +         Y here if you want to use Hi3660 mailbox controller.
> > +
> >  config HI6220_MBOX
> >         tristate "Hi6220 Mailbox"
> >         depends on ARCH_HISI
> > diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
> > index d54e412..7d1bd51 100644
> > --- a/drivers/mailbox/Makefile
> > +++ b/drivers/mailbox/Makefile
> > @@ -26,6 +26,8 @@ obj-$(CONFIG_TI_MESSAGE_MANAGER) += ti-msgmgr.o
> >
> >  obj-$(CONFIG_XGENE_SLIMPRO_MBOX) += mailbox-xgene-slimpro.o
> >
> > +obj-$(CONFIG_HI3660_MBOX)      += hi3660-mailbox.o
> > +
> >  obj-$(CONFIG_HI6220_MBOX)      += hi6220-mailbox.o
> >
> >  obj-$(CONFIG_BCM_PDC_MBOX)     += bcm-pdc-mailbox.o
> > diff --git a/drivers/mailbox/hi3660-mailbox.c b/drivers/mailbox/hi3660-mailbox.c
> > new file mode 100644
> > index 0000000..ba80834
> > --- /dev/null
> > +++ b/drivers/mailbox/hi3660-mailbox.c
> > @@ -0,0 +1,322 @@
> > +/*
> > + * Hisilicon's Hi3660 mailbox controller driver
> > + *
> > + * Copyright (c) 2017 Hisilicon Limited.
> > + * Copyright (c) 2017 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.
> > + *
> >
> We now use SPDX licence

Thanks for quick response, Jassi.

Will change to SPDX licence fashion.

> > + */
> > +
> > +#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)
> > +
> Please, no brackets around numbers.

Sure, will remove brackets.

> > +#define MBOX_STATE_IDLE                        BIT(4)
> > +#define MBOX_STATE_ACK                 BIT(7)
> > +
> > +#define MBOX_MSG_LEN                   8
> > +
> > +/**
> > + * Hi3660 mailbox channel device data
> > + *
> > + * 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_mbox_dev {
> >
> Better than dev, maybe 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
> > + * @mdev:      Representation of channel device data
> > + * @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_mbox_dev mdev[MBOX_CHAN_MAX];
> >
> Maybe mchan, instead of mdev.

Will refactor structure name.

> > +       struct mbox_controller controller;
> > +};
> > +
> > +static inline 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_mbox_dev *mdev = &mbox->mdev[ch];
> > +       void __iomem *base = MBOX_BASE(mbox, ch);
> > +       unsigned long val;
> > +       unsigned int state, ret;
> > +
> > +       /* Mailbox is idle so directly bail out */
> > +       state = readl_relaxed(base + MBOX_MODE_REG);
> > +       if (state & MBOX_STATE_IDLE)
> > +               return 0;
> > +
> > +       /* Wait for acknowledge from remote */
> > +       ret = readx_poll_timeout_atomic(readl_relaxed, 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_relaxed(0xffffffff, base + MBOX_IMASK_REG);
> > +       writel_relaxed(BIT(mdev->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_relaxed(MBOX_IPC_UNLOCK, mbox->base + MBOX_IPC_LOCK_REG);
> > +
> > +               val = readl_relaxed(mbox->base + MBOX_IPC_LOCK_REG);
> > +               if (!val)
> > +                       break;
> > +
> > +               udelay(10);
> > +       } while (retry--);
> > +
> > +       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_mbox_dev *mdev = &mbox->mdev[ch];
> > +       void __iomem *base = MBOX_BASE(mbox, ch);
> > +       unsigned int val, retry;
> > +
> > +       for (retry = 10; retry; retry--) {
> > +               /* Check if channel has been acquired */
> > +               if (readl_relaxed(base + MBOX_MODE_REG) & MBOX_STATE_IDLE) {
> > +                       writel_relaxed(BIT(mdev->ack_irq), base + MBOX_SRC_REG);
> > +                       val = readl_relaxed(base + MBOX_SRC_REG);
> > +                       if (val & BIT(mdev->ack_irq))
> > +                               break;
> > +               }
> > +       }
> > +
> > +       return retry ? 0 : -ETIMEDOUT;
> > +}
> > +
> > +static int hi3660_mbox_send(struct mbox_chan *chan, u32 *msg)
> > +{
> > +       unsigned long ch = (unsigned long)chan->con_priv;
> > +       struct hi3660_mbox *mbox = to_hi3660_mbox(chan->mbox);
> > +       struct hi3660_mbox_dev *mdev = &mbox->mdev[ch];
> > +       void __iomem *base = MBOX_BASE(mbox, ch);
> > +       unsigned int i;
> > +
> > +       /* Clear mask for destination interrupt */
> > +       writel_relaxed(~BIT(mdev->dst_irq), base + MBOX_IMASK_REG);
> > +
> > +       /* Config destination for interrupt vector */
> > +       writel_relaxed(BIT(mdev->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(msg[i], base + MBOX_DATA_REG + i * 4);
> > +
> > +       /* Trigger data transferring */
> > +       writel_relaxed(BIT(mdev->ack_irq), base + MBOX_SEND_REG);
> > +       return 0;
> > +}
> > +
> > +static int hi3660_mbox_send_data(struct mbox_chan *chan, void *msg)
> > +{
> > +       struct hi3660_mbox *mbox = to_hi3660_mbox(chan->mbox);
> > +       int err;
> > +
> > +       err = hi3660_mbox_check_state(chan);
> > +       if (err) {
> > +               dev_err(mbox->dev, "checking state failed\n");
> > +               return err;
> > +       }
> > +
> > +       err = hi3660_mbox_unlock(chan);
> > +       if (err) {
> > +               dev_err(mbox->dev, "unlocking mailbox failed\n");
> > +               return err;
> > +       }
> > +
> > +       err = hi3660_mbox_acquire_channel(chan);
> > +       if (err) {
> > +               dev_err(mbox->dev, "acquiring channel failed\n");
> > +               return err;
> > +       }
> > +
> Please remember .send_data() is called with irqs disabled spinlock
> All these polling functions hurt. Please move the above three checks
> in last_tx_done()

I have tried to move these three checks in last_tx_done(), since these
three functions tightly couple with mailbox state machine, so I failed
to move them to last_tx_done().

Anyway, I will try to move them to last_tx_done() for next version
patch.

Thanks,
Leo Yan