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From:   Mathieu Poirier <mathieu.poirier@linaro.org>
Date:   Fri, 17 Apr 2020 10:02:01 -0600
Message-ID: <CANLsYkwun87oVw5ZG_g0niq7Yns5+xWJEVb72FwP=d3PruXCcQ@mail.gmail.com>
Subject: Re: [PATCH v2 2/3] remoteproc: imx_rproc: mailbox support
To:     Nikita Shubin <nikita.shubin@maquefel.me>
Cc:     Nikita Shubin <NShubin@topcon.com>,
        Ohad Ben-Cohen <ohad@wizery.com>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        NXP Linux Team <linux-imx@nxp.com>,
        linux-remoteproc <linux-remoteproc@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
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On Fri, 17 Apr 2020 at 02:38, Nikita Shubin <nikita.shubin@maquefel.me> wrote:
>
> On Tue, 14 Apr 2020 11:20:05 -0600
> Mathieu Poirier <mathieu.poirier@linaro.org> wrote:
>
> > On Mon, Apr 06, 2020 at 02:33:09PM +0300, nikita.shubin@maquefel.me
> > wrote:
> > > Add support for mailboxes to imx_rproc
> > >
> > > Signed-off-by: Nikita Shubin <NShubin@topcon.com>
> > > ---
> > >  drivers/remoteproc/Kconfig     |   2 +
> > >  drivers/remoteproc/imx_rproc.c | 142
> > > ++++++++++++++++++++++++++++++++- 2 files changed, 143
> > > insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
> > > index 94afdde4bc9f..02d23a54c9cf 100644
> > > --- a/drivers/remoteproc/Kconfig
> > > +++ b/drivers/remoteproc/Kconfig
> > > @@ -17,6 +17,8 @@ if REMOTEPROC
> > >  config IMX_REMOTEPROC
> > >     tristate "IMX6/7 remoteproc support"
> > >     depends on ARCH_MXC
> > > +   select MAILBOX
> > > +   select IMX_MBOX
> > >     help
> > >       Say y here to support iMX's remote processors (Cortex M4
> > >       on iMX7D) via the remote processor framework.
> > > diff --git a/drivers/remoteproc/imx_rproc.c
> > > b/drivers/remoteproc/imx_rproc.c index bebc58d0f711..d2bede4ccb70
> > > 100644 --- a/drivers/remoteproc/imx_rproc.c
> > > +++ b/drivers/remoteproc/imx_rproc.c
> > > @@ -14,6 +14,9 @@
> > >  #include <linux/platform_device.h>
> > >  #include <linux/regmap.h>
> > >  #include <linux/remoteproc.h>
> > > +#include <linux/mailbox_client.h>
> > > +
> > > +#include "remoteproc_internal.h"
> > >
> > >  #define IMX7D_SRC_SCR                      0x0C
> > >  #define IMX7D_ENABLE_M4                    BIT(3)
> > > @@ -47,6 +50,12 @@
> > >
> > >  #define IMX_BOOT_PC                        0x4
> > >
> > > +#define IMX_MBOX_NB_VQ                     2
> > > +#define IMX_MBOX_NB_MBX            2
> >
> > Please align this.
> >
> > > +
> > > +#define IMX_MBX_VQ0                "vq0"
> > > +#define IMX_MBX_VQ1                "vq1"
> > > +
> > >  /**
> > >   * struct imx_rproc_mem - slim internal memory structure
> > >   * @cpu_addr: MPU virtual address of the memory region
> > > @@ -80,6 +89,14 @@ struct imx_rproc_dcfg {
> > >     size_t                          att_size;
> > >  };
> > >
> > > +struct imx_mbox {
> > > +   const unsigned char name[10];
> > > +   struct mbox_chan *chan;
> > > +   struct mbox_client client;
> > > +   struct work_struct vq_work;
> > > +   int vq_id;
> > > +};
> > > +
> > >  struct imx_rproc {
> > >     struct device                   *dev;
> > >     struct regmap                   *regmap;
> > > @@ -88,6 +105,8 @@ struct imx_rproc {
> > >     struct imx_rproc_mem
> > > mem[IMX7D_RPROC_MEM_MAX]; struct clk                        *clk;
> > >     void __iomem                    *bootreg;
> > > +   struct imx_mbox mb[IMX_MBOX_NB_MBX];
> > > +   struct workqueue_struct *workqueue;
> > >  };
> > >
> > >  static const struct imx_rproc_att imx_rproc_att_imx7d[] = {
> > > @@ -251,10 +270,118 @@ static void *imx_rproc_da_to_va(struct rproc
> > > *rproc, u64 da, int len) return va;
> > >  }
> > >
> > > +static void imx_rproc_mb_vq_work(struct work_struct *work)
> > > +{
> > > +   struct imx_mbox *mb = container_of(work, struct imx_mbox,
> > > vq_work);
> > > +   struct rproc *rproc = dev_get_drvdata(mb->client.dev);
> > > +
> > > +   if (rproc_vq_interrupt(rproc, mb->vq_id) == IRQ_NONE)
> > > +           dev_dbg(&rproc->dev, "no message found in vq%d\n",
> > > mb->vq_id); +}
> > > +
> > > +static void imx_rproc_mb_callback(struct mbox_client *cl, void
> > > *data) +{
> > > +   struct rproc *rproc = dev_get_drvdata(cl->dev);
> > > +   struct imx_mbox *mb = container_of(cl, struct imx_mbox,
> > > client);
> > > +   struct imx_rproc *ddata = rproc->priv;
> > > +
> > > +   queue_work(ddata->workqueue, &mb->vq_work);
> > > +}
> > > +
> > > +static const struct imx_mbox imx_rproc_mbox[IMX_MBOX_NB_MBX] = {
> > > +   {
> > > +           .name = IMX_MBX_VQ0,
> > > +           .vq_id = 0,
> > > +           .client = {
> > > +                   .rx_callback = imx_rproc_mb_callback,
> > > +                   .tx_block = false,
> > > +           },
> > > +   },
> > > +   {
> > > +           .name = IMX_MBX_VQ1,
> > > +           .vq_id = 1,
> > > +           .client = {
> > > +                   .rx_callback = imx_rproc_mb_callback,
> > > +                   .tx_block = false,
> > > +           },
> > > +   },
> > > +};
> > > +
> > > +static void imx_rproc_request_mbox(struct rproc *rproc)
> > > +{
> > > +   struct imx_rproc *ddata = rproc->priv;
> > > +   struct device *dev = &rproc->dev;
> > > +   unsigned int i;
> > > +   const unsigned char *name;
> > > +   struct mbox_client *cl;
> > > +
> > > +   /* Initialise mailbox structure table */
> > > +   memcpy(ddata->mb, imx_rproc_mbox, sizeof(imx_rproc_mbox));
> > > +
> > > +   for (i = 0; i < IMX_MBOX_NB_MBX; i++) {
> > > +           name = ddata->mb[i].name;
> > > +
> > > +           cl = &ddata->mb[i].client;
> > > +           cl->dev = dev->parent;
> > > +
> > > +           ddata->mb[i].chan =
> > > mbox_request_channel_byname(cl, name); +
> > > +           dev_dbg(dev, "%s: name=%s, idx=%u\n",
> > > +                   __func__, name, ddata->mb[i].vq_id);
> > > +
> > > +           if (IS_ERR(ddata->mb[i].chan)) {
> > > +                   dev_warn(dev, "cannot get %s mbox\n",
> > > name);
> > > +                   ddata->mb[i].chan = NULL;
> >
> > If the mailbox isn't ready this driver will fail without a chance of
> > recovery. Since most of the code in this patch is a carbon copy of
> > the implementation found in stm32_proc.c, I suggest you do the same
> > as they did in stm32_rproc_request_mbox() and privision for cases
> > where requesting a channel returns -EPROBE_DEFER.
> >
>
> Noted, will be fixed.
>
> > > +           }
> > > +
> > > +           if (ddata->mb[i].vq_id >= 0)
> > > +                   INIT_WORK(&ddata->mb[i].vq_work,
> > > imx_rproc_mb_vq_work);
> > > +   }
> > > +}
> > > +
> > > +static void imx_rproc_free_mbox(struct rproc *rproc)
> > > +{
> > > +   struct imx_rproc *ddata = rproc->priv;
> > > +   unsigned int i;
> > > +
> > > +   dev_dbg(&rproc->dev, "%s: %d boxes\n",
> > > +           __func__, ARRAY_SIZE(ddata->mb));
> > > +
> > > +   for (i = 0; i < ARRAY_SIZE(ddata->mb); i++) {
> > > +           if (ddata->mb[i].chan)
> > > +                   mbox_free_channel(ddata->mb[i].chan);
> > > +           ddata->mb[i].chan = NULL;
> > > +   }
> > > +}
> > > +
> > > +static void imx_rproc_kick(struct rproc *rproc, int vqid)
> > > +{
> > > +   struct imx_rproc *ddata = rproc->priv;
> > > +   unsigned int i;
> > > +   int err;
> > > +
> > > +   if (WARN_ON(vqid >= IMX_MBOX_NB_VQ))
> > > +           return;
> > > +
> > > +   for (i = 0; i < IMX_MBOX_NB_MBX; i++) {
> > > +           if (vqid != ddata->mb[i].vq_id)
> > > +                   continue;
> > > +           if (!ddata->mb[i].chan)
> > > +                   return;
> > > +           dev_dbg(&rproc->dev, "sending message : vqid =
> > > %d\n", vqid);
> > > +           err = mbox_send_message(ddata->mb[i].chan, &vqid);
> > > +           if (err < 0)
> > > +                   dev_err(&rproc->dev, "%s: failed (%s,
> > > err:%d)\n",
> > > +                                   __func__,
> > > ddata->mb[i].name, err);
> > > +                   return;
> > > +   }
> > > +}
> > > +
> > >  static const struct rproc_ops imx_rproc_ops = {
> > >     .start          = imx_rproc_start,
> > >     .stop           = imx_rproc_stop,
> > >     .da_to_va       = imx_rproc_da_to_va,
> > > +   .kick           = imx_rproc_kick,
> > >     .get_boot_addr  = rproc_elf_get_boot_addr,
> > >  };
> > >
> > > @@ -384,14 +511,26 @@ static int imx_rproc_probe(struct
> > > platform_device *pdev) goto err_put_rproc;
> > >     }
> > >
> > > +   priv->workqueue = create_workqueue(dev_name(dev));
> > > +   if (!priv->workqueue) {
> > > +           dev_err(dev, "cannot create workqueue\n");
> > > +           ret = -ENOMEM;
> > > +           goto err_put_clk;
> > > +   }
> > > +
> > > +   imx_rproc_request_mbox(rproc);
> > > +
> > >     ret = rproc_add(rproc);
> > >     if (ret) {
> > >             dev_err(dev, "rproc_add failed\n");
> > > -           goto err_put_clk;
> > > +           goto err_free_mb;
> > >     }
> > >
> > >     return 0;
> > >
> > > +err_free_mb:
> > > +   imx_rproc_free_mbox(rproc);
> > > +   destroy_workqueue(priv->workqueue);
> > >  err_put_clk:
> > >     clk_disable_unprepare(priv->clk);
> > >  err_put_rproc:
> > > @@ -407,6 +546,7 @@ static int imx_rproc_remove(struct
> > > platform_device *pdev)
> > >     clk_disable_unprepare(priv->clk);
> > >     rproc_del(rproc);
> > > +   imx_rproc_free_mbox(rproc);
> >
> > I have no issues with people reusing code already found in the kernel
> > - in fact I encourage it because it makes reviewing patches much
> > easier.  On the flip side you have to give credit where it is due.
> > Here adding a line in the changelog that mentions where you took your
> > inspiration from will be much appreciated.
>
> Please don't blame on things i never did citing my own self from 0/0:

I am not blaming you at all.

>
> | Regarding mailboxes and memory regions :
>
> | This code is heavily derived from stm32-rproc (i.e. copy pasted) and
> | this fact needs to reflected in commits, please tell me how to
> | emphasize this fact.
>
> I am eager to give credits.

I didn't notice that in the original cover letter.  In the changelog,
between the description of the work and the signed-off-by and on a
line on its own, simply write that "the work is inspired from the
STM32 platform driver (drivers/remoteproc/stm32_rproc.c)".

>
>
> >
> > Thanks,
> > Mathieu
> >
> > >     rproc_free(rproc);
> > >
> > >     return 0;
> > > --
> > > 2.25.1
> > >
>