Date:   Fri, 26 Jul 2019 09:23:42 +0000
From:   Richard Zhu <hongxing.zhu@....com>
To:     Oleksij Rempel <o.rempel@...gutronix.de>
CC:     "jassisinghbrar@...il.com" <jassisinghbrar@...il.com>,
        Aisheng Dong <aisheng.dong@....com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>
Subject: RE: [EXT] Re: [RFC] mailbox: imx: Add support for i.MX v1 messaging
 unit

Hi Oleksij:
Thanks for your comments.

> -----Original Message-----
> From: Oleksij Rempel <o.rempel@...gutronix.de>
> Sent: 2019年7月26日 17:17
> To: Richard Zhu <hongxing.zhu@....com>
> Cc: jassisinghbrar@...il.com; Aisheng Dong <aisheng.dong@....com>;
> linux-kernel@...r.kernel.org; linux-arm-kernel@...ts.infradead.org
> Subject: Re: [RFC] mailbox: imx: Add support for i.MX v1 messaging unit
> 
> 
> On Fri, Jul 26, 2019 at 04:29:36PM +0800, Richard Zhu wrote:
> > There is a version1.0 MU on i.MX7ULP platform.
> > One new version ID register is added, and the offset is 0.
> > TRn registers are defined at the offset 0x20 ~ 0x2C.
> > RRn registers are defined at the offset 0x40 ~ 0x4C.
> > SR/CR registers are defined at 0x60/0x64.
> > Extend this driver to support it.
> 
> Heh.. i feel like NXP/Freescale have old tradition of moving around registers and
> adding/removing the version register :)
> 
> Since it is not first time, I would prefer to have register layout linked on probe
> and not calculating or if-ing it on runtime. Especially, because I assume it is not
> the last layout change.
> 
> For example see:
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Felixir.boo
> tlin.com%2Flinux%2Fv5.3-rc1%2Fsource%2Fdrivers%2Fremoteproc%2Fimx_rpro
> c.c%23L336&amp;data=02%7C01%7Chongxing.zhu%40nxp.com%7C275ed465c
> a75424f583008d711aa0e58%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7
> C0%7C636997294396884235&amp;sdata=tTikxc3oIpCEkmQELWTz3XB%2BN8f5
> cudEAWhmNziOHtQ%3D&amp;reserved=0
>         dcfg = of_device_get_match_data(dev);
> 
> or
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Felixir.boo
> tlin.com%2Flinux%2Fv5.3-rc1%2Fsource%2Fdrivers%2Fnet%2Fethernet%2Fathe
> ros%2Fag71xx.c%23L1651&amp;data=02%7C01%7Chongxing.zhu%40nxp.com
> %7C275ed465ca75424f583008d711aa0e58%7C686ea1d3bc2b4c6fa92cd99c5c3
> 01635%7C0%7C0%7C636997294396884235&amp;sdata=jtPuiAvgvO3gyrzCo6S
> WooBtNrgyNUm8bPpyJ7%2FwHyk%3D&amp;reserved=0
> 
> and please, do not try to detect version by reading wrong register. We have
> devicetree compatible for this use case.
> 
[Richard Zhu] Okay, devicetree compatible is a better method. Thanks.

> > Signed-off-by: Richard Zhu <hongxing.zhu@....com>
> > ---
> >  drivers/mailbox/imx-mailbox.c | 45
> > +++++++++++++++++++++++++++++++++----------
> >  1 file changed, 35 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/mailbox/imx-mailbox.c
> > b/drivers/mailbox/imx-mailbox.c index 25be8bb..eb55bbe 100644
> > --- a/drivers/mailbox/imx-mailbox.c
> > +++ b/drivers/mailbox/imx-mailbox.c
> > @@ -12,10 +12,14 @@
> >  #include <linux/of_device.h>
> >  #include <linux/slab.h>
> >
> > +#define MU_VER_ID_V1         0x0100
> > +
> >  /* Transmit Register */
> >  #define IMX_MU_xTRn(x)               (0x00 + 4 * (x))
> > +#define IMX_MU_xTRn_V1(x)    (0x20 + 4 * (x))
> >  /* Receive Register */
> >  #define IMX_MU_xRRn(x)               (0x10 + 4 * (x))
> > +#define IMX_MU_xRRn_V1(x)    (0x40 + 4 * (x))
> >  /* Status Register */
> >  #define IMX_MU_xSR           0x20
> >  #define IMX_MU_xSR_GIPn(x)   BIT(28 + (3 - (x)))
> > @@ -25,6 +29,7 @@
> >
> >  /* Control Register */
> >  #define IMX_MU_xCR           0x24
> > +#define IMX_MU_xSCR_V1_OFFSET        0x40
> >  /* General Purpose Interrupt Enable */
> >  #define IMX_MU_xCR_GIEn(x)   BIT(28 + (3 - (x)))
> >  /* Receive Interrupt Enable */
> > @@ -63,6 +68,7 @@ struct imx_mu_priv {
> >       struct imx_mu_con_priv  con_priv[IMX_MU_CHANS];
> >       struct clk              *clk;
> >       int                     irq;
> > +     int                     version;
> >
> >       bool                    side_b;
> >  };
> > @@ -85,13 +91,16 @@ static u32 imx_mu_read(struct imx_mu_priv *priv,
> > u32 offs)  static u32 imx_mu_xcr_rmw(struct imx_mu_priv *priv, u32
> > set, u32 clr)  {
> >       unsigned long flags;
> > -     u32 val;
> > +     u32 val, offset;
> > +
> > +     offset = unlikely(priv->version == MU_VER_ID_V1) ?
> > +                     IMX_MU_xSCR_V1_OFFSET : 0;
> >
> >       spin_lock_irqsave(&priv->xcr_lock, flags);
> > -     val = imx_mu_read(priv, IMX_MU_xCR);
> > +     val = imx_mu_read(priv, IMX_MU_xCR + offset);
> >       val &= ~clr;
> >       val |= set;
> > -     imx_mu_write(priv, val, IMX_MU_xCR);
> > +     imx_mu_write(priv, val, IMX_MU_xCR + offset);
> >       spin_unlock_irqrestore(&priv->xcr_lock, flags);
> >
> >       return val;
> > @@ -109,10 +118,13 @@ static irqreturn_t imx_mu_isr(int irq, void *p)
> >       struct mbox_chan *chan = p;
> >       struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
> >       struct imx_mu_con_priv *cp = chan->con_priv;
> > -     u32 val, ctrl, dat;
> > +     u32 val, ctrl, dat, offset;
> > +
> > +     offset = unlikely(priv->version == MU_VER_ID_V1) ?
> > +                     IMX_MU_xSCR_V1_OFFSET : 0;
> >
> > -     ctrl = imx_mu_read(priv, IMX_MU_xCR);
> > -     val = imx_mu_read(priv, IMX_MU_xSR);
> > +     ctrl = imx_mu_read(priv, IMX_MU_xCR + offset);
> > +     val = imx_mu_read(priv, IMX_MU_xSR + offset);
> >
> >       switch (cp->type) {
> >       case IMX_MU_TYPE_TX:
> > @@ -138,10 +150,14 @@ static irqreturn_t imx_mu_isr(int irq, void *p)
> >               imx_mu_xcr_rmw(priv, 0, IMX_MU_xCR_TIEn(cp->idx));
> >               mbox_chan_txdone(chan, 0);
> >       } else if (val == IMX_MU_xSR_RFn(cp->idx)) {
> > -             dat = imx_mu_read(priv, IMX_MU_xRRn(cp->idx));
> > +             if (unlikely(priv->version == MU_VER_ID_V1))
> > +                     dat = imx_mu_read(priv,
> IMX_MU_xRRn_V1(cp->idx));
> > +             else
> > +                     dat = imx_mu_read(priv, IMX_MU_xRRn(cp->idx));
> >               mbox_chan_received_data(chan, (void *)&dat);
> >       } else if (val == IMX_MU_xSR_GIPn(cp->idx)) {
> > -             imx_mu_write(priv, IMX_MU_xSR_GIPn(cp->idx),
> IMX_MU_xSR);
> > +             imx_mu_write(priv, IMX_MU_xSR_GIPn(cp->idx),
> > +                             IMX_MU_xSR + offset);
> >               mbox_chan_received_data(chan, NULL);
> >       } else {
> >               dev_warn_ratelimited(priv->dev, "Not handled
> > interrupt\n"); @@ -159,7 +175,10 @@ static int imx_mu_send_data(struct
> > mbox_chan *chan, void *data)
> >
> >       switch (cp->type) {
> >       case IMX_MU_TYPE_TX:
> > -             imx_mu_write(priv, *arg, IMX_MU_xTRn(cp->idx));
> > +             if (unlikely(priv->version == MU_VER_ID_V1))
> > +                     imx_mu_write(priv, *arg,
> IMX_MU_xTRn_V1(cp->idx));
> > +             else
> > +                     imx_mu_write(priv, *arg,
> IMX_MU_xTRn(cp->idx));
> >               imx_mu_xcr_rmw(priv, IMX_MU_xCR_TIEn(cp->idx), 0);
> >               break;
> >       case IMX_MU_TYPE_TXDB:
> > @@ -253,11 +272,17 @@ static struct mbox_chan * imx_mu_xlate(struct
> > mbox_controller *mbox,
> >
> >  static void imx_mu_init_generic(struct imx_mu_priv *priv)  {
> > +     u32 offset;
> > +
> >       if (priv->side_b)
> >               return;
> >
> > +     priv->version = imx_mu_read(priv, 0) >> 16;
> > +     offset = unlikely(priv->version == MU_VER_ID_V1) ?
> > +                     IMX_MU_xSCR_V1_OFFSET : 0;
> > +
> >       /* Set default MU configuration */
> > -     imx_mu_write(priv, 0, IMX_MU_xCR);
> > +     imx_mu_write(priv, 0, IMX_MU_xCR + offset);
> >  }
> >
> >  static int imx_mu_probe(struct platform_device *pdev)
> > --
> > 2.7.4
> >
> >
> > _______________________________________________
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> d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C636997294396884235&amp;sdat
> a=hNCv
> > QJXtXRWAJT84NNrXyVfnQ1V2uxWxbVqN%2Bvy7hOg%3D&amp;reserved=0
> >
> 
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