[U-Boot] [v2, 1/3] mmc: fsl_esdhc: add esdhc_imx flag

[Y.b. Lu]

Hi Lukasz,

> -----Original Message-----
> From: Lukasz Majewski <lukma at denx.de>
> Sent: Tuesday, February 19, 2019 2:39 PM
> To: Y.b. Lu <yangbo.lu at nxp.com>
> Cc: u-boot at lists.denx.de
> Subject: Re: [U-Boot] [v2, 1/3] mmc: fsl_esdhc: add esdhc_imx flag
> 
> Hi "Y.b. Lu",
> 
> > Hi Lukasz,
> >
> > > -----Original Message-----
> > > From: Lukasz Majewski <lukma at denx.de>
> > > Sent: Monday, February 18, 2019 7:12 AM
> > > To: Y.b. Lu <yangbo.lu at nxp.com>
> > > Cc: u-boot at lists.denx.de
> > > Subject: Re: [U-Boot] [v2, 1/3] mmc: fsl_esdhc: add esdhc_imx flag
> > >
> > > Dear "Y.b. Lu",
> > >
> > > > The fsl_esdhc driver was for Freescale eSDHC on MPC83XX/MPC85XX
> > > > initially. The later QoriQ series processors (which were
> > > > evolutions of MPC83XX/MPC85XX) and i.MX series processors were
> > > > using this driver for their eSDHCs too.
> > > >
> > > > So there are two evolution directions for eSDHC now. For the two
> > > > series processors, the eSDHCs are becoming more and more
> > > > different. We should have split it into two drivers, like them
> > > > (sdhci-of-esdhc.c/sdhci-esdhc-imx.c) in linux kernel.
> > >
> > > Why we cannot do it right just from the very beginning?
> > >
> > > In the end of the day we will try to mimic Linux kernel anyway, IMHO
> > > it is better to start the split now and save some effort on a
> > > half-step solution.
> >
> > [Y.b. Lu] I understand. The perfect way is to split them.
> > However, if you grep 'CONFIG_FSL_ESDHC' in the whole u-boot source,
> > you would find there are 607 results.
> 
> Those are boards, which use the driver. The modification would be done in one
> or two files (fsl_esdhc.c|h).

[Y.b. Lu] Sorry, I can't get your point.
Since we split fsl_esdhc into fsl_esdhc and fsl_esdhc_imx driver, all i.mx boards files should convert to use new CONFIG_FSL_ESDHC_IMX instead as I understand.

> 
> > There will be so many companies
> > boards affected.
> 
> I guess that the task of your patch set is to separate imx6q and ppc specific
> code for those IP blocks.
> 
> > I just don't know who could make all of these boards tested.
> 
> Your patch set also makes some changes in the generic driver depending on
> the priv->esdhc_imx flag. Those changes also need to be tested on all before
> mentioned boards.

[Y.b. Lu] Right...

> 
> In the end you logically split the driver, having it in a single file, which IMHO is
> not proper long-term solution.
> 
> >
> > My current patch-set is also to cleaning up the driver waiting for
> > splitting them someday on the other hand. After you check
> > CONFIG_FSL_ESDHC in u-boot source, if you think it's better we should
> > split them right now, I could work on the driver splitting.
> 
> You can think about having common part (in one file - fsl_esdhc.c) and then
> separate files with code specific to imx and ppc. This would reduce the number
> of changes needed.

[Y.b. Lu] Actually, it's not only imx and ppc.
In linux, esdhc driver is for MPC83XX/MPC85XX, QorIQ PowerPC processors, QoriQ ARM processors (Layerscape).
Esdhc-imx driver is for i.MX processors.

Anyway there would be a lot files changed if we split the driver. Let me send out a patch-set to split them for your reviewing.
Thanks a lot for your comments.

> 
> >
> > Thanks a lot.
> >
> > > > But it seemed
> > > > to be a lot of work now. So let's keep as it is. Be very careful
> > > > to change the driver if the changes are not common for all eSDHCs,
> > > > and clarify i.MX eSDHC specific things to distingush them with
> > > > QorIQ eSDHC.
> > > >
> > > > This patch is to added an esdhc_imx flag for the development of
> > > > i.MX eSDHC, to distinguish it with QoriQ eSDHC.
> > > >
> > > > Signed-off-by: Yangbo Lu <yangbo.lu at nxp.com>
> > > > ---
> > > > Changes for v2:
> > > > 	- Converted to use device_is_compatible().
> > > > ---
> > > >  drivers/mmc/fsl_esdhc.c | 11 +++++++++++
> > > >  1 file changed, 11 insertions(+)
> > > >
> > > > diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c
> > > > index 21fa2ab1d4..a647bc7f1c 100644
> > > > --- a/drivers/mmc/fsl_esdhc.c
> > > > +++ b/drivers/mmc/fsl_esdhc.c
> > > > @@ -147,6 +147,7 @@ struct fsl_esdhc_priv {
> > > >  	struct gpio_desc cd_gpio;
> > > >  	struct gpio_desc wp_gpio;
> > > >  #endif
> > > > +	bool esdhc_imx;
> > > >  };
> > > >
> > > >  /* Return the XFERTYP flags for a given command and data packet
> > > > */ @@ -1462,6 +1463,16 @@ static int fsl_esdhc_probe(struct
> > > > udevice *dev) priv->caps = data->caps;
> > > >  	}
> > > >
> > > > +	/*
> > > > +	 * This is to specify whether current eSDHC is an i.MX
> > > > eSDHC,
> > > > +	 * since the i.MX eSDHC has been becoming more and more
> > > > different
> > > > +	 * with QorIQ eSDHC and initial MPC83XX/MPC85XX.
> > > > +	 */
> > > > +	if (!device_is_compatible(dev, "fsl,esdhc"))
> > > > +		priv->esdhc_imx = true;
> > > > +	else
> > > > +		priv->esdhc_imx = false;
> > > > +
> > > >  	val = dev_read_u32_default(dev, "bus-width", -1);
> > > >  	if (val == 8)
> > > >  		priv->bus_width = 8;
> > >
> > >
> > >
> > >
> > > Best regards,
> > >
> > > Lukasz Majewski
> > >
> > > --
> > >
> > > DENX Software Engineering GmbH,      Managing Director: Wolfgang
> > > Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell,
> > > Germany Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email:
> > > lukma at denx.de
> 
> 
> 
> 
> Best regards,
> 
> Lukasz Majewski
> 
> --
> 
> DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
> Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email:
> lukma at denx.de