[U-Boot] [PATCH] Revert "imx: mx7: implement reset_misc"

[Peng Fan]

Hi Fabio,

> -----Original Message-----
> From: Fabio Estevam [mailto:festevam at gmail.com]
> Sent: Wednesday, February 22, 2017 5:34 PM
> To: Stefano Babic <sbabic at denx.de>
> Cc: Tom Rini <trini at konsulko.com>; U-Boot-Denx <u-boot at lists.denx.de>;
> Peng Fan <peng.fan at nxp.com>; Fabio Estevam <fabio.estevam at nxp.com>
> Subject: Re: [PATCH] Revert "imx: mx7: implement reset_misc"
> 
> Hi Stefano and Peng,
> 
> On Tue, Feb 21, 2017 at 11:21 PM, Fabio Estevam <festevam at gmail.com>
> wrote:
> > From: Fabio Estevam <fabio.estevam at nxp.com>
> >
> > Commit 9f8fa184fc1ac ("imx: mx7: implement reset_misc") says it needs
> > to to power down lcdif to make 'reset' can pass stress test.
> >
> > However I see 100% of reset failures with this commit applied, so
> > better revert it for now.
> >
> > This reverts commit 9f8fa184fc1acb6fe8e15e3bbbfcb916e6bc4cc1.
> >
> > Signed-off-by: Fabio Estevam <fabio.estevam at nxp.com>
> 
> I realized that the reset failure always happen only when 'videomode'
> variable is not present:
> 
> => setenv videomode
> => saveenv
> => reset
> 
> Then reset hangs.
> 
> If I do the check like this, then it does not hang:
> 
> --- a/drivers/video/mxsfb.c
> +++ b/drivers/video/mxsfb.c
> @@ -135,6 +135,11 @@ void lcdif_power_down(void)  {
>         struct mxs_lcdif_regs *regs = (struct mxs_lcdif_regs *)MXS_LCDIF_BASE;
>         int timeout = 1000000;
> +       char *penv;
> +
> +       penv = getenv("videomode");
> +       if (!penv)
> +               return;
> 
>         writel(panel.frameAdrs, &regs->hw_lcdif_cur_buf_reg);
>         writel(panel.frameAdrs, &regs->hw_lcdif_next_buf_reg);
> 
> What do you think of such proposal instead of doing the revert?

If no videomode set, that means lcd will not be initialized.  So there is no need to power down the lcdif, agree with your new approach.
Because when lcdif is initialized, there is also a risk that system hang if lcdif is not powered down, so no revert.

Regards,
Peng.