Hi Adrian,
> -----Original Message-----
> From: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> Sent: Friday, October 16, 2020 5:06 PM
> To: Y.b. Lu <yangbo.lu@xxxxxxx>; linux-mmc@xxxxxxxxxxxxxxx
> Cc: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> Subject: Re: [PATCH] mmc: sdhci-of-esdhc: make sure delay chain locked for
> HS400
>
> On 16/10/20 7:25 am, Yangbo Lu wrote:
> > For eMMC HS400 mode initialization, the DLL reset is a required step
> > if DLL is enabled to use previously, like in bootloader.
> > This step has not been documented in reference manual, but the RM will
> > be fixed sooner or later.
> >
> > This patch is to add the step of DLL reset, and make sure delay chain
> > locked for HS400.
> >
> > Signed-off-by: Yangbo Lu <yangbo.lu@xxxxxxx>
> > ---
> > drivers/mmc/host/sdhci-esdhc.h | 2 ++
> > drivers/mmc/host/sdhci-of-esdhc.c | 24 ++++++++++++++++++++++++
> > 2 files changed, 26 insertions(+)
> >
> > diff --git a/drivers/mmc/host/sdhci-esdhc.h
> b/drivers/mmc/host/sdhci-esdhc.h
> > index a30796e..6de02f0 100644
> > --- a/drivers/mmc/host/sdhci-esdhc.h
> > +++ b/drivers/mmc/host/sdhci-esdhc.h
> > @@ -5,6 +5,7 @@
> > * Copyright (c) 2007 Freescale Semiconductor, Inc.
> > * Copyright (c) 2009 MontaVista Software, Inc.
> > * Copyright (c) 2010 Pengutronix e.K.
> > + * Copyright 2020 NXP
> > * Author: Wolfram Sang <kernel@xxxxxxxxxxxxxx>
> > */
> >
> > @@ -88,6 +89,7 @@
> > /* DLL Config 0 Register */
> > #define ESDHC_DLLCFG0 0x160
> > #define ESDHC_DLL_ENABLE 0x80000000
> > +#define ESDHC_DLL_RESET 0x40000000
> > #define ESDHC_DLL_FREQ_SEL 0x08000000
> >
> > /* DLL Config 1 Register */
> > diff --git a/drivers/mmc/host/sdhci-of-esdhc.c
> b/drivers/mmc/host/sdhci-of-esdhc.c
> > index 0b45eff..a39ff86 100644
> > --- a/drivers/mmc/host/sdhci-of-esdhc.c
> > +++ b/drivers/mmc/host/sdhci-of-esdhc.c
> > @@ -4,6 +4,7 @@
> > *
> > * Copyright (c) 2007, 2010, 2012 Freescale Semiconductor, Inc.
> > * Copyright (c) 2009 MontaVista Software, Inc.
> > + * Copyright 2020 NXP
> > *
> > * Authors: Xiaobo Xie <X.Xie@xxxxxxxxxxxxx>
> > * Anton Vorontsov <avorontsov@xxxxxxxxxxxxx>
> > @@ -743,6 +744,29 @@ static void esdhc_of_set_clock(struct sdhci_host
> *host, unsigned int clock)
> > if (host->mmc->actual_clock == MMC_HS200_MAX_DTR)
> > temp |= ESDHC_DLL_FREQ_SEL;
> > sdhci_writel(host, temp, ESDHC_DLLCFG0);
> > +
> > + temp |= ESDHC_DLL_RESET;
> > + sdhci_writel(host, temp, ESDHC_DLLCFG0);
> > + udelay(1);
> > + temp &= ~ESDHC_DLL_RESET;
> > + sdhci_writel(host, temp, ESDHC_DLLCFG0);
> > +
> > + /* Wait max 20 ms */
> > + timeout = ktime_add_ms(ktime_get(), 20);
> > + while (1) {
> > + bool timedout = ktime_after(ktime_get(), timeout);
> > +
> > + if (sdhci_readl(host, ESDHC_DLLSTAT0) &
> > + ESDHC_DLL_STS_SLV_LOCK)
> > + break;
> > + if (timedout) {
> > + pr_err("%s: timeout for delay chain lock.\n",
> > + mmc_hostname(host->mmc));
> > + break;
> > + }
> > + usleep_range(10, 20);
> > + }
>
> It is possible now to do these loops using read_poll_timeout
> e.g. something like this:
>
> if (read_poll_timeout(sdhci_readl, temp, temp &
> ESDHC_DLL_STS_SLV_LOCK,
> 10, 20000, false, host, ESDHC_DLLSTAT0))
> pr_err("%s: timeout for delay chain lock.\n",
> mmc_hostname(host->mmc));
Thank you very much.
I sent out v2 converting to use it.
>
>
>
> > +
> > temp = sdhci_readl(host, ESDHC_TBCTL);
> > sdhci_writel(host, temp | ESDHC_HS400_WNDW_ADJUST,
> ESDHC_TBCTL);
> >
> >
