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));
> +
> temp = sdhci_readl(host, ESDHC_TBCTL);
> sdhci_writel(host, temp | ESDHC_HS400_WNDW_ADJUST, ESDHC_TBCTL);
>
>
