From: Yangbo Lu <[email protected]> commit 011fde48394b7dc8dfd6660d1013b26a00157b80 upstream.
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 <[email protected]> Acked-by: Adrian Hunter <[email protected]> Link: https://lore.kernel.org/r/[email protected] Fixes: 54e08d9a95ca ("mmc: sdhci-of-esdhc: add hs400 mode support") Cc: [email protected] Signed-off-by: Ulf Hansson <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/mmc/host/sdhci-esdhc.h | 2 ++ drivers/mmc/host/sdhci-of-esdhc.c | 17 +++++++++++++++++ 2 files changed, 19 insertions(+) --- 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 <[email protected]> */ @@ -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 */ --- 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 <[email protected]> * Anton Vorontsov <[email protected]> @@ -19,6 +20,7 @@ #include <linux/clk.h> #include <linux/ktime.h> #include <linux/dma-mapping.h> +#include <linux/iopoll.h> #include <linux/mmc/host.h> #include <linux/mmc/mmc.h> #include "sdhci-pltfm.h" @@ -743,6 +745,21 @@ static void esdhc_of_set_clock(struct sd 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 */ + 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);
