[U-Boot] [PATCHv2 1/3] mmc: meson-gx: Fix clk phase tuning for MMC

[Jerome Brunet]

On Tue 24 Dec 2019 at 14:25, Anand Moon <linux.amoon at gmail.com> wrote:

> As per mainline line kernel fix the clk tunnig phase for
> mmc, set Core=180, Tx=0, Rx=0 clk phase for mmc initialization.
>
> Signed-off-by: Anand Moon <linux.amoon at gmail.com>
> ---
> Changes from previous
> use the mainline kernel tuning for clk tuning.
> Fixed the commmit messages.
> Patch v1:
> https://patchwork.ozlabs.org/patch/1201208/
>
> Before these changes.
>     clock is enabled (380953Hz)
>     clock is enabled (25000000Hz)
> After these changes
>     clock is enabled (380953Hz)
>     clock is enabled (25000000Hz)
>     clock is enabled (52000000Hz)
> Test on Odroid N2 and Odroid C2 with eMMC and microSD cards
> ---
>  arch/arm/include/asm/arch-meson/sd_emmc.h | 14 ++++++--------
>  drivers/mmc/meson_gx_mmc.c                |  9 +++++----
>  2 files changed, 11 insertions(+), 12 deletions(-)
>
> diff --git a/arch/arm/include/asm/arch-meson/sd_emmc.h b/arch/arm/include/asm/arch-meson/sd_emmc.h
> index e3a72c8b66..d70fe4f03e 100644
> --- a/arch/arm/include/asm/arch-meson/sd_emmc.h
> +++ b/arch/arm/include/asm/arch-meson/sd_emmc.h
> @@ -7,6 +7,7 @@
>  #define __SD_EMMC_H__
>  
>  #include <mmc.h>
> +#include <linux/bitops.h>
>  
>  #define SDIO_PORT_A			0
>  #define SDIO_PORT_B			1
> @@ -19,14 +20,11 @@
>  #define   CLK_MAX_DIV			63
>  #define   CLK_SRC_24M			(0 << 6)
>  #define   CLK_SRC_DIV2			(1 << 6)
> -#define   CLK_CO_PHASE_000		(0 << 8)
> -#define   CLK_CO_PHASE_090		(1 << 8)
> -#define   CLK_CO_PHASE_180		(2 << 8)
> -#define   CLK_CO_PHASE_270		(3 << 8)
> -#define   CLK_TX_PHASE_000		(0 << 10)
> -#define   CLK_TX_PHASE_090		(1 << 10)
> -#define   CLK_TX_PHASE_180		(2 << 10)
> -#define   CLK_TX_PHASE_270		(3 << 10)
> +
> +#define   CLK_CORE_PHASE_MASK		GENMASK(9, 8)
> +#define   CLK_TX_PHASE_MASK		GENMASK(11, 10)
> +#define   CLK_RX_PHASE_MASK		GENMASK(13, 12)
> +
>  #define   CLK_ALWAYS_ON			BIT(24)
>  
>  #define MESON_SD_EMMC_CFG		0x44
> diff --git a/drivers/mmc/meson_gx_mmc.c b/drivers/mmc/meson_gx_mmc.c
> index 86c1a7164a..402981c3bb 100644
> --- a/drivers/mmc/meson_gx_mmc.c
> +++ b/drivers/mmc/meson_gx_mmc.c
> @@ -52,10 +52,11 @@ static void meson_mmc_config_clock(struct mmc *mmc)
>  	clk_div = DIV_ROUND_UP(clk, mmc->clock);
>  
>  	/* 180 phase core clock */
> -	meson_mmc_clk |= CLK_CO_PHASE_180;
> -
> -	/* 180 phase tx clock */
> -	meson_mmc_clk |= CLK_TX_PHASE_000;
> +	meson_mmc_clk |= CLK_CORE_PHASE_MASK;
> +	/* 000 phase rx clock */
> +	meson_mmc_clk |= CLK_RX_PHASE_MASK;
> +	/* 000 phase tx clock */
> +	meson_mmc_clk |= CLK_TX_PHASE_MASK;
>

I'm not sure how this acheive what is descibed in the commit
description.

It looks more that it would set a 270 degree phase on all clocks, which
is not desirable.

>  	/* clock settings */
>  	meson_mmc_clk |= clk_src;