Re: [PATCH 2/2] mci: sdhci: drop unused re-tuning timer plumbing

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

On 5/19/26 4:15 PM, Sascha Hauer wrote:
> From: Sascha Hauer <sascha@saschahauer.de>
> 
> tuning_count and tuning_mode are populated from the host's
> CAPABILITIES_1 register at probe time but never consumed. In Linux
> they feed an automatic re-tuning timer that periodically re-runs
> tuning every N seconds after the controller's re-tuning timer (mode 1)
> expires. barebox is a bootloader - tuning runs once at probe and the
> controller is then handed to the OS - so the timer infrastructure
> doesn't exist and the fields are dead weight.
> 
> Drop:
>   - tuning_count / tuning_mode struct members
>   - SDHCI_TUNING_MODE_1/2/3 defines
>   - SDHCI_RETUNING_TIMER_COUNT_MASK / SDHCI_RETUNING_MODE_MASK
>   - the dead read into a local tuning_count in sdhci_execute_tuning()
>   - the populate block in sdhci_setup_host()
> 
> No behavioural change.
> 
> Assisted-By: Claude Opus 4.7
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Reviewed-by: Ahmad Fatoum <a.fatoum@pengutronix.de>

> ---
>  drivers/mci/sdhci.c | 18 ------------------
>  drivers/mci/sdhci.h |  7 -------
>  2 files changed, 25 deletions(-)
> 
> diff --git a/drivers/mci/sdhci.c b/drivers/mci/sdhci.c
> index 1b13df8583..861e5c7862 100644
> --- a/drivers/mci/sdhci.c
> +++ b/drivers/mci/sdhci.c
> @@ -311,10 +311,6 @@ int sdhci_execute_tuning(struct sdhci *sdhci, u32 opcode)
>  {
>  	struct mci_host *host = sdhci->mci;
>  	int err = 0;
> -	unsigned int tuning_count = 0;
> -
> -	if (sdhci->tuning_mode == SDHCI_TUNING_MODE_1)
> -		tuning_count = sdhci->tuning_count;
>  
>  	/*
>  	 * The Host Controller needs tuning in case of SDR104 and DDR50
> @@ -1197,19 +1193,5 @@ int sdhci_setup_host(struct sdhci *host)
>  	host->tuning_delay = -1;
>  	host->tuning_loop_count = MAX_TUNING_LOOP;
>  
> -	/* Initial value for re-tuning timer count */
> -	host->tuning_count = FIELD_GET(SDHCI_RETUNING_TIMER_COUNT_MASK,
> -				       host->caps1);
> -
> -	/*
> -	 * In case Re-tuning Timer is not disabled, the actual value of
> -	 * re-tuning timer will be 2 ^ (n - 1).
> -	 */
> -	if (host->tuning_count)
> -		host->tuning_count = 1 << (host->tuning_count - 1);
> -
> -	/* Re-tuning mode supported by the Host Controller */
> -	host->tuning_mode = FIELD_GET(SDHCI_RETUNING_MODE_MASK, host->caps1);
> -
>  	return 0;
>  }
> diff --git a/drivers/mci/sdhci.h b/drivers/mci/sdhci.h
> index 4a326f9d84..3c678d7999 100644
> --- a/drivers/mci/sdhci.h
> +++ b/drivers/mci/sdhci.h
> @@ -175,9 +175,7 @@
>  #define  SDHCI_DRIVER_TYPE_A			0x00000010
>  #define  SDHCI_DRIVER_TYPE_C			0x00000020
>  #define  SDHCI_DRIVER_TYPE_D			0x00000040
> -#define  SDHCI_RETUNING_TIMER_COUNT_MASK	GENMASK(11, 8)
>  #define  SDHCI_USE_SDR50_TUNING			0x00002000
> -#define  SDHCI_RETUNING_MODE_MASK		GENMASK(15, 14)
>  #define  SDHCI_CLOCK_MUL_MASK			GENMASK(23, 16)
>  #define  SDHCI_CAN_DO_ADMA3			0x08000000
>  #define  SDHCI_SUPPORT_HS400			0x80000000 /* Non-standard */
> @@ -278,11 +276,6 @@ struct sdhci {
>  	bool read_caps;	/* Capability flags have been read */
>  	u32 sdma_boundary;
>  
> -	unsigned int		tuning_count;	/* Timer count for re-tuning */
> -	unsigned int		tuning_mode;	/* Re-tuning mode supported by host */
> -#define SDHCI_TUNING_MODE_1	0
> -#define SDHCI_TUNING_MODE_2	1
> -#define SDHCI_TUNING_MODE_3	2
>  	/* Delay (ms) between tuning commands */
>  	int			tuning_delay;
>  	int			tuning_loop_count;

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