Re: [PATCH v8 3/5] mmc: sdhci-msm: Set ICE clk to TURBO at sdhci ICE init

[Harshal Dev <harshal.dev@oss.qualcomm.com>]

On 4/9/2026 5:14 PM, Abhinaba Rakshit wrote:
> MMC controller lacks a clock scaling mechanism, unlike the UFS
> controller. By default, the MMC controller is set to TURBO mode
> during probe, but the ICE clock remains at XO frequency,
> leading to read/write performance degradation on eMMC.
> 
> To address this, set the ICE clock to TURBO during sdhci_msm_ice_init
> to align it with the controller clock. This ensures consistent
> performance and avoids mismatches between the controller
> and ICE clock frequencies.
> 
> For platforms where ICE is represented as a separate device,
> use the OPP framework to vote for TURBO mode, maintaining
> proper voltage and power domain constraints.
> 
> Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
> Signed-off-by: Abhinaba Rakshit <abhinaba.rakshit@oss.qualcomm.com>
> ---
>  drivers/mmc/host/sdhci-msm.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 

[...]

>  
>  static const struct blk_crypto_ll_ops sdhci_msm_crypto_ops; /* forward decl */
> +static int sdhci_msm_ice_scale_clk(struct sdhci_msm_host *msm_host, unsigned long target_freq,
> +				   bool round_ceil); /* forward decl */
>  
>  static int sdhci_msm_ice_init(struct sdhci_msm_host *msm_host,
>  			      struct cqhci_host *cq_host)
> @@ -1964,6 +1966,11 @@ static int sdhci_msm_ice_init(struct sdhci_msm_host *msm_host,
>  	}
>  
>  	mmc->caps2 |= MMC_CAP2_CRYPTO;
> +
> +	err = sdhci_msm_ice_scale_clk(msm_host, INT_MAX, false);

The 2nd parameter is an unsigned long, do you really want to pass INT_MAX here? I would go with
UINT_MAX. But still, why go with such a high value? Do we not have an upper bound for the clk
frequency that we know we can't ever exceed for any target across OPP tables? If not, then maybe
UINT_MAX is best we can do here.

Regards,
Harshal

> +	if (err && err != -EOPNOTSUPP)
> +		dev_warn(dev, "Unable to boost ICE clock to TURBO\n");
> +
>  	return 0;
>  }
>  
> @@ -1989,6 +1996,16 @@ static int sdhci_msm_ice_suspend(struct sdhci_msm_host *msm_host)
>  	return 0;
>  }
>  
> +static int sdhci_msm_ice_scale_clk(struct sdhci_msm_host *msm_host,
> +				   unsigned long target_freq,
> +				   bool round_ceil)
> +{
> +	if (msm_host->mmc->caps2 & MMC_CAP2_CRYPTO)
> +		return qcom_ice_scale_clk(msm_host->ice, target_freq, round_ceil);
> +
> +	return 0;
> +}
> +