linux-kernel - Re: [PATCH V3 3/4] mmc: sdhci-msm: Add Device tree parsing logic for DLL settings

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Message-ID: <c6ca33b2-f8c5-66e7-bb3b-dd595ed040c5@quicinc.com>
Date: Tue, 10 Jun 2025 17:47:22 +0530
From: Ram Prakash Gupta <quic_rampraka@...cinc.com>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Sachin Gupta
	<quic_sachgupt@...cinc.com>
CC: Ulf Hansson <ulf.hansson@...aro.org>, Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Bhupesh Sharma
	<bhupesh.sharma@...aro.org>,
        <linux-mmc@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <linux-arm-msm@...r.kernel.org>,
        <quic_cang@...cinc.com>, <quic_nguyenb@...cinc.com>,
        <quic_bhaskarv@...cinc.com>, <quic_mapa@...cinc.com>,
        <quic_narepall@...cinc.com>, <quic_nitirawa@...cinc.com>,
        <quic_sartgarg@...cinc.com>
Subject: Re: [PATCH V3 3/4] mmc: sdhci-msm: Add Device tree parsing logic for
 DLL settings

Hi Dmitry,

As updated in [PATCH V3 2/2] of this series, I have started now to continue
this work. Will address your comment next.

Thanks,
Ram

On 1/22/2025 3:27 PM, Dmitry Baryshkov wrote:
> On Wed, Jan 22, 2025 at 03:17:06PM +0530, Sachin Gupta wrote:
>> This update introduces the capability to configure HS200
>> and HS400 DLL settings via the device tree and parsing it.
>>
>> Signed-off-by: Sachin Gupta <quic_sachgupt@...cinc.com>
>> ---
>>  drivers/mmc/host/sdhci-msm.c | 86 ++++++++++++++++++++++++++++++++++++
>>  1 file changed, 86 insertions(+)
>>
>> diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
>> index 2a5e588779fc..cc7756a59c55 100644
>> --- a/drivers/mmc/host/sdhci-msm.c
>> +++ b/drivers/mmc/host/sdhci-msm.c
>> @@ -256,6 +256,19 @@ struct sdhci_msm_variant_info {
>>  	const struct sdhci_msm_offset *offset;
>>  };
>>  
>> +/*
>> + * DLL registers which needs be programmed with HSR settings.
>> + * Add any new register only at the end and don't change the
>> + * sequence.
>> + */
>> +struct sdhci_msm_dll {
>> +	u32 dll_config[2];
>> +	u32 dll_config_2[2];
>> +	u32 dll_config_3[2];
>> +	u32 dll_usr_ctl[2];
>> +	u32 ddr_config[2];
>> +};
>> +
>>  struct sdhci_msm_host {
>>  	struct platform_device *pdev;
>>  	void __iomem *core_mem;	/* MSM SDCC mapped address */
>> @@ -264,6 +277,7 @@ struct sdhci_msm_host {
>>  	struct clk *xo_clk;	/* TCXO clk needed for FLL feature of cm_dll*/
>>  	/* core, iface, cal and sleep clocks */
>>  	struct clk_bulk_data bulk_clks[4];
>> +	struct sdhci_msm_dll dll;
>>  #ifdef CONFIG_MMC_CRYPTO
>>  	struct qcom_ice *ice;
>>  #endif
>> @@ -292,6 +306,7 @@ struct sdhci_msm_host {
>>  	u32 dll_config;
>>  	u32 ddr_config;
>>  	bool vqmmc_enabled;
>> +	bool artanis_dll;
>>  };
>>  
>>  static const struct sdhci_msm_offset *sdhci_priv_msm_offset(struct sdhci_host *host)
>> @@ -2400,6 +2415,74 @@ static int sdhci_msm_gcc_reset(struct device *dev, struct sdhci_host *host)
>>  	return ret;
>>  }
>>  
>> +static int sdhci_msm_dt_get_array(struct device *dev, const char *prop_name,
>> +				  u32 **bw_vecs, int *len)
> It just reads an array from the DT, please rename the bw_vecs param
> which is inaccurate in this case.
>
>> +{
>> +	struct device_node *np = dev->of_node;
>> +	u32 *arr = NULL;
>> +	int ret = 0;
>> +	int sz;
>> +
>> +	if (!np)
>> +		return -ENODEV;
>> +
>> +	if (!of_get_property(np, prop_name, &sz))
>> +		return -EINVAL;
>> +
>> +	sz = sz / sizeof(*arr);
>> +	if (sz <= 0)
>> +		return -EINVAL;
>> +
>> +	arr = devm_kzalloc(dev, sz * sizeof(*arr), GFP_KERNEL);
>> +	if (!arr)
>> +		return -ENOMEM;
>> +
>> +	ret = of_property_read_u32_array(np, prop_name, arr, sz);
>> +	if (ret) {
>> +		dev_err(dev, "%s failed reading array %d\n", prop_name, ret);
>> +		*len = 0;
>> +		return ret;
>> +	}
>> +
>> +	*bw_vecs = arr;
>> +	*len = sz;
>> +	ret = 0;
>> +
>> +	return ret;
>> +}
>> +
>> +static int sdhci_msm_dt_parse_dll_info(struct device *dev, struct sdhci_msm_host *msm_host)
>> +{
>> +	int dll_table_len, dll_reg_count;
>> +	u32 *dll_table = NULL;
>> +	int i;
>> +
>> +	msm_host->artanis_dll = false;
>> +
>> +	if (sdhci_msm_dt_get_array(dev, "qcom,dll-hsr-list",
>> +				   &dll_table, &dll_table_len))
>> +		return -EINVAL;
>> +
>> +	dll_reg_count = sizeof(struct sdhci_msm_dll) / sizeof(u32);
>> +
>> +	if (dll_table_len != dll_reg_count) {
>> +		dev_err(dev, "Number of HSR entries are not matching\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	for (i = 0; i < 2; i++) {
>> +		msm_host->dll.dll_config[i] = dll_table[i];
>> +		msm_host->dll.dll_config_2[i] = dll_table[i + 1];
>> +		msm_host->dll.dll_config_3[i] = dll_table[i + 2];
>> +		msm_host->dll.dll_usr_ctl[i] = dll_table[i + 3];
>> +		msm_host->dll.ddr_config[i] = dll_table[i + 4];
>> +	}
>> +
>> +	msm_host->artanis_dll = true;
> And the pointer to dll_table is lost, lingering for the driver lifetime.
> Please drop the devm_ part and kfree() it once it is not used anymore.
>
>> +
>> +	return 0;
>> +}
>> +
>>  static int sdhci_msm_probe(struct platform_device *pdev)
>>  {
>>  	struct sdhci_host *host;
>> @@ -2446,6 +2529,9 @@ static int sdhci_msm_probe(struct platform_device *pdev)
>>  
>>  	msm_host->saved_tuning_phase = INVALID_TUNING_PHASE;
>>  
>> +	if (sdhci_msm_dt_parse_dll_info(&pdev->dev, msm_host))
>> +		goto pltfm_free;
>> +
>>  	ret = sdhci_msm_gcc_reset(&pdev->dev, host);
>>  	if (ret)
>>  		goto pltfm_free;
>> -- 
>> 2.17.1
>>