Message-ID: <20230814234720.GW1428172@hu-bjorande-lv.qualcomm.com>
Date:   Mon, 14 Aug 2023 16:47:20 -0700
From:   Bjorn Andersson <quic_bjorande@...cinc.com>
To:     Nitin Rawat <quic_nitirawa@...cinc.com>
CC:     <mani@...nel.org>, <quic_cang@...cinc.com>,
        <quic_asutoshd@...cinc.com>, <avri.altman@....com>,
        <martin.petersen@...cle.com>, <beanhuo@...ron.com>,
        <bvanassche@....org>, <linux-scsi@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <agross@...nel.org>,
        <andersson@...nel.org>, <konrad.dybcio@...aro.org>,
        <jejb@...ux.ibm.com>, <linux-arm-msm@...r.kernel.org>,
        <quic_ziqichen@...cinc.com>,
        "Naveen Kumar Goud Arepalli" <quic_narepall@...cinc.com>
Subject: Re: [PATCH V4] scsi: ufs: qcom: Align programming sequence as per HW
 spec

On Mon, Aug 14, 2023 at 07:59:03PM +0530, Nitin Rawat wrote:
> Align clock configuration as per Qualcomm UFS controller hardware
> specification. As part of this patch we are aligning sequence
> for SYS1CLK_1US, MAX_CORE_CLK_1US_CYCLES and
> PA_VS_CORE_CLK_40NS_CYCLES.
> 
> SYS1CLK_1US_REG represents the required number of system 1-clock
> cycles for one microsecond. MAX_CORE_CLK_1US_CYCLES represents the
> required number of Qunipro core clock for one microsecond.
> PA_VS_CORE_CLK_40NS_CYCLES represents the required number of
> Qunipro core clock for 40 nanoseconds.
> 
> a) Support CORE_CLK_1US_CYCLES and PA_VS_CORE_CLK_40NS_CYCLES
> for multiple unipro clock frequencies. This is currently handled
> only for only 150Mhz and 75MHz. Also Configure SYS1CLK_1US_REG for
> pre scale up condition.
> 
> b) Update offset for core_clk_1us_cycles in DME_VS_CORE_CLK_CTRL. This
> offset is changed from Qualcomm UFS Controller V4.0.0 onwards.
> 
> c) Qualcomm UFS controller V4.0 and onwards PA_VS_CORE_CLK_40NS_CYCLES
> attribute needs to be programmed with frequency of unipro core clk of
> UFS host controller.
> 
> d) Enable internal HW division of unipro core_clk based on scale up and
> scale down condition. This bit should be cleared before entering any
> SVS mode.
> 

Thank you for expanding this, now it's much easier to reason about the
content of the patch.


The change refactors ufs_qcom_set_dme_vs_core_clk_ctrl_clear_div(),
adjusts the configuration for versions before 4, add new clock
configuration for version 4.

With such an impact across many generations of hardware, and the
refactoring, there is a significant risk of regressions. By lumping all
these changes into one commit, it wouldn't be possible to distinguish
regressions due to typos in the refactoring, changes to the existing
clock support or regressions due to changes for version 4.


I'd therefor like for you to split this in multiple patches, to isolate
these different categories of changes.

> Co-developed-by: Naveen Kumar Goud Arepalli <quic_narepall@...cinc.com>
> Signed-off-by: Naveen Kumar Goud Arepalli <quic_narepall@...cinc.com>
> Signed-off-by: Nitin Rawat <quic_nitirawa@...cinc.com>
> ---
> 
> Changes from v3:
> -Addressed bjorn comment to update commit msg to capture change details.
> 
> Changes from v2:
> - Addressed bao comment, removed duplicate clock timer cfg API call
> 
> Changes from v1:
> - Addressed bao comment, removed wrapper function
> - Tab alignment
> ---
>  drivers/ufs/host/ufs-qcom.c | 261 ++++++++++++++++++++++++++----------
>  drivers/ufs/host/ufs-qcom.h |  20 ++-
>  2 files changed, 207 insertions(+), 74 deletions(-)
> 
> diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
> index f88febb23123..5b603886f3d1 100644
> --- a/drivers/ufs/host/ufs-qcom.c
> +++ b/drivers/ufs/host/ufs-qcom.c
> @@ -91,10 +91,7 @@ static const struct __ufs_qcom_bw_table {
>  };
> 
>  static struct ufs_qcom_host *ufs_qcom_hosts[MAX_UFS_QCOM_HOSTS];
> -
>  static void ufs_qcom_get_default_testbus_cfg(struct ufs_qcom_host *host);
> -static int ufs_qcom_set_dme_vs_core_clk_ctrl_clear_div(struct ufs_hba *hba,
> -						       u32 clk_cycles);
> 
>  static struct ufs_qcom_host *rcdev_to_ufs_host(struct reset_controller_dev *rcd)
>  {
> @@ -532,7 +529,8 @@ static int ufs_qcom_hce_enable_notify(struct ufs_hba *hba,
>   * Return: zero for success and non-zero in case of a failure.
>   */
>  static int ufs_qcom_cfg_timers(struct ufs_hba *hba, u32 gear,
> -			       u32 hs, u32 rate, bool update_link_startup_timer)
> +				 u32 hs, u32 rate, bool link_startup,
> +				 bool is_pre_scale_up)
>  {
>  	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
>  	struct ufs_clk_info *clki;
> @@ -563,11 +561,16 @@ static int ufs_qcom_cfg_timers(struct ufs_hba *hba, u32 gear,
>  	/*
>  	 * The Qunipro controller does not use following registers:
>  	 * SYS1CLK_1US_REG, TX_SYMBOL_CLK_1US_REG, CLK_NS_REG &
> -	 * UFS_REG_PA_LINK_STARTUP_TIMER
> -	 * But UTP controller uses SYS1CLK_1US_REG register for Interrupt
> -	 * Aggregation logic.
> -	*/
> -	if (ufs_qcom_cap_qunipro(host) && !ufshcd_is_intr_aggr_allowed(hba))
> +	 * UFS_REG_PA_LINK_STARTUP_TIMER.
> +	 * However UTP controller uses SYS1CLK_1US_REG register for Interrupt
> +	 * Aggregation logic and Auto hibern8 logic.
> +	 * It is mandatory to write SYS1CLK_1US_REG register on UFS host
> +	 * controller V4.0.0 onwards.
> +	 */
> +	if (ufs_qcom_cap_qunipro(host) &&
> +	    !(ufshcd_is_intr_aggr_allowed(hba) ||
> +	    ufshcd_is_auto_hibern8_supported(hba) ||
> +	    host->hw_ver.major >= 4))
>  		return 0;
> 
>  	if (gear == 0) {
> @@ -576,8 +579,14 @@ static int ufs_qcom_cfg_timers(struct ufs_hba *hba, u32 gear,
>  	}
> 
>  	list_for_each_entry(clki, &hba->clk_list_head, list) {
> -		if (!strcmp(clki->name, "core_clk"))
> -			core_clk_rate = clk_get_rate(clki->clk);
> +		if (!strcmp(clki->name, "core_clk")) {
> +			if (is_pre_scale_up)
> +				core_clk_rate = clki->max_freq;
> +			else
> +				core_clk_rate = clk_get_rate(clki->clk);
> +			break;
> +		}
> +
>  	}
> 
>  	/* If frequency is smaller than 1MHz, set to 1MHz */
> @@ -657,7 +666,7 @@ static int ufs_qcom_cfg_timers(struct ufs_hba *hba, u32 gear,
>  		mb();
>  	}
> 
> -	if (update_link_startup_timer && host->hw_ver.major != 0x5) {
> +	if (link_startup && host->hw_ver.major != 0x5) {
>  		ufshcd_writel(hba, ((core_clk_rate / MSEC_PER_SEC) * 100),
>  			      REG_UFS_CFG0);
>  		/*
> @@ -670,6 +679,105 @@ static int ufs_qcom_cfg_timers(struct ufs_hba *hba, u32 gear,
>  	return 0;
>  }
> 
> +static int ufs_qcom_set_core_clk_ctrl(struct ufs_hba *hba,
> +				      u32 clk_1us_cycles,
> +				      u32 clk_40ns_cycles,
> +				      bool scale_up)
> +{
> +	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
> +	u32 mask = MAX_CORE_CLK_1US_CYCLES_MASK;
> +	u32 offset = 0;
> +	u32 reg;
> +	int err;
> +
> +	/* Bit mask and offset changed on UFS host controller V4.0.0 onwards */
> +	if (host->hw_ver.major >= 4) {
> +		mask = MAX_CORE_CLK_1US_CYCLES_MASK_V4;
> +		offset = MAX_CORE_CLK_1US_CYCLES_OFFSET_V4;
> +	}
> +
> +	if (clk_1us_cycles > mask)
> +		return -EINVAL;
> +
> +	err = ufshcd_dme_get(hba, UIC_ARG_MIB(DME_VS_CORE_CLK_CTRL), &reg);
> +	if (err)
> +		return err;
> +
> +	reg &= ~(mask << offset);
> +	reg |= clk_1us_cycles << offset;
> +
> +	if (scale_up)
> +		reg |= CORE_CLK_DIV_EN_BIT;
> +
> +	err = ufshcd_dme_set(hba, UIC_ARG_MIB(DME_VS_CORE_CLK_CTRL), reg);
> +	if (err)
> +		return err;
> +
> +	/*
> +	 * UFS host controller V4.0.0 onwards needs to program
> +	 * PA_VS_CORE_CLK_40NS_CYCLES attribute per programmed
> +	 * frequency of unipro core clk of UFS host controller.
> +	 */
> +	if (host->hw_ver.major >= 4) {
> +		if (clk_40ns_cycles > PA_VS_CORE_CLK_40NS_CYCLES_MASK)
> +			return -EINVAL;
> +
> +		err = ufshcd_dme_get(hba,
> +				     UIC_ARG_MIB(PA_VS_CORE_CLK_40NS_CYCLES),
> +				     &reg);
> +		if (err)
> +			return err;
> +
> +		reg &= ~PA_VS_CORE_CLK_40NS_CYCLES_MASK;
> +		reg |= clk_40ns_cycles;
> +
> +		err = ufshcd_dme_set(hba,
> +				     UIC_ARG_MIB(PA_VS_CORE_CLK_40NS_CYCLES),
> +				     reg);
> +	}
> +
> +	return err;
> +}
> +
> +static int ufs_qcom_cfg_core_clk_ctrl(struct ufs_hba *hba)
> +{
> +	struct list_head *head = &hba->clk_list_head;
> +	struct ufs_clk_info *clki;
> +	u32 max_freq = 0;
> +	int err;
> +
> +	list_for_each_entry(clki, head, list) {
> +		if (!IS_ERR_OR_NULL(clki->clk) &&
> +		    (!strcmp(clki->name, "core_clk_unipro"))) {

Unnecessary parenthesis, and line wrap (you may go beyond 80 characters
if that improves readability).

> +			max_freq = clki->max_freq;
> +			break;
> +		}
> +	}
> +
> +	switch (max_freq) {
> +	case MHZ_403:
> +		err = ufs_qcom_set_core_clk_ctrl(hba, 403, 16, true);
> +		break;
> +	case MHZ_300:
> +		err = ufs_qcom_set_core_clk_ctrl(hba, 300, 12, true);
> +		break;
> +	case MHZ_201_5:
> +		err = ufs_qcom_set_core_clk_ctrl(hba, 202, 8, true);
> +		break;
> +	case MHZ_150:
> +		err = ufs_qcom_set_core_clk_ctrl(hba, 150, 6, true);
> +		break;
> +	case MHZ_100:
> +		err = ufs_qcom_set_core_clk_ctrl(hba, 100, 4, true);
> +		break;
> +	default:
> +		dev_err(hba->dev, "unipro max_freq=%u entry missing\n", max_freq);
> +		err = -EINVAL;
> +		break;
> +	}
> +
> +	return err;
> +}
>  static int ufs_qcom_link_startup_notify(struct ufs_hba *hba,
>  					enum ufs_notify_change_status status)
>  {
> @@ -679,19 +787,21 @@ static int ufs_qcom_link_startup_notify(struct ufs_hba *hba,
>  	switch (status) {
>  	case PRE_CHANGE:
>  		if (ufs_qcom_cfg_timers(hba, UFS_PWM_G1, SLOWAUTO_MODE,
> -					0, true)) {
> +					0, true, false)) {
>  			dev_err(hba->dev, "%s: ufs_qcom_cfg_timers() failed\n",
>  				__func__);
>  			return -EINVAL;
>  		}
> 
> -		if (ufs_qcom_cap_qunipro(host))
> -			/*
> -			 * set unipro core clock cycles to 150 & clear clock
> -			 * divider
> -			 */
> -			err = ufs_qcom_set_dme_vs_core_clk_ctrl_clear_div(hba,
> -									  150);
> +		if (ufs_qcom_cap_qunipro(host)) {
> +			err = ufs_qcom_cfg_core_clk_ctrl(hba);
> +			if (err) {
> +				dev_err(hba->dev,
> +					"%s cfg core clk ctrl failed\n",
> +					__func__);
> +				return err;
> +			}
> +		}
> 
>  		/*
>  		 * Some UFS devices (and may be host) have issues if LCC is
> @@ -926,7 +1036,7 @@ static int ufs_qcom_pwr_change_notify(struct ufs_hba *hba,
>  	case POST_CHANGE:
>  		if (ufs_qcom_cfg_timers(hba, dev_req_params->gear_rx,
>  					dev_req_params->pwr_rx,
> -					dev_req_params->hs_rate, false)) {
> +					dev_req_params->hs_rate, false, false)) {
>  			dev_err(hba->dev, "%s: ufs_qcom_cfg_timers() failed\n",
>  				__func__);
>  			/*
> @@ -1296,69 +1406,52 @@ static void ufs_qcom_exit(struct ufs_hba *hba)
>  	phy_exit(host->generic_phy);
>  }
> 
> -static int ufs_qcom_set_dme_vs_core_clk_ctrl_clear_div(struct ufs_hba *hba,
> -						       u32 clk_cycles)
> +static int ufs_qcom_clk_scale_up_pre_change(struct ufs_hba *hba)
>  {
> -	int err;
> -	u32 core_clk_ctrl_reg;
> -
> -	if (clk_cycles > DME_VS_CORE_CLK_CTRL_MAX_CORE_CLK_1US_CYCLES_MASK)
> -		return -EINVAL;
> -
> -	err = ufshcd_dme_get(hba,
> -			    UIC_ARG_MIB(DME_VS_CORE_CLK_CTRL),
> -			    &core_clk_ctrl_reg);
> -	if (err)
> -		return err;
> -
> -	core_clk_ctrl_reg &= ~DME_VS_CORE_CLK_CTRL_MAX_CORE_CLK_1US_CYCLES_MASK;
> -	core_clk_ctrl_reg |= clk_cycles;
> -
> -	/* Clear CORE_CLK_DIV_EN */
> -	core_clk_ctrl_reg &= ~DME_VS_CORE_CLK_CTRL_CORE_CLK_DIV_EN_BIT;
> +	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
> +	struct ufs_pa_layer_attr *attr = &host->dev_req_params;
> +	int err = 0;
> 
> -	return ufshcd_dme_set(hba,
> -			    UIC_ARG_MIB(DME_VS_CORE_CLK_CTRL),
> -			    core_clk_ctrl_reg);
> -}
> +	if (!ufs_qcom_cap_qunipro(host))
> +		goto out;
> 
> -static int ufs_qcom_clk_scale_up_pre_change(struct ufs_hba *hba)
> -{
> -	/* nothing to do as of now */
> -	return 0;
> +	if (attr) {
> +		err = ufs_qcom_cfg_timers(hba, attr->gear_rx,
> +					    attr->pwr_rx, attr->hs_rate,
> +					    false, true);
> +		if (err)
> +			dev_err(hba->dev, "%s ufs cfg timer failed\n",
> +					  __func__);
> +	}
> +	err = ufs_qcom_cfg_core_clk_ctrl(hba);
> +out:
> +	return err;
>  }
> 
>  static int ufs_qcom_clk_scale_up_post_change(struct ufs_hba *hba)
>  {
> -	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
> -
> -	if (!ufs_qcom_cap_qunipro(host))
> -		return 0;
> -
> -	/* set unipro core clock cycles to 150 and clear clock divider */
> -	return ufs_qcom_set_dme_vs_core_clk_ctrl_clear_div(hba, 150);
> +	return 0;
>  }
> 
>  static int ufs_qcom_clk_scale_down_pre_change(struct ufs_hba *hba)
>  {
>  	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
>  	int err;
> -	u32 core_clk_ctrl_reg;
> +	u32 reg;

Really nice to see these variable names being cleaned up, but it makes
it harder to determine what the functional change is. So again, better
to keep that in a separate patch.

> 
>  	if (!ufs_qcom_cap_qunipro(host))
>  		return 0;
> 
> -	err = ufshcd_dme_get(hba,
> -			    UIC_ARG_MIB(DME_VS_CORE_CLK_CTRL),
> -			    &core_clk_ctrl_reg);
> +	err = ufshcd_dme_get(hba, UIC_ARG_MIB(DME_VS_CORE_CLK_CTRL), &reg);
> +	if (err)
> +		return err;
> 
>  	/* make sure CORE_CLK_DIV_EN is cleared */
> -	if (!err &&
> -	    (core_clk_ctrl_reg & DME_VS_CORE_CLK_CTRL_CORE_CLK_DIV_EN_BIT)) {
> -		core_clk_ctrl_reg &= ~DME_VS_CORE_CLK_CTRL_CORE_CLK_DIV_EN_BIT;
> +	if (reg & CORE_CLK_DIV_EN_BIT) {
> +		reg &= ~CORE_CLK_DIV_EN_BIT;
>  		err = ufshcd_dme_set(hba,
>  				    UIC_ARG_MIB(DME_VS_CORE_CLK_CTRL),
> -				    core_clk_ctrl_reg);
> +				    reg);
>  	}
> 
>  	return err;
> @@ -1367,19 +1460,50 @@ static int ufs_qcom_clk_scale_down_pre_change(struct ufs_hba *hba)
>  static int ufs_qcom_clk_scale_down_post_change(struct ufs_hba *hba)
>  {
>  	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
> +	struct ufs_pa_layer_attr *attr = &host->dev_req_params;
> +	struct list_head *head = &hba->clk_list_head;
> +	struct ufs_clk_info *clki;
> +	u32 curr_freq = 0;
> +	int err;
> 
>  	if (!ufs_qcom_cap_qunipro(host))
>  		return 0;
> 
> -	/* set unipro core clock cycles to 75 and clear clock divider */
> -	return ufs_qcom_set_dme_vs_core_clk_ctrl_clear_div(hba, 75);
> +	if (attr)
> +		ufs_qcom_cfg_timers(hba, attr->gear_rx, attr->pwr_rx,
> +					 attr->hs_rate, false, false);
> +
> +	list_for_each_entry(clki, head, list) {
> +		if (!IS_ERR_OR_NULL(clki->clk) &&
> +		   (!strcmp(clki->name, "core_clk_unipro"))) {

Unnecessary parenthesis, and line wrap (you may go beyond 80 characters
if that improves readability).

> +			curr_freq = clk_get_rate(clki->clk);
> +			break;
> +		}
> +	}
> +
> +	switch (curr_freq) {
> +	case MHZ_37_5:
> +		err = ufs_qcom_set_core_clk_ctrl(hba, 38, 2, false);
> +		break;
> +	case MHZ_75:
> +		err = ufs_qcom_set_core_clk_ctrl(hba, 75, 3, false);
> +		break;
> +	case MHZ_100:
> +	err = ufs_qcom_set_core_clk_ctrl(hba, 100, 4, false);

Odd indentation.

Regards,
Bjorn

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