[1/2] scsi: ufs: ufs-qcom: add basic interconnect support

The firmware on the Qualcomm platforms expects the interconnect votes to
be present. Let's add very basic support where the maximum throughput is
requested to match what's done in a few other drivers.

This will not break boot on systems where the interconnects and
interconnect-names properties are not specified in device tree for UFS
since the interconnect framework will silently return.

Signed-off-by: Brian Masney <bmasney@redhat.com>
---
 drivers/ufs/host/ufs-qcom.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

On 17/11/2022 12:49, Brian Masney wrote:
> The firmware on the Qualcomm platforms expects the interconnect votes to
> be present. Let's add very basic support where the maximum throughput is
> requested to match what's done in a few other drivers.
> 
> This will not break boot on systems where the interconnects and
> interconnect-names properties are not specified in device tree for UFS
> since the interconnect framework will silently return.
> 
> Signed-off-by: Brian Masney <bmasney@redhat.com>
> ---
>   drivers/ufs/host/ufs-qcom.c | 25 +++++++++++++++++++++++++
>   1 file changed, 25 insertions(+)
> 
> diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
> index 8ad1415e10b6..55bf8dd88985 100644
> --- a/drivers/ufs/host/ufs-qcom.c
> +++ b/drivers/ufs/host/ufs-qcom.c
> @@ -7,6 +7,7 @@
>   #include <linux/time.h>
>   #include <linux/clk.h>
>   #include <linux/delay.h>
> +#include <linux/interconnect.h>
>   #include <linux/module.h>
>   #include <linux/of.h>
>   #include <linux/platform_device.h>
> @@ -936,6 +937,22 @@ static const struct reset_control_ops ufs_qcom_reset_ops = {
>   	.deassert = ufs_qcom_reset_deassert,
>   };
>   
> +static int ufs_qcom_icc_init(struct device *dev, char *pathname)
> +{
> +	struct icc_path *path;
> +	int ret;
> +
> +	path = devm_of_icc_get(dev, pathname);
> +	if (IS_ERR(path))
> +		return dev_err_probe(dev, PTR_ERR(path), "failed to acquire interconnect path\n");
> +
> +	ret = icc_set_bw(path, 0, UINT_MAX);

I noticed that this patch bumps peak_bw (and leaves average_bw as 0), 
while vendor kernels bump average_bw, but ib (peak_bw) is set to 0.

> +	if (ret < 0)
> +		return dev_err_probe(dev, ret, "failed to set bandwidth request\n");
> +
> +	return 0;
> +}
> +
>   /**
>    * ufs_qcom_init - bind phy with controller
>    * @hba: host controller instance
> @@ -991,6 +1008,14 @@ static int ufs_qcom_init(struct ufs_hba *hba)
>   			err = dev_err_probe(dev, PTR_ERR(host->generic_phy), "Failed to get PHY\n");
>   			goto out_variant_clear;
>   		}
> +
> +		err = ufs_qcom_icc_init(dev, "ufs-ddr");
> +		if (err)
> +			goto out_variant_clear;
> +
> +		err = ufs_qcom_icc_init(dev, "cpu-ufs");
> +		if (err)
> +			goto out_variant_clear;
>   	}
>   
>   	host->device_reset = devm_gpiod_get_optional(dev, "reset",

On 17.11.2022 11:49, Brian Masney wrote:
> The firmware on the Qualcomm platforms expects the interconnect votes to
> be present. Let's add very basic support where the maximum throughput is
> requested to match what's done in a few other drivers.
> 
> This will not break boot on systems where the interconnects and
> interconnect-names properties are not specified in device tree for UFS
> since the interconnect framework will silently return.
> 
> Signed-off-by: Brian Masney <bmasney@redhat.com>
> ---
Hi everyone!

This was never merged, but it's actually strictly necessary!

For example UFS dies on SM8450 if we add sync_state to its interconnect
driver, as there's no votes cast.

Can we look into this again?

Konrad
>  drivers/ufs/host/ufs-qcom.c | 25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
> 
> diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
> index 8ad1415e10b6..55bf8dd88985 100644
> --- a/drivers/ufs/host/ufs-qcom.c
> +++ b/drivers/ufs/host/ufs-qcom.c
> @@ -7,6 +7,7 @@
>  #include <linux/time.h>
>  #include <linux/clk.h>
>  #include <linux/delay.h>
> +#include <linux/interconnect.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/platform_device.h>
> @@ -936,6 +937,22 @@ static const struct reset_control_ops ufs_qcom_reset_ops = {
>  	.deassert = ufs_qcom_reset_deassert,
>  };
>  
> +static int ufs_qcom_icc_init(struct device *dev, char *pathname)
> +{
> +	struct icc_path *path;
> +	int ret;
> +
> +	path = devm_of_icc_get(dev, pathname);
> +	if (IS_ERR(path))
> +		return dev_err_probe(dev, PTR_ERR(path), "failed to acquire interconnect path\n");
> +
> +	ret = icc_set_bw(path, 0, UINT_MAX);
> +	if (ret < 0)
> +		return dev_err_probe(dev, ret, "failed to set bandwidth request\n");
> +
> +	return 0;
> +}
> +
>  /**
>   * ufs_qcom_init - bind phy with controller
>   * @hba: host controller instance
> @@ -991,6 +1008,14 @@ static int ufs_qcom_init(struct ufs_hba *hba)
>  			err = dev_err_probe(dev, PTR_ERR(host->generic_phy), "Failed to get PHY\n");
>  			goto out_variant_clear;
>  		}
> +
> +		err = ufs_qcom_icc_init(dev, "ufs-ddr");
> +		if (err)
> +			goto out_variant_clear;
> +
> +		err = ufs_qcom_icc_init(dev, "cpu-ufs");
> +		if (err)
> +			goto out_variant_clear;
>  	}
>  
>  	host->device_reset = devm_gpiod_get_optional(dev, "reset",