[EXTERNAL] Re: [PATCH v4 4/5] soc: ti: pruss: Add helper functions to set GPI mode, MII_RT_event and XFR

[Md Danish Anwar]

Hi Roger,

On 15/03/23 17:52, Roger Quadros wrote:
> 
> 
> On 13/03/2023 13:11, MD Danish Anwar wrote:
>> From: Suman Anna <s-anna at ti.com>
>>
>> The PRUSS CFG module is represented as a syscon node and is currently
>> managed by the PRUSS platform driver. Add easy accessor functions to set
>> GPI mode, MII_RT event enable/disable and XFR (XIN XOUT) enable/disable
>> to enable the PRUSS Ethernet usecase. These functions reuse the generic
>> pruss_cfg_update() API function.
>>
>> Signed-off-by: Suman Anna <s-anna at ti.com>
>> Co-developed-by: Grzegorz Jaszczyk <grzegorz.jaszczyk at linaro.org>
>> Signed-off-by: Grzegorz Jaszczyk <grzegorz.jaszczyk at linaro.org>
>> Signed-off-by: Puranjay Mohan <p-mohan at ti.com>
>> Signed-off-by: MD Danish Anwar <danishanwar at ti.com>
>> ---
>>  drivers/soc/ti/pruss.c           | 60 ++++++++++++++++++++++++++++++++
>>  include/linux/remoteproc/pruss.h | 22 ++++++++++++
>>  2 files changed, 82 insertions(+)
>>
>> diff --git a/drivers/soc/ti/pruss.c b/drivers/soc/ti/pruss.c
>> index 26d8129b515c..2f04b7922ddb 100644
>> --- a/drivers/soc/ti/pruss.c
>> +++ b/drivers/soc/ti/pruss.c
>> @@ -203,6 +203,66 @@ static int pruss_cfg_update(struct pruss *pruss, unsigned int reg,
>>  	return regmap_update_bits(pruss->cfg_regmap, reg, mask, val);
>>  }
>>  
>> +/**
>> + * pruss_cfg_gpimode() - set the GPI mode of the PRU
>> + * @pruss: the pruss instance handle
>> + * @pru_id: id of the PRU core within the PRUSS
>> + * @mode: GPI mode to set
>> + *
>> + * Sets the GPI mode for a given PRU by programming the
>> + * corresponding PRUSS_CFG_GPCFGx register
>> + *
>> + * Return: 0 on success, or an error code otherwise
>> + */
>> +int pruss_cfg_gpimode(struct pruss *pruss, enum pruss_pru_id pru_id,
>> +		      enum pruss_gpi_mode mode)
>> +{
>> +	if (pru_id < 0 || pru_id >= PRUSS_NUM_PRUS)
>> +		return -EINVAL;
>> +
>> +	if (mode < 0 || mode > PRUSS_GPI_MODE_MAX)
>> +		return -EINVAL;
>> +
>> +	return pruss_cfg_update(pruss, PRUSS_CFG_GPCFG(pru_id),
>> +				PRUSS_GPCFG_PRU_GPI_MODE_MASK,
>> +				mode << PRUSS_GPCFG_PRU_GPI_MODE_SHIFT);
>> +}
>> +EXPORT_SYMBOL_GPL(pruss_cfg_gpimode);
>> +
>> +/**
>> + * pruss_cfg_miirt_enable() - Enable/disable MII RT Events
>> + * @pruss: the pruss instance
>> + * @enable: enable/disable
>> + *
>> + * Enable/disable the MII RT Events for the PRUSS.
>> + *
>> + * Return: 0 on success, or an error code otherwise
>> + */
>> +int pruss_cfg_miirt_enable(struct pruss *pruss, bool enable)
>> +{
>> +	u32 set = enable ? PRUSS_MII_RT_EVENT_EN : 0;
>> +
>> +	return pruss_cfg_update(pruss, PRUSS_CFG_MII_RT,
>> +				PRUSS_MII_RT_EVENT_EN, set);
>> +}
>> +EXPORT_SYMBOL_GPL(pruss_cfg_miirt_enable);
>> +
>> +/**
>> + * pruss_cfg_xfr_enable() - Enable/disable XIN XOUT shift functionality
>> + * @pruss: the pruss instance
>> + * @enable: enable/disable
>> + * @mask: Mask for PRU / RTU
> 
> You should not expect the user to provide the mask but only
> the core type e.g. 
> 
> enum pru_type {
>         PRU_TYPE_PRU = 0,
>         PRU_TYPE_RTU,
>         PRU_TYPE_TX_PRU,
>         PRU_TYPE_MAX,
> };
> 
> Then you figure out the mask in the function.
> Also check for invalid pru_type and return error if so.
> 

Sure Roger, I will create a enum and take it as parameter in API. Based on
these enum I will calculate mask and do XFR shifting inside the API
pruss_cfg_xfr_enable().

There are two registers for XFR shift.

#define PRUSS_SPP_XFER_SHIFT_EN                 BIT(1)
#define PRUSS_SPP_RTU_XFR_SHIFT_EN              BIT(3)

For PRU XFR shifting, the mask should be PRUSS_SPP_XFER_SHIFT_EN,
for RTU shifting mask should be PRUSS_SPP_RTU_XFR_SHIFT_EN and for PRU and RTU
shifting mask should be (PRUSS_SPP_XFER_SHIFT_EN | PRUSS_SPP_RTU_XFR_SHIFT_EN)

So the enum would be something like this.

/**
 * enum xfr_shift_type - XFR shift type
 * @XFR_SHIFT_PRU: Enables XFR shift for PRU
 * @XFR_SHIFT_RTU: Enables XFR shift for RTU
 * @XFR_SHIFT_PRU_RTU: Enables XFR shift for both PRU and RTU
 * @XFR_SHIFT_MAX: Total number of XFR shift types available.
 *
 */

enum xfr_shift_type {
        XFR_SHIFT_PRU = 0,
        XFR_SHIFT_RTU,
        XFR_SHIFT_PRU_RTU,
        XFR_SHIFT_MAX,
};

In pruss_cfg_xfr_enable() API, I will use switch case, and for first three
enums, I will calculate the mask.

If input is anything other than first three, I will retun -EINVAL. This will
serve as check for valid xfr_shift_type.

The API will look like this.

int pruss_cfg_xfr_enable(struct pruss *pruss, enum xfr_shift_type xfr_type,
			 bool enable);
{
	u32 mask;

	switch (xfr_type) {
	case XFR_SHIFT_PRU:
		mask = PRUSS_SPP_XFER_SHIFT_EN;
		break;
	case XFR_SHIFT_RTU:
		mask = PRUSS_SPP_RTU_XFR_SHIFT_EN;
		break;
	case XFR_SHIFT_PRU_RTU:
		mask = PRUSS_SPP_XFER_SHIFT_EN | PRUSS_SPP_RTU_XFR_SHIFT_EN;
		break;
	default:
		return -EINVAL;
	}

	u32 set = enable ? mask : 0;

	return pruss_cfg_update(pruss, PRUSS_CFG_SPP, mask, set);
}

This entire change I will keep as part of this patch only.

Please let me know if this looks OK to you.


>> + *
>> + * Return: 0 on success, or an error code otherwise
>> + */
>> +int pruss_cfg_xfr_enable(struct pruss *pruss, bool enable, u32 mask)
> 
> re-arrange so it is (struct pruss, enum pru_type, bool enable)
> 
>> +{
>> +	u32 set = enable ? mask : 0;
>> +
>> +	return pruss_cfg_update(pruss, PRUSS_CFG_SPP, mask, set);
>> +}
>> +EXPORT_SYMBOL_GPL(pruss_cfg_xfr_enable);
>> +
>>  static void pruss_of_free_clk_provider(void *data)
>>  {
>>  	struct device_node *clk_mux_np = data;
>> diff --git a/include/linux/remoteproc/pruss.h b/include/linux/remoteproc/pruss.h
>> index 12ef10b9fe9a..51a3eedd2be6 100644
>> --- a/include/linux/remoteproc/pruss.h
>> +++ b/include/linux/remoteproc/pruss.h
>> @@ -101,6 +101,7 @@ enum pruss_gpi_mode {
>>  	PRUSS_GPI_MODE_PARALLEL,
>>  	PRUSS_GPI_MODE_28BIT_SHIFT,
>>  	PRUSS_GPI_MODE_MII,
>> +	PRUSS_GPI_MODE_MAX,
> 
> This could have come as part of patch 3.
> 
>>  };
>>  
>>  /**
>> @@ -165,6 +166,10 @@ int pruss_request_mem_region(struct pruss *pruss, enum pruss_mem mem_id,
>>  			     struct pruss_mem_region *region);
>>  int pruss_release_mem_region(struct pruss *pruss,
>>  			     struct pruss_mem_region *region);
>> +int pruss_cfg_gpimode(struct pruss *pruss, enum pruss_pru_id pru_id,
>> +		      enum pruss_gpi_mode mode);
>> +int pruss_cfg_miirt_enable(struct pruss *pruss, bool enable);
>> +int pruss_cfg_xfr_enable(struct pruss *pruss, bool enable, u32 mask);
>>  
>>  #else
>>  
>> @@ -188,6 +193,23 @@ static inline int pruss_release_mem_region(struct pruss *pruss,
>>  	return -EOPNOTSUPP;
>>  }
>>  
>> +static inline int pruss_cfg_gpimode(struct pruss *pruss,
>> +				    enum pruss_pru_id pru_id,
>> +				    enum pruss_gpi_mode mode)
>> +{
>> +	return ERR_PTR(-EOPNOTSUPP);
>> +}
>> +
>> +static inline int pruss_cfg_miirt_enable(struct pruss *pruss, bool enable)
>> +{
>> +	return ERR_PTR(-EOPNOTSUPP);
>> +}
>> +
>> +static inline int pruss_cfg_xfr_enable(struct pruss *pruss, bool enable, u32 mask)
>> +{
>> +	return ERR_PTR(-EOPNOTSUPP);
>> +}
>> +
>>  #endif /* CONFIG_TI_PRUSS */
>>  
>>  #if IS_ENABLED(CONFIG_PRU_REMOTEPROC)
> 
> cheers,
> -roger

-- 
Thanks and Regards,
Danish.