Subject: Re: [PATCH v8 3/4] soc: ti: pruss: Add pruss_cfg_read()/update(), pruss_cfg_get_gpmux()/set_gpmux() APIs

From: Mathieu Poirier <[email-masked]>
Date: Wed, 12 Apr 2023 11:06:54 -0600

On Wed, Apr 12, 2023 at 04:00:11PM +0530, MD Danish Anwar wrote:
> From: Suman Anna <[email-masked]>
> 
> Add two new generic API pruss_cfg_read() and pruss_cfg_update() to
> the PRUSS platform driver to read and program respectively a register
> within the PRUSS CFG sub-module represented by a syscon driver. These
> APIs are internal to PRUSS driver.
> 
> Add two new helper functions pruss_cfg_get_gpmux() & pruss_cfg_set_gpmux()
> to get and set the GP MUX mode for programming the PRUSS internal wrapper
> mux functionality as needed by usecases.
> 
> Various useful registers and macros for certain register bit-fields and
> their values have also been added.
> 
> Signed-off-by: Suman Anna <[email-masked]>
> Co-developed-by: Grzegorz Jaszczyk <[email-masked]>
> Signed-off-by: Grzegorz Jaszczyk <[email-masked]>
> Signed-off-by: Puranjay Mohan <[email-masked]>
> Reviewed-by: Roger Quadros <[email-masked]>
> Reviewed-by: Tony Lindgren <[email-masked]>
> Reviewed-by: Simon Horman <[email-masked]>
> Signed-off-by: MD Danish Anwar <[email-masked]>
> ---
>  drivers/soc/ti/pruss.c       | 45 ++++++++++++++++++
>  drivers/soc/ti/pruss.h       | 88 ++++++++++++++++++++++++++++++++++++
>  include/linux/pruss_driver.h | 32 +++++++++++++
>  3 files changed, 165 insertions(+)
>  create mode 100644 drivers/soc/ti/pruss.h
> 
> diff --git a/drivers/soc/ti/pruss.c b/drivers/soc/ti/pruss.c
> index 8ada3758b31a..34d513816a9d 100644
> --- a/drivers/soc/ti/pruss.c
> +++ b/drivers/soc/ti/pruss.c
> @@ -21,6 +21,7 @@
>  #include <linux/regmap.h>
>  #include <linux/remoteproc.h>
>  #include <linux/slab.h>
> +#include "pruss.h"
>  
>  /**
>   * struct pruss_private_data - PRUSS driver private data
> @@ -168,6 +169,50 @@ int pruss_release_mem_region(struct pruss *pruss,
>  }
>  EXPORT_SYMBOL_GPL(pruss_release_mem_region);
>  
> +/**
> + * pruss_cfg_get_gpmux() - get the current GPMUX value for a PRU device
> + * @pruss: pruss instance
> + * @pru_id: PRU identifier (0-1)
> + * @mux: pointer to store the current mux value into
> + *
> + * Return: 0 on success, or an error code otherwise
> + */
> +int pruss_cfg_get_gpmux(struct pruss *pruss, enum pruss_pru_id pru_id, u8 *mux)
> +{
> +	int ret = 0;

Variable initialization is not needed.

> +	u32 val;
> +
> +	if (pru_id < 0 || pru_id >= PRUSS_NUM_PRUS || !mux)

If @pru_id is an enum, how can it be smaller than 0?

> +		return -EINVAL;
> +
> +	ret = pruss_cfg_read(pruss, PRUSS_CFG_GPCFG(pru_id), &val);
> +	if (!ret)
> +		*mux = (u8)((val & PRUSS_GPCFG_PRU_MUX_SEL_MASK) >>
> +			    PRUSS_GPCFG_PRU_MUX_SEL_SHIFT);
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(pruss_cfg_get_gpmux);
> +
> +/**
> + * pruss_cfg_set_gpmux() - set the GPMUX value for a PRU device
> + * @pruss: pruss instance
> + * @pru_id: PRU identifier (0-1)
> + * @mux: new mux value for PRU
> + *
> + * Return: 0 on success, or an error code otherwise
> + */
> +int pruss_cfg_set_gpmux(struct pruss *pruss, enum pruss_pru_id pru_id, u8 mux)
> +{
> +	if (mux >= PRUSS_GP_MUX_SEL_MAX ||
> +	    pru_id < 0 || pru_id >= PRUSS_NUM_PRUS)

Same

> +		return -EINVAL;
> +
> +	return pruss_cfg_update(pruss, PRUSS_CFG_GPCFG(pru_id),
> +				PRUSS_GPCFG_PRU_MUX_SEL_MASK,
> +				(u32)mux << PRUSS_GPCFG_PRU_MUX_SEL_SHIFT);
> +}
> +EXPORT_SYMBOL_GPL(pruss_cfg_set_gpmux);
> +
>  static void pruss_of_free_clk_provider(void *data)
>  {
>  	struct device_node *clk_mux_np = data;
> diff --git a/drivers/soc/ti/pruss.h b/drivers/soc/ti/pruss.h
> new file mode 100644
> index 000000000000..6c55987e0e55
> --- /dev/null
> +++ b/drivers/soc/ti/pruss.h
> @@ -0,0 +1,88 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * PRU-ICSS Subsystem user interfaces
> + *
> + * Copyright (C) 2015-2023 Texas Instruments Incorporated - http://www.ti.com
> + *	MD Danish Anwar <[email-masked]>
> + */
> +
> +#ifndef _SOC_TI_PRUSS_H_
> +#define _SOC_TI_PRUSS_H_
> +
> +#include <linux/bits.h>
> +#include <linux/regmap.h>
> +
> +/*
> + * PRU_ICSS_CFG registers
> + * SYSCFG, ISRP, ISP, IESP, IECP, SCRP applicable on AMxxxx devices only
> + */
> +#define PRUSS_CFG_REVID         0x00
> +#define PRUSS_CFG_SYSCFG        0x04
> +#define PRUSS_CFG_GPCFG(x)      (0x08 + (x) * 4)
> +#define PRUSS_CFG_CGR           0x10
> +#define PRUSS_CFG_ISRP          0x14
> +#define PRUSS_CFG_ISP           0x18
> +#define PRUSS_CFG_IESP          0x1C
> +#define PRUSS_CFG_IECP          0x20
> +#define PRUSS_CFG_SCRP          0x24
> +#define PRUSS_CFG_PMAO          0x28
> +#define PRUSS_CFG_MII_RT        0x2C
> +#define PRUSS_CFG_IEPCLK        0x30
> +#define PRUSS_CFG_SPP           0x34
> +#define PRUSS_CFG_PIN_MX        0x40
> +
> +/* PRUSS_GPCFG register bits */
> +#define PRUSS_GPCFG_PRU_GPI_MODE_MASK           GENMASK(1, 0)
> +#define PRUSS_GPCFG_PRU_GPI_MODE_SHIFT          0
> +
> +#define PRUSS_GPCFG_PRU_MUX_SEL_SHIFT           26
> +#define PRUSS_GPCFG_PRU_MUX_SEL_MASK            GENMASK(29, 26)
> +
> +/* PRUSS_MII_RT register bits */
> +#define PRUSS_MII_RT_EVENT_EN                   BIT(0)
> +
> +/* PRUSS_SPP register bits */
> +#define PRUSS_SPP_XFER_SHIFT_EN                 BIT(1)
> +#define PRUSS_SPP_PRU1_PAD_HP_EN                BIT(0)
> +#define PRUSS_SPP_RTU_XFR_SHIFT_EN              BIT(3)
> +
> +/**
> + * pruss_cfg_read() - read a PRUSS CFG sub-module register
> + * @pruss: the pruss instance handle
> + * @reg: register offset within the CFG sub-module
> + * @val: pointer to return the value in
> + *
> + * Reads a given register within the PRUSS CFG sub-module and
> + * returns it through the passed-in @val pointer
> + *
> + * Return: 0 on success, or an error code otherwise
> + */
> +static int pruss_cfg_read(struct pruss *pruss, unsigned int reg, unsigned int *val)
> +{
> +	if (IS_ERR_OR_NULL(pruss))
> +		return -EINVAL;
> +
> +	return regmap_read(pruss->cfg_regmap, reg, val);
> +}
> +
> +/**
> + * pruss_cfg_update() - configure a PRUSS CFG sub-module register
> + * @pruss: the pruss instance handle
> + * @reg: register offset within the CFG sub-module
> + * @mask: bit mask to use for programming the @val
> + * @val: value to write
> + *
> + * Programs a given register within the PRUSS CFG sub-module
> + *
> + * Return: 0 on success, or an error code otherwise
> + */
> +static int pruss_cfg_update(struct pruss *pruss, unsigned int reg,
> +			    unsigned int mask, unsigned int val)
> +{
> +	if (IS_ERR_OR_NULL(pruss))
> +		return -EINVAL;
> +
> +	return regmap_update_bits(pruss->cfg_regmap, reg, mask, val);
> +}
> +
> +#endif  /* _SOC_TI_PRUSS_H_ */
> diff --git a/include/linux/pruss_driver.h b/include/linux/pruss_driver.h
> index c8f2e53b911b..c70e08c90165 100644
> --- a/include/linux/pruss_driver.h
> +++ b/include/linux/pruss_driver.h
> @@ -14,6 +14,24 @@
>  #include <linux/types.h>
>  #include <linux/err.h>
>  
> +/*
> + * enum pruss_gp_mux_sel - PRUSS GPI/O Mux modes for the
> + * PRUSS_GPCFG0/1 registers
> + *
> + * NOTE: The below defines are the most common values, but there
> + * are some exceptions like on 66AK2G, where the RESERVED and MII2
> + * values are interchanged. Also, this bit-field does not exist on
> + * AM335x SoCs
> + */
> +enum pruss_gp_mux_sel {
> +	PRUSS_GP_MUX_SEL_GP = 0,

Initialization not needed

> +	PRUSS_GP_MUX_SEL_ENDAT,
> +	PRUSS_GP_MUX_SEL_RESERVED,
> +	PRUSS_GP_MUX_SEL_SD,
> +	PRUSS_GP_MUX_SEL_MII2,
> +	PRUSS_GP_MUX_SEL_MAX,
> +};
> +
>  /*
>   * enum pruss_mem - PRUSS memory range identifiers
>   */
> @@ -66,6 +84,8 @@ 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_get_gpmux(struct pruss *pruss, enum pruss_pru_id pru_id, u8 *mux);
> +int pruss_cfg_set_gpmux(struct pruss *pruss, enum pruss_pru_id pru_id, u8 mux);
>  
>  #else
>  
> @@ -89,6 +109,18 @@ static inline int pruss_release_mem_region(struct pruss *pruss,
>  	return -EOPNOTSUPP;
>  }
>  
> +static inline int pruss_cfg_get_gpmux(struct pruss *pruss,
> +				      enum pruss_pru_id pru_id, u8 *mux)
> +{
> +	return ERR_PTR(-EOPNOTSUPP);
> +}
> +
> +static inline int pruss_cfg_set_gpmux(struct pruss *pruss,
> +				      enum pruss_pru_id pru_id, u8 mux)
> +{
> +	return ERR_PTR(-EOPNOTSUPP);
> +}
> +
>  #endif /* CONFIG_TI_PRUSS */
>  
>  #endif	/* _PRUSS_DRIVER_H_ */
> -- 
> 2.34.1
>