Re: [EXTERNAL] Re: [PATCH v5 3/5] soc: ti: pruss: Add pruss_cfg_read()/update() API

[Md Danish Anwar <a0501179@ti.com>]

Hi Mathieu,

On 28/03/23 02:31, Mathieu Poirier wrote:
> On Thu, Mar 23, 2023 at 11:54:49AM +0530, MD Danish Anwar wrote:
>> From: Suman Anna <s-anna@ti.com>
>>
>> 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. Various useful registers
>> and macros for certain register bit-fields and their values have also
>> been added.
>>
>> Signed-off-by: Suman Anna <s-anna@ti.com>
>> Co-developed-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@linaro.org>
>> Signed-off-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@linaro.org>
>> Signed-off-by: Puranjay Mohan <p-mohan@ti.com>
>> Signed-off-by: MD Danish Anwar <danishanwar@ti.com>
>> ---
>>  drivers/soc/ti/pruss.c |   1 +
>>  drivers/soc/ti/pruss.h | 112 +++++++++++++++++++++++++++++++++++++++++
>>  2 files changed, 113 insertions(+)
>>  create mode 100644 drivers/soc/ti/pruss.h
>>
> 
> This patch doesn't compile without warnings.
> 

I checked the warnings. Below are the warnings that I am getting for these patch.

In file included from drivers/soc/ti/pruss.c:24:
drivers/soc/ti/pruss.h:103:12: warning: ‘pruss_cfg_update’ defined but not used
[-Wunused-function]
  103 | static int pruss_cfg_update(struct pruss *pruss, unsigned int reg,
      |            ^~~~~~~~~~~~~~~~
drivers/soc/ti/pruss.h:84:12: warning: ‘pruss_cfg_read’ defined but not used
[-Wunused-function]
   84 | static int pruss_cfg_read(struct pruss *pruss, unsigned int reg,
unsigned int *val)

These warnings are coming because pruss_cfg_read() / update() APIs are
introduced in this patch but they are used later.

One way to resolve this warning is to make this API "inline". I compiled after
making these APIs inline, it got compiled without any warnings.

The other solution is to merge a user API of these APIs in this patch. Patch 4
and 5 introduces some APIs that uses pruss_cfg_read() / update() APIs. If we
squash patch 5 (as patch 5 uses both read() and update() APIs where as patch 4
only uses update() API) with this patch and make it a single patch where
pruss_cfg_read() / update() is introduced as well as used, then this warning
will be resolved.

I still think making these APIs "inline" is a better option as these APIs
implement very simple one line logic and can be made inline.

Please let me know what do you think and which approach sounds better.


>> diff --git a/drivers/soc/ti/pruss.c b/drivers/soc/ti/pruss.c
>> index 126b672b9b30..2fa7df667592 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
>> diff --git a/drivers/soc/ti/pruss.h b/drivers/soc/ti/pruss.h
>> new file mode 100644
>> index 000000000000..4626d5f6b874
>> --- /dev/null
>> +++ b/drivers/soc/ti/pruss.h
>> @@ -0,0 +1,112 @@
>> +/* 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 <danishanwar@ti.com>
>> + */
>> +
>> +#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_GPO_SH_SEL              BIT(25)
>> +
>> +#define PRUSS_GPCFG_PRU_DIV1_SHIFT              20
>> +#define PRUSS_GPCFG_PRU_DIV1_MASK               GENMASK(24, 20)
>> +
>> +#define PRUSS_GPCFG_PRU_DIV0_SHIFT              15
>> +#define PRUSS_GPCFG_PRU_DIV0_MASK               GENMASK(15, 19)
>> +
>> +#define PRUSS_GPCFG_PRU_GPO_MODE                BIT(14)
>> +#define PRUSS_GPCFG_PRU_GPO_MODE_DIRECT         0
>> +#define PRUSS_GPCFG_PRU_GPO_MODE_SERIAL         BIT(14)
>> +
>> +#define PRUSS_GPCFG_PRU_GPI_SB                  BIT(13)
>> +
>> +#define PRUSS_GPCFG_PRU_GPI_DIV1_SHIFT          8
>> +#define PRUSS_GPCFG_PRU_GPI_DIV1_MASK           GENMASK(12, 8)
>> +
>> +#define PRUSS_GPCFG_PRU_GPI_DIV0_SHIFT          3
>> +#define PRUSS_GPCFG_PRU_GPI_DIV0_MASK           GENMASK(7, 3)
>> +
>> +#define PRUSS_GPCFG_PRU_GPI_CLK_MODE_POSITIVE   0
>> +#define PRUSS_GPCFG_PRU_GPI_CLK_MODE_NEGATIVE   BIT(2)
>> +#define PRUSS_GPCFG_PRU_GPI_CLK_MODE            BIT(2)
>> +
>> +#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_ */
>> -- 
>> 2.25.1
>>

-- 
Thanks and Regards,
Danish.