Date:   Tue, 30 Mar 2021 11:53:29 -0600
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     Mike Leach <mike.leach@...aro.org>
Cc:     linux-arm-kernel@...ts.infradead.org, coresight@...ts.linaro.org,
        linux-doc@...r.kernel.org, suzuki.poulose@....com,
        yabinc@...gle.com, corbet@....net, leo.yan@...aro.org,
        alexander.shishkin@...ux.intel.com, tingwei@...eaurora.org,
        gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 03/10] coresight: config: Add configuration and
 feature generic functions

On Tue, Mar 16, 2021 at 06:03:53PM +0000, Mike Leach wrote:
> Adds a set of generic support functions that allow devices to set and save
> features values on the device, and enable and disable configurations.
> 
> Additional functions for other common operations including feature
> reset.
> 
> Signed-off-by: Mike Leach <mike.leach@...aro.org>
> ---
>  drivers/hwtracing/coresight/Makefile          |   2 +-
>  .../hwtracing/coresight/coresight-config.c    | 274 ++++++++++++++++++
>  .../hwtracing/coresight/coresight-config.h    |   9 +
>  .../hwtracing/coresight/coresight-syscfg.c    |   3 +-
>  4 files changed, 286 insertions(+), 2 deletions(-)
>  create mode 100644 drivers/hwtracing/coresight/coresight-config.c
>

This patch is so much easier to review with a consistent naming convention...

With the kernel test robot warning addressed: 

Reviewed-by: Mathieu Poirier <mathieu.poirier@...aro.org>

 
> diff --git a/drivers/hwtracing/coresight/Makefile b/drivers/hwtracing/coresight/Makefile
> index 4ce854c434b1..daad9f103a78 100644
> --- a/drivers/hwtracing/coresight/Makefile
> +++ b/drivers/hwtracing/coresight/Makefile
> @@ -4,7 +4,7 @@
>  #
>  obj-$(CONFIG_CORESIGHT) += coresight.o
>  coresight-y := coresight-core.o  coresight-etm-perf.o coresight-platform.o \
> -		coresight-sysfs.o coresight-syscfg.o
> +		coresight-sysfs.o coresight-syscfg.o coresight-config.o
>  obj-$(CONFIG_CORESIGHT_LINK_AND_SINK_TMC) += coresight-tmc.o
>  coresight-tmc-y := coresight-tmc-core.o coresight-tmc-etf.o \
>  		      coresight-tmc-etr.o
> diff --git a/drivers/hwtracing/coresight/coresight-config.c b/drivers/hwtracing/coresight/coresight-config.c
> new file mode 100644
> index 000000000000..571e90485c06
> --- /dev/null
> +++ b/drivers/hwtracing/coresight/coresight-config.c
> @@ -0,0 +1,274 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright(C) 2020 Linaro Limited. All rights reserved.
> + * Author: Mike Leach <mike.leach@...aro.org>
> + */
> +
> +#include <linux/sysfs.h>
> +#include "coresight-config.h"
> +#include "coresight-priv.h"
> +
> +/*
> + * This provides a set of generic functions that operate on configurations
> + * and features to manage the handling of parameters, the programming and
> + * saving of registers used by features on devices.
> + */
> +
> +/*
> + * Write the value held in the register structure into the driver internal memory
> + * location.
> + */
> +static void cscfg_set_reg(struct cscfg_regval_csdev *reg_csdev)
> +{
> +	u32 *p_val32 = (u32 *)reg_csdev->driver_regval;
> +	u32 tmp32 = reg_csdev->reg_desc.val32;
> +
> +	if (reg_csdev->reg_desc.type & CS_CFG_REG_TYPE_VAL_64BIT) {
> +		*((u64 *)reg_csdev->driver_regval) = reg_csdev->reg_desc.val64;
> +		return;
> +	}
> +
> +	if (reg_csdev->reg_desc.type & CS_CFG_REG_TYPE_VAL_MASK) {
> +		tmp32 = *p_val32;
> +		tmp32 &= ~reg_csdev->reg_desc.mask32;
> +		tmp32 |= reg_csdev->reg_desc.val32 & reg_csdev->reg_desc.mask32;
> +	}
> +	*p_val32 = tmp32;
> +}
> +
> +/*
> + * Read the driver value into the reg if this is marked as one we want to save.
> + */
> +static void cscfg_save_reg(struct cscfg_regval_csdev *reg_csdev)
> +{
> +	if (!(reg_csdev->reg_desc.type & CS_CFG_REG_TYPE_VAL_SAVE))
> +		return;
> +	if (reg_csdev->reg_desc.type & CS_CFG_REG_TYPE_VAL_64BIT)
> +		reg_csdev->reg_desc.val64 = *(u64 *)(reg_csdev->driver_regval);
> +	else
> +		reg_csdev->reg_desc.val32 = *(u32 *)(reg_csdev->driver_regval);
> +}
> +
> +/*
> + * Some register values are set from parameters. Initialise these registers
> + * from the current parameter values.
> + */
> +static void cscfg_init_reg_param(struct cscfg_feature_csdev *feat_csdev,
> +				 struct cscfg_regval_desc *reg_desc,
> +				 struct cscfg_regval_csdev *reg_csdev)
> +{
> +	struct cscfg_parameter_csdev *param_csdev;
> +
> +	/* for param, load routines have validated the index */
> +	param_csdev = &feat_csdev->params_csdev[reg_desc->param_idx];
> +	param_csdev->reg_csdev = reg_csdev;
> +	param_csdev->val64 = reg_csdev->reg_desc.type & CS_CFG_REG_TYPE_VAL_64BIT;
> +
> +	if (param_csdev->val64)
> +		reg_csdev->reg_desc.val64 = param_csdev->current_value;
> +	else
> +		reg_csdev->reg_desc.val32 = (u32)param_csdev->current_value;
> +}
> +
> +/* set values into the driver locations referenced in cscfg_reg_csdev */
> +static int cscfg_set_on_enable(struct cscfg_feature_csdev *feat_csdev)
> +{
> +	int i;
> +
> +	spin_lock(feat_csdev->drv_spinlock);
> +	for (i = 0; i < feat_csdev->nr_regs; i++)
> +		cscfg_set_reg(&feat_csdev->regs_csdev[i]);
> +	spin_unlock(feat_csdev->drv_spinlock);
> +	dev_dbg(&feat_csdev->csdev->dev, "Feature %s: %s",
> +		feat_csdev->feat_desc->name, "set on enable");
> +	return 0;
> +}
> +
> +/* copy back values from the driver locations referenced in cscfg_reg_csdev */
> +static void cscfg_save_on_disable(struct cscfg_feature_csdev *feat_csdev)
> +{
> +	int i;
> +
> +	spin_lock(feat_csdev->drv_spinlock);
> +	for (i = 0; i < feat_csdev->nr_regs; i++)
> +		cscfg_save_reg(&feat_csdev->regs_csdev[i]);
> +	spin_unlock(feat_csdev->drv_spinlock);
> +	dev_dbg(&feat_csdev->csdev->dev, "Feature %s: %s",
> +		feat_csdev->feat_desc->name, "save on disable");
> +}
> +
> +/* default reset - restore default values */
> +void cscfg_reset_feat(struct cscfg_feature_csdev *feat_csdev)
> +{
> +	struct cscfg_regval_desc *reg_desc;
> +	struct cscfg_regval_csdev *reg_csdev;
> +	int i;
> +
> +	/*
> +	 * set the default values for all parameters and regs from the
> +	 * relevant static descriptors.
> +	 */
> +	for (i = 0; i < feat_csdev->nr_params; i++)
> +		feat_csdev->params_csdev[i].current_value =
> +			feat_csdev->feat_desc->params_desc[i].value;
> +
> +	for (i = 0; i < feat_csdev->nr_regs; i++) {
> +		reg_desc = &feat_csdev->feat_desc->regs_desc[i];
> +		reg_csdev = &feat_csdev->regs_csdev[i];
> +		reg_csdev->reg_desc.type = reg_desc->type;
> +
> +		/* check if reg set from a parameter otherwise desc default */
> +		if (reg_desc->type & CS_CFG_REG_TYPE_VAL_PARAM)
> +			cscfg_init_reg_param(feat_csdev, reg_desc, reg_csdev);
> +		else
> +			/*
> +			 * for normal values the union between val64 & val32 + mask32
> +			 * allows us to init using the 64 bit value
> +			 */
> +			reg_csdev->reg_desc.val64 = reg_desc->val64;
> +	}
> +}
> +
> +/*
> + * For the selected presets, we set the register associated with the parameter, to
> + * the value of the preset index associated with the parameter.
> + */
> +static int cscfg_update_presets(struct cscfg_config_csdev *config_csdev, int preset)
> +{
> +	int i, j, val_idx = 0, nr_cfg_params;
> +	struct cscfg_parameter_csdev *param_csdev;
> +	struct cscfg_feature_csdev *feat_csdev;
> +	const struct cscfg_config_desc *config_desc = config_csdev->config_desc;
> +	const char *name;
> +	const u64 *preset_base;
> +	u64 val;
> +
> +	/* preset in range 1 to nr_presets */
> +	if (preset < 1 || preset > config_desc->nr_presets)
> +		return -EINVAL;
> +	/*
> +	 * Go through the array of features, assigning preset values to
> +	 * feature parameters in the order they appear.
> +	 * There should be precisely the same number of preset values as the
> +	 * sum of number of parameters over all the features - but we will
> +	 * ensure there is no overrun.
> +	 */
> +	nr_cfg_params = config_desc->nr_total_params;
> +	preset_base = &config_desc->presets[(preset - 1) * nr_cfg_params];
> +	for (i = 0; i < config_csdev->nr_feat; i++) {
> +		feat_csdev = config_csdev->feats_csdev[i];
> +		if (!feat_csdev->nr_params)
> +			continue;
> +
> +		for (j = 0; j < feat_csdev->nr_params; j++) {
> +			param_csdev = &feat_csdev->params_csdev[j];
> +			name = feat_csdev->feat_desc->params_desc[j].name;
> +			val = preset_base[val_idx++];
> +			if (param_csdev->val64) {
> +				dev_dbg(&config_csdev->csdev->dev,
> +					"set param %s (%lld)", name, val);
> +				param_csdev->reg_csdev->reg_desc.val64 = val;
> +			} else {
> +				param_csdev->reg_csdev->reg_desc.val32 = (u32)val;
> +				dev_dbg(&config_csdev->csdev->dev,
> +					"set param %s (%d)", name, (u32)val);
> +			}
> +		}
> +
> +		/* exit early if all params filled */
> +		if (val_idx >= nr_cfg_params)
> +			break;
> +	}
> +	return 0;
> +}
> +
> +/*
> + * if we are not using a preset, then need to update the feature params
> + * with current values. This sets the register associated with the parameter
> + * with the current value of that parameter.
> + */
> +static int cscfg_update_curr_params(struct cscfg_config_csdev *config_csdev)
> +{
> +	int i, j;
> +	struct cscfg_feature_csdev *feat_csdev;
> +	struct cscfg_parameter_csdev *param_csdev;
> +	const char *name;
> +	u64 val;
> +
> +	for (i = 0; i < config_csdev->nr_feat; i++) {
> +		feat_csdev = config_csdev->feats_csdev[i];
> +		if (!feat_csdev->nr_params)
> +			continue;
> +		for (j = 0; j < feat_csdev->nr_params; j++) {
> +			param_csdev = &feat_csdev->params_csdev[j];
> +			name = feat_csdev->feat_desc->params_desc[j].name;
> +			val = param_csdev->current_value;
> +			if (param_csdev->val64) {
> +				dev_dbg(&config_csdev->csdev->dev,
> +					"set param %s (%lld)", name, val);
> +				param_csdev->reg_csdev->reg_desc.val64 = val;
> +			} else {
> +				param_csdev->reg_csdev->reg_desc.val32 = (u32)val;
> +				dev_dbg(&config_csdev->csdev->dev,
> +					"set param %s (%d)", name, (u32)val);
> +			}
> +		}
> +	}
> +	return 0;
> +}
> +
> +/*
> + * Configuration values will be programmed into the driver locations if enabling, or read
> + * from relevant locations on disable.
> + */
> +static int cscfg_prog_config(struct cscfg_config_csdev *config_csdev, bool enable)
> +{
> +	int i, err = 0;
> +	struct cscfg_feature_csdev *feat_csdev;
> +	struct coresight_device *csdev;
> +
> +	for (i = 0; i < config_csdev->nr_feat; i++) {
> +		feat_csdev = config_csdev->feats_csdev[i];
> +		csdev = feat_csdev->csdev;
> +		dev_dbg(&csdev->dev, "cfg %s;  %s feature:%s", config_csdev->config_desc->name,
> +			enable ? "enable" : "disable", feat_csdev->feat_desc->name);
> +
> +		if (enable)
> +			err = cscfg_set_on_enable(feat_csdev);
> +		else
> +			cscfg_save_on_disable(feat_csdev);
> +
> +		if (err)
> +			break;
> +	}
> +	return err;
> +}
> +
> +/**
> + * Enable configuration for the device.
> + *
> + * @config_csdev:	config_csdev to set.
> + * @preset:		preset values to use - 0 for default.
> + */
> +int cscfg_csdev_enable_config(struct cscfg_config_csdev *config_csdev, int preset)
> +{
> +	int err = 0;
> +
> +	if (preset)
> +		err = cscfg_update_presets(config_csdev, preset);
> +	else
> +		err = cscfg_update_curr_params(config_csdev);
> +	if (!err)
> +		err = cscfg_prog_config(config_csdev, true);
> +	if (!err)
> +		config_csdev->enabled = true;
> +	return err;
> +}
> +
> +void cscfg_csdev_disable_config(struct cscfg_config_csdev *config_csdev)
> +{
> +	if (config_csdev->enabled) {
> +		cscfg_prog_config(config_csdev, false);
> +		config_csdev->enabled = false;
> +	}
> +}
> diff --git a/drivers/hwtracing/coresight/coresight-config.h b/drivers/hwtracing/coresight/coresight-config.h
> index 685fb46ce893..f70561c1504b 100644
> --- a/drivers/hwtracing/coresight/coresight-config.h
> +++ b/drivers/hwtracing/coresight/coresight-config.h
> @@ -237,4 +237,13 @@ struct cscfg_csdev_feat_ops {
>  			 struct cscfg_feature_csdev *feat_csdev);
>  };
>  
> +/* coresight config helper functions*/
> +
> +/* enable / disable config on a device - called with appropriate locks set.*/
> +int cscfg_csdev_enable_config(struct cscfg_config_csdev *cfg, int preset);
> +void cscfg_csdev_disable_config(struct cscfg_config_csdev *cfg);
> +
> +/* reset a feature to default values */
> +void cscfg_reset_feat(struct cscfg_feature_csdev *feat);
> +
>  #endif /* _CORESIGHT_CORESIGHT_CONFIG_H */
> diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c
> index d6471eab8a5f..11d1422f0ed3 100644
> --- a/drivers/hwtracing/coresight/coresight-syscfg.c
> +++ b/drivers/hwtracing/coresight/coresight-syscfg.c
> @@ -190,9 +190,10 @@ static int cscfg_load_feat_csdev(struct coresight_device *csdev,
>  	if (err)
>  		return err;
>  
> -	/* add to internal csdev feature list */
> +	/* add to internal csdev feature list & initialise using reset call */
>  	mutex_lock(&cscfg_csdev_mutex);
>  	list_add(&feat_csdev->node, &csdev->feature_csdev_list);
> +	cscfg_reset_feat(feat_csdev);
>  	mutex_unlock(&cscfg_csdev_mutex);
>  
>  	return 0;
> -- 
> 2.17.1
> 

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