Re: [RFC PATCH v3 5/9] coresight: etm4x: Add complex configuration handlers to etmv4

[Mathieu Poirier <mathieu.poirier@linaro.org>]

On Fri, Oct 30, 2020 at 05:56:51PM +0000, Mike Leach wrote:
> Adds in handlers to allow the ETMv4 to use the complex configuration
> support. Features and configurations can be loaded and selected in the
> device.
> 
> Signed-off-by: Mike Leach <mike.leach@linaro.org>
> ---
>  drivers/hwtracing/coresight/Makefile          |   3 +-
>  .../hwtracing/coresight/coresight-etm4x-cfg.c | 181 ++++++++++++++++++
>  .../hwtracing/coresight/coresight-etm4x-cfg.h |  29 +++
>  .../coresight/coresight-etm4x-core.c          |  36 +++-
>  .../coresight/coresight-etm4x-sysfs.c         |   3 +
>  5 files changed, 249 insertions(+), 3 deletions(-)
>  create mode 100644 drivers/hwtracing/coresight/coresight-etm4x-cfg.c
>  create mode 100644 drivers/hwtracing/coresight/coresight-etm4x-cfg.h
> 
> diff --git a/drivers/hwtracing/coresight/Makefile b/drivers/hwtracing/coresight/Makefile
> index daad9f103a78..ea544206204d 100644
> --- a/drivers/hwtracing/coresight/Makefile
> +++ b/drivers/hwtracing/coresight/Makefile
> @@ -16,7 +16,8 @@ obj-$(CONFIG_CORESIGHT_SOURCE_ETM3X) += coresight-etm3x.o
>  coresight-etm3x-y := coresight-etm3x-core.o coresight-etm-cp14.o \
>  		     coresight-etm3x-sysfs.o
>  obj-$(CONFIG_CORESIGHT_SOURCE_ETM4X) += coresight-etm4x.o
> -coresight-etm4x-y := coresight-etm4x-core.o coresight-etm4x-sysfs.o
> +coresight-etm4x-y := coresight-etm4x-core.o coresight-etm4x-sysfs.o \
> +			coresight-etm4x-cfg.o
>  obj-$(CONFIG_CORESIGHT_STM) += coresight-stm.o
>  obj-$(CONFIG_CORESIGHT_CPU_DEBUG) += coresight-cpu-debug.o
>  obj-$(CONFIG_CORESIGHT_CATU) += coresight-catu.o
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-cfg.c b/drivers/hwtracing/coresight/coresight-etm4x-cfg.c
> new file mode 100644
> index 000000000000..9589d43e7947
> --- /dev/null
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-cfg.c
> @@ -0,0 +1,181 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright(C) 2020 Linaro Limited. All rights reserved.
> + * Author: Mike Leach <mike.leach@linaro.org>
> + */
> +
> +#include "coresight-etm4x.h"
> +#include "coresight-etm4x-cfg.h"
> +#include "coresight-priv.h"
> +#include "coresight-syscfg.h"
> +
> +/**
> + * etm4_cfg_map_reg_offset - validate and map the register offset into a
> + *			     location in the driver config struct.
> + *
> + * Limits the number of registers that can be accessed and programmed in
> + * features, to those which are used to control the trace capture parameters.
> + *
> + * Omits or limits access to those which the driver must use exclusively.
> + *
> + * Invalid offsets will result in fail code return and feature load failure.
> + *
> + * @drvdata:	driver data to map into.
> + * @reg:	register to map.
> + * @offset:	device offset for the register
> + */
> +static int etm4_cfg_map_reg_offset(struct etmv4_drvdata *drvdata,
> +				   struct cscfg_reg_csdev *reg, u32 offset)
> +{
> +	int err = -EINVAL, idx;
> +	struct etmv4_config *drvcfg = &drvdata->config;
> +	u32 off_mask;
> +
> +#define CHECKREG(cval, elem) \
> +	{ \
> +		if (offset == cval) { \
> +			reg->drv_store = &drvcfg->elem; \
> +			err = 0; \
> +			break; \
> +		} \
> +	}
> +
> +#define CHECKREGIDX(cval, elem, off_idx) \
> +	{ \
> +		if (off_mask == cval) { \
> +			reg->drv_store = &drvcfg->elem[off_idx]; \
> +			err = 0; \
> +			break; \
> +		} \
> +	}
> +
> +	if (((offset >= TRCEVENTCTL0R) && (offset <= TRCVIPCSSCTLR)) ||
> +	    ((offset >= TRCSEQRSTEVR) && (offset <= TRCEXTINSELR)) ||
> +	    ((offset >= TRCCIDCCTLR0) && (offset <= TRCVMIDCCTLR1))) {
> +		do {
> +			CHECKREG(TRCEVENTCTL0R, eventctrl0);
> +			CHECKREG(TRCEVENTCTL1R, eventctrl1);
> +			CHECKREG(TRCSTALLCTLR, stall_ctrl);
> +			CHECKREG(TRCTSCTLR, ts_ctrl);
> +			CHECKREG(TRCSYNCPR, syncfreq);
> +			CHECKREG(TRCCCCTLR, ccctlr);
> +			CHECKREG(TRCBBCTLR, bb_ctrl);
> +			CHECKREG(TRCVICTLR, vinst_ctrl);
> +			CHECKREG(TRCVIIECTLR, viiectlr);
> +			CHECKREG(TRCVISSCTLR, vissctlr);
> +			CHECKREG(TRCVIPCSSCTLR, vipcssctlr);
> +			CHECKREG(TRCSEQRSTEVR, seq_rst);
> +			CHECKREG(TRCSEQSTR, seq_state);
> +			CHECKREG(TRCEXTINSELR, ext_inp);
> +			CHECKREG(TRCCIDCCTLR0, ctxid_mask0);
> +			CHECKREG(TRCCIDCCTLR1, ctxid_mask1);
> +			CHECKREG(TRCVMIDCCTLR0, vmid_mask0);
> +			CHECKREG(TRCVMIDCCTLR1, vmid_mask1);
> +		} while (0);
> +	} else if ((offset & GENMASK(11, 4)) == TRCSEQEVRn(0)) {
> +		/* sequencer state control registers */
> +		idx = (offset & GENMASK(3, 0)) / 4;
> +		if (idx < ETM_MAX_SEQ_STATES) {
> +			reg->drv_store = &drvcfg->seq_ctrl[idx];
> +			err = 0;
> +		}
> +	} else if ((offset >= TRCSSCCRn(0)) && (offset <= TRCSSPCICRn(7))) {
> +		/* 32 bit, 8 off indexed register sets */
> +		idx = (offset & GENMASK(4, 0)) / 4;
> +		off_mask =  (offset & GENMASK(11, 5));
> +		do {
> +			CHECKREGIDX(TRCSSCCRn(0), ss_ctrl, idx);
> +			CHECKREGIDX(TRCSSCSRn(0), ss_status, idx);
> +			CHECKREGIDX(TRCSSPCICRn(0), ss_pe_cmp, idx);

This one is harder to understand because of @off_mask - please add it to the
list of parameters to the marcro so that all the element needed to understand
what is going on is at the same place.


> +		} while (0);
> +	} else if ((offset >= TRCCIDCVRn(0)) && (offset <= TRCVMIDCVRn(7))) {
> +		/* 64 bit, 8 off indexed register sets */
> +		idx = (offset & GENMASK(5, 0)) / 8;
> +		off_mask = (offset & GENMASK(11, 6));
> +		do {
> +			CHECKREGIDX(TRCCIDCVRn(0), ctxid_pid, idx);
> +			CHECKREGIDX(TRCVMIDCVRn(0), vmid_val, idx);
> +		} while (0);
> +	} else if ((offset >= TRCRSCTLRn(2)) &&
> +		   (offset <= TRCRSCTLRn((ETM_MAX_RES_SEL - 1)))) {
> +		/* 32 bit resource selection regs, 32 off, skip fixed 0,1 */
> +		idx = (offset & GENMASK(6, 0)) / 4;
> +		if (idx < ETM_MAX_RES_SEL) {
> +			reg->drv_store = &drvcfg->res_ctrl[idx];
> +			err = 0;
> +		}
> +	} else if ((offset >= TRCACVRn(0)) &&
> +		   (offset <= TRCACATRn((ETM_MAX_SINGLE_ADDR_CMP - 1)))) {
> +		/* 64 bit addr cmp regs, 16 off */
> +		idx = (offset & GENMASK(6, 0)) / 8;
> +		off_mask = offset & GENMASK(11, 7);
> +		do {
> +			CHECKREGIDX(TRCACVRn(0), addr_val, idx);
> +			CHECKREGIDX(TRCACATRn(0), addr_acc, idx);
> +		} while (0);
> +	} else if ((offset >= TRCCNTRLDVRn(0)) &&
> +		   (offset <= TRCCNTVRn((ETMv4_MAX_CNTR - 1)))) {
> +		/* 32 bit counter regs, 4 off (ETMv4_MAX_CNTR - 1) */
> +		idx = (offset &  GENMASK(3, 0)) / 4;
> +		off_mask = offset &  GENMASK(11, 4);
> +		do {
> +			CHECKREGIDX(TRCCNTRLDVRn(0), cntrldvr, idx);
> +			CHECKREGIDX(TRCCNTCTLRn(0), cntr_ctrl, idx);
> +			CHECKREGIDX(TRCCNTVRn(0), cntr_val, idx);
> +		} while (0);
> +	}
> +	return err;
> +}
> +
> +/**
> + * etm4_cfg_load_feature - load a feature into a device instance.
> + *
> + * @csdev:	An ETMv4 CoreSight device.
> + * @feat:	The feature to be loaded.
> + *
> + * The function will load a feature instance into the device, checking that
> + * the register definitions are valid for the device.
> + *
> + * Parameter and register definitions will be converted into internal
> + * structures that are used to set the values in the driver when the
> + * feature is enabled for the device.
> + *
> + * The feature spinlock pointer is initialised to the same spinlock
> + * that the driver uses to protect the internal register values.
> + */
> +static int etm4_cfg_load_feature(struct coresight_device *csdev,
> +				 struct cscfg_feature_csdev *feat)
> +{
> +	struct device *dev = csdev->dev.parent;
> +	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev);
> +	const struct cscfg_feature_desc *feat_desc = feat->desc;
> +	u32 offset;
> +	int i = 0, err = 0;
> +
> +	/* essential we set the device spinlock */

Please explain why you are doing this.  Otherwise we know it has to be done but
still wonder about the motivation.

> +	feat->csdev_spinlock = &drvdata->spinlock;
> +
> +	/* process the register descriptions */
> +	for (i = 0; i < feat->nr_regs && !err; i++) {
> +		offset = feat_desc->regs[i].flags & CS_CFG_REG_ID_MASK;

This confirms my comment from a previous patch.  Embedding the offset
in a variable called "flags" is very confusing.

> +		err = etm4_cfg_map_reg_offset(drvdata, &feat->regs[i], offset);
> +	}
> +	return err;
> +}
> +
> +/* match information when loading configurations */
> +#define CS_CFG_ETM4_MATCH_FLAGS	(CS_CFG_MATCH_CLASS_SRC_ALL | \
> +					 CS_CFG_MATCH_CLASS_SRC_ETM4)
> +
> +int etm4_cs_cfg_register(struct coresight_device *csdev, const char *dev_name)
> +{

s/etm4_cs_cfg_register/etm4_cscfg_register()

> +	struct cscfg_match_info cfg_info;
> +	struct cscfg_csdev_feat_ops ops;
> +
> +	cfg_info.dev_name = dev_name;
> +	cfg_info.match_flags = CS_CFG_ETM4_MATCH_FLAGS;
> +
> +	ops.load_feat = &etm4_cfg_load_feature;
> +
> +	return cscfg_register_csdev(csdev, &cfg_info, &ops);
> +}
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-cfg.h b/drivers/hwtracing/coresight/coresight-etm4x-cfg.h
> new file mode 100644
> index 000000000000..bf33c720b5e9
> --- /dev/null
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-cfg.h
> @@ -0,0 +1,29 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (c) 2014-2015, The Linux Foundation. All rights reserved.
> + */
> +
> +#ifndef _CORESIGHT_CORESIGHT_ETM4X_CFG_H
> +#define _CORESIGHT_CORESIGHT_ETM4X_CFG_H
> +
> +#include "coresight-config.h"
> +#include "coresight-etm4x.h"
> +
> +/* ETMv4 specific config defines */
> +
> +/* resource IDs */
> +
> +#define ETM4_CFG_RES_CTR	0x00001000
> +#define ETM4_CFG_RES_CMP	0x00002000
> +#define ETM4_CFG_RES_CMP_PAIR0	0x00003000
> +#define ETM4_CFG_RES_CMP_PAIR1	0x00004000
> +#define ETM4_CFG_RES_SEL	0x00005000
> +#define ETM4_CFG_RES_SEL_PAIR0	0x00006000
> +#define ETM4_CFG_RES_SEL_PAIR1	0x00007000
> +#define ETM4_CFG_RES_SEQ	0x00008000
> +#define ETM4_CFG_RES_TS		0x00009000
> +#define ETM4_CFG_RES_MASK	0x0000F000
> +

The first #define is used in the next patch but none of the others are.

> +int etm4_cs_cfg_register(struct coresight_device *csdev, const char *dev_name);
> +
> +#endif /* _CORESIGHT_CORESIGHT_ETM4X_CFG_H */
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> index 6096d7abf80d..88213aa7a72e 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> @@ -34,6 +34,8 @@
>  
>  #include "coresight-etm4x.h"
>  #include "coresight-etm-perf.h"
> +#include "coresight-etm4x-cfg.h"
> +#include "coresight-syscfg.h"
>  
>  static int boot_enable;
>  module_param(boot_enable, int, 0444);
> @@ -321,12 +323,15 @@ static int etm4_config_timestamp_event(struct etmv4_drvdata *drvdata)
>  	return ret;
>  }
>  
> -static int etm4_parse_event_config(struct etmv4_drvdata *drvdata,
> +static int etm4_parse_event_config(struct coresight_device *csdev,
>  				   struct perf_event *event)
>  {
>  	int ret = 0;
> +	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
>  	struct etmv4_config *config = &drvdata->config;
>  	struct perf_event_attr *attr = &event->attr;
> +	unsigned long cfg_id;
> +	int preset;
>  
>  	if (!attr) {
>  		ret = -EINVAL;
> @@ -384,6 +389,19 @@ static int etm4_parse_event_config(struct etmv4_drvdata *drvdata,
>  		/* bit[12], Return stack enable bit */
>  		config->cfg |= BIT(12);
>  
> +	/*
> +	 * Set any selected configuration and preset.
> +	 *
> +	 * This extracts the values of PMU_FORMAT_ATTR(configid) and PMU_FORMAT_ATTR(preset)
> +	 * in the perf attributes defined in coresight-etm-perf.c.
> +	 * configid uses bits 63:32 of attr->config2, preset uses bits 3:0 of attr->config.
> +	 */
> +	if (attr->config2 & GENMASK_ULL(63, 32)) {

I understand why you have used a mask of 63-32 but it would be extremely cryptic
for anyone else.  Please add a comment that justify your choice. 

> +		cfg_id = (u32)(attr->config2 >> 32);
> +		preset = attr->config & 0xF;

This implies that presets need to start at 1 rather than 0.  Otherwise there is
no way to specify the absence of a preset.  There is a comment for
cscfg_csdev_enable_config() but adding another one here to complete the equation
would be appreciated.

> +		ret = cscfg_csdev_enable_config(csdev, cfg_id, preset);
> +	}
> +
>  out:
>  	return ret;
>  }
> @@ -400,7 +418,7 @@ static int etm4_enable_perf(struct coresight_device *csdev,
>  	}
>  
>  	/* Configure the tracer based on the session's specifics */
> -	ret = etm4_parse_event_config(drvdata, event);
> +	ret = etm4_parse_event_config(csdev, event);
>  	if (ret)
>  		goto out;
>  	/* And enable it */
> @@ -416,6 +434,8 @@ static int etm4_enable_sysfs(struct coresight_device *csdev)
>  	struct etm4_enable_arg arg = { };
>  	int ret;
>  
> +	cscfg_csdev_set_enabled_feats(csdev);
> +
>  	spin_lock(&drvdata->spinlock);
>  
>  	/*
> @@ -530,11 +550,14 @@ static int etm4_disable_perf(struct coresight_device *csdev,
>  	u32 control;
>  	struct etm_filters *filters = event->hw.addr_filters;
>  	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
> +	struct perf_event_attr *attr = &event->attr;
>  
>  	if (WARN_ON_ONCE(drvdata->cpu != smp_processor_id()))
>  		return -EINVAL;
>  
>  	etm4_disable_hw(drvdata);
> +	if (attr->config2 & GENMASK_ULL(63, 32))

Here too.

I will continue tomorrow.

Thanks,
Mathieu

> +		cscfg_csdev_disable_config(csdev);
>  
>  	/*
>  	 * Check if the start/stop logic was active when the unit was stopped.
> @@ -569,6 +592,7 @@ static void etm4_disable_sysfs(struct coresight_device *csdev)
>  	smp_call_function_single(drvdata->cpu, etm4_disable_hw, drvdata, 1);
>  
>  	spin_unlock(&drvdata->spinlock);
> +	cscfg_csdev_save_enabled_feats(csdev);
>  	cpus_read_unlock();
>  
>  	dev_dbg(&csdev->dev, "ETM tracing disabled\n");
> @@ -1536,6 +1560,13 @@ static int etm4_probe(struct amba_device *adev, const struct amba_id *id)
>  		return ret;
>  	}
>  
> +	/* register with config infrastructure & load any current features */
> +	ret = etm4_cs_cfg_register(drvdata->csdev, dev_name(dev));
> +	if (ret) {
> +		coresight_unregister(drvdata->csdev);
> +		return ret;
> +	}
> +
>  	etmdrvdata[drvdata->cpu] = drvdata;
>  
>  	pm_runtime_put(&adev->dev);
> @@ -1588,6 +1619,7 @@ static int __exit etm4_remove(struct amba_device *adev)
>  
>  	cpus_read_unlock();
>  
> +	cscfg_unregister_csdev(drvdata->csdev);
>  	coresight_unregister(drvdata->csdev);
>  
>  	return 0;
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> index 989ce7b8ade7..78e68f3032d5 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> @@ -9,6 +9,7 @@
>  #include <linux/sysfs.h>
>  #include "coresight-etm4x.h"
>  #include "coresight-priv.h"
> +#include "coresight-config.h"
>  
>  static int etm4_set_mode_exclude(struct etmv4_drvdata *drvdata, bool exclude)
>  {
> @@ -269,6 +270,8 @@ static ssize_t reset_store(struct device *dev,
>  
>  	spin_unlock(&drvdata->spinlock);
>  
> +	cscfg_csdev_reset_feats(to_coresight_device(dev));
> +
>  	return size;
>  }
>  static DEVICE_ATTR_WO(reset);
> -- 
> 2.17.1
> 

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