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Date:   Mon, 16 May 2022 17:26:14 +0100
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Subject: Re: [PATCH v8 3/8] hwtracing: hisi_ptt: Add tune function support for
 HiSilicon PCIe Tune and Trace device
To:     Yicong Yang <yangyicong@hisilicon.com>,
        <gregkh@linuxfoundation.org>, <alexander.shishkin@linux.intel.com>,
        <leo.yan@linaro.org>, <james.clark@arm.com>, <will@kernel.org>,
        <robin.murphy@arm.com>, <acme@kernel.org>,
        <jonathan.cameron@huawei.com>
CC:     <helgaas@kernel.org>, <lorenzo.pieralisi@arm.com>,
        <mathieu.poirier@linaro.org>, <suzuki.poulose@arm.com>,
        <mark.rutland@arm.com>, <joro@8bytes.org>,
        <shameerali.kolothum.thodi@huawei.com>, <peterz@infradead.org>,
        <mingo@redhat.com>, <linux-kernel@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-pci@vger.kernel.org>, <linux-perf-users@vger.kernel.org>,
        <iommu@lists.linux-foundation.org>, <prime.zeng@huawei.com>,
        <liuqi115@huawei.com>, <zhangshaokun@hisilicon.com>,
        <linuxarm@huawei.com>
References: <20220516125223.32012-1-yangyicong@hisilicon.com>
 <20220516125223.32012-4-yangyicong@hisilicon.com>
From:   John Garry <john.garry@huawei.com>
In-Reply-To: <20220516125223.32012-4-yangyicong@hisilicon.com>
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On 16/05/2022 13:52, Yicong Yang wrote:
> Add tune function for the HiSilicon Tune and Trace device. The interface
> of tune is exposed through sysfs attributes of PTT PMU device.
> 
> Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Apart from a comment on preferential style:

Reviewed-by: John Garry <john.garry@huawei.com>

> ---
>   drivers/hwtracing/ptt/hisi_ptt.c | 157 +++++++++++++++++++++++++++++++
>   drivers/hwtracing/ptt/hisi_ptt.h |  23 +++++
>   2 files changed, 180 insertions(+)
> 
> diff --git a/drivers/hwtracing/ptt/hisi_ptt.c b/drivers/hwtracing/ptt/hisi_ptt.c
> index ef25ce98f664..c3fdb9bfb1b4 100644
> --- a/drivers/hwtracing/ptt/hisi_ptt.c
> +++ b/drivers/hwtracing/ptt/hisi_ptt.c
> @@ -25,6 +25,161 @@
>   /* Dynamic CPU hotplug state used by PTT */
>   static enum cpuhp_state hisi_ptt_pmu_online;
>   
> +static bool hisi_ptt_wait_tuning_finish(struct hisi_ptt *hisi_ptt)
> +{
> +	u32 val;
> +
> +	return !readl_poll_timeout(hisi_ptt->iobase + HISI_PTT_TUNING_INT_STAT,
> +				  val, !(val & HISI_PTT_TUNING_INT_STAT_MASK),
> +				  HISI_PTT_WAIT_POLL_INTERVAL_US,
> +				  HISI_PTT_WAIT_TUNE_TIMEOUT_US);
> +}
> +
> +static int hisi_ptt_tune_data_get(struct hisi_ptt *hisi_ptt,
> +				  u32 event, u16 *data)

this only has 1x caller so may inline it

> +{
> +	u32 reg;
> +
> +	reg = readl(hisi_ptt->iobase + HISI_PTT_TUNING_CTRL);
> +	reg &= ~(HISI_PTT_TUNING_CTRL_CODE | HISI_PTT_TUNING_CTRL_SUB);
> +	reg |= FIELD_PREP(HISI_PTT_TUNING_CTRL_CODE | HISI_PTT_TUNING_CTRL_SUB,
> +			  event);
> +	writel(reg, hisi_ptt->iobase + HISI_PTT_TUNING_CTRL);
> +
> +	/* Write all 1 to indicates it's the read process */
> +	writel(~0U, hisi_ptt->iobase + HISI_PTT_TUNING_DATA);
> +
> +	if (!hisi_ptt_wait_tuning_finish(hisi_ptt))
> +		return -ETIMEDOUT;
> +
> +	reg = readl(hisi_ptt->iobase + HISI_PTT_TUNING_DATA);
> +	reg &= HISI_PTT_TUNING_DATA_VAL_MASK;
> +	*data = FIELD_GET(HISI_PTT_TUNING_DATA_VAL_MASK, reg);
> +
> +	return 0;
> +}
> +
> +static int hisi_ptt_tune_data_set(struct hisi_ptt *hisi_ptt,
> +				  u32 event, u16 data)

again only 1x caller

> +{
> +	u32 reg;
> +
> +	reg = readl(hisi_ptt->iobase + HISI_PTT_TUNING_CTRL);
> +	reg &= ~(HISI_PTT_TUNING_CTRL_CODE | HISI_PTT_TUNING_CTRL_SUB);
> +	reg |= FIELD_PREP(HISI_PTT_TUNING_CTRL_CODE | HISI_PTT_TUNING_CTRL_SUB,
> +			  event);
> +	writel(reg, hisi_ptt->iobase + HISI_PTT_TUNING_CTRL);
> +
> +	writel(FIELD_PREP(HISI_PTT_TUNING_DATA_VAL_MASK, data),
> +	       hisi_ptt->iobase + HISI_PTT_TUNING_DATA);
> +
> +	if (!hisi_ptt_wait_tuning_finish(hisi_ptt))
> +		return -ETIMEDOUT;
> +
> +	return 0;
> +}
> +
> +static ssize_t hisi_ptt_tune_attr_show(struct device *dev,
> +				       struct device_attribute *attr,
> +				       char *buf)
> +{
> +	struct hisi_ptt *hisi_ptt = to_hisi_ptt(dev_get_drvdata(dev));
> +	struct dev_ext_attribute *ext_attr;
> +	struct hisi_ptt_tune_desc *desc;
> +	int ret;
> +	u16 val;
> +
> +	ext_attr = container_of(attr, struct dev_ext_attribute, attr);
> +	desc = ext_attr->var;
> +
> +	mutex_lock(&hisi_ptt->tune_lock);
> +	ret = hisi_ptt_tune_data_get(hisi_ptt, desc->event_code, &val);
> +	mutex_unlock(&hisi_ptt->tune_lock);
> +
> +	if (ret)
> +		return ret;
> +
> +	return sysfs_emit(buf, "%u\n", val);
> +}
> +
> +static ssize_t hisi_ptt_tune_attr_store(struct device *dev,
> +					struct device_attribute *attr,
> +					const char *buf, size_t count)
> +{
> +	struct hisi_ptt *hisi_ptt = to_hisi_ptt(dev_get_drvdata(dev));
> +	struct dev_ext_attribute *ext_attr;
> +	struct hisi_ptt_tune_desc *desc;
> +	int ret;
> +	u16 val;
> +
> +	ext_attr = container_of(attr, struct dev_ext_attribute, attr);
> +	desc = ext_attr->var;
> +
> +	if (kstrtou16(buf, 10, &val))
> +		return -EINVAL;
> +
> +	mutex_lock(&hisi_ptt->tune_lock);
> +	ret = hisi_ptt_tune_data_set(hisi_ptt, desc->event_code, val);
> +	mutex_unlock(&hisi_ptt->tune_lock);
> +
> +	if (ret)
> +		return ret;
> +
> +	return count;
> +}
> +
> +#define HISI_PTT_TUNE_ATTR(_name, _val, _show, _store)			\
> +	static struct hisi_ptt_tune_desc _name##_desc = {		\
> +		.name = #_name,						\
> +		.event_code = _val,					\
> +	};								\
> +	static struct dev_ext_attribute hisi_ptt_##_name##_attr = {	\
> +		.attr	= __ATTR(_name, 0600, _show, _store),		\
> +		.var	= &_name##_desc,				\
> +	}
> +
> +#define HISI_PTT_TUNE_ATTR_COMMON(_name, _val)		\
> +	HISI_PTT_TUNE_ATTR(_name, _val,			\
> +			   hisi_ptt_tune_attr_show,	\
> +			   hisi_ptt_tune_attr_store)
> +
> +/*
> + * The value of the tuning event are composed of two parts: main event code in bit[0,15] and
> + * subevent code in bit[16,23]. For example, qox_tx_cpl is a subevent of 'Tx path QoS control'
> + * which for tuning the weight of Tx completion TLPs. See hisi_ptt.rst documentation for
> + * more information.
> + */
> +#define HISI_PTT_TUNE_QOS_TX_CPL				(0x4 | (3 << 16))
> +#define HISI_PTT_TUNE_QOS_TX_NP					(0x4 | (4 << 16))
> +#define HISI_PTT_TUNE_QOS_TX_P					(0x4 | (5 << 16))
> +#define HISI_PTT_TUNE_TX_PATH_IOB_RX_REQ_ALLOC_BUF_LEVEL	(0x5 | (6 << 16))
> +#define HISI_PTT_TUNE_TX_PATH_TX_REQ_ALLOC_BUF_LEVEL		(0x5 | (7 << 16))
> +
> +HISI_PTT_TUNE_ATTR_COMMON(qos_tx_cpl,
> +			  HISI_PTT_TUNE_QOS_TX_CPL);
> +HISI_PTT_TUNE_ATTR_COMMON(qos_tx_np,
> +			  HISI_PTT_TUNE_QOS_TX_NP);
> +HISI_PTT_TUNE_ATTR_COMMON(qos_tx_p,
> +			  HISI_PTT_TUNE_QOS_TX_P);
> +HISI_PTT_TUNE_ATTR_COMMON(tx_path_iob_rx_req_alloc_buf_level,
> +			  HISI_PTT_TUNE_TX_PATH_IOB_RX_REQ_ALLOC_BUF_LEVEL);
> +HISI_PTT_TUNE_ATTR_COMMON(tx_path_tx_req_alloc_buf_level,
> +			  HISI_PTT_TUNE_TX_PATH_TX_REQ_ALLOC_BUF_LEVEL);
> +
> +static struct attribute *hisi_ptt_tune_attrs[] = {
> +	&hisi_ptt_qos_tx_cpl_attr.attr.attr,
> +	&hisi_ptt_qos_tx_np_attr.attr.attr,
> +	&hisi_ptt_qos_tx_p_attr.attr.attr,
> +	&hisi_ptt_tx_path_iob_rx_req_alloc_buf_level_attr.attr.attr,
> +	&hisi_ptt_tx_path_tx_req_alloc_buf_level_attr.attr.attr,
> +	NULL,
> +};
> +
> +static struct attribute_group hisi_ptt_tune_group = {
> +	.attrs	= hisi_ptt_tune_attrs,
> +	.name	= "tune",
> +};
> +
>   static u16 hisi_ptt_get_filter_val(u16 devid, bool is_port)
>   {
>   	if (is_port)
> @@ -448,6 +603,7 @@ static const struct attribute_group *hisi_ptt_pmu_groups[] = {
>   	&hisi_ptt_cpumask_attr_group,
>   	&hisi_ptt_pmu_format_group,
>   	&hisi_ptt_pmu_filter_group,
> +	&hisi_ptt_tune_group,
>   	NULL
>   };
>   
> @@ -783,6 +939,7 @@ static int hisi_ptt_register_pmu(struct hisi_ptt *hisi_ptt)
>   	if (ret)
>   		return ret;
>   
> +	mutex_init(&hisi_ptt->tune_lock);
>   	spin_lock_init(&hisi_ptt->pmu_lock);
>   
>   	hisi_ptt->hisi_ptt_pmu = (struct pmu) {
> diff --git a/drivers/hwtracing/ptt/hisi_ptt.h b/drivers/hwtracing/ptt/hisi_ptt.h
> index 2344e4195648..439583e5fbcf 100644
> --- a/drivers/hwtracing/ptt/hisi_ptt.h
> +++ b/drivers/hwtracing/ptt/hisi_ptt.h
> @@ -12,6 +12,7 @@
>   #include <linux/bits.h>
>   #include <linux/cpumask.h>
>   #include <linux/list.h>
> +#include <linux/mutex.h>
>   #include <linux/pci.h>
>   #include <linux/perf_event.h>
>   #include <linux/spinlock.h>
> @@ -22,6 +23,11 @@
>   /*
>    * The definition of the device registers and register fields.
>    */
> +#define HISI_PTT_TUNING_CTRL		0x0000
> +#define   HISI_PTT_TUNING_CTRL_CODE	GENMASK(15, 0)
> +#define   HISI_PTT_TUNING_CTRL_SUB	GENMASK(23, 16)
> +#define HISI_PTT_TUNING_DATA		0x0004
> +#define   HISI_PTT_TUNING_DATA_VAL_MASK	GENMASK(15, 0)
>   #define HISI_PTT_TRACE_ADDR_SIZE	0x0800
>   #define HISI_PTT_TRACE_ADDR_BASE_LO_0	0x0810
>   #define HISI_PTT_TRACE_ADDR_BASE_HI_0	0x0814
> @@ -37,6 +43,8 @@
>   #define HISI_PTT_TRACE_INT_STAT		0x0890
>   #define   HISI_PTT_TRACE_INT_STAT_MASK	GENMASK(3, 0)
>   #define HISI_PTT_TRACE_INT_MASK		0x0894
> +#define HISI_PTT_TUNING_INT_STAT	0x0898
> +#define   HISI_PTT_TUNING_INT_STAT_MASK	BIT(0)
>   #define HISI_PTT_TRACE_WR_STS		0x08a0
>   #define   HISI_PTT_TRACE_WR_STS_WRITE	GENMASK(27, 0)
>   #define   HISI_PTT_TRACE_WR_STS_BUFFER	GENMASK(29, 28)
> @@ -59,6 +67,7 @@
>   #define HISI_PTT_RESET_TIMEOUT_US	10UL
>   #define HISI_PTT_RESET_POLL_INTERVAL_US	1UL
>   /* Poll timeout and interval for waiting hardware work to finish */
> +#define HISI_PTT_WAIT_TUNE_TIMEOUT_US	1000000UL
>   #define HISI_PTT_WAIT_TRACE_TIMEOUT_US	100UL
>   #define HISI_PTT_WAIT_POLL_INTERVAL_US	10UL
>   
> @@ -71,6 +80,18 @@
>   #define HISI_PTT_PMU_TYPE_MASK		GENMASK(31, 24)
>   #define HISI_PTT_PMU_FORMAT_MASK	GENMASK(35, 32)
>   
> +/**
> + * struct hisi_ptt_tune_desc - Describe tune event for PTT tune
> + * @hisi_ptt:   PTT device this tune event belongs to
> + * @name:       name of this event
> + * @event_code: code of the event
> + */
> +struct hisi_ptt_tune_desc {
> +	struct hisi_ptt *hisi_ptt;
> +	const char *name;
> +	u32 event_code;
> +};
> +
>   /**
>    * struct hisi_ptt_dma_buffer - Describe a single trace buffer of PTT trace.
>    *                              The detail of the data format is described
> @@ -144,6 +165,7 @@ struct hisi_ptt_pmu_buf {
>    * @hisi_ptt_pmu: the pum device of trace
>    * @iobase:       base IO address of the device
>    * @pdev:         pci_dev of this PTT device
> + * @tune_lock:    lock to serialize the tune process
>    * @pmu_lock:     lock to serialize the perf process
>    * @upper_bdf:    the upper BDF range of the PCI devices managed by this PTT device
>    * @lower_bdf:    the lower BDF range of the PCI devices managed by this PTT device
> @@ -157,6 +179,7 @@ struct hisi_ptt {
>   	struct pmu hisi_ptt_pmu;
>   	void __iomem *iobase;
>   	struct pci_dev *pdev;
> +	struct mutex tune_lock;
>   	spinlock_t pmu_lock;
>   	u32 upper_bdf;
>   	u32 lower_bdf;