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Message-ID: <2181ae69-f681-41d7-65aa-bb44473802ee@quicinc.com>
Date:   Fri, 1 Jul 2022 23:10:20 +0800
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Subject: Re: [PATCH v11 6/9] Coresight: Add TPDA link driver
Content-Language: en-US
To:     Suzuki K Poulose <suzuki.poulose@arm.com>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Konrad Dybcio <konradybcio@gmail.com>,
        Mike Leach <mike.leach@linaro.org>
CC:     Leo Yan <leo.yan@linaro.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        <coresight@lists.linaro.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>,
        Tingwei Zhang <quic_tingweiz@quicinc.com>,
        Yuanfang Zhang <quic_yuanfang@quicinc.com>,
        Tao Zhang <quic_taozha@quicinc.com>,
        Trilok Soni <quic_tsoni@quicinc.com>,
        Hao Zhang <quic_hazha@quicinc.com>,
        <linux-arm-msm@vger.kernel.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>
References: <20220620120101.2906-1-quic_jinlmao@quicinc.com>
 <20220620120101.2906-7-quic_jinlmao@quicinc.com>
 <36f1cb8f-5ad9-9b3a-276e-2774a05707ca@arm.com>
From:   Jinlong Mao <quic_jinlmao@quicinc.com>
In-Reply-To: <36f1cb8f-5ad9-9b3a-276e-2774a05707ca@arm.com>
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Hi Suzuki,

Thanks for the review.

On 7/1/2022 6:24 PM, Suzuki K Poulose wrote:
> On 20/06/2022 13:00, Mao Jinlong wrote:
>> TPDA(Trace, Profiling and Diagnostics Aggregator) is
>> to provide packetization, funneling and timestamping of
>> TPDM data. Multiple monitors are connected to different
>> input ports of TPDA.This change is to add tpda
>> enable/disable/probe functions for coresight tpda driver.
>>
>>   - - - -         - - - -        - - - -
>> | TPDM 0|      | TPDM 1 |     | TPDM 2|
>>   - - - -         - - - -        - - - -
>>      |               |             |
>>      |_ _ _ _ _ _    |     _ _ _ _ |
>>                  |   |    |
>>                  |   |    |
>>             ------------------
>>            |        TPDA      |
>>             ------------------
>>
>> Signed-off-by: Tao Zhang <quic_taozha@quicinc.com>
>> Signed-off-by: Mao Jinlong <quic_jinlmao@quicinc.com>
>> ---
>>   drivers/hwtracing/coresight/Kconfig          |  11 +
>>   drivers/hwtracing/coresight/Makefile         |   1 +
>>   drivers/hwtracing/coresight/coresight-tpda.c | 206 +++++++++++++++++++
>>   drivers/hwtracing/coresight/coresight-tpda.h |  35 ++++
>>   4 files changed, 253 insertions(+)
>>   create mode 100644 drivers/hwtracing/coresight/coresight-tpda.c
>>   create mode 100644 drivers/hwtracing/coresight/coresight-tpda.h
>>
>> diff --git a/drivers/hwtracing/coresight/Kconfig 
>> b/drivers/hwtracing/coresight/Kconfig
>> index b2b72a35e416..0cbebfd0d23e 100644
>> --- a/drivers/hwtracing/coresight/Kconfig
>> +++ b/drivers/hwtracing/coresight/Kconfig
>> @@ -205,6 +205,7 @@ config CORESIGHT_TRBE
>>   config CORESIGHT_TPDM
>>       tristate "CoreSight Trace, Profiling & Diagnostics Monitor driver"
>>       select CORESIGHT_LINKS_AND_SINKS
>> +    select CORESIGHT_TPDA
>>       help
>>         This driver provides support for configuring monitor. 
>> Monitors are
>>         primarily responsible for data set collection and support the
>> @@ -213,4 +214,14 @@ config CORESIGHT_TPDM
>>         To compile this driver as a module, choose M here: the module 
>> will be
>>         called coresight-tpdm.
>>   +config CORESIGHT_TPDA
>> +    tristate "CoreSight Trace, Profiling & Diagnostics Aggregator 
>> driver"
>> +    help
>> +      This driver provides support for configuring aggregator. This is
>> +      primarily useful for pulling the data sets from one or more
>> +      attached monitors and pushing the resultant data out. Multiple
>> +      monitors are connected on different input ports of TPDA.
>> +
>> +      To compile this driver as a module, choose M here: the module 
>> will be
>> +      called coresight-tpda.
>>   endif
>> diff --git a/drivers/hwtracing/coresight/Makefile 
>> b/drivers/hwtracing/coresight/Makefile
>> index 6bb9b1746bc7..1712d82e7260 100644
>> --- a/drivers/hwtracing/coresight/Makefile
>> +++ b/drivers/hwtracing/coresight/Makefile
>> @@ -26,5 +26,6 @@ obj-$(CONFIG_CORESIGHT_CATU) += coresight-catu.o
>>   obj-$(CONFIG_CORESIGHT_CTI) += coresight-cti.o
>>   obj-$(CONFIG_CORESIGHT_TRBE) += coresight-trbe.o
>>   obj-$(CONFIG_CORESIGHT_TPDM) += coresight-tpdm.o
>> +obj-$(CONFIG_CORESIGHT_TPDA) += coresight-tpda.o
>>   coresight-cti-y := coresight-cti-core.o coresight-cti-platform.o \
>>              coresight-cti-sysfs.o
>> diff --git a/drivers/hwtracing/coresight/coresight-tpda.c 
>> b/drivers/hwtracing/coresight/coresight-tpda.c
>> new file mode 100644
>> index 000000000000..7a0478a8b63e
>> --- /dev/null
>> +++ b/drivers/hwtracing/coresight/coresight-tpda.c
>> @@ -0,0 +1,206 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights 
>> reserved.
>> + */
>> +
>> +#include <linux/amba/bus.h>
>> +#include <linux/bitfield.h>
>> +#include <linux/coresight.h>
>> +#include <linux/device.h>
>> +#include <linux/err.h>
>> +#include <linux/fs.h>
>> +#include <linux/io.h>
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/platform_device.h>
>> +
>> +#include "coresight-priv.h"
>> +#include "coresight-tpda.h"
>> +#include "coresight-trace-id.h"
>> +
>> +DEFINE_CORESIGHT_DEVLIST(tpda_devs, "tpda");
>> +
>> +/* Settings pre enabling port control register */
>> +static void tpda_enable_pre_port(struct tpda_drvdata *drvdata)
>> +{
>> +    u32 val;
>> +
>> +    val = readl_relaxed(drvdata->base + TPDA_CR);
>
>
> Even though the drvdata->atid is constant during the life time
> of the driver, I would recommend clearing the field and then
> setting it. e.g, if you get a different ATID on unload-load
> sequence of the driver, the field will corrupted.
I will release the id in module exist function.
>
>     val &= ~TPDA_CR_ATID;
>
>> +    val |= FIELD_PREP(TPDA_CR_ATID, drvdata->atid);
>
>
>> +    writel_relaxed(val, drvdata->base + TPDA_CR);
>> +}
>> +
>
> Is there no global turn-ON for the TPDA ? Or is it per-port
> enable only via TPDA_Pn_CR ?


No global turn-on for the TPDA.  It is per-port enable via TPDA_Pn_CR.

>
>> +static void tpda_enable_port(struct tpda_drvdata *drvdata, int port)
>> +{
>> +    u32 val;
>> +
>> +    val = readl_relaxed(drvdata->base + TPDA_Pn_CR(port));
>> +    /* Enable the port */
>> +    val |= TPDA_Pn_CR_ENA;
>> +    writel_relaxed(val, drvdata->base + TPDA_Pn_CR(port));
>> +}
>> +
>> +static void __tpda_enable(struct tpda_drvdata *drvdata, int port)
>> +{
>> +    CS_UNLOCK(drvdata->base);
>> +
>> +    if (!drvdata->csdev->enable)
>> +        tpda_enable_pre_port(drvdata);
>> +
>> +    tpda_enable_port(drvdata, port);
>> +
>> +    CS_LOCK(drvdata->base);
>> +}
>> +
>> +static int tpda_enable(struct coresight_device *csdev, int inport, 
>> int outport)
>> +{
>> +    struct tpda_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
>> +
>> +    spin_lock(&drvdata->spinlock);
>> +    if (atomic_read(&csdev->refcnt[inport]) == 0)
>> +        __tpda_enable(drvdata, inport);
>> +
>> +    atomic_inc(&csdev->refcnt[inport]);
>> +    spin_unlock(&drvdata->spinlock);
>> +
>> +    dev_dbg(drvdata->dev, "TPDA inport %d enabled.\n", inport);
>> +    return 0;
>> +}
>> +
>> +static void __tpda_disable(struct tpda_drvdata *drvdata, int port)
>> +{
>> +    u32 val;
>> +
>> +    CS_UNLOCK(drvdata->base);
>> +
>> +    val = readl_relaxed(drvdata->base + TPDA_Pn_CR(port));
>> +    val &= ~TPDA_Pn_CR_ENA;
>> +    writel_relaxed(val, drvdata->base + TPDA_Pn_CR(port));
>> +
>> +    CS_LOCK(drvdata->base);
>> +}
>> +
>> +static void tpda_disable(struct coresight_device *csdev, int inport,
>> +               int outport)
>> +{
>> +    struct tpda_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
>> +
>> +    spin_lock(&drvdata->spinlock);
>> +    if (atomic_dec_return(&csdev->refcnt[inport]) == 0)
>> +        __tpda_disable(drvdata, inport);
>> +
>> +    spin_unlock(&drvdata->spinlock);
>> +
>> +    dev_dbg(drvdata->dev, "TPDA inport %d disabled\n", inport);
>> +}
>> +
>> +static const struct coresight_ops_link tpda_link_ops = {
>> +    .enable        = tpda_enable,
>> +    .disable    = tpda_disable,
>> +};
>> +
>> +static const struct coresight_ops tpda_cs_ops = {
>> +    .link_ops    = &tpda_link_ops,
>> +};
>> +
>> +static int tpda_init_default_data(struct tpda_drvdata *drvdata)
>> +{
>
> Is there a register that indicates the number of ports on the device ?
> We don't seem to be using that information.
No such register.
>
>> +    int atid;
>> +    /*
>> +     * TPDA must has a unique atid. This atid can uniquely
>> +     * identify the TPDM trace source connected to the TPDA.
>> +     */
>> +    atid = 
>> coresight_trace_id_get_system_id(coresight_get_trace_id_map());
>> +    if (atid < 0)
>> +        return atid;
>> +
>
> You need to release this id at module exit. Otherwise, we are leaking
> the id.
>
I will address the comments.
>
> Suzuki