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Message-ID: <b36940af-648d-2620-3086-81b30de6e401@arm.com>
Date: Mon, 7 Aug 2023 12:35:15 +0100
From: Suzuki K Poulose <suzuki.poulose@....com>
To: Tao Zhang <quic_taozha@...cinc.com>,
Mathieu Poirier <mathieu.poirier@...aro.org>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Konrad Dybcio <konradybcio@...il.com>,
Mike Leach <mike.leach@...aro.org>,
Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>
Cc: Jinlong Mao <quic_jinlmao@...cinc.com>,
Leo Yan <leo.yan@...aro.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
Tingwei Zhang <quic_tingweiz@...cinc.com>,
Yuanfang Zhang <quic_yuanfang@...cinc.com>,
Trilok Soni <quic_tsoni@...cinc.com>,
Hao Zhang <quic_hazha@...cinc.com>,
linux-arm-msm@...r.kernel.org, andersson@...nel.org
Subject: Re: [PATCH v7 13/13] coresight-tpdm: Add nodes for dsb msr support
On 25/07/2023 08:15, Tao Zhang wrote:
> Add the nodes for DSB subunit MSR(mux select register) support.
> The TPDM MSR (mux select register) interface is an optional
> interface and associated bank of registers per TPDM subunit.
> The intent of mux select registers is to control muxing structures
> driving the TPDM’s’ various subunit interfaces.
>
> Signed-off-by: Tao Zhang <quic_taozha@...cinc.com>
> ---
> .../ABI/testing/sysfs-bus-coresight-devices-tpdm | 19 ++++-
> drivers/hwtracing/coresight/coresight-tpdm.c | 98 ++++++++++++++++++++++
> drivers/hwtracing/coresight/coresight-tpdm.h | 7 ++
> 3 files changed, 123 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> index 74a0126..ee41a14 100644
> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> @@ -185,4 +185,21 @@ Description:
>
> Accepts only one of the 2 values - 0 or 1.
> 0 : Set the DSB pattern type to value.
> - 1 : Set the DSB pattern type to toggle.
> \ No newline at end of file
> + 1 : Set the DSB pattern type to toggle.
> +
> +What: /sys/bus/coresight/devices/<tpdm-name>/dsb_msr_idx
> +Date: March 2023
> +KernelVersion 6.5
> +Contact: Jinlong Mao (QUIC) <quic_jinlmao@...cinc.com>, Tao Zhang (QUIC) <quic_taozha@...cinc.com>
> +Description:
> + Read/Write the index number of MSR(mux select register) on DSB
> + TPDM. This index number should not be greater than the number
> + of MSR supported by this DSB TPDM.
How does a user find it ? Why don't we expose it ? Scratch all of that,
you could create a register file per exising msr.
dsb_msrs/msr0 ... msrN
You may :
1. either dynamically add files as you find the number
OR
2. If there is a hard limit, create that many files and control
visibility based on the dynamic number.
> +
> +What: /sys/bus/coresight/devices/<tpdm-name>/dsb_msr
> +Date: March 2023
> +KernelVersion 6.5
> +Contact: Jinlong Mao (QUIC) <quic_jinlmao@...cinc.com>, Tao Zhang (QUIC) <quic_taozha@...cinc.com>
> +Description:
> + (Write) Set the MSR(mux select register) of DSB tpdm. Read
> + the MSR(mux select register) of DSB tpdm.
(RW)
> \ No newline at end of file
> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c
> index f9e5a1d..be7776b 100644
> --- a/drivers/hwtracing/coresight/coresight-tpdm.c
> +++ b/drivers/hwtracing/coresight/coresight-tpdm.c
> @@ -90,6 +90,18 @@ static void set_dsb_tier(struct tpdm_drvdata *drvdata, u32 *val)
>
> }
>
> +static void set_dsb_msr(struct tpdm_drvdata *drvdata)
> +{
> + int i;
> +
> + if (drvdata->dsb->msr_num == 0)
> + return;
> +
> + for (i = 0; i < drvdata->dsb->msr_num; i++)
> + writel_relaxed(drvdata->dsb->msr[i],
> + drvdata->base + TPDM_DSB_MSR(i));
> +}
> +
> static void tpdm_enable_dsb(struct tpdm_drvdata *drvdata)
> {
> u32 val, i;
> @@ -116,6 +128,8 @@ static void tpdm_enable_dsb(struct tpdm_drvdata *drvdata)
> set_dsb_tier(drvdata, &val);
> writel_relaxed(val, drvdata->base + TPDM_DSB_TIER);
>
> + set_dsb_msr(drvdata);
> +
> val = readl_relaxed(drvdata->base + TPDM_DSB_CR);
> /* Set the test accurate mode */
> set_dsb_test_mode(drvdata, &val);
> @@ -234,6 +248,14 @@ static int tpdm_datasets_setup(struct tpdm_drvdata *drvdata)
> if (!drvdata->dsb)
> return -ENOMEM;
> }
> + if (!of_property_read_u32(drvdata->dev->of_node,
> + "qcom,dsb_msr_num", &drvdata->dsb->msr_num)) {
> + drvdata->dsb->msr = devm_kzalloc(drvdata->dev, > + (drvdata->dsb->msr_num * sizeof(*drvdata->dsb->msr)),
devm_kcalloc() ?
> + GFP_KERNEL);
> + if (!drvdata->dsb->msr)
> + return -ENOMEM;
> + }
> }
>
> return 0;
> @@ -830,6 +852,80 @@ static ssize_t dsb_trig_ts_store(struct device *dev,
> }
> static DEVICE_ATTR_RW(dsb_trig_ts);
>
> +static ssize_t dsb_msr_idx_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> +
> + return sysfs_emit(buf, "%u\n",
> + (unsigned int)drvdata->dsb->msr_idx);
> +
> +}
> +
> +static ssize_t dsb_msr_idx_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf,
> + size_t size)
> +{
> + struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> + unsigned long index;
> +
> + if (kstrtoul(buf, 0, &index))
> + return -EINVAL;
> + if (index >= drvdata->dsb->msr_num)
> + return -EPERM;
> +
> + spin_lock(&drvdata->spinlock);
> + drvdata->dsb->msr_idx = index;
> + spin_unlock(&drvdata->spinlock);
> + return size;
> +}
> +static DEVICE_ATTR_RW(dsb_msr_idx);
> +
> +static ssize_t dsb_msr_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> + unsigned int i;
> + unsigned long bytes;
> + ssize_t size = 0;
> +
> + if (drvdata->dsb->msr_num == 0)
> + return -EINVAL;
> +
> + spin_lock(&drvdata->spinlock);
> + for (i = 0; i < drvdata->dsb->msr_num; i++) {
> + bytes = sysfs_emit_at(buf, size,
> + "0x%x\n", drvdata->dsb->msr[i]);
Single value per single file.
Suzuki
> + if (bytes <= 0)
> + break;
> + size += bytes;
> + }
> + spin_unlock(&drvdata->spinlock);
> +
> + return size;
> +}
> +
> +static ssize_t dsb_msr_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf,
> + size_t size)
> +{
> + struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> + unsigned long val;
> +
> + if (kstrtoul(buf, 0, &val))
> + return -EINVAL;
> +
> + spin_lock(&drvdata->spinlock);
> + drvdata->dsb->msr[drvdata->dsb->msr_idx] = val;
> + spin_unlock(&drvdata->spinlock);
> + return size;
> +}
> +static DEVICE_ATTR_RW(dsb_msr);
> +
> static struct attribute *tpdm_dsb_attrs[] = {
> &dev_attr_dsb_mode.attr,
> &dev_attr_dsb_edge_ctrl_idx.attr,
> @@ -845,6 +941,8 @@ static struct attribute *tpdm_dsb_attrs[] = {
> &dev_attr_dsb_trig_patt_mask.attr,
> &dev_attr_dsb_trig_ts.attr,
> &dev_attr_dsb_trig_type.attr,
> + &dev_attr_dsb_msr_idx.attr,
> + &dev_attr_dsb_msr.attr,
> NULL,
> };
>
> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.h b/drivers/hwtracing/coresight/coresight-tpdm.h
> index 7c52cf4..7b70db3 100644
> --- a/drivers/hwtracing/coresight/coresight-tpdm.h
> +++ b/drivers/hwtracing/coresight/coresight-tpdm.h
> @@ -18,6 +18,7 @@
> #define TPDM_DSB_XPMR(n) (0x7E8 + (n * 4))
> #define TPDM_DSB_EDCR(n) (0x808 + (n * 4))
> #define TPDM_DSB_EDCMR(n) (0x848 + (n * 4))
> +#define TPDM_DSB_MSR(n) (0x980 + (n * 4))
>
> /* Enable bit for DSB subunit */
> #define TPDM_DSB_CR_ENA BIT(0)
> @@ -100,6 +101,9 @@
> * @patt_mask: Save value for pattern mask
> * @trig_patt: Save value for trigger pattern
> * @trig_patt_mask: Save value for trigger pattern mask
> + * @msr_num Number of MSR supported by DSB TPDM
> + * @msr_idx Index number of the MSR
> + * @msr Save value for MSR
> * @patt_ts: Enable/Disable pattern timestamp
> * @patt_type: Set pattern type
> * @trig_ts: Enable/Disable trigger timestamp.
> @@ -116,6 +120,9 @@ struct dsb_dataset {
> u32 patt_mask[TPDM_DSB_MAX_PATT];
> u32 trig_patt[TPDM_DSB_MAX_PATT];
> u32 trig_patt_mask[TPDM_DSB_MAX_PATT];
> + u32 msr_num;
> + u32 msr_idx;
> + u32 *msr;
> bool patt_ts;
> bool patt_type;
> bool trig_ts;
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