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Message-ID: <c5c28ab8-7d6a-f8e7-ad34-8716ac77d2dc@quicinc.com>
Date: Fri, 2 Jun 2023 16:21:27 +0800
From: Tao Zhang <quic_taozha@...cinc.com>
To: Suzuki K Poulose <suzuki.poulose@....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 v4 07/11] coresight-tpdm: Add nodes for dsb edge control
On 6/1/2023 8:14 PM, Suzuki K Poulose wrote:
> On 27/04/2023 10:00, Tao Zhang wrote:
>> Add the nodes to set value for DSB edge control and DSB edge
>> control mask. Each DSB subunit TPDM has maximum of n(n<16) EDCR
>> resgisters to configure edge control. DSB edge detection control
>> 00: Rising edge detection
>> 01: Falling edge detection
>> 10: Rising and falling edge detection (toggle detection)
>> And each DSB subunit TPDM has maximum of m(m<8) ECDMR registers to
>> configure mask. Eight 32 bit registers providing DSB interface
>> edge detection mask control.
>>
>> Signed-off-by: Tao Zhang <quic_taozha@...cinc.com>
>> ---
>> .../ABI/testing/sysfs-bus-coresight-devices-tpdm | 32 +++++
>> drivers/hwtracing/coresight/coresight-tpdm.c | 135
>> ++++++++++++++++++++-
>> drivers/hwtracing/coresight/coresight-tpdm.h | 21 ++++
>> 3 files changed, 187 insertions(+), 1 deletion(-)
>>
>> diff --git
>> a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
>> b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
>> index 348e167..a57f000 100644
>> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
>> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
>> @@ -60,3 +60,35 @@ Description:
>> Bit[3] : Set to 0 for low performance mode.
>> Set to 1 for high performance mode.
>> Bit[4:8] : Select byte lane for high performance mode.
>> +
>> +What: /sys/bus/coresight/devices/<tpdm-name>/dsb_edge_ctrl
>> +Date: March 2023
>> +KernelVersion 6.3
>> +Contact: Jinlong Mao (QUIC) <quic_jinlmao@...cinc.com>, Tao Zhang
>> (QUIC) <quic_taozha@...cinc.com>
>> +Description:
>> + Read/Write a set of the edge control registers of the DSB
>> + in TPDM.
>> +
>> + Expected format is the following:
>> + <integer1> <integer2> <integer3>
>> +
>> + Where:
>> + <integer1> : Start EDCR register number
>> + <integer2> : End EDCR register number
>> + <integer3> : The value need to be written
>> +
>> +What: /sys/bus/coresight/devices/<tpdm-name>/dsb_edge_ctrl_mask
>> +Date: March 2023
>> +KernelVersion 6.3
>> +Contact: Jinlong Mao (QUIC) <quic_jinlmao@...cinc.com>, Tao Zhang
>> (QUIC) <quic_taozha@...cinc.com>
>> +Description:
>> + Read/Write a set of the edge control mask registers of the
>> + DSB in TPDM.
>> +
>> + Expected format is the following:
>> + <integer1> <integer2> <integer3>
>> +
>> + Where:
>> + <integer1> : Start EDCMR register number
>> + <integer2> : End EDCMR register number
>> + <integer3> : The value need to be written
>> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c
>> b/drivers/hwtracing/coresight/coresight-tpdm.c
>> index 1bacaa5..a40e458 100644
>> --- a/drivers/hwtracing/coresight/coresight-tpdm.c
>> +++ b/drivers/hwtracing/coresight/coresight-tpdm.c
>> @@ -80,7 +80,14 @@ static void set_trigger_type(struct tpdm_drvdata
>> *drvdata, u32 *val)
>> static void tpdm_enable_dsb(struct tpdm_drvdata *drvdata)
>> {
>> - u32 val;
>> + u32 val, i;
>> +
>> + for (i = 0; i < TPDM_DSB_MAX_EDCR; i++)
>> + writel_relaxed(drvdata->dsb->edge_ctrl[i],
>> + drvdata->base + TPDM_DSB_EDCR(i));
>> + for (i = 0; i < TPDM_DSB_MAX_EDCMR; i++)
>> + writel_relaxed(drvdata->dsb->edge_ctrl_mask[i],
>> + drvdata->base + TPDM_DSB_EDCMR(i));
>
> Do all TPDM DSBs have MAX_EDCR registers ? Or some have less than that ?
> If it is latter, do we need special care to avoid writing to inexistent
> registers ?
>
You are right, not all DSB TPDMs have MAX_EDCR registers. In our design,
the inexistent register addresses
are not occupied and safe for accessing.
Currently we don't have a good way to know the quantity of EDCR/EDCMR
registers for DSB TPDMs.
The only way we can think of is to set it in device tree manually.
Do you have other suggestion for this?
>> val = readl_relaxed(drvdata->base + TPDM_DSB_TIER);
>> /* Set trigger timestamp */
>> @@ -313,6 +320,130 @@ static ssize_t dsb_mode_store(struct device *dev,
>> }
>> static DEVICE_ATTR_RW(dsb_mode);
>> +static ssize_t dsb_edge_ctrl_show(struct device *dev,
>> + struct device_attribute *attr,
>> + char *buf)
>> +{
>> + struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
>> + ssize_t size = 0;
>> + int i;
>> +
>> + spin_lock(&drvdata->spinlock);
>> + for (i = 0; i < TPDM_DSB_MAX_EDCR; i++) {
>> + size += sysfs_emit_at(buf, size,
>> + "Index:0x%x Val:0x%x\n", i,
>> + drvdata->dsb->edge_ctrl[i]);
>
> It may be safe, but please add a check to make sure that we don't
> overflow. At least bail out when we hit a return of 0, indicating
> reached the end of buffer.
>
Can I add the following check to replace the current code??
int ret = 0;
for (i = 0; i < TPDM_DSB_MAX_EDCR; i++) {
ret = sysfs_emit_at(buf, size, "Index:0x%x Val:0x%x\n", i,
drvdata->dsb->edge_ctrl[i]);
if (!ret) {
dev_warn(drvdata->dev, "The buffer has been overflowed\n");
spin_unlock(&drvdata->spinlock);
return size;
} else
size += ret;
}
>> + }
>> + spin_unlock(&drvdata->spinlock);
>> + return size;
>> +}
>> +
>> +/*
>> + * value 1: Start EDCR register number
>> + * value 2: End EDCR register number
>> + * value 3: The value need to be written
>> + * The EDCR registers can include up to 16 32-bit registers, and each
>> + * one can be configured to control up to 16 edge detections(2 bits
>> + * control one edge detection). So a total 256 edge detections can be
>> + * configured. So the starting number(value 1) and ending
>> number(value 2)
>> + * cannot be greater than 256, and value 1 should be less than value 2.
>> + * The following values are the rage of value 3.
>> + * 0 - Rising edge detection
>> + * 1 - Falling edge detection
>> + * 2 - Rising and falling edge detection (toggle detection)
>> + */
>> +static ssize_t dsb_edge_ctrl_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, mask, start, end, edge_ctrl, edge_ctrl_shift;
>> + int i, reg;
>> +
>> + if (sscanf(buf, "%lx %lx %lx", &start, &end, &edge_ctrl) != 3)
>> + return -EINVAL;
>> + if ((start >= TPDM_DSB_MAX_LINES) || (end >= TPDM_DSB_MAX_LINES) ||
>> + (start > end) || (edge_ctrl > 0x2))
>> + return -EPERM;
>> +
>> + spin_lock(&drvdata->spinlock);
>> + for (i = start; i <= end; i++) {
>> + /*
>> + * There are 2 bit per DSB Edge Control line.
>> + * Thus we have 16 lines in a 32bit word.
>> + */
>> + reg = EDCR_TO_WORD_IDX(i);
>> + mask = EDCR_TO_WORD_MASK(i);
>> + val = drvdata->dsb->edge_ctrl[reg];
>
>> + edge_ctrl_shift = EDCR_TO_WORD_VAL(edge_ctrl, i);
>> + bitmap_replace(&val, &val, &edge_ctrl_shift, &mask, 32);
>
> Could we simply do :
>
> reg &= ~mask;
> reg |= FIELD_PREP(mask, edge_ctrl);
>
Perhaps "FIELD_PREP" cannot be used here since "mask" must be constant
in this macro.
But in our code, the variable "mask" is not constant.
>
>> + drvdata->dsb->edge_ctrl[reg] = val;
>> + }
>> + spin_unlock(&drvdata->spinlock);
>> +
>> + return size;
>> +}
>> +static DEVICE_ATTR_RW(dsb_edge_ctrl);
>> +
>> +static ssize_t dsb_edge_ctrl_mask_show(struct device *dev,
>> + struct device_attribute *attr,
>> + char *buf)
>> +{
>> + struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
>> + ssize_t size = 0;
>> + int i;
>> +
>> + spin_lock(&drvdata->spinlock);
>> + for (i = 0; i < TPDM_DSB_MAX_EDCMR; i++) {
>> + size += sysfs_emit_at(buf, size,
>> + "Index:0x%x Val:0x%x\n", i,
>> + drvdata->dsb->edge_ctrl_mask[i]);
>> + }
>> + spin_unlock(&drvdata->spinlock);
>> + return size;
>> +}
>> +
>> +/*
>> + * value 1: Start EDCMR register number
>> + * value 2: End EDCMR register number
>> + * value 3: The value need to be written
>> + */
>> +static ssize_t dsb_edge_ctrl_mask_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 start, end, val;
>> + u32 set;
>> + int i, reg;
>> +
>> + if (sscanf(buf, "%lx %lx %lx", &start, &end, &val) != 3)
>> + return -EINVAL;
>> + if ((start >= TPDM_DSB_MAX_LINES) || (end >= TPDM_DSB_MAX_LINES)
>> + || (start > end) || (val & ~1UL))
>> + return -EPERM;
>> +
>> + spin_lock(&drvdata->spinlock);
>> + for (i = start; i <= end; i++) {
>> + /*
>> + * There is 1 bit per DSB Edge Control Mark line.
>> + * Thus we have 32 lines in a 32bit word.
>> + */
>> + reg = EDCMR_TO_WORD_IDX(i);
>> + set = drvdata->dsb->edge_ctrl_mask[reg];
>> + if (val)
>> + set |= BIT(EDCR_TO_WORD_SHIFT(i));
>> + else
>> + set &= ~BIT(EDCR_TO_WORD_SHIFT(i));
>> + drvdata->dsb->edge_ctrl_mask[reg] = set;
>> + }
>> + spin_unlock(&drvdata->spinlock);
>> + return size;
>> +}
>> +static DEVICE_ATTR_RW(dsb_edge_ctrl_mask);
>> +
>> static ssize_t dsb_trig_type_show(struct device *dev,
>> struct device_attribute *attr, char *buf)
>> {
>> @@ -385,6 +516,8 @@ static DEVICE_ATTR_RW(dsb_trig_ts);
>> static struct attribute *tpdm_dsb_attrs[] = {
>> &dev_attr_dsb_mode.attr,
>> + &dev_attr_dsb_edge_ctrl.attr,
>> + &dev_attr_dsb_edge_ctrl_mask.attr,
>> &dev_attr_dsb_trig_ts.attr,
>> &dev_attr_dsb_trig_type.attr,
>> NULL,
>> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.h
>> b/drivers/hwtracing/coresight/coresight-tpdm.h
>> index 79df07e..f25dcdec 100644
>> --- a/drivers/hwtracing/coresight/coresight-tpdm.h
>> +++ b/drivers/hwtracing/coresight/coresight-tpdm.h
>> @@ -12,6 +12,8 @@
>> /* DSB Subunit Registers */
>> #define TPDM_DSB_CR (0x780)
>> #define TPDM_DSB_TIER (0x784)
>> +#define TPDM_DSB_EDCR(n) (0x808 + (n * 4))
>> +#define TPDM_DSB_EDCMR(n) (0x848 + (n * 4))
>> /* Enable bit for DSB subunit */
>> #define TPDM_DSB_CR_ENA BIT(0)
>> @@ -34,6 +36,15 @@
>> #define TPDM_DSB_TEST_MODE GENMASK(10, 9)
>> #define TPDM_DSB_HPSEL GENMASK(6, 2)
>> +#define EDCRS_PER_WORD 16
>> +#define EDCR_TO_WORD_IDX(r) ((r) / EDCRS_PER_WORD)
>> +#define EDCR_TO_WORD_SHIFT(r) ((r % EDCRS_PER_WORD) * 2)
>> +#define EDCR_TO_WORD_VAL(val, r) (val << EDCR_TO_WORD_SHIFT(r))
>> +#define EDCR_TO_WORD_MASK(r) EDCR_TO_WORD_VAL(0x3, r)
>
> minor nit: add a new line here please
Sure, I will update this in the next patch series.
>
>> +#define EDCMRS_PER_WORD 32
>> +#define EDCMR_TO_WORD_IDX(r) ((r) / EDCMRS_PER_WORD)
>> +#define EDCMR_TO_WORD_SHIFT(r) ((r) % EDCMRS_PER_WORD)
>> +
>> /* TPDM integration test registers */
>> #define TPDM_ITATBCNTRL (0xEF0)
>> #define TPDM_ITCNTRL (0xF00)
>> @@ -60,14 +71,24 @@
>> #define TPDM_PIDR0_DS_IMPDEF BIT(0)
>> #define TPDM_PIDR0_DS_DSB BIT(1)
>> +#define TPDM_DSB_MAX_LINES 256
>> +/* MAX number of EDCR registers */
>> +#define TPDM_DSB_MAX_EDCR 16
>> +/* MAX number of EDCMR registers */
>> +#define TPDM_DSB_MAX_EDCMR 8
>> +
>> /**
>> * struct dsb_dataset - specifics associated to dsb dataset
>> * @mode: DSB programming mode
>> + * @edge_ctrl: Save value for edge control
>> + * @edge_ctrl_mask: Save value for edge control mask
>> * @trig_ts: Enable/Disable trigger timestamp.
>> * @trig_type: Enable/Disable trigger type.
>> */
>> struct dsb_dataset {
>> u32 mode;
>> + u32 edge_ctrl[TPDM_DSB_MAX_EDCR];
>> + u32 edge_ctrl_mask[TPDM_DSB_MAX_EDCMR];
>
> minor nit: Please align it with the fields below.
Sure, I will update this in the next patch series.
Best,
Tao
>
>> bool trig_ts;
>> bool trig_type;
>> };
>
> Suzuki
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