Re: [PATCH v3 2/8] coresight-tpda: Add support to configure CMB element

[Suzuki K Poulose <suzuki.poulose@xxxxxxx>]

On 18/12/2023 10:27, Suzuki K Poulose wrote:
> On 21/11/2023 02:24, Tao Zhang wrote:
> > Read the CMB element size from the device tree. Set the register
> > bit that controls the CMB element size of the corresponding port.
> >
> > Signed-off-by: Tao Zhang <quic_taozha@xxxxxxxxxxx>
> > Signed-off-by: Mao Jinlong <quic_jinlmao@xxxxxxxxxxx>
> > ---
> >   drivers/hwtracing/coresight/coresight-tpda.c | 117 +++++++++++--------
> >   drivers/hwtracing/coresight/coresight-tpda.h |   6 +
> >   2 files changed, 74 insertions(+), 49 deletions(-)
> >
> > diff --git a/drivers/hwtracing/coresight/coresight-tpda.c 
> > b/drivers/hwtracing/coresight/coresight-tpda.c
> > index 5f82737c37bb..e3762f38abb3 100644
> > --- a/drivers/hwtracing/coresight/coresight-tpda.c
> > +++ b/drivers/hwtracing/coresight/coresight-tpda.c
> > @@ -28,24 +28,54 @@ static bool coresight_device_is_tpdm(struct 
> > coresight_device *csdev)
> >               CORESIGHT_DEV_SUBTYPE_SOURCE_TPDM);
> >   }
> > +static void tpdm_clear_element_size(struct coresight_device *csdev)
> > +{
> > +    struct tpda_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
> > +
> > +    if (drvdata->dsb_esize)
> > +        drvdata->dsb_esize = 0;
> > +    if (drvdata->cmb_esize)
> > +        drvdata->cmb_esize = 0;
>
> Why do we need the if (...) check here ?
>
> > +}
> > +
> > +static void tpda_set_element_size(struct tpda_drvdata *drvdata, u32 
> > *val)
> > +{
> > +
> > +    if (drvdata->dsb_esize == 64)
> > +        *val |= TPDA_Pn_CR_DSBSIZE;
> > +    else if (drvdata->dsb_esize == 32)
> > +        *val &= ~TPDA_Pn_CR_DSBSIZE;
> > +
> > +    if (drvdata->cmb_esize == 64)
> > +        *val |= FIELD_PREP(TPDA_Pn_CR_CMBSIZE, 0x2);
> > +    else if (drvdata->cmb_esize == 32)
> > +        *val |= FIELD_PREP(TPDA_Pn_CR_CMBSIZE, 0x1);
> > +    else if (drvdata->cmb_esize == 8)
> > +        *val &= ~TPDA_Pn_CR_CMBSIZE;
> > +}
> > +
>
>
> >   /*
> > - * Read the DSB element size from the TPDM device
> > + * Read the element size from the TPDM device
> >    * Returns
> > - *    The dsb element size read from the devicetree if available.
> > + *    The element size read from the devicetree if available.
> >    *    0 - Otherwise, with a warning once.
>
> This doesn't match the function ? It return 0 on success and
> error (-EINVAL) on failure ?
>
> >    */
> > -static int tpdm_read_dsb_element_size(struct coresight_device *csdev)
> > +static int tpdm_read_element_size(struct tpda_drvdata *drvdata,
> > +                  struct coresight_device *csdev)
> >   {
> > -    int rc = 0;
> > -    u8 size = 0;
> > -
> > -    rc = fwnode_property_read_u8(dev_fwnode(csdev->dev.parent),
> > -            "qcom,dsb-element-size", &size);
> > +    int rc = -EINVAL;
> > +
> > +    if (!fwnode_property_read_u8(dev_fwnode(csdev->dev.parent),
> > +            "qcom,dsb-element-size", &drvdata->dsb_esize))
> > +        rc = 0;
> > +    if (!fwnode_property_read_u8(dev_fwnode(csdev->dev.parent),
> > +            "qcom,cmb-element-size", &drvdata->cmb_esize))

At this point we have the csdev->dev.parent as the TPDM device and with:

#include <coresight-tpdm.h>

	struct tpdm_drvdata *tpdm_data = get_drvdata(csdev->dev.parent);

	if (tpdm_has_cmb(tpdm_data)) {
		rc = fwnode_...(... "qcom,cmb-element-size"...)
	}

	if (tpdm_has_dsb(tpdm_data)) {
		rc = fwnode_...(..., "qcom,dsb-element-size"..)
	}

Suzuki


> > +        rc = 0;
>
> Are we not silently resetting the error if the former failed ?
>
> Could we not :
>
>      rc |= fwnode_...
>
>      rc |= fwnode_...
>
> instead ?
>
> Also what is the expectation here ? Are these properties a MUST for
> TPDM ?
>
> >       if (rc)
> >           dev_warn_once(&csdev->dev,
> > -            "Failed to read TPDM DSB Element size: %d\n", rc);
> > +            "Failed to read TPDM Element size: %d\n", rc);
> > -    return size;
> > +    return rc;
> >   }
> >   /*
> > @@ -56,11 +86,12 @@ static int tpdm_read_dsb_element_size(struct 
> > coresight_device *csdev)
> >    * Parameter "inport" is used to pass in the input port number
> >    * of TPDA, and it is set to -1 in the recursize call.
> >    */
> > -static int tpda_get_element_size(struct coresight_device *csdev,
> > +static int tpda_get_element_size(struct tpda_drvdata *drvdata,
> > +                 struct coresight_device *csdev,
> >                    int inport)
> >   {
> > -    int dsb_size = -ENOENT;
> > -    int i, size;
> > +    int rc = 0;
> > +    int i;
> >       struct coresight_device *in;
> >       for (i = 0; i < csdev->pdata->nr_inconns; i++) {
> > @@ -74,25 +105,21 @@ static int tpda_get_element_size(struct 
> > coresight_device *csdev,
> >               continue;
> >           if (coresight_device_is_tpdm(in)) {
> > -            size = tpdm_read_dsb_element_size(in);
> > +            if ((drvdata->dsb_esize) || (drvdata->cmb_esize))
> > +                return -EEXIST;
> > +            rc = tpdm_read_element_size(drvdata, in);
> > +            if (rc)
> > +                return rc;
> >           } else {
> >               /* Recurse down the path */
> > -            size = tpda_get_element_size(in, -1);
> > -        }
> > -
> > -        if (size < 0)
> > -            return size;
> > -
> > -        if (dsb_size < 0) {
> > -            /* Found a size, save it. */
> > -            dsb_size = size;
> > -        } else {
> > -            /* Found duplicate TPDMs */
> > -            return -EEXIST;
> > +            rc = tpda_get_element_size(drvdata, in, -1);
> > +            if (rc)
> > +                return rc;
> >           }
> >       }
> > -    return dsb_size;
> > +
> > +    return rc;
> >   }
> >   /* Settings pre enabling port control register */
> > @@ -109,7 +136,7 @@ static void tpda_enable_pre_port(struct 
> > tpda_drvdata *drvdata)
> >   static int tpda_enable_port(struct tpda_drvdata *drvdata, int port)
> >   {
> >       u32 val;
> > -    int size;
> > +    int rc;
> >       val = readl_relaxed(drvdata->base + TPDA_Pn_CR(port));
> >       /*
> > @@ -117,29 +144,21 @@ static int tpda_enable_port(struct tpda_drvdata 
> > *drvdata, int port)
> >        * Set the bit to 0 if the size is 32
> >        * Set the bit to 1 if the size is 64
> >        */
> > -    size = tpda_get_element_size(drvdata->csdev, port);
> > -    switch (size) {
> > -    case 32:
> > -        val &= ~TPDA_Pn_CR_DSBSIZE;
> > -        break;
> > -    case 64:
> > -        val |= TPDA_Pn_CR_DSBSIZE;
> > -        break;
> > -    case 0:
> > -        return -EEXIST;
> > -    case -EEXIST:
> > +    tpdm_clear_element_size(drvdata->csdev);
> > +    rc = tpda_get_element_size(drvdata, drvdata->csdev, port);
> > +    if (!rc && ((drvdata->dsb_esize) || (drvdata->cmb_esize))) {
> > +        tpda_set_element_size(drvdata, &val);
> > +        /* Enable the port */
> > +        val |= TPDA_Pn_CR_ENA;
> > +        writel_relaxed(val, drvdata->base + TPDA_Pn_CR(port));
> > +    } else if (rc == -EEXIST)
> >           dev_warn_once(&drvdata->csdev->dev,
> > -            "Detected multiple TPDMs on port %d", -EEXIST);
> > -        return -EEXIST;
> > -    default:
> > -        return -EINVAL;
> > -    }
> > -
> > -    /* Enable the port */
> > -    val |= TPDA_Pn_CR_ENA;
> > -    writel_relaxed(val, drvdata->base + TPDA_Pn_CR(port));
> > +                  "Detected multiple TPDMs on port %d", -EEXIST);
> > +    else
> > +        dev_warn_once(&drvdata->csdev->dev,
> > +                  "Didn't find TPDM elem size");
>
> "element size"
>
> > -    return 0;
> > +    return rc;
> >   }
> >   static int __tpda_enable(struct tpda_drvdata *drvdata, int port)
> > diff --git a/drivers/hwtracing/coresight/coresight-tpda.h 
> > b/drivers/hwtracing/coresight/coresight-tpda.h
> > index b3b38fd41b64..29164fd9711f 100644
> > --- a/drivers/hwtracing/coresight/coresight-tpda.h
> > +++ b/drivers/hwtracing/coresight/coresight-tpda.h
> > @@ -10,6 +10,8 @@
> >   #define TPDA_Pn_CR(n)        (0x004 + (n * 4))
> >   /* Aggregator port enable bit */
> >   #define TPDA_Pn_CR_ENA        BIT(0)
> > +/* Aggregator port CMB data set element size bit */
> > +#define TPDA_Pn_CR_CMBSIZE        GENMASK(7, 6)
> >   /* Aggregator port DSB data set element size bit */
> >   #define TPDA_Pn_CR_DSBSIZE        BIT(8)
> > @@ -25,6 +27,8 @@
> >    * @csdev:      component vitals needed by the framework.
> >    * @spinlock:   lock for the drvdata value.
> >    * @enable:     enable status of the component.
> > + * @dsb_esize   Record the DSB element size.
> > + * @cmb_esize   Record the CMB element size.
> >    */
> >   struct tpda_drvdata {
> >       void __iomem        *base;
> > @@ -32,6 +36,8 @@ struct tpda_drvdata {
> >       struct coresight_device    *csdev;
> >       spinlock_t        spinlock;
> >       u8            atid;
> > +    u8            dsb_esize;
> > +    u8            cmb_esize;
> >   };
> >   #endif  /* _CORESIGHT_CORESIGHT_TPDA_H */
>
> Suzuki