Re: [PATCH v5 05/10] coresight-tpda: Add support to configure CMB element

[Tao Zhang]

On 1/30/2024 8:35 PM, Suzuki K Poulose wrote:
> On 30/01/2024 09:02, 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.
> >
> > Reviewed-by: James Clark <james.clark@xxxxxxx>
> > Signed-off-by: Tao Zhang <quic_taozha@xxxxxxxxxxx>
> > Signed-off-by: Mao Jinlong <quic_jinlmao@xxxxxxxxxxx>
> > ---
> >   drivers/hwtracing/coresight/coresight-tpda.c | 123 +++++++++++--------
> >   drivers/hwtracing/coresight/coresight-tpda.h |   6 +
> >   2 files changed, 79 insertions(+), 50 deletions(-)
> >
> > diff --git a/drivers/hwtracing/coresight/coresight-tpda.c 
> > b/drivers/hwtracing/coresight/coresight-tpda.c
> > index 4ac954f4bc13..fcddff3ded81 100644
> > --- a/drivers/hwtracing/coresight/coresight-tpda.c
> > +++ b/drivers/hwtracing/coresight/coresight-tpda.c
> > @@ -18,6 +18,7 @@
> >   #include "coresight-priv.h"
> >   #include "coresight-tpda.h"
> >   #include "coresight-trace-id.h"
> > +#include "coresight-tpdm.h"
> >     DEFINE_CORESIGHT_DEVLIST(tpda_devs, "tpda");
> >   @@ -28,24 +29,57 @@ 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);
> > +
> > +    drvdata->dsb_esize = 0;
> > +    drvdata->cmb_esize = 0;
> > +}
> > +
> > +static void tpda_set_element_size(struct tpda_drvdata *drvdata, u32 
> > *val)
> > +{
> > +
>
>
>
> > +    if (drvdata->dsb_esize == 64)
> > +        *val |= TPDA_Pn_CR_DSBSIZE;
>
> We don't seem to be clearing the fields we modify, before updating 
> them. This may be OK in real world where the device connected to TPDA 
> port
> may not change. But it is always safer to clear the bits and set it.
>
> e.g.:
>     *val &= ~(TPDA_Pn_CR_DSBSIZE | TPDA_Pn_CR_CMBSIZE);
>
>
>
> > +    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);
>
> Similarly here ^^^. I am happy to fix it up if you are OK with it 
> (unless there are other changes that need a respin)

Thank you. I would be very grateful if you could help for this.


Best,

Tao

> > +    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. One TPDM must have at 
> > least one of the
> > + * element size property.
> >    * Returns
> > - *    The dsb element size read from the devicetree if available.
> > - *    0 - Otherwise, with a warning once.
> > + *    0 - The element size property is read
> > + *    Others - Cannot read the property of the element size
> >    */
> > -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;
> > +    int rc = -EINVAL;
> > +    struct tpdm_drvdata *tpdm_data = 
> > dev_get_drvdata(csdev->dev.parent);
> > +
> > +    if (tpdm_has_dsb_dataset(tpdm_data)) {
> > +        rc = fwnode_property_read_u8(dev_fwnode(csdev->dev.parent),
> > +                "qcom,dsb-element-size", &drvdata->dsb_esize);
> > +    }
> > +    if (tpdm_has_cmb_dataset(tpdm_data)) {
> > +        rc = fwnode_property_read_u32(dev_fwnode(csdev->dev.parent),
> > +                "qcom,cmb-element-bits", &drvdata->cmb_esize);
> > +    }
> >   -    rc = fwnode_property_read_u8(dev_fwnode(csdev->dev.parent),
> > -            "qcom,dsb-element-size", &size);
> >       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 +90,12 @@ 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++) {
> > @@ -69,30 +104,26 @@ static int tpda_get_element_size(struct 
> > coresight_device *csdev,
> >               continue;
> >             /* Ignore the paths that do not match port */
> > -        if (inport > 0 &&
> > +        if (inport >= 0 &&
>
> That looks like a bug fix, but if you don't care about fixing this in 
> < v6.8,  I don't mind.
>
>
> Rest looks fine to me
>
> Suzuki