Messages in this thread | | | Date | Sat, 25 Mar 2023 19:31:15 +0000 | Subject | Re: [PATCH v3 02/11] coresight-tpda: Add DSB dataset support | From | Suzuki K Poulose <> |
| |
On 24/03/2023 14:58, Tao Zhang wrote: > Hi Suzuki, > > 在 3/23/2023 7:51 PM, Suzuki K Poulose 写道: >> On 23/03/2023 06:03, Tao Zhang wrote: >>> Read the DSB element size from the device tree. Set the register >>> bit that controls the DSB element size of the corresponding port. >>> >>> Signed-off-by: Tao Zhang <quic_taozha@quicinc.com> >>> --- >>> drivers/hwtracing/coresight/coresight-tpda.c | 58 >>> ++++++++++++++++++++++++++++ >>> drivers/hwtracing/coresight/coresight-tpda.h | 4 ++ >>> 2 files changed, 62 insertions(+) >>> >>> diff --git a/drivers/hwtracing/coresight/coresight-tpda.c >>> b/drivers/hwtracing/coresight/coresight-tpda.c >>> index f712e11..8dcfc4a 100644 >>> --- a/drivers/hwtracing/coresight/coresight-tpda.c >>> +++ b/drivers/hwtracing/coresight/coresight-tpda.c >>> @@ -21,6 +21,47 @@ >>> DEFINE_CORESIGHT_DEVLIST(tpda_devs, "tpda"); >>> +/* Search and read element data size from the TPDM node in >>> + * the devicetree. Each input port of TPDA is connected to >>> + * a TPDM. Different TPDM supports different types of dataset, >>> + * and some may support more than one type of dataset. >>> + * Parameter "inport" is used to pass in the input port number >>> + * of TPDA, and it is set to 0 in the recursize call. >>> + * Parameter "parent" is used to pass in the original call. >>> + */ >> >> I am still not clear why we need to do this recursively ? > > Some TPDMs are not directly output connected to the TPDAs. So here I > > use a recursive method to check from the TPDA input port until I find > > the connected TPDM. > > Do you have a better suggestion besides a recursive method? > >> >>> +static int tpda_set_element_size(struct tpda_drvdata *drvdata, >>> + struct coresight_device *csdev, int inport, bool parent) >> >> Please could we renamse csdev => tpda_dev > > Since this is a recursively called function, this Coresight device is not > > necessarily TPDA, it can be other Coresight device. > >> >>> +{ >>> + static int nr_inport; >>> + int i; >>> + struct coresight_device *in_csdev; >> >> similarly tpdm_dev ? > Same as above, this variable may not necessarily be a TPDM. >> >> Could we not add a check here to see if the dsb_esize[inport] is already >> set and then bail out, reading this over and over ? >> > I will update this in the next patch series. >>> + >>> + if (inport > (TPDA_MAX_INPORTS - 1)) >>> + return -EINVAL; >>> + >>> + if (parent) >>> + nr_inport = inport; >>> + >>> + for (i = 0; i < csdev->pdata->nr_inconns; i++) { >>> + in_csdev = csdev->pdata->in_conns[i].remote_dev; >> >> Please note, the names of the structure field might change in the >> next version of James' series > Got it. I will keep an eye out for the James' patch series. >> >>> + if (!in_csdev) >>> + break; >>> + >>> + if (parent) >>> + if (csdev->pdata->in_conns[i].port != inport) >>> + continue; >>> + >>> + if (in_csdev && strstr(dev_name(&in_csdev->dev), "tpdm")) { >> >> Isn't there a better way to distinguish a device to be TPDM ? May be we >> could even add a source_sub_type - SOURCE_TPDM instead of using >> SOURCE_OTHERS ? Do you expect other sources to be connected to TPDA? >> e.g., STMs ? > > I can add "SOURCE_TPDM" as a source_sub_type, but SOURCE_OTHERS needs > > to be kept since the other Coresight component we will upstream later may > > need it. > >> >>> + of_property_read_u32(in_csdev->dev.parent->of_node, >>> + "qcom,dsb-element-size", >>> &drvdata->dsb_esize[nr_inport]); >>> + break; >>> + } >>> + tpda_set_element_size(drvdata, in_csdev, 0, false); >> >> What is the point of this ? Is this for covering the a TPDA connected to >> another TPDA ? >> >> e.g., { TPDM0, TPDM1 } -> TPDA0 -> TPDA1 ? > > A TPDM may not connect to the TPDA directly, for example, > > TPDM0 ->FUNNEL0->FUNNEL1->TPDA0 > > And many TPDMs can connect to one TPDA, one input port on TPDA only has > > one TPDM connected. Therefore, we use a recursive method to find the TPDM > > corresponding to the input port of TPDA.
How do you find out decide what to choose, if there are multiple TPDMs connected to FUNNEL0 or even FUNNEL1 ?
e.g
TPDM0->FUNNEL0->FUNNEL1->TPDA0 / TPDM1 Suzuki
| |