Re: [PATCH v3 21/26] coresight: etm4x: Use TRCDEVARCH for component discovery

Mathieu Poirier
2020-11-06T21:42:33Z

On Wed, Oct 28, 2020 at 10:09:40PM +0000, Suzuki K Poulose wrote:
> We have been using TRCIDR1 for detecting the ETM version. This
> is in preparation for the future IP support.
>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> ---
> .../coresight/coresight-etm4x-core.c | 46 +++++++++----------
> 1 file changed, 23 insertions(+), 23 deletions(-)

Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>

I'm out of time for today, I will resume on Monday.

Thanks,
Mathieu

>
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> index 4ef47a2946a4..e36bc1c722c7 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> @@ -141,18 +141,6 @@ static void etm4_cs_unlock(struct etmv4_drvdata *drvdata,
> CS_UNLOCK(csa->base);
> }
>
> -static bool etm4_arch_supported(u8 arch)
> -{
> - /* Mask out the minor version number */
> - switch (arch & 0xf0) {
> - case ETM_ARCH_V4:
> - break;
> - default:
> - return false;
> - }
> - return true;
> -}
> -
> static int etm4_cpu_id(struct coresight_device *csdev)
> {
> struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
> @@ -677,6 +665,26 @@ static const struct coresight_ops etm4_cs_ops = {
> static bool etm_init_iomem_access(struct etmv4_drvdata *drvdata,
> struct csdev_access *csa)
> {
> + u32 devarch = readl_relaxed(drvdata->base + TRCDEVARCH);
> + u32 idr1 = readl_relaxed(drvdata->base + TRCIDR1);
> +
> + /*
> + * All ETMs must implement TRCDEVARCH to indicate that
> + * the component is an ETMv4. To support any broken
> + * implementations we fall back to TRCIDR1 check, which
> + * is not really reliable.
> + */
> + if ((devarch & ETM_DEVARCH_ID_MASK) == ETM_DEVARCH_ETMv4x_ARCH) {
> + drvdata->arch = etm_devarch_to_arch(devarch);
> + } else {
> + pr_warn("CPU%d: ETM4x incompatible TRCDEVARCH: %x, falling back to TRCIDR1\n",
> + smp_processor_id(), devarch);
> +
> + if (ETM_TRCIDR1_ARCH_MAJOR(idr1) != ETM_TRCIDR1_ARCH_ETMv4)
> + return false;
> + drvdata->arch = etm_trcidr_to_arch(idr1);
> + }
> +
> *csa = CSDEV_ACCESS_IOMEM(drvdata->base);
> return true;
> }
> @@ -693,7 +701,6 @@ static bool etm_init_csdev_access(struct etmv4_drvdata *drvdata,
> static void etm4_init_arch_data(void *info)
> {
> u32 etmidr0;
> - u32 etmidr1;
> u32 etmidr2;
> u32 etmidr3;
> u32 etmidr4;
> @@ -758,14 +765,6 @@ static void etm4_init_arch_data(void *info)
> /* TSSIZE, bits[28:24] Global timestamp size field */
> drvdata->ts_size = BMVAL(etmidr0, 24, 28);
>
> - /* base architecture of trace unit */
> - etmidr1 = etm4x_relaxed_read32(csa, TRCIDR1);
> - /*
> - * TRCARCHMIN, bits[7:4] architecture the minor version number
> - * TRCARCHMAJ, bits[11:8] architecture major versin number
> - */
> - drvdata->arch = BMVAL(etmidr1, 4, 11);
> -
> /* maximum size of resources */
> etmidr2 = etm4x_relaxed_read32(csa, TRCIDR2);
> /* CIDSIZE, bits[9:5] Indicates the Context ID size */
> @@ -1602,7 +1601,7 @@ static int etm4_probe(struct amba_device *adev, const struct amba_id *id)
> etm4_init_arch_data, &init_arg, 1))
> dev_err(dev, "ETM arch init failed\n");
>
> - if (etm4_arch_supported(drvdata->arch) == false)
> + if (!drvdata->arch)
> return -EINVAL;
>
> etm4_init_trace_id(drvdata);
> @@ -1634,7 +1633,8 @@ static int etm4_probe(struct amba_device *adev, const struct amba_id *id)
>
> pm_runtime_put(&adev->dev);
> dev_info(&drvdata->csdev->dev, "CPU%d: ETM v%d.%d initialized\n",
> - drvdata->cpu, drvdata->arch >> 4, drvdata->arch & 0xf);
> + drvdata->cpu, ETM_ARCH_MAJOR_VERSION(drvdata->arch),
> + ETM_ARCH_MINOR_VERSION(drvdata->arch));
>
> if (boot_enable) {
> coresight_enable(drvdata->csdev);
> --
> 2.24.1
>