From: Tingwei Zhang tingwei@codeaurora.org
On some Qualcomm Technologies Inc. SoCs like SC7180, there exists a hardware errata where the APSS (Application Processor SubSystem)/CPU watchdog counter is stopped when the trace unit power up ETM register is set (TRCPDCR.PU = 1). Since the ETMs share the same power domain as that of respective CPU cores, they are powered on when the CPU core is powered on. So we can skip powering up of trace unit after checking for this errata via new property called "qcom,skip-power-up".
Signed-off-by: Tingwei Zhang tingwei@codeaurora.org Co-developed-by: Sai Prakash Ranjan saiprakash.ranjan@codeaurora.org Signed-off-by: Sai Prakash Ranjan saiprakash.ranjan@codeaurora.org --- drivers/hwtracing/coresight/coresight-etm4x.c | 27 ++++++++++++------- drivers/hwtracing/coresight/coresight-etm4x.h | 3 +++ 2 files changed, 20 insertions(+), 10 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c index fb0f5f4f3a91..c16532e1e968 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x.c +++ b/drivers/hwtracing/coresight/coresight-etm4x.c @@ -196,12 +196,14 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata) writel_relaxed(config->vmid_mask0, drvdata->base + TRCVMIDCCTLR0); writel_relaxed(config->vmid_mask1, drvdata->base + TRCVMIDCCTLR1);
- /* - * Request to keep the trace unit powered and also - * emulation of powerdown - */ - writel_relaxed(readl_relaxed(drvdata->base + TRCPDCR) | TRCPDCR_PU, - drvdata->base + TRCPDCR); + if (!drvdata->skip_power_up) { + /* + * Request to keep the trace unit powered and also + * emulation of powerdown + */ + writel_relaxed(readl_relaxed(drvdata->base + TRCPDCR) | + TRCPDCR_PU, drvdata->base + TRCPDCR); + }
/* Enable the trace unit */ writel_relaxed(1, drvdata->base + TRCPRGCTLR); @@ -476,10 +478,12 @@ static void etm4_disable_hw(void *info)
CS_UNLOCK(drvdata->base);
- /* power can be removed from the trace unit now */ - control = readl_relaxed(drvdata->base + TRCPDCR); - control &= ~TRCPDCR_PU; - writel_relaxed(control, drvdata->base + TRCPDCR); + if (!drvdata->skip_power_up) { + /* power can be removed from the trace unit now */ + control = readl_relaxed(drvdata->base + TRCPDCR); + control &= ~TRCPDCR_PU; + writel_relaxed(control, drvdata->base + TRCPDCR); + }
control = readl_relaxed(drvdata->base + TRCPRGCTLR);
@@ -1429,6 +1433,9 @@ static int etm4_probe(struct amba_device *adev, const struct amba_id *id) return -ENOMEM; }
+ if (fwnode_property_present(dev_fwnode(dev), "qcom,skip-power-up")) + drvdata->skip_power_up = true; + /* Validity for the resource is already checked by the AMBA core */ base = devm_ioremap_resource(dev, res); if (IS_ERR(base)) diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h index 4a695bf90582..72c9a55e67df 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x.h +++ b/drivers/hwtracing/coresight/coresight-etm4x.h @@ -407,6 +407,8 @@ struct etmv4_save_state { * @config: structure holding configuration parameters. * @save_state: State to be preserved across power loss * @state_needs_restore: True when there is context to restore after PM exit + * @skip_power_up: Indicates if an implementation can skip powering up + * the trace unit. */ struct etmv4_drvdata { void __iomem *base; @@ -454,6 +456,7 @@ struct etmv4_drvdata { struct etmv4_config config; struct etmv4_save_state *save_state; bool state_needs_restore; + bool skip_power_up; };
/* Address comparator access types */