From 02510a5aa78df45ff9a22def37e5c18677d4d659 Mon Sep 17 00:00:00 2001 From: Tingwei Zhang Date: Thu, 16 Jul 2020 11:57:32 -0600 Subject: [PATCH] coresight: etm4x: Add support to skip trace unit power up 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 Co-developed-by: Sai Prakash Ranjan Signed-off-by: Sai Prakash Ranjan Signed-off-by: Mathieu Poirier Link: https://lore.kernel.org/r/20200716175746.3338735-4-mathieu.poirier@linaro.org Signed-off-by: Greg Kroah-Hartman --- 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 0c35cd5e..2290f41 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); @@ -1468,6 +1472,9 @@ 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 4a695bf..72c9a55 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 */ -- 2.7.4