coresight: cti: Add sysfs access to program function registers

Adds in sysfs programming support for the CTI function register sets.
Allows direct manipulation of channel / trigger association registers.
Signed-off-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200320165303.13681-4-mathieu.poirier@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hwtracing/coresight/Kconfig

@@ -122,4 +122,13 @@ config CORESIGHT_CTI
 	  halt compared to disabling sources and sinks normally in driver
 	  software.
 
+config CORESIGHT_CTI_INTEGRATION_REGS
+	bool "Access CTI CoreSight Integration Registers"
+	depends on CORESIGHT_CTI
+	help
+	  This option adds support for the CoreSight integration registers on
+	  this device. The integration registers allow the exploration of the
+	  CTI trigger connections between this and other devices.These
+	  registers are not used in normal operation and can leave devices in
+	  an inconsistent state.
 endif

drivers/hwtracing/coresight/coresight-cti.c

@@ -149,6 +149,25 @@ static int cti_disable_hw(struct cti_drvdata *drvdata)
 	return 0;
 }
 
+void cti_write_single_reg(struct cti_drvdata *drvdata, int offset, u32 value)
+{
+	CS_UNLOCK(drvdata->base);
+	writel_relaxed(value, drvdata->base + offset);
+	CS_LOCK(drvdata->base);
+}
+
+void cti_write_intack(struct device *dev, u32 ackval)
+{
+	struct cti_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	struct cti_config *config = &drvdata->config;
+
+	spin_lock(&drvdata->spinlock);
+	/* write if enabled */
+	if (cti_active(config))
+		cti_write_single_reg(drvdata, CTIINTACK, ackval);
+	spin_unlock(&drvdata->spinlock);
+}
+
 /*
  * Look at the HW DEVID register for some of the HW settings.
  * DEVID[15:8] - max number of in / out triggers.

drivers/hwtracing/coresight/coresight-cti.h

@@ -180,7 +180,15 @@ struct cti_trig_con *cti_allocate_trig_con(struct device *dev, int in_sigs,
 					   int out_sigs);
 int cti_enable(struct coresight_device *csdev);
 int cti_disable(struct coresight_device *csdev);
+void cti_write_intack(struct device *dev, u32 ackval);
+void cti_write_single_reg(struct cti_drvdata *drvdata, int offset, u32 value);
 struct coresight_platform_data *
 coresight_cti_get_platform_data(struct device *dev);
 
+/* cti powered and enabled */
+static inline bool cti_active(struct cti_config *cfg)
+{
+	return cfg->hw_powered && cfg->hw_enabled;
+}
+
 #endif  /* _CORESIGHT_CORESIGHT_CTI_H */