coresight: cti: Add device tree support for v8 arch CTI

The v8 architecture defines the relationship between a PE, its optional ETM
and a CTI. Unlike non-architectural CTIs which are implementation defined,
this has a fixed set of connections which can therefore be represented as a
simple tag in the device tree.

This patch defines the tags needed to create an entry for this PE/ETM/CTI
relationship, and provides functionality to implement the connection model
in the CTI driver.

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/20200320165303.13681-7-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hwtracing/coresight/coresight-cti-platform.c

@@ -3,17 +3,222 @@
  * Copyright (c) 2019, The Linaro Limited. All rights reserved.
  */
 
+#include <dt-bindings/arm/coresight-cti-dt.h>
 #include <linux/of.h>
 
 #include "coresight-cti.h"
 
+/* Number of CTI signals in the v8 architecturally defined connection */
+#define NR_V8PE_IN_SIGS		2
+#define NR_V8PE_OUT_SIGS	3
+#define NR_V8ETM_INOUT_SIGS	4
+
+/* CTI device tree connection property keywords */
+#define CTI_DT_V8ARCH_COMPAT	"arm,coresight-cti-v8-arch"
+#define CTI_DT_CSDEV_ASSOC	"arm,cs-dev-assoc"
+
+#ifdef CONFIG_OF
+/*
+ * CTI can be bound to a CPU, or a system device.
+ * CPU can be declared at the device top level or in a connections node
+ * so need to check relative to node not device.
+ */
+static int of_cti_get_cpu_at_node(const struct device_node *node)
+{
+	int cpu;
+	struct device_node *dn;
+
+	if (node == NULL)
+		return -1;
+
+	dn = of_parse_phandle(node, "cpu", 0);
+	/* CTI affinity defaults to no cpu */
+	if (!dn)
+		return -1;
+	cpu = of_cpu_node_to_id(dn);
+	of_node_put(dn);
+
+	/* No Affinity  if no cpu nodes are found */
+	return (cpu < 0) ? -1 : cpu;
+}
+
+#else
+static int of_cti_get_cpu_at_node(const struct device_node *node)
+{
+	return -1;
+}
+
+#endif
+
+/*
+ * CTI can be bound to a CPU, or a system device.
+ * CPU can be declared at the device top level or in a connections node
+ * so need to check relative to node not device.
+ */
+static int cti_plat_get_cpu_at_node(struct fwnode_handle *fwnode)
+{
+	if (is_of_node(fwnode))
+		return of_cti_get_cpu_at_node(to_of_node(fwnode));
+	return -1;
+}
+
+const char *cti_plat_get_node_name(struct fwnode_handle *fwnode)
+{
+	if (is_of_node(fwnode))
+		return of_node_full_name(to_of_node(fwnode));
+	return "unknown";
+}
+
+/*
+ * Extract a name from the fwnode.
+ * If the device associated with the node is a coresight_device, then return
+ * that name and the coresight_device pointer, otherwise return the node name.
+ */
+static const char *
+cti_plat_get_csdev_or_node_name(struct fwnode_handle *fwnode,
+				struct coresight_device **csdev)
+{
+	const char *name = NULL;
+	*csdev = coresight_find_csdev_by_fwnode(fwnode);
+	if (*csdev)
+		name = dev_name(&(*csdev)->dev);
+	else
+		name = cti_plat_get_node_name(fwnode);
+	return name;
+}
+
+static int cti_plat_create_v8_etm_connection(struct device *dev,
+					     struct cti_drvdata *drvdata)
+{
+	int ret = -ENOMEM, i;
+	struct fwnode_handle *root_fwnode, *cs_fwnode;
+	const char *assoc_name = NULL;
+	struct coresight_device *csdev;
+	struct cti_trig_con *tc = NULL;
+
+	root_fwnode = dev_fwnode(dev);
+	if (IS_ERR_OR_NULL(root_fwnode))
+		return -EINVAL;
+
+	/* Can optionally have an etm node - return if not  */
+	cs_fwnode = fwnode_find_reference(root_fwnode, CTI_DT_CSDEV_ASSOC, 0);
+	if (IS_ERR_OR_NULL(cs_fwnode))
+		return 0;
+
+	/* allocate memory */
+	tc = cti_allocate_trig_con(dev, NR_V8ETM_INOUT_SIGS,
+				   NR_V8ETM_INOUT_SIGS);
+	if (!tc)
+		goto create_v8_etm_out;
+
+	/* build connection data */
+	tc->con_in->used_mask = 0xF0; /* sigs <4,5,6,7> */
+	tc->con_out->used_mask = 0xF0; /* sigs <4,5,6,7> */
+
+	/*
+	 * The EXTOUT type signals from the ETM are connected to a set of input
+	 * triggers on the CTI, the EXTIN being connected to output triggers.
+	 */
+	for (i = 0; i < NR_V8ETM_INOUT_SIGS; i++) {
+		tc->con_in->sig_types[i] = ETM_EXTOUT;
+		tc->con_out->sig_types[i] = ETM_EXTIN;
+	}
+
+	/*
+	 * We look to see if the ETM coresight device associated with this
+	 * handle has been registered with the system - i.e. probed before
+	 * this CTI. If so csdev will be non NULL and we can use the device
+	 * name and pass the csdev to the connection entry function where
+	 * the association will be recorded.
+	 * If not, then simply record the name in the connection data, the
+	 * probing of the ETM will call into the CTI driver API to update the
+	 * association then.
+	 */
+	assoc_name = cti_plat_get_csdev_or_node_name(cs_fwnode, &csdev);
+	ret = cti_add_connection_entry(dev, drvdata, tc, csdev, assoc_name);
+
+create_v8_etm_out:
+	fwnode_handle_put(cs_fwnode);
+	return ret;
+}
+
+/*
+ * Create an architecturally defined v8 connection
+ * must have a cpu, can have an ETM.
+ */
+static int cti_plat_create_v8_connections(struct device *dev,
+					  struct cti_drvdata *drvdata)
+{
+	struct cti_device *cti_dev = &drvdata->ctidev;
+	struct cti_trig_con *tc = NULL;
+	int cpuid = 0;
+	char cpu_name_str[16];
+	int ret = -ENOMEM;
+
+	/* Must have a cpu node */
+	cpuid = cti_plat_get_cpu_at_node(dev_fwnode(dev));
+	if (cpuid < 0) {
+		dev_warn(dev,
+			 "ARM v8 architectural CTI connection: missing cpu\n");
+		return -EINVAL;
+	}
+	cti_dev->cpu = cpuid;
+
+	/* Allocate the v8 cpu connection memory */
+	tc = cti_allocate_trig_con(dev, NR_V8PE_IN_SIGS, NR_V8PE_OUT_SIGS);
+	if (!tc)
+		goto of_create_v8_out;
+
+	/* Set the v8 PE CTI connection data */
+	tc->con_in->used_mask = 0x3; /* sigs <0 1> */
+	tc->con_in->sig_types[0] = PE_DBGTRIGGER;
+	tc->con_in->sig_types[1] = PE_PMUIRQ;
+	tc->con_out->used_mask = 0x7; /* sigs <0 1 2 > */
+	tc->con_out->sig_types[0] = PE_EDBGREQ;
+	tc->con_out->sig_types[1] = PE_DBGRESTART;
+	tc->con_out->sig_types[2] = PE_CTIIRQ;
+	scnprintf(cpu_name_str, sizeof(cpu_name_str), "cpu%d", cpuid);
+
+	ret = cti_add_connection_entry(dev, drvdata, tc, NULL, cpu_name_str);
+	if (ret)
+		goto of_create_v8_out;
+
+	/* Create the v8 ETM associated connection */
+	ret = cti_plat_create_v8_etm_connection(dev, drvdata);
+	if (ret)
+		goto of_create_v8_out;
+
+	/* filter pe_edbgreq - PE trigout sig <0> */
+	drvdata->config.trig_out_filter |= 0x1;
+
+of_create_v8_out:
+	return ret;
+}
+
+static int cti_plat_check_v8_arch_compatible(struct device *dev)
+{
+	struct fwnode_handle *fwnode = dev_fwnode(dev);
+
+	if (is_of_node(fwnode))
+		return of_device_is_compatible(to_of_node(fwnode),
+					       CTI_DT_V8ARCH_COMPAT);
+	return 0;
+}
+
 /* get the hardware configuration & connection data. */
 int cti_plat_get_hw_data(struct device *dev,
 			 struct cti_drvdata *drvdata)
 {
 	int rc = 0;
 	struct cti_device *cti_dev = &drvdata->ctidev;
 
+	/* check for a v8 architectural CTI device */
+	if (cti_plat_check_v8_arch_compatible(dev)) {
+		rc = cti_plat_create_v8_connections(dev, drvdata);
+		if (rc)
+			return rc;
+	}
+
 	/* if no connections, just add a single default based on max IN-OUT */
 	if (cti_dev->nr_trig_con == 0)
 		rc = cti_add_default_connection(dev, drvdata);

drivers/hwtracing/coresight/coresight-platform.c

@@ -57,6 +57,26 @@ coresight_find_device_by_fwnode(struct fwnode_handle *fwnode)
 	return bus_find_device_by_fwnode(&amba_bustype, fwnode);
 }
 
+/*
+ * Find a registered coresight device from a device fwnode.
+ * The node info is associated with the AMBA parent, but the
+ * csdev keeps a copy so iterate round the coresight bus to
+ * find the device.
+ */
+struct coresight_device *
+coresight_find_csdev_by_fwnode(struct fwnode_handle *r_fwnode)
+{
+	struct device *dev;
+	struct coresight_device *csdev = NULL;
+
+	dev = bus_find_device_by_fwnode(&coresight_bustype, r_fwnode);
+	if (dev) {
+		csdev = to_coresight_device(dev);
+		put_device(dev);
+	}
+	return csdev;
+}
+
 #ifdef CONFIG_OF
 static inline bool of_coresight_legacy_ep_is_input(struct device_node *ep)
 {

drivers/hwtracing/coresight/coresight-priv.h

@@ -202,5 +202,7 @@ static inline void *coresight_get_uci_data(const struct amba_id *id)
 }
 
 void coresight_release_platform_data(struct coresight_platform_data *pdata);
+struct coresight_device *
+coresight_find_csdev_by_fwnode(struct fwnode_handle *r_fwnode);
 
 #endif

drivers/hwtracing/coresight/coresight.c

@@ -1030,17 +1030,11 @@ static void coresight_fixup_device_conns(struct coresight_device *csdev)
 
 	for (i = 0; i < csdev->pdata->nr_outport; i++) {
 		struct coresight_connection *conn = &csdev->pdata->conns[i];
-		struct device *dev = NULL;
 
-		dev = bus_find_device_by_fwnode(&coresight_bustype, conn->child_fwnode);
-		if (dev) {
-			conn->child_dev = to_coresight_device(dev);
-			/* and put reference from 'bus_find_device()' */
-			put_device(dev);
-		} else {
+		conn->child_dev =
+			coresight_find_csdev_by_fwnode(conn->child_fwnode);
+		if (!conn->child_dev)
 			csdev->orphan = true;
-			conn->child_dev = NULL;
-		}
 	}
 }