Re: [RFC PATCH v4 06/15] coresight: cti: Add device tree support for v8 arch CTI

On Mon, Aug 19, 2019 at 10:13:52PM +0100, Mike Leach wrote:

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

.../coresight/coresight-cti-platform.c | 155 ++++++++++++++++++ 1 file changed, 155 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-cti-platform.c b/drivers/hwtracing/coresight/coresight-cti-platform.c index eb4f8a835c10..3ee5b8f8d245 100644 --- a/drivers/hwtracing/coresight/coresight-cti-platform.c +++ b/drivers/hwtracing/coresight/coresight-cti-platform.c @@ -3,11 +3,159 @@

• Copyright (c) 2019, The Linux Foundation. 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 "arm,cti-v8-arch" +#define CTI_DT_CSDEV_ASSOC "arm,cs-dev-assoc"

+/*

• • 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.
• */

+static struct coresight_device * +cti_get_assoc_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 +/*

• • 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;
• 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;

+}

+static int of_cti_create_v8_etm_connection(struct device *dev,

• 			   struct cti_drvdata *drvdata,
  

• 			   struct device_node *np)
  

+{

• int ret = -ENOMEM, i;
• struct device_node *cs_np;
• const char *assoc_name = NULL;
• struct coresight_device *csdev;
• struct fwnode_handle *r_fwnode;
• struct cti_trig_con *tc = NULL;
• /* Can optionally have an etm node - return if not */
• cs_np = of_parse_phandle(np, CTI_DT_CSDEV_ASSOC, 0);

extra space after "np,"

• if (!cs_np)

• return 0;
  

• /* allocate memory */
• tc = cti_allocate_trig_con(dev, NR_V8ETM_INOUT_SIGS,

• 		   NR_V8ETM_INOUT_SIGS);
  

• if (!tc)

• goto of_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> */
• 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;
  

• }

So far I understand that connection names (and the processing going with them) has been centered on the CTI itself. Either the above is a mistake and should read: tc->con_in->sig_types[i] = ETM_EXTIN; tc->con_out->sig_types[i] = ETM_EXTOUT;

or the logic is that ETM_EXTOUT becomes an input for the CTI. If so please add a comment to make it clear that a CTI IN is an ETM OUT and vice versa. Otherwise I can already see patches to correct the "bug" accumulating in my inbox.

• r_fwnode = of_fwnode_handle(cs_np);
• csdev = cti_get_assoc_csdev_by_fwnode(r_fwnode);
• if (csdev)

• assoc_name = dev_name(&csdev->dev);
  

• else

• assoc_name = cs_np->full_name;
  

I understand what is happening here only because I am familiar with CS and the chicken-and-egg conundrum inherent to device discovery. Please add a comment describing what is happening and exactly where, i.e function name, things are fixed in the future.

• ret = cti_add_connection_entry(dev, drvdata, tc, csdev, assoc_name);

+of_create_v8_etm_out:

• of_node_put(cs_np);
• return ret;

+}

+/*

• • Create an architecturally defined v8 connection
• • must have a cpu, can have an ETM.
• */

+static int of_cti_create_v8_connections(struct device *dev,

• 			struct cti_drvdata *drvdata,
  

• 			struct device_node *np)
  

+{

• 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 = of_cti_get_cpu_at_node(np);
• if (cpuid < 0) {

• dev_warn(dev, "CTI v8 DT binding no 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 = of_cti_create_v8_etm_connection(dev, drvdata, np);
• 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;

+}

/* get the hardware configuration & connection data. */ int of_cti_get_hw_data(struct device *dev, struct device_node *np, @@ -16,6 +164,13 @@ int of_cti_get_hw_data(struct device *dev, int rc = 0; struct cti_device *cti_dev = &drvdata->ctidev;

• /* check for a v8 architectural CTI device */
• if (of_property_read_bool(np, CTI_DT_V8ARCH)) {

• rc = of_cti_create_v8_connections(dev, drvdata, np);
  

Please refer to the new comment I posted in patch 01 about making functions generic to lessen the burden of adding ACPI support.

Thanks, Mathieu

• 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);

-- 2.17.1