Parse device tree to detect supported nest pmu units. Traverse
through each nest pmu unit folder to find supported events and
corresponding unit/scale files (if any).

The nest unit event file from DT, will contain the offset in the
reserved memory region to get the counter data for a given event.
Kernel code uses this offset as event configuration value.

Device tree parser code also looks for scale/unit in the file name and
passes on the file as an event attr for perf tool to use in the post
processing.

Cc: Michael Ellerman <m...@ellerman.id.au>
Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Cc: Paul Mackerras <pau...@samba.org>
Cc: Anton Blanchard <an...@samba.org>
Cc: Sukadev Bhattiprolu <suka...@linux.vnet.ibm.com>
Cc: Anshuman Khandual <khand...@linux.vnet.ibm.com>
Cc: Stephane Eranian <eran...@google.com>
Signed-off-by: Madhavan Srinivasan <ma...@linux.vnet.ibm.com>
---
 arch/powerpc/perf/nest-pmu.c | 124 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 123 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/perf/nest-pmu.c b/arch/powerpc/perf/nest-pmu.c
index e7d45ed..6116ff3 100644
--- a/arch/powerpc/perf/nest-pmu.c
+++ b/arch/powerpc/perf/nest-pmu.c
@@ -11,6 +11,119 @@
 #include "nest-pmu.h"
 
 static struct perchip_nest_info p8_nest_perchip_info[P8_NEST_MAX_CHIPS];
+static struct nest_pmu *per_nest_pmu_arr[P8_NEST_MAX_PMUS];
+
+static int nest_event_info(struct property *pp, char *start,
+                       struct nest_ima_events *p8_events, int flg, u32 val)
+{
+       char *buf;
+
+       /* memory for event name */
+       buf = kzalloc(P8_NEST_MAX_PMU_NAME_LEN, GFP_KERNEL);
+       if (!buf)
+               return -ENOMEM;
+
+       strncpy(buf, start, strlen(start));
+       p8_events->ev_name = buf;
+
+       /* memory for content */
+       buf = kzalloc(P8_NEST_MAX_PMU_NAME_LEN, GFP_KERNEL);
+       if (!buf)
+               return -ENOMEM;
+
+       if (flg) {
+               /* string content*/
+               if (!pp->value ||
+                  (strnlen(pp->value, pp->length) == pp->length))
+                       return -EINVAL;
+
+               strncpy(buf, (const char *)pp->value, pp->length);
+       } else
+               sprintf(buf, "event=0x%x", val);
+
+       p8_events->ev_value = buf;
+       return 0;
+}
+
+static int nest_pmu_create(struct device_node *dev, int pmu_index)
+{
+       struct nest_ima_events **p8_events_arr, *p8_events;
+       struct nest_pmu *pmu_ptr;
+       struct property *pp;
+       char *buf, *start;
+       const __be32 *lval;
+       u32 val;
+       int idx = 0, ret;
+
+       if (!dev)
+               return -EINVAL;
+
+       /* memory for nest pmus */
+       pmu_ptr = kzalloc(sizeof(struct nest_pmu), GFP_KERNEL);
+       if (!pmu_ptr)
+               return -ENOMEM;
+
+       /* Needed for hotplug/migration */
+       per_nest_pmu_arr[pmu_index] = pmu_ptr;
+
+       /* memory for nest pmu events */
+       p8_events_arr = kzalloc((sizeof(struct nest_ima_events) * 64),
+                                                               GFP_KERNEL);
+       if (!p8_events_arr)
+               return -ENOMEM;
+       p8_events = (struct nest_ima_events *)p8_events_arr;
+
+       /*
+        * Loop through each property
+        */
+       for_each_property_of_node(dev, pp) {
+               start = pp->name;
+
+               if (!strcmp(pp->name, "name")) {
+                       if (!pp->value ||
+                          (strnlen(pp->value, pp->length) == pp->length))
+                               return -EINVAL;
+
+                       buf = kzalloc(P8_NEST_MAX_PMU_NAME_LEN, GFP_KERNEL);
+                       if (!buf)
+                               return -ENOMEM;
+
+                       /* Save the name to register it later */
+                       sprintf(buf, "Nest_%s", (char *)pp->value);
+                       pmu_ptr->pmu.name = (char *)buf;
+                       continue;
+               }
+
+               /* Skip these, we dont need it */
+               if (!strcmp(pp->name, "phandle") ||
+                   !strcmp(pp->name, "device_type") ||
+                   !strcmp(pp->name, "linux,phandle"))
+                       continue;
+
+               if (strncmp(pp->name, "unit.", 5) == 0) {
+                       /* Skip first few chars in the name */
+                       start += 5;
+                       ret = nest_event_info(pp, start, p8_events++, 1, 0);
+               } else if (strncmp(pp->name, "scale.", 6) == 0) {
+                       /* Skip first few chars in the name */
+                       start += 6;
+                       ret = nest_event_info(pp, start, p8_events++, 1, 0);
+               } else {
+                       lval = of_get_property(dev, pp->name, NULL);
+                       val = (uint32_t)be32_to_cpup(lval);
+
+                       ret = nest_event_info(pp, start, p8_events++, 0, val);
+               }
+
+               if (ret)
+                       return ret;
+
+               /* book keeping */
+               idx++;
+       }
+
+       return 0;
+}
 
 static int nest_ima_dt_parser(void)
 {
@@ -19,7 +132,7 @@ static int nest_ima_dt_parser(void)
        const __be64 *chip_ima_size;
        struct device_node *dev;
        struct perchip_nest_info *p8ni;
-       int idx;
+       int idx, ret;
 
        /*
         * "nest-ima" folder contains two things,
@@ -50,6 +163,15 @@ static int nest_ima_dt_parser(void)
                p8ni->vbase = (uint64_t) phys_to_virt(p8ni->pbase);
        }
 
+       /* Look for supported Nest PMU units */
+       idx = 0;
+       for_each_node_by_type(dev, "nest-ima-unit") {
+               ret = nest_pmu_create(dev, idx);
+               if (ret)
+                       return ret;
+               idx++;
+       }
+
        return 0;
 }
 
-- 
1.9.1

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