[RFC PATCH 8/9] perf: cxl: Make the cpmu driver also work with auxiliary_devices

Jonathan Cameron
2024-05-29T16:45:12Z

CXL PMUs can be found both in endpoints (already supported) and
in switch usp/dsp and root ports. Those ports are all handled
by pcie/portdrv which will register auxiliary_devices rather
than devices on the CXL bus.

Make the CXL PMU driver register an auxiliary driver as well as
the existing one for device on /sys/bus/cxl.
There is no particular need for this driver to register early
or to deal with particularly compact kernel configurations, so just
make it dependent on both bus drivers.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
drivers/perf/Kconfig | 1 +
drivers/perf/cxl_pmu.c | 99 +++++++++++++++++++++++++++++++++++-------
2 files changed, 85 insertions(+), 15 deletions(-)

diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig
index 7526a9e714fa..4b7893a03a4c 100644
--- a/drivers/perf/Kconfig
+++ b/drivers/perf/Kconfig
@@ -255,6 +255,7 @@ source "drivers/perf/amlogic/Kconfig"
config CXL_PMU
tristate "CXL Performance Monitoring Unit"
depends on CXL_BUS
+ depends on AUXILIARY_BUS
help
Support performance monitoring as defined in CXL rev 3.0
section 13.2: Performance Monitoring. CXL components may have
diff --git a/drivers/perf/cxl_pmu.c b/drivers/perf/cxl_pmu.c
index 65a8437ee236..30b2aad556ad 100644
--- a/drivers/perf/cxl_pmu.c
+++ b/drivers/perf/cxl_pmu.c
@@ -12,6 +12,7 @@
*/

#include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/auxiliary_bus.h>
#include <linux/perf_event.h>
#include <linux/bitops.h>
#include <linux/device.h>
@@ -20,6 +21,7 @@
#include <linux/bug.h>
#include <linux/pci.h>

+#include "../pci/pcie/portdrv.h"
#include "../cxl/cxlpci.h"
#include "../cxl/cxl.h"
#include "../cxl/pmu.h"
@@ -753,13 +755,12 @@ static void cxl_pmu_cpuhp_remove(void *_info)
cpuhp_state_remove_instance_nocalls(cxl_pmu_cpuhp_state_num, &info->node);
}

-static int cxl_pmu_probe(struct device *dev)
+static int __cxl_pmu_probe(struct device *dev, const char *dev_name,
+ void __iomem *base)
{
- struct cxl_pmu *pmu = to_cxl_pmu(dev);
struct pci_dev *pdev = to_pci_dev(dev->parent);
struct cxl_pmu_info *info;
char *irq_name;
- char *dev_name;
int rc, irq;

info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
@@ -767,10 +768,10 @@ static int cxl_pmu_probe(struct device *dev)
return -ENOMEM;

dev_set_drvdata(dev, info);
+
INIT_LIST_HEAD(&info->event_caps_fixed);
INIT_LIST_HEAD(&info->event_caps_configurable);
-
- info->base = pmu->base;
+ info->base = base;

info->on_cpu = -1;
rc = cxl_pmu_parse_caps(dev, info);
@@ -782,15 +783,6 @@ static int cxl_pmu_probe(struct device *dev)
if (!info->hw_events)
return -ENOMEM;

- switch (pmu->type) {
- case CXL_PMU_MEMDEV:
- dev_name = devm_kasprintf(dev, GFP_KERNEL, "cxl_pmu_mem%d.%d",
- pmu->assoc_id, pmu->index);
- break;
- }
- if (!dev_name)
- return -ENOMEM;
-
info->pmu = (struct pmu) {
.name = dev_name,
.parent = dev,
@@ -843,6 +835,60 @@ static int cxl_pmu_probe(struct device *dev)
return rc;

return 0;
+
+}
+
+static int cxl_pmu_port_probe(struct auxiliary_device *adev,
+ const struct auxiliary_device_id *id)
+{
+
+ struct pcie_port_aux_dev *pcie_adev = to_pcie_port_aux_dev(adev);
+ struct device *parent = adev->dev.parent;
+ struct pci_dev *pdev = to_pci_dev(parent);
+ struct device *dev = &adev->dev;
+ char *dev_name;
+ void __iomem *base;
+ struct resource *res;
+
+ /*
+ * Map only the CPMU region because other parts are in control
+ * of the CXL port driver.
+ */
+ res = devm_request_mem_region(&adev->dev, pcie_adev->addr,
+ CXL_PMU_REGMAP_SIZE, NULL);
+ if (!res) {
+ pci_err(pdev, "CPMU: could not map\n");
+ return -ENOMEM;
+ }
+
+ base = devm_ioremap(&adev->dev, pcie_adev->addr, CXL_PMU_REGMAP_SIZE);
+ if (!base) {
+ pci_err(pdev, "CPU: ioremap fail\n");
+ return -ENOMEM;
+ }
+ dev_name = devm_kasprintf(dev, GFP_KERNEL, "cxl_pmu_port%d",
+ adev->id);
+ if (!dev_name)
+ return -ENOMEM;
+
+ return __cxl_pmu_probe(dev, dev_name, base);
+}
+
+static int cxl_pmu_probe(struct device *dev)
+{
+ struct cxl_pmu *pmu = to_cxl_pmu(dev);
+ char *dev_name;
+
+ switch (pmu->type) {
+ case CXL_PMU_MEMDEV:
+ dev_name = devm_kasprintf(dev, GFP_KERNEL, "cxl_pmu_mem%d.%d",
+ pmu->assoc_id, pmu->index);
+ break;
+ }
+ if (!dev_name)
+ return -ENOMEM;
+
+ return __cxl_pmu_probe(dev, dev_name, pmu->base);
}

static struct cxl_driver cxl_pmu_driver = {
@@ -851,6 +897,17 @@ static struct cxl_driver cxl_pmu_driver = {
.id = CXL_DEVICE_PMU,
};

+static const struct auxiliary_device_id cxl_port_pmu_ids[] = {
+ { .name = "pcieportdrv.cpmu" },
+ { }
+};
+
+static struct auxiliary_driver cxl_port_pmu_driver = {
+ .name = "cxl_port_pmu",
+ .probe = cxl_pmu_port_probe,
+ .id_table = cxl_port_pmu_ids,
+};
+
static int cxl_pmu_online_cpu(unsigned int cpu, struct hlist_node *node)
{
struct cxl_pmu_info *info = hlist_entry_safe(node, struct cxl_pmu_info, node);
@@ -907,13 +964,25 @@ static __init int cxl_pmu_init(void)

rc = cxl_driver_register(&cxl_pmu_driver);
if (rc)
- cpuhp_remove_multi_state(cxl_pmu_cpuhp_state_num);
+ goto cleanup_hp;
+
+ rc = auxiliary_driver_register(&cxl_port_pmu_driver);
+ if (rc)
+ goto unregister_cxl_driver;
+
+ return 0;
+
+unregister_cxl_driver:
+ cxl_driver_unregister(&cxl_pmu_driver);
+cleanup_hp:
+ cpuhp_remove_multi_state(cxl_pmu_cpuhp_state_num);

return rc;
}

static __exit void cxl_pmu_exit(void)
{
+ auxiliary_driver_unregister(&cxl_port_pmu_driver);
cxl_driver_unregister(&cxl_pmu_driver);
cpuhp_remove_multi_state(cxl_pmu_cpuhp_state_num);
}
--
2.39.2