On Thu, 2020-03-05 at 11:46 +1100, Andrew Donnellan wrote:

On 21/2/20 2:27 pm, Alastair D'Silva wrote:

quoted

From: Alastair D'Silva <redacted>

The controller can report a number of statistics that are useful
in evaluating the performance and reliability of the card.

This patch exposes this information via an IOCTL.

Signed-off-by: Alastair D'Silva <redacted>
---
  arch/powerpc/platforms/powernv/pmem/ocxl.c | 185
+++++++++++++++++++++
  include/uapi/nvdimm/ocxl-pmem.h            |  17 ++
  2 files changed, 202 insertions(+)

diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl.c

b/arch/powerpc/platforms/powernv/pmem/ocxl.c
index 2cabafe1fc58..009d4fd29e7d 100644

--- a/arch/powerpc/platforms/powernv/pmem/ocxl.c
+++ b/arch/powerpc/platforms/powernv/pmem/ocxl.c

@@ -758,6 +758,186 @@ static int

ioctl_controller_dump_complete(struct ocxlpmem *ocxlpmem)
  				    GLOBAL_MMIO_HCI_CONTROLLER_DUMP_COL
LECTED);
  }
  
+/**
+ * controller_stats_header_parse() - Parse the first 64 bits of
the controller stats admin command response
+ * @ocxlpmem: the device metadata
+ * @length: out, returns the number of bytes in the response
(excluding the 64 bit header)
+ */
+static int controller_stats_header_parse(struct ocxlpmem
*ocxlpmem,
+	u32 *length)
+{
+	int rc;
+	u64 val;
+
+	u16 data_identifier;
+	u32 data_length;
+
+	rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu,
+				     ocxlpmem-

quoted

admin_command.data_offset,

+				     OCXL_LITTLE_ENDIAN, &val);
+	if (rc)
+		return rc;
+
+	data_identifier = val >> 48;
+	data_length = val & 0xFFFFFFFF;
+
+	if (data_identifier != 0x4353) { // 'CS'
+		dev_err(&ocxlpmem->dev,
+			"Bad data identifier for controller stats,
expected 'CS', got '%-.*s'\n",
+			2, (char *)&data_identifier);
+		return -EINVAL;

Same comment as earlier patches re EINVAL

I don't think I've seen a comment yet on these particular blocks. Can
you suggest a better return value?

quoted

+	}
+
+	*length = data_length;
+	return 0;
+}
+
+static int ioctl_controller_stats(struct ocxlpmem *ocxlpmem,
+				  struct
ioctl_ocxl_pmem_controller_stats __user *uarg)
+{
+	struct ioctl_ocxl_pmem_controller_stats args;
+	u32 length;
+	int rc;
+	u64 val;
+
+	memset(&args, '\0', sizeof(args));
+
+	mutex_lock(&ocxlpmem->admin_command.lock);
+
+	rc = admin_command_request(ocxlpmem,
ADMIN_COMMAND_CONTROLLER_STATS);
+	if (rc)
+		goto out;
+
+	rc = ocxl_global_mmio_write64(ocxlpmem->ocxl_afu,
+				      ocxlpmem-

quoted

admin_command.request_offset + 0x08,

+				      OCXL_LITTLE_ENDIAN, 0);
+	if (rc)
+		goto out;
+
+	rc = admin_command_execute(ocxlpmem);
+	if (rc)
+		goto out;
+
+
+	rc = admin_command_complete_timeout(ocxlpmem,
+					    ADMIN_COMMAND_CONTROLLER_ST
ATS);
+	if (rc < 0) {
+		dev_warn(&ocxlpmem->dev, "Controller stats timed
out\n");
+		goto out;
+	}
+
+	rc = admin_response(ocxlpmem);
+	if (rc < 0)
+		goto out;
+	if (rc != STATUS_SUCCESS) {
+		warn_status(ocxlpmem,
+			    "Unexpected status from controller stats",
rc);
+		goto out;
+	}
+
+	rc = controller_stats_header_parse(ocxlpmem, &length);
+	if (rc)
+		goto out;
+
+	if (length != 0x140)
+		warn_status(ocxlpmem,
+			    "Unexpected length for controller stats
data, expected 0x140, got 0x%x",
+			    length);

Might be worth a comment to explain where 0x140 comes from (it looks 
correct from my reading of the spec)

Ok

quoted

+
+	rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu,
+				     ocxlpmem-

quoted

admin_command.data_offset + 0x08 + 0x08,

+				     OCXL_LITTLE_ENDIAN, &val);
+	if (rc)
+		goto out;
+
+	args.reset_count = val >> 32;
+	args.reset_uptime = val & 0xFFFFFFFF;
+
+	rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu,
+				     ocxlpmem-

quoted

admin_command.data_offset + 0x08 + 0x10,

+				     OCXL_LITTLE_ENDIAN, &val);
+	if (rc)
+		goto out;
+
+	args.power_on_uptime = val >> 32;

We're not collecting life remaining?

It looks like my implementation is out of date. I'll bring it in line
with the spec.

quoted

+
+	rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu,
+				     ocxlpmem-

quoted

admin_command.data_offset + 0x08 + 0x40 + 0x08,

+				     OCXL_LITTLE_ENDIAN,
&args.host_load_count);

My reading of the spec says HLC is at +0x10

Ditto

quoted

+	if (rc)
+		goto out;
+
+	rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu,
+				     ocxlpmem-

quoted

admin_command.data_offset + 0x08 + 0x40 + 0x10,

+				     OCXL_LITTLE_ENDIAN,
&args.host_store_count);

HSC at +0x18

Ditto

quoted

+	if (rc)
+		goto out;
+
+	rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu,
+				     ocxlpmem-

quoted

admin_command.data_offset + 0x08 + 0x40 + 0x18,

+				     OCXL_LITTLE_ENDIAN,
&args.media_read_count);

MRC is at +0x50

And you're missing CRU, HLD, HSD

quoted

+	if (rc)
+		goto out;
+
+	rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu,
+				     ocxlpmem-

quoted

admin_command.data_offset + 0x08 + 0x40 + 0x20,

+				     OCXL_LITTLE_ENDIAN,
&args.media_write_count);

MWC at +0x58

quoted

+	if (rc)
+		goto out;
+
+	rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu,
+				     ocxlpmem-

quoted

admin_command.data_offset + 0x08 + 0x40 + 0x28,

+				     OCXL_LITTLE_ENDIAN,
&args.cache_hit_count);

CRHC at +0x90

quoted

+	if (rc)
+		goto out;
+
+	rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu,
+				     ocxlpmem-

quoted

admin_command.data_offset + 0x08 + 0x40 + 0x30,

+				     OCXL_LITTLE_ENDIAN,
&args.cache_miss_count);

This field doesn't seem to exist at all in my copy of the spec

quoted

+	if (rc)
+		goto out;
+
+	rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu,
+				     ocxlpmem-

quoted

admin_command.data_offset + 0x08 + 0x40 + 0x38,

+				     OCXL_LITTLE_ENDIAN,
&args.media_read_latency);

Nor this one

quoted

+	if (rc)
+		goto out;
+
+	rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu,
+				     ocxlpmem-

quoted

admin_command.data_offset + 0x08 + 0x40 + 0x40,

+				     OCXL_LITTLE_ENDIAN,
&args.media_write_latency);

Nor this one

quoted

+	if (rc)
+		goto out;
+
+	rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu,
+				     ocxlpmem-

quoted

admin_command.data_offset + 0x08 + 0x40 + 0x48,

+				     OCXL_LITTLE_ENDIAN,
&args.cache_read_latency);

Nor this one

quoted

+	if (rc)
+		goto out;
+
+	rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu,
+				     ocxlpmem-

quoted

admin_command.data_offset + 0x08 + 0x40 + 0x50,

+				     OCXL_LITTLE_ENDIAN,
&args.cache_write_latency);

Nor this one

quoted

+	if (rc)
+		goto out;
+
+	if (copy_to_user(uarg, &args, sizeof(args))) {
+		rc = -EFAULT;
+		goto out;
+	}
+
+	rc = admin_response_handled(ocxlpmem);
+	if (rc)
+		goto out;
+
+	rc = 0;
+	goto out;

Per Fred this pattern isn't common in the kernel, but perhaps this
is 
just personal taste

Ok

quoted

+
+out:
+	mutex_unlock(&ocxlpmem->admin_command.lock);
+	return rc;
+}
+
  static long file_ioctl(struct file *file, unsigned int cmd,
unsigned long args)
  {
  	struct ocxlpmem *ocxlpmem = file->private_data;

@@ -781,6 +961,11 @@ static long file_ioctl(struct file *file,

unsigned int cmd, unsigned long args)
  	case IOCTL_OCXL_PMEM_CONTROLLER_DUMP_COMPLETE:
  		rc = ioctl_controller_dump_complete(ocxlpmem);
  		break;
+
+	case IOCTL_OCXL_PMEM_CONTROLLER_STATS:
+		rc = ioctl_controller_stats(ocxlpmem,
+					    (struct
ioctl_ocxl_pmem_controller_stats __user *)args);
+		break;
  	}
  
  	return rc;

diff --git a/include/uapi/nvdimm/ocxl-pmem.h

b/include/uapi/nvdimm/ocxl-pmem.h
index d4d8512d03f7..add223aa2fdb 100644

--- a/include/uapi/nvdimm/ocxl-pmem.h
+++ b/include/uapi/nvdimm/ocxl-pmem.h

@@ -50,6 +50,22 @@ struct ioctl_ocxl_pmem_controller_dump_data {
  	__u64 reserved[8];
  };
  
+struct ioctl_ocxl_pmem_controller_stats {
+	__u32 reset_count;
+	__u32 reset_uptime; /* seconds */
+	__u32 power_on_uptime; /* seconds */
+	__u64 host_load_count;
+	__u64 host_store_count;
+	__u64 media_read_count;
+	__u64 media_write_count;
+	__u64 cache_hit_count;
+	__u64 cache_miss_count;
+	__u64 media_read_latency; /* nanoseconds */
+	__u64 media_write_latency; /* nanoseconds */
+	__u64 cache_read_latency; /* nanoseconds */
+	__u64 cache_write_latency; /* nanoseconds */
+};
+
  /* ioctl numbers */
  #define OCXL_PMEM_MAGIC 0x5C
  /* SCM devices */

@@ -57,5 +73,6 @@ struct ioctl_ocxl_pmem_controller_dump_data {
  #define IOCTL_OCXL_PMEM_CONTROLLER_DUMP			_IO(OCX

L_PMEM_MAGIC, 0x02)
  #define IOCTL_OCXL_PMEM_CONTROLLER_DUMP_DATA		_IOWR(O
CXL_PMEM_MAGIC, 0x03, struct ioctl_ocxl_pmem_controller_dump_data)
  #define IOCTL_OCXL_PMEM_CONTROLLER_DUMP_COMPLETE	_IO(OCXL_PMEM_M
AGIC, 0x04)
+#define IOCTL_OCXL_PMEM_CONTROLLER_STATS		_IO(OCXL_PMEM_M
AGIC, 0x05)
  
  #endif /* _UAPI_OCXL_SCM_H */

-- 
Alastair D'Silva
Open Source Developer
Linux Technology Centre, IBM Australia
mob: 0423 762 819