[PATCH v2 17/27] nvdimm/ocxl: Add controller dump IOCTLs

[Alastair D'Silva]

From: Alastair D'Silva <alastair at d-silva.org>

This patch adds IOCTLs to allow userspace to request & fetch dumps
of the internal controller state.

This is useful during debugging or when a fatal error on the controller
has occurred.

Signed-off-by: Alastair D'Silva <alastair at d-silva.org>
---
 drivers/nvdimm/ocxl/scm.c      | 132 +++++++++++++++++++++++++++++++++
 include/uapi/nvdimm/ocxl-scm.h |  15 ++++
 2 files changed, 147 insertions(+)

diff --git a/drivers/nvdimm/ocxl/scm.c b/drivers/nvdimm/ocxl/scm.c
index 0bbe1a14291e..a520f209d626 100644
--- a/drivers/nvdimm/ocxl/scm.c
+++ b/drivers/nvdimm/ocxl/scm.c
@@ -688,6 +688,124 @@ static int scm_ioctl_error_log(struct scm_data *scm_data,
 	return 0;
 }
 
+static int scm_ioctl_controller_dump_data(struct scm_data *scm_data,
+	struct scm_ioctl_controller_dump_data __user *uarg)
+{
+	struct scm_ioctl_controller_dump_data args;
+	u16 i;
+	u64 val;
+	int rc;
+
+	if (copy_from_user(&args, uarg, sizeof(args)))
+		return -EFAULT;
+
+	if (args.buf_size % 8)
+		return -EINVAL;
+
+	if (args.buf_size > scm_data->admin_command.data_size)
+		return -EINVAL;
+
+	mutex_lock(&scm_data->admin_command.lock);
+
+	rc = scm_admin_command_request(scm_data, ADMIN_COMMAND_CONTROLLER_DUMP);
+	if (rc)
+		goto out;
+
+	val = ((u64)args.offset) << 32;
+	val |= args.buf_size;
+	rc = ocxl_global_mmio_write64(scm_data->ocxl_afu,
+				      scm_data->admin_command.request_offset + 0x08,
+				      OCXL_LITTLE_ENDIAN, val);
+	if (rc)
+		goto out;
+
+	rc = scm_admin_command_execute(scm_data);
+	if (rc)
+		goto out;
+
+	rc = scm_admin_command_complete_timeout(scm_data,
+						ADMIN_COMMAND_CONTROLLER_DUMP);
+	if (rc < 0) {
+		dev_warn(&scm_data->dev, "Controller dump timed out\n");
+		goto out;
+	}
+
+	rc = scm_admin_response(scm_data);
+	if (rc < 0)
+		goto out;
+	if (rc != STATUS_SUCCESS) {
+		scm_warn_status(scm_data,
+				"Unexpected status from retrieve error log",
+				rc);
+		goto out;
+	}
+
+	for (i = 0; i < args.buf_size; i += 8) {
+		u64 val;
+
+		rc = ocxl_global_mmio_read64(scm_data->ocxl_afu,
+					     scm_data->admin_command.data_offset + i,
+					     OCXL_HOST_ENDIAN, &val);
+		if (rc)
+			goto out;
+
+		if (copy_to_user(&args.buf[i], &val, sizeof(u64))) {
+			rc = -EFAULT;
+			goto out;
+		}
+	}
+
+	if (copy_to_user(uarg, &args, sizeof(args))) {
+		rc = -EFAULT;
+		goto out;
+	}
+
+	rc = scm_admin_response_handled(scm_data);
+	if (rc)
+		goto out;
+
+out:
+	mutex_unlock(&scm_data->admin_command.lock);
+	return rc;
+}
+
+int scm_request_controller_dump(struct scm_data *scm_data)
+{
+	int rc;
+	u64 busy = 1;
+
+	rc = ocxl_global_mmio_set64(scm_data->ocxl_afu, GLOBAL_MMIO_CHIC,
+				    OCXL_LITTLE_ENDIAN,
+				    GLOBAL_MMIO_CHI_CDA);
+
+
+	rc = ocxl_global_mmio_set64(scm_data->ocxl_afu, GLOBAL_MMIO_HCI,
+				    OCXL_LITTLE_ENDIAN,
+				    GLOBAL_MMIO_HCI_CONTROLLER_DUMP);
+	if (rc)
+		return rc;
+
+	while (busy) {
+		rc = ocxl_global_mmio_read64(scm_data->ocxl_afu,
+					     GLOBAL_MMIO_HCI,
+					     OCXL_LITTLE_ENDIAN, &busy);
+		if (rc)
+			return rc;
+
+		busy &= GLOBAL_MMIO_HCI_CONTROLLER_DUMP;
+		cond_resched();
+	}
+
+	return 0;
+}
+
+static int scm_ioctl_controller_dump_complete(struct scm_data *scm_data)
+{
+	return ocxl_global_mmio_set64(scm_data->ocxl_afu, GLOBAL_MMIO_HCI,
+				    OCXL_LITTLE_ENDIAN,
+				    GLOBAL_MMIO_HCI_CONTROLLER_DUMP_COLLECTED);
+}
+
 static long scm_file_ioctl(struct file *file, unsigned int cmd,
 			   unsigned long args)
 {
@@ -699,7 +817,21 @@ static long scm_file_ioctl(struct file *file, unsigned int cmd,
 		rc = scm_ioctl_error_log(scm_data,
 					 (struct scm_ioctl_error_log __user *)args);
 		break;
+
+	case SCM_IOCTL_CONTROLLER_DUMP:
+		rc = scm_request_controller_dump(scm_data);
+		break;
+
+	case SCM_IOCTL_CONTROLLER_DUMP_DATA:
+		rc = scm_ioctl_controller_dump_data(scm_data,
+						    (struct scm_ioctl_controller_dump_data __user *)args);
+		break;
+
+	case SCM_IOCTL_CONTROLLER_DUMP_COMPLETE:
+		rc = scm_ioctl_controller_dump_complete(scm_data);
+		break;
 	}
+
 	return rc;
 }
 
diff --git a/include/uapi/nvdimm/ocxl-scm.h b/include/uapi/nvdimm/ocxl-scm.h
index b34dd1ba06ff..abd2dc9ea112 100644
--- a/include/uapi/nvdimm/ocxl-scm.h
+++ b/include/uapi/nvdimm/ocxl-scm.h
@@ -38,9 +38,24 @@ struct scm_ioctl_error_log {
 	__u8 *buf; // pointer to output buffer
 };
 
+struct scm_ioctl_controller_dump_data {
+	__u8 *buf; // pointer to output buffer
+	__u16 buf_size; /* in/out, buffer size provided/required.
+			 * If required is greater than provided, the buffer
+			 * will be truncated to the amount provided. If its
+			 * less, then only the required bytes will be populated.
+			 * If it is 0, then there is no more dump data available.
+			 */
+	__u32 offset; // in, Offset within the dump
+	__u64 reserved[8];
+};
+
 /* ioctl numbers */
 #define SCM_MAGIC 0x5C
 /* SCM devices */
 #define SCM_IOCTL_ERROR_LOG	_IOWR(SCM_MAGIC, 0x01, struct scm_ioctl_error_log)
+#define SCM_IOCTL_CONTROLLER_DUMP _IO(SCM_MAGIC, 0x02)
+#define SCM_IOCTL_CONTROLLER_DUMP_DATA _IOWR(SCM_MAGIC, 0x03, struct scm_ioctl_controller_dump_data)
+#define SCM_IOCTL_CONTROLLER_DUMP_COMPLETE _IO(SCM_MAGIC, 0x04)
 
 #endif /* _UAPI_OCXL_SCM_H */
-- 
2.23.0