[PATCH v4 14/25] nvdimm/ocxl: Add support for Admin commands

["Alastair D'Silva" <alastair@d-silva.org>]

Admin commands for these devices are the primary means of interacting
with the device controller to provide functionality beyond the load/store
capabilities offered via the NPU.

For example, SMART data, firmware update, and device error logs are
implemented via admin commands.

This patch requests the metadata required to issue admin commands, as well
as some helper functions to construct and check the completion of the
commands.

Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
---
 drivers/nvdimm/ocxl/main.c              |  65 ++++++
 drivers/nvdimm/ocxl/ocxlpmem.h          |  50 ++++-
 drivers/nvdimm/ocxl/ocxlpmem_internal.c | 261 ++++++++++++++++++++++++
 3 files changed, 375 insertions(+), 1 deletion(-)

diff --git a/drivers/nvdimm/ocxl/main.c b/drivers/nvdimm/ocxl/main.c
index be76acd33d74..8db573036423 100644
--- a/drivers/nvdimm/ocxl/main.c
+++ b/drivers/nvdimm/ocxl/main.c
@@ -217,6 +217,58 @@ static int register_lpc_mem(struct ocxlpmem *ocxlpmem)
 	return 0;
 }
 
+/**
+ * extract_command_metadata() - Extract command data from MMIO & save it for further use
+ * @ocxlpmem: the device metadata
+ * @offset: The base address of the command data structures (address of CREQO)
+ * @command_metadata: A pointer to the command metadata to populate
+ * Return: 0 on success, negative on failure
+ */
+static int extract_command_metadata(struct ocxlpmem *ocxlpmem, u32 offset,
+				    struct command_metadata *command_metadata)
+{
+	int rc;
+	u64 tmp;
+
+	rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, offset,
+				     OCXL_LITTLE_ENDIAN, &tmp);
+	if (rc)
+		return rc;
+
+	command_metadata->request_offset = tmp >> 32;
+	command_metadata->response_offset = tmp & 0xFFFFFFFF;
+
+	rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, offset + 8,
+				     OCXL_LITTLE_ENDIAN, &tmp);
+	if (rc)
+		return rc;
+
+	command_metadata->data_offset = tmp >> 32;
+	command_metadata->data_size = tmp & 0xFFFFFFFF;
+
+	command_metadata->id = 0;
+
+	return 0;
+}
+
+/**
+ * setup_command_metadata() - Set up the command metadata
+ * @ocxlpmem: the device metadata
+ */
+static int setup_command_metadata(struct ocxlpmem *ocxlpmem)
+{
+	int rc;
+
+	mutex_init(&ocxlpmem->admin_command.lock);
+
+	rc = extract_command_metadata(ocxlpmem, GLOBAL_MMIO_ACMA_CREQO,
+				      &ocxlpmem->admin_command);
+	if (rc)
+		return rc;
+
+	return 0;
+}
+
 /**
  * allocate_minor() - Allocate a minor number to use for an OpenCAPI pmem device
  * @ocxlpmem: the device metadata
@@ -421,6 +473,14 @@ static int probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 	ocxlpmem->pdev = pci_dev_get(pdev);
 
+	ocxlpmem->timeouts[ADMIN_COMMAND_ERRLOG] = 2000; // ms
+	ocxlpmem->timeouts[ADMIN_COMMAND_HEARTBEAT] = 100; // ms
+	ocxlpmem->timeouts[ADMIN_COMMAND_SMART] = 100; // ms
+	ocxlpmem->timeouts[ADMIN_COMMAND_CONTROLLER_DUMP] = 1000; // ms
+	ocxlpmem->timeouts[ADMIN_COMMAND_CONTROLLER_STATS] = 100; // ms
+	ocxlpmem->timeouts[ADMIN_COMMAND_SHUTDOWN] = 1000; // ms
+	ocxlpmem->timeouts[ADMIN_COMMAND_FW_UPDATE] = 16000; // ms
+
 	pci_set_drvdata(pdev, ocxlpmem);
 
 	ocxlpmem->ocxl_fn = ocxl_function_open(pdev);
@@ -467,6 +527,11 @@ static int probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		goto err;
 	}
 
+	if (setup_command_metadata(ocxlpmem)) {
+		dev_err(&pdev->dev, "Could not read command metadata\n");
+		goto err;
+	}
+
 	elapsed = 0;
 	timeout = ocxlpmem->readiness_timeout +
 		  ocxlpmem->memory_available_timeout;
diff --git a/drivers/nvdimm/ocxl/ocxlpmem.h b/drivers/nvdimm/ocxl/ocxlpmem.h
index 3eadbe19f6d0..b72b3f909fc3 100644
--- a/drivers/nvdimm/ocxl/ocxlpmem.h
+++ b/drivers/nvdimm/ocxl/ocxlpmem.h
@@ -7,6 +7,7 @@
 #include <linux/mm.h>
 
 #define LABEL_AREA_SIZE	BIT_ULL(PA_SECTION_SHIFT)
+#define DEFAULT_TIMEOUT 100
 
 #define GLOBAL_MMIO_CHI		0x000
 #define GLOBAL_MMIO_CHIC	0x008
@@ -57,6 +58,7 @@
 #define GLOBAL_MMIO_HCI_CONTROLLER_DUMP_COLLECTED	BIT_ULL(5) // CDC
 #define GLOBAL_MMIO_HCI_REQ_HEALTH_PERF			BIT_ULL(6) // CHPD
 
+// must be maintained with admin_command_names in ocxlpmem_internal.c
 #define ADMIN_COMMAND_HEARTBEAT		0x00u
 #define ADMIN_COMMAND_SHUTDOWN		0x01u
 #define ADMIN_COMMAND_FW_UPDATE		0x02u
@@ -68,6 +70,13 @@
 #define ADMIN_COMMAND_CMD_CAPS		0x08u
 #define ADMIN_COMMAND_MAX		0x08u
 
+#define NS_COMMAND_SECURE_ERASE	0x20ull
+
+#define NS_RESPONSE_SECURE_ERASE_ACCESSIBLE_SUCCESS 0x20
+#define NS_RESPONSE_SECURE_ERASE_ACCESSIBLE_ATTEMPTED 0x28
+#define NS_RESPONSE_SECURE_ERASE_DEFECTIVE_SUCCESS 0x30
+#define NS_RESPONSE_SECURE_ERASE_DEFECTIVE_ATTEMPTED 0x38
+
 #define STATUS_SUCCESS		0x00
 #define STATUS_MEM_UNAVAILABLE	0x20
 #define STATUS_BLOCKED_BG_TASK	0x21
@@ -81,6 +90,16 @@
 #define STATUS_FW_ARG_INVALID	STATUS_BAD_REQUEST_PARM
 #define STATUS_FW_INVALID	STATUS_BAD_DATA_PARM
 
+struct command_metadata {
+	u32 request_offset;
+	u32 response_offset;
+	u32 data_offset;
+	u32 data_size;
+	struct mutex lock; /* locks access to this command */
+	u16 id;
+	u8 op_code;
+};
+
 struct ocxlpmem {
 	struct device dev;
 	struct pci_dev *pdev;
@@ -91,10 +110,11 @@ struct ocxlpmem {
 	struct ocxl_afu *ocxl_afu;
 	struct ocxl_context *ocxl_context;
 	void *metadata_addr;
+	struct command_metadata admin_command;
 	struct resource pmem_res;
 	struct nd_region *nd_region;
 	char fw_version[8 + 1];
-
+	u32 timeouts[ADMIN_COMMAND_MAX + 1];
 	u32 max_controller_dump_size;
 	u16 scm_revision; // major/minor
 	u8 readiness_timeout;  /* The worst case time (in seconds) that the host
@@ -123,3 +143,31 @@ struct ocxlpmem {
  * Returns 0 on success, negative on error
  */
 int ocxlpmem_chi(const struct ocxlpmem *ocxlpmem, u64 *chi);
+
+/**
+ * admin_command_execute() - Execute an admin command and wait for completion
+ *
+ * Additional MMIO registers (dependent on the command) may
+ * need to be initialized
+ *
+ * @ocxlpmem: the device metadata
+ * @op_code: the code for the admin command
+ * Returns 0 on success, -EINVAL for a bad op code, -EBUSY on timeout
+ */
+int admin_command_execute(struct ocxlpmem *ocxlpmem, u8 op_code);
+
+/**
+ * admin_response_handled() - Notify the controller that the admin response has been handled
+ * @ocxlpmem: the device metadata
+ * Returns 0 on success, negative on failure
+ */
+int admin_response_handled(const struct ocxlpmem *ocxlpmem);
+
+/**
+ * warn_status() - Emit a kernel warning showing a command status.
+ * @ocxlpmem: the device metadata
+ * @message: A message to accompany the warning
+ * @status: The command status
+ */
+void warn_status(const struct ocxlpmem *ocxlpmem, const char *message,
+		 u8 status);
diff --git a/drivers/nvdimm/ocxl/ocxlpmem_internal.c b/drivers/nvdimm/ocxl/ocxlpmem_internal.c
index 5578169b7515..7470a6ab3b08 100644
--- a/drivers/nvdimm/ocxl/ocxlpmem_internal.c
+++ b/drivers/nvdimm/ocxl/ocxlpmem_internal.c
@@ -17,3 +17,264 @@ int ocxlpmem_chi(const struct ocxlpmem *ocxlpmem, u64 *chi)
 
 	return 0;
 }
+
+#define COMMAND_REQUEST_SIZE (8 * sizeof(u64))
+/**
+ * scm_command_request() - Set up a command request
+ * @cmd: The metadata for the type of command to be issued
+ * @op_code: the op code for the command
+ * @valid_bytes: the number of bytes in the header to preserve (these must be set before calling)
+ */
+static int scm_command_request(const struct ocxlpmem *ocxlpmem,
+			       struct command_metadata *cmd, u8 op_code,
+			       u8 valid_bytes)
+{
+	u64 val = op_code;
+	int rc;
+	u8 i;
+
+	cmd->op_code = op_code;
+	cmd->id++;
+
+	val |= ((u64)cmd->id) << 16;
+
+	rc = ocxl_global_mmio_write64(ocxlpmem->ocxl_afu, cmd->request_offset,
+				      OCXL_LITTLE_ENDIAN, val);
+	if (rc)
+		return rc;
+
+	for (i = valid_bytes; i < COMMAND_REQUEST_SIZE; i += sizeof(u64)) {
+		rc = ocxl_global_mmio_write64(ocxlpmem->ocxl_afu,
+					      cmd->request_offset + i,
+					      OCXL_LITTLE_ENDIAN, 0);
+		if (rc)
+			return rc;
+	}
+
+	return 0;
+}
+
+/**
+ * admin_command_request() - Issue an admin command request
+ * @ocxlpmem: the device metadata
+ * @op_code: The op-code for the command
+ *
+ * Returns an identifier for the command, or negative on error
+ */
+static int admin_command_request(struct ocxlpmem *ocxlpmem, u8 op_code)
+{
+	u8 valid_bytes = sizeof(u64);
+
+	switch (op_code) {
+	case ADMIN_COMMAND_HEARTBEAT:
+	case ADMIN_COMMAND_SHUTDOWN:
+	case ADMIN_COMMAND_ERRLOG:
+	case ADMIN_COMMAND_CMD_CAPS:
+		valid_bytes += 0;
+		break;
+	case ADMIN_COMMAND_FW_UPDATE:
+	case ADMIN_COMMAND_SMART:
+	case ADMIN_COMMAND_CONTROLLER_STATS:
+	case ADMIN_COMMAND_CONTROLLER_DUMP:
+		valid_bytes += sizeof(u64);
+		break;
+	case ADMIN_COMMAND_FW_DEBUG:
+		valid_bytes += 3 * sizeof(u64);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return scm_command_request(ocxlpmem, &ocxlpmem->admin_command, op_code,
+				   valid_bytes);
+}
+
+static int command_response(const struct ocxlpmem *ocxlpmem,
+			    const struct command_metadata *cmd)
+{
+	u64 val;
+	u16 id;
+	u8 status;
+	int rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu,
+					 cmd->response_offset,
+					 OCXL_LITTLE_ENDIAN, &val);
+	if (rc)
+		return rc;
+
+	status = val & 0xff;
+	id = (val >> 16) & 0xffff;
+
+	if (id != cmd->id) {
+		dev_err(&ocxlpmem->dev,
+			"Expected response for command %d, but received response for command %d instead.\n",
+			cmd->id, id);
+		return -EBUSY;
+	}
+
+	return status;
+}
+
+/**
+ * admin_response() - Validate an admin response
+ * @ocxlpmem: the device metadata
+ * Returns the status code of the command, or negative on error
+ */
+static int admin_response(const struct ocxlpmem *ocxlpmem)
+{
+	return command_response(ocxlpmem, &ocxlpmem->admin_command);
+}
+
+/**
+ * admin_command_exec() - Notify the controller to start processing a pending admin command
+ * @ocxlpmem: the device metadata
+ * Returns 0 on success, negative on error
+ */
+static int admin_command_exec(const struct ocxlpmem *ocxlpmem)
+{
+	return ocxl_global_mmio_set64(ocxlpmem->ocxl_afu, GLOBAL_MMIO_HCI,
+				      OCXL_LITTLE_ENDIAN, GLOBAL_MMIO_HCI_ACRW);
+}
+
+static bool admin_command_complete(const struct ocxlpmem *ocxlpmem)
+{
+	u64 val = 0;
+
+	int rc = ocxlpmem_chi(ocxlpmem, &val);
+
+	WARN_ON(rc);
+
+	return (val & GLOBAL_MMIO_CHI_ACRA) != 0;
+}
+
+/**
+ * admin_command_complete_timeout() - Wait for an admin command to finish executing
+ * @ocxlpmem: the device metadata
+ * @command: the admin command to wait for completion (determines the timeout)
+ * Returns 0 on success, -EBUSY on timeout
+ */
+static int admin_command_complete_timeout(const struct ocxlpmem *ocxlpmem,
+					  int command)
+{
+	unsigned long timeout = jiffies +
+				msecs_to_jiffies(ocxlpmem->timeouts[command]);
+
+	// 32 is the next power of 2 greater than the 20ms minimum for msleep
+#define TIMEOUT_SLEEP_MILLIS 32
+	do {
+		if (admin_command_complete(ocxlpmem))
+			return 0;
+		msleep(TIMEOUT_SLEEP_MILLIS);
+	} while (time_before(jiffies, timeout));
+
+	if (admin_command_complete(ocxlpmem))
+		return 0;
+
+	return -EBUSY;
+}
+
+// Must be maintained with ADMIN_COMMAND_* in ocxlpmem.h
+static const char * const admin_command_names[] = {
+	"heartbeat",
+	"shutdown",
+	"firmware update",
+	"firmware debug",
+	"retrieve error log",
+	"retrieve SMART data",
+	"controller statistics",
+	"controller dump",
+	"command capabilities",
+};
+
+/**
+ * admin_command_name() - get the name of an admin command
+ * @ocxlpmem: the device metadata
+ * @op_code: the code for the admin command
+ * Returns a string representing the name of the command
+ */
+static const char *admin_command_name(u8 op_code)
+{
+	if (op_code > ADMIN_COMMAND_MAX)
+		return "unknown command";
+
+	return admin_command_names[op_code];
+}
+
+/**
+ * admin_command_execute() - Execute an admin command and wait for completion
+ *
+ * Additional MMIO registers (dependent on the command) may
+ * need to be initialized
+ *
+ * @ocxlpmem: the device metadata
+ * @op_code: the code for the admin command
+ * Returns 0 on success, -EINVAL for a bad op code, -EBUSY on timeout
+ */
+int admin_command_execute(struct ocxlpmem *ocxlpmem, u8 op_code)
+{
+	int rc;
+
+	if (op_code > ADMIN_COMMAND_MAX)
+		return -EINVAL;
+
+	rc = admin_command_request(ocxlpmem, op_code);
+	if (rc)
+		return rc;
+
+	rc = admin_command_exec(ocxlpmem);
+	if (rc)
+		return rc;
+
+	rc = admin_command_complete_timeout(ocxlpmem, op_code);
+	if (rc < 0) {
+		dev_warn(&ocxlpmem->dev, "%s timed out\n",
+			 admin_command_name(op_code));
+		return rc;
+	}
+
+	return admin_response(ocxlpmem);
+}
+
+int admin_response_handled(const struct ocxlpmem *ocxlpmem)
+{
+	// writing to the CHIC register clears the bit in CHI
+	return ocxl_global_mmio_set64(ocxlpmem->ocxl_afu, GLOBAL_MMIO_CHIC,
+				      OCXL_LITTLE_ENDIAN, GLOBAL_MMIO_CHI_ACRA);
+}
+
+void warn_status(const struct ocxlpmem *ocxlpmem, const char *message,
+		 u8 status)
+{
+	const char *text = "Unknown";
+
+	switch (status) {
+	case STATUS_SUCCESS:
+		text = "Success";
+		break;
+
+	case STATUS_MEM_UNAVAILABLE:
+		text = "Persistent memory unavailable";
+		break;
+
+	case STATUS_BAD_OPCODE:
+		text = "Bad opcode";
+		break;
+
+	case STATUS_BAD_REQUEST_PARM:
+		text = "Bad request parameter";
+		break;
+
+	case STATUS_BAD_DATA_PARM:
+		text = "Bad data parameter";
+		break;
+
+	case STATUS_DEBUG_BLOCKED:
+		text = "Debug action blocked";
+		break;
+
+	case STATUS_FAIL:
+		text = "Failed";
+		break;
+	}
+
+	dev_warn(&ocxlpmem->dev, "%s: %s (%x)\n", message, text, status);
+}
-- 
2.24.1
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