On Thu, 2020-02-27 at 19:22 +1100, Andrew Donnellan wrote:

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

quoted

From: Alastair D'Silva <redacted>

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 <redacted>
---
  arch/powerpc/platforms/powernv/pmem/ocxl.c    |  65 ++++++++
  .../platforms/powernv/pmem/ocxl_internal.c    | 153
++++++++++++++++++
  .../platforms/powernv/pmem/ocxl_internal.h    |  61 +++++++
  3 files changed, 279 insertions(+)

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

b/arch/powerpc/platforms/powernv/pmem/ocxl.c
index 431212c9f0cc..4e782d22605b 100644

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

@@ -216,6 +216,58 @@ 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;
+}
+
  /**
   * is_usable() - Is a controller usable?
   * @ocxlpmem: the device metadata

@@ -456,6 +508,14 @@ static int probe(struct pci_dev *pdev, const

struct pci_device_id *ent)
  	}
  	ocxlpmem->pdev = 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

Why are we keeping these timeouts in a per device struct? I can't
see 
anywhere where we change these values.

These are overwritten in a later patch, which I've missed! thanks for
pointing this out.

These initial values will be overwritten by card specific timeouts.

quoted

+
  	pci_set_drvdata(pdev, ocxlpmem);
  
  	ocxlpmem->ocxl_fn = ocxl_function_open(pdev);

@@ -501,6 +561,11 @@ 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 OCXL command
matada\n");

metadata

Wow, not sure how that happened.

Also, "OCXL command metadata" is misleading, this is a pmem specific 
thing, not an OpenCAPI thing, I would prefer just "command metadata".

Ok

quoted

+		goto err;
+	}
+
  	elapsed = 0;
  	timeout = ocxlpmem->readiness_timeout + ocxlpmem-

quoted

memory_available_timeout;

  	while (!is_usable(ocxlpmem, false)) {

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

b/arch/powerpc/platforms/powernv/pmem/ocxl_internal.c
index 617ca943b1b8..583f48023025 100644

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

@@ -17,3 +17,156 @@ int ocxlpmem_chi(const struct ocxlpmem

*ocxlpmem, u64 *chi)
  
  	return 0;
  }
+
+#define COMMAND_REQUEST_SIZE (8 * sizeof(u64))
+static int scm_command_request(const struct ocxlpmem *ocxlpmem,
+			       struct command_metadata *cmd, u8
op_code)
+{
+	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-

quoted

request_offset,

+				      OCXL_LITTLE_ENDIAN, val);
+	if (rc)
+		return rc;
+
+	for (i = sizeof(u64); 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;
+}
+
+int admin_command_request(struct ocxlpmem *ocxlpmem, u8 op_code)
+{
+	u64 val;
+	int rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu,
GLOBAL_MMIO_CHI,
+					 OCXL_LITTLE_ENDIAN, &val);
+	if (rc)
+		return rc;

Ignoring the value here expected, you're just trying to verify that
you 
don't see an error on the read?

This was some vestigial code that should be removed.

quoted

+
+	return scm_command_request(ocxlpmem, &ocxlpmem->admin_command,
op_code);
+}
+
+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_warn(&ocxlpmem->dev,
+			 "Expected response for command %d, but
received response for command %d instead.\n",
+			 cmd->id, id);

If this happens I imagine something's gone pretty wrong - this
should 
probably be a dev_err()? And perhaps we want to make sure we return
an 
error code rather than whatever status code we get from the MMIO?

Ok

quoted

+	}
+
+	return status;
+}
+
+int admin_response(const struct ocxlpmem *ocxlpmem)
+{
+	return command_response(ocxlpmem, &ocxlpmem->admin_command);
+}
+
+
+int admin_command_execute(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;
+}
+
+int admin_command_complete_timeout(const struct ocxlpmem
*ocxlpmem,
+				   int command)
+{
+	u32 timeout = ocxlpmem->timeouts[command];
+	// 32 is the next power of 2 greater than the 20ms minimum for
msleep
+#define TIMEOUT_SLEEP_MILLIS 32
+	timeout /= TIMEOUT_SLEEP_MILLIS;
+	if (!timeout)
+		timeout = DEFAULT_TIMEOUT / TIMEOUT_SLEEP_MILLIS;
+
+	while (timeout-- > 0) {
+		if (admin_command_complete(ocxlpmem))
+			return 0;
+		msleep(TIMEOUT_SLEEP_MILLIS);
+	}

I think the more traditional way to implement timeouts is something
more 
like:

   unsigned long timeout = jiffies + msecs_to_jiffies(<timeout
period>);
   do {
     <check>
     <sleep>
   } while (time_before(jiffies, timeout));

ok

quoted

+
+	if (admin_command_complete(ocxlpmem))
+		return 0;
+
+	return -EBUSY;
+}
+
+int admin_response_handled(const struct ocxlpmem *ocxlpmem)
+{
+	return ocxl_global_mmio_set64(ocxlpmem->ocxl_afu,
GLOBAL_MMIO_CHIC,
+				      OCXL_LITTLE_ENDIAN,
GLOBAL_MMIO_CHI_ACRA);
+}

This looks wrong? My reading of the spec is that you're meant to
*clear* 
ACRA upon completion of handing, this looks like it's setting ACRA to
1.

Writing a 1 to the CHIC register clears the respective bit in the CHI
register. I'll add a comment.

quoted

+
+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);
+}

diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h

b/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h
index ba0301533d00..2fef68c71271 100644

--- a/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h
+++ b/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h

@@ -7,6 +7,7 @@
  #include <linux/mm.h>
  
  #define LABEL_AREA_SIZE	(1UL << PA_SECTION_SHIFT)
+#define DEFAULT_TIMEOUT 100
  
  #define GLOBAL_MMIO_CHI		0x000
  #define GLOBAL_MMIO_CHIC	0x008

@@ -80,6 +81,16 @@
  #define STATUS_FW_ARG_INVALID	0x51
  #define STATUS_FW_INVALID	0x52
  
+struct command_metadata {
+	u32 request_offset;
+	u32 response_offset;
+	u32 data_offset;
+	u32 data_size;
+	struct mutex lock;
+	u16 id;
+	u8 op_code;
+};
+
  struct ocxlpmem_function0 {
  	struct pci_dev *pdev;
  	struct ocxl_fn *ocxl_fn;

@@ -95,9 +106,11 @@ 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

@@ -122,3 +135,51 @@ struct ocxlpmem {
   * Returns 0 on success, negative on error
   */
  int ocxlpmem_chi(const struct ocxlpmem *ocxlpmem, u64 *chi);
+
+/**
+ * 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
+ */
+int admin_command_request(struct ocxlpmem *ocxlpmem, u8 op_code);
+
+/**
+ * admin_response() - Validate an admin response
+ * @ocxlpmem: the device metadata
+ * Returns the status code of the command, or negative on error
+ */
+int admin_response(const struct ocxlpmem *ocxlpmem);
+
+/**
+ * admin_command_execute() - Notify the controller to start

processing a pending admin command
+ * @ocxlpmem: the device metadata
+ * Returns 0 on success, negative on error
+ */
+int admin_command_execute(const struct ocxlpmem *ocxlpmem);
+
+/**
+ * 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
+ */
+int admin_command_complete_timeout(const struct ocxlpmem
*ocxlpmem,
+				   int command);
+
+/**
+ * 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);

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