PCI/DOE: Make mailbox creation API private

The PCI core has just been amended to create a pci_doe_mb struct for
every DOE instance on device enumeration.  CXL (the only in-tree DOE
user so far) has been migrated to use those mailboxes instead of
creating its own.

That leaves pcim_doe_create_mb() and pci_doe_for_each_off() without any
callers, so drop them.

pci_doe_supports_prot() is now only used internally, so declare it
static.

pci_doe_destroy_mb() is no longer used as callback for
devm_add_action(), so refactor it to accept a struct pci_doe_mb pointer
instead of a generic void pointer.

Because pci_doe_create_mb() is only called on device enumeration, i.e.
before driver binding, the workqueue name never contains a driver name.
So replace dev_driver_string() with dev_bus_name() when generating the
workqueue name.

Tested-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Ming Li <ming4.li@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/64f614b6584982986c55d2c6229b4ee2b276dd59.1678543498.git.lukas@wunner.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

.clang-format

@@ -520,7 +520,6 @@ ForEachMacros:
   - 'of_property_for_each_string'
   - 'of_property_for_each_u32'
   - 'pci_bus_for_each_resource'
-  - 'pci_doe_for_each_off'
   - 'pcl_for_each_chunk'
   - 'pcl_for_each_segment'
   - 'pcm_for_each_format'

drivers/pci/doe.c

@@ -455,7 +455,7 @@ static struct pci_doe_mb *pci_doe_create_mb(struct pci_dev *pdev,
 	xa_init(&doe_mb->prots);
 
 	doe_mb->work_queue = alloc_ordered_workqueue("%s %s DOE [%x]", 0,
-						dev_driver_string(&pdev->dev),
+						dev_bus_name(&pdev->dev),
 						pci_name(pdev),
 						doe_mb->cap_offset);
 	if (!doe_mb->work_queue) {
@@ -499,50 +499,18 @@ err_free:
 /**
  * pci_doe_destroy_mb() - Destroy a DOE mailbox object
  *
- * @ptr: Pointer to DOE mailbox
+ * @doe_mb: DOE mailbox
  *
  * Destroy all internal data structures created for the DOE mailbox.
  */
-static void pci_doe_destroy_mb(void *ptr)
+static void pci_doe_destroy_mb(struct pci_doe_mb *doe_mb)
 {
-	struct pci_doe_mb *doe_mb = ptr;
-
 	pci_doe_cancel_tasks(doe_mb);
 	xa_destroy(&doe_mb->prots);
 	destroy_workqueue(doe_mb->work_queue);
 	kfree(doe_mb);
 }
 
-/**
- * pcim_doe_create_mb() - Create a DOE mailbox object
- *
- * @pdev: PCI device to create the DOE mailbox for
- * @cap_offset: Offset of the DOE mailbox
- *
- * Create a single mailbox object to manage the mailbox protocol at the
- * cap_offset specified.  The mailbox will automatically be destroyed on
- * driver unbinding from @pdev.
- *
- * RETURNS: created mailbox object on success
- *	    ERR_PTR(-errno) on failure
- */
-struct pci_doe_mb *pcim_doe_create_mb(struct pci_dev *pdev, u16 cap_offset)
-{
-	struct pci_doe_mb *doe_mb;
-	int rc;
-
-	doe_mb = pci_doe_create_mb(pdev, cap_offset);
-	if (IS_ERR(doe_mb))
-		return doe_mb;
-
-	rc = devm_add_action_or_reset(&pdev->dev, pci_doe_destroy_mb, doe_mb);
-	if (rc)
-		return ERR_PTR(rc);
-
-	return doe_mb;
-}
-EXPORT_SYMBOL_GPL(pcim_doe_create_mb);
-
 /**
  * pci_doe_supports_prot() - Return if the DOE instance supports the given
  *			     protocol
@@ -552,7 +520,7 @@ EXPORT_SYMBOL_GPL(pcim_doe_create_mb);
  *
  * RETURNS: True if the DOE mailbox supports the protocol specified
  */
-bool pci_doe_supports_prot(struct pci_doe_mb *doe_mb, u16 vid, u8 type)
+static bool pci_doe_supports_prot(struct pci_doe_mb *doe_mb, u16 vid, u8 type)
 {
 	unsigned long index;
 	void *entry;
@@ -567,7 +535,6 @@ bool pci_doe_supports_prot(struct pci_doe_mb *doe_mb, u16 vid, u8 type)
 
 	return false;
 }
-EXPORT_SYMBOL_GPL(pci_doe_supports_prot);
 
 /**
  * pci_doe_submit_task() - Submit a task to be processed by the state machine

include/linux/pci-doe.h

@@ -15,20 +15,6 @@
 
 struct pci_doe_mb;
 
-/**
- * pci_doe_for_each_off - Iterate each DOE capability
- * @pdev: struct pci_dev to iterate
- * @off: u16 of config space offset of each mailbox capability found
- */
-#define pci_doe_for_each_off(pdev, off) \
-	for (off = pci_find_next_ext_capability(pdev, off, \
-					PCI_EXT_CAP_ID_DOE); \
-		off > 0; \
-		off = pci_find_next_ext_capability(pdev, off, \
-					PCI_EXT_CAP_ID_DOE))
-
-struct pci_doe_mb *pcim_doe_create_mb(struct pci_dev *pdev, u16 cap_offset);
-bool pci_doe_supports_prot(struct pci_doe_mb *doe_mb, u16 vid, u8 type);
 struct pci_doe_mb *pci_find_doe_mailbox(struct pci_dev *pdev, u16 vendor,
 					u8 type);