[PATCH V3 09/13] PCI: Add 'override_only' field to struct pci_device_id

Yishai Hadas
2021-08-22T14:37:41Z

Add 'override_only' field to struct pci_device_id to be used as part of
pci_match_device().

When set, it means that matching is true only when dev->driver_override
is this driver.

In addition, add a helper macro named 'PCI_DEVICE_DRIVER_OVERRIDE' to
enable setting some data on it.

Next patch from this series will use the above functionality.

Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
---
Documentation/PCI/pci.rst | 1 +
drivers/pci/pci-driver.c | 28 +++++++++++++++++++++-------
include/linux/mod_devicetable.h | 2 ++
include/linux/pci.h | 15 +++++++++++++++
4 files changed, 39 insertions(+), 7 deletions(-)

diff --git a/Documentation/PCI/pci.rst b/Documentation/PCI/pci.rst
index fa651e25d98c..87c6f4a6ca32 100644
--- a/Documentation/PCI/pci.rst
+++ b/Documentation/PCI/pci.rst
@@ -103,6 +103,7 @@ need pass only as many optional fields as necessary:
- subvendor and subdevice fields default to PCI_ANY_ID (FFFFFFFF)
- class and classmask fields default to 0
- driver_data defaults to 0UL.
+ - override_only field defaults to 0.

Note that driver_data must match the value used by any of the pci_device_id
entries defined in the driver. This makes the driver_data field mandatory
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 3a72352aa5cf..123c590ebe1d 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -136,7 +136,7 @@ static const struct pci_device_id *pci_match_device(struct pci_driver *drv,
struct pci_dev *dev)
{
struct pci_dynid *dynid;
- const struct pci_device_id *found_id = NULL;
+ const struct pci_device_id *found_id = NULL, *ids;

/* When driver_override is set, only bind to the matching driver */
if (dev->driver_override && strcmp(dev->driver_override, drv->name))
@@ -152,14 +152,28 @@ static const struct pci_device_id *pci_match_device(struct pci_driver *drv,
}
spin_unlock(&drv->dynids.lock);

- if (!found_id)
- found_id = pci_match_id(drv->id_table, dev);
+ if (found_id)
+ return found_id;

- /* driver_override will always match, send a dummy id */
- if (!found_id && dev->driver_override)
- found_id = &pci_device_id_any;
+ for (ids = drv->id_table; (found_id = pci_match_id(ids, dev));
+ ids = found_id + 1) {
+ /*
+ * The match table is split based on driver_override.
+ * In case override_only was set, enforce driver_override
+ * matching.
+ */
+ if (found_id->override_only) {
+ if (dev->driver_override)
+ return found_id;
+ } else {
+ return found_id;
+ }
+ }

- return found_id;
+ /* driver_override will always match, send a dummy id */
+ if (dev->driver_override)
+ return &pci_device_id_any;
+ return NULL;
}

/**
diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 8e291cfdaf06..2e3ba6d9ece0 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -34,12 +34,14 @@ typedef unsigned long kernel_ulong_t;
* Best practice is to use driver_data as an index
* into a static list of equivalent device types,
* instead of using it as a pointer.
+ * @override_only: Match only when dev->driver_override is this driver.
*/
struct pci_device_id {
__u32 vendor, device; /* Vendor and device ID or PCI_ANY_ID*/
__u32 subvendor, subdevice; /* Subsystem ID's or PCI_ANY_ID */
__u32 class, class_mask; /* (class,subclass,prog-if) triplet */
kernel_ulong_t driver_data; /* Data private to the driver */
+ __u32 override_only;
};

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 540b377ca8f6..0506b1a8c921 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -901,6 +901,21 @@ struct pci_driver {
.vendor = (vend), .device = (dev), \
.subvendor = PCI_ANY_ID, .subdevice = PCI_ANY_ID

+/**
+ * PCI_DEVICE_DRIVER_OVERRIDE - macro used to describe a PCI device with
+ * override_only flags.
+ * @vend: the 16 bit PCI Vendor ID
+ * @dev: the 16 bit PCI Device ID
+ * @driver_override: the 32 bit PCI Device override_only
+ *
+ * This macro is used to create a struct pci_device_id that matches only a
+ * driver_override device. The subvendor and subdevice fields will be set to
+ * PCI_ANY_ID.
+ */
+#define PCI_DEVICE_DRIVER_OVERRIDE(vend, dev, driver_override) \
+ .vendor = (vend), .device = (dev), .subvendor = PCI_ANY_ID, \
+ .subdevice = PCI_ANY_ID, .override_only = (driver_override)
+
/**
* PCI_DEVICE_SUB - macro used to describe a specific PCI device with subsystem
* @vend: the 16 bit PCI Vendor ID
--
2.18.1