Hi,
This patch adds initial support for driver matching priorities to the
driver model. It is needed for my work on converting the pci bridge
driver to use "struct device_driver". It may also be helpful for driver
with more complex (or long id lists as I've seen in many cases) matching
criteria.
"match" has been added to "struct device_driver". There are now two
steps in the matching process. The first step is a bus specific filter
that determines possible driver candidates. The second step is a driver
specific match function that verifies if the driver will work with the
hardware, and returns a priority code (how well it is able to handle the
device). The bus layer could override the driver's match function if
necessary (similar to how it passes *probe through it's layer and then
on to the actual driver).
The current priorities are as follows:
enum {
MATCH_PRIORITY_FAILURE = 0,
MATCH_PRIORITY_GENERIC,
MATCH_PRIORITY_NORMAL,
MATCH_PRIORITY_VENDOR,
};
let me know if any of this would need to be changed. For example, the
"struct bus_type" match function could return a priority code.
Of course this patch is not going to be effective alone. We also need
to change the init order. If a driver is registered early but isn't the
best available, it will be bound to the device prematurely. This would
be a problem for carbus (yenta) bridges.
I think we may have to load all in kernel drivers first, and then begin
matching them to hardware. Do you agree? If so, I'd be happy to make a
patch for that too.
Thanks,
Adam
--- a/drivers/base/bus.c 2005-01-20 17:37:46.000000000 -0500
+++ b/drivers/base/bus.c 2005-01-28 16:59:00.000000000 -0500
@@ -286,6 +286,9 @@
if (drv->bus->match && !drv->bus->match(dev, drv))
return -ENODEV;
+ if (drv->match && !drv->match(dev))
+ return -ENODEV;
+
dev->driver = drv;
if (drv->probe) {
int error = drv->probe(dev);
@@ -299,6 +302,42 @@
return 0;
}
+/**
+ * driver_probe_device_priority - attempt to bind device & driver with a
+ * given match level priority
+ * @drv: driver.
+ * @dev: device.
+ * @priority the match level priority
+ */
+
+static int driver_probe_device_priority(struct device_driver * drv,
+ struct device * dev, int priority)
+{
+ int matchp;
+
+ if (drv->bus->match && !drv->bus->match(dev, drv))
+ return -ENODEV;
+
+ if (drv->match) {
+ matchp = drv->match(dev);
+ } else
+ matchp = MATCH_PRIORITY_NORMAL;
+
+ if (matchp != priority)
+ return -ENODEV;
+
+ dev->driver = drv;
+ if (drv->probe) {
+ int error = drv->probe(dev);
+ if (error) {
+ dev->driver = NULL;
+ return error;
+ }
+ }
+
+ device_bind_driver(dev);
+ return 0;
+}
/**
* device_attach - try to attach device to a driver.
@@ -312,17 +351,20 @@
{
struct bus_type * bus = dev->bus;
struct list_head * entry;
- int error;
+ int error, matchp = MATCH_PRIORITY_VENDOR;
if (dev->driver) {
device_bind_driver(dev);
return 1;
}
- if (bus->match) {
+ if (!bus->match)
+ return 0;
+
+ while (matchp > 0) {
list_for_each(entry, &bus->drivers.list) {
struct device_driver * drv = to_drv(entry);
- error = driver_probe_device(drv, dev);
+ error = driver_probe_device_priority(drv, dev, matchp);
if (!error)
/* success, driver matched */
return 1;
@@ -332,6 +374,7 @@
"%s: probe of %s failed with error %d\n",
drv->name, dev->bus_id, error);
}
+ matchp--;
}
return 0;
--- a/include/linux/device.h 2005-01-20 17:37:26.000000000 -0500
+++ b/include/linux/device.h 2005-01-28 16:40:22.000000000 -0500
@@ -41,6 +41,13 @@
RESUME_ENABLE,
};
+enum {
+ MATCH_PRIORITY_FAILURE = 0,
+ MATCH_PRIORITY_GENERIC,
+ MATCH_PRIORITY_NORMAL,
+ MATCH_PRIORITY_VENDOR,
+};
+
struct device;
struct device_driver;
struct class;
@@ -108,6 +115,7 @@
struct module * owner;
+ int (*match) (struct device * dev);
int (*probe) (struct device * dev);
int (*remove) (struct device * dev);
void (*shutdown) (struct device * dev);
-
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