| Message ID | 20200222014038.180923-3-saravanak@google.com (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
| Series | Add fw_devlink kernel commandline option | expand |
On Fri, Feb 21, 2020 at 5:40 PM Saravana Kannan <saravanak@google.com> wrote: > > fwnode_operations.add_links allows creating device links from > information provided by firmware. > > fwnode_operations.add_links is currently implemented only by > OF/devicetree code and a specific case of efi. However, there's nothing > preventing ACPI or other firmware types from implementing it. > > The OF implementation is currently controlled by a kernel commandline > parameter called of_devlink. > > Since this feature is generic isn't limited to OF, add a generic > fw_devlink kernel commandline parameter to control this feature across > firmware types. > > Signed-off-by: Saravana Kannan <saravanak@google.com> > --- > .../admin-guide/kernel-parameters.txt | 18 +++++++++++++ > drivers/base/core.c | 27 ++++++++++++++++++- > include/linux/fwnode.h | 2 ++ > 3 files changed, 46 insertions(+), 1 deletion(-) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index dbc22d684627..29985152b66d 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -1350,6 +1350,24 @@ > can be changed at run time by the max_graph_depth file > in the tracefs tracing directory. default: 0 (no limit) > > + fw_devlink= [KNL] Create device links between consumer and supplier > + devices by scanning the firmware to infer the > + consumer/supplier relationships. This feature is > + especially useful when drivers are loaded as modules as > + it ensures proper ordering of tasks like device probing > + (suppliers first, then consumers), supplier boot state > + clean up (only after all consumers have probed), > + suspend/resume & runtime PM (consumers first, then > + suppliers). > + Format: { off | permissive | on | rpm } > + off -- Don't create device links from firmware info. > + permissive -- Create device links from firmware info > + but use it only for ordering boot state clean > + up (sync_state() calls). > + on -- Create device links from firmware info and use it > + to enforce probe and suspend/resume ordering. > + rpm -- Like "on", but also use to order runtime PM. > + A bit of bikeshedding myself: I could rename "on" to "enforce" and "rpm" to "enforce-rpm". Let me know if any of you have a strong preference on these two options. -Saravana > gamecon.map[2|3]= > [HW,JOY] Multisystem joystick and NES/SNES/PSX pad > support via parallel port (up to 5 devices per port) > diff --git a/drivers/base/core.c b/drivers/base/core.c > index d32a3aefff32..aeaca8a3aad9 100644 > --- a/drivers/base/core.c > +++ b/drivers/base/core.c > @@ -2345,6 +2345,31 @@ static int device_private_init(struct device *dev) > return 0; > } > > +u32 fw_devlink_flags; > +static int __init fw_devlink_setup(char *arg) > +{ > + if (!arg) > + return -EINVAL; > + > + if (strcmp(arg, "off") == 0) { > + fw_devlink_flags = 0; > + } else if (strcmp(arg, "permissive") == 0) { > + fw_devlink_flags = DL_FLAG_SYNC_STATE_ONLY; > + } else if (strcmp(arg, "on") == 0) { > + fw_devlink_flags = DL_FLAG_AUTOPROBE_CONSUMER; > + } else if (strcmp(arg, "rpm") == 0) { > + fw_devlink_flags = DL_FLAG_AUTOPROBE_CONSUMER | > + DL_FLAG_PM_RUNTIME; > + } > + return 0; > +} > +early_param("fw_devlink", fw_devlink_setup); > + > +u32 fw_devlink_get_flags(void) > +{ > + return fw_devlink_flags; > +} > + > /** > * device_add - add device to device hierarchy. > * @dev: device. > @@ -2493,7 +2518,7 @@ int device_add(struct device *dev) > */ > device_link_add_missing_supplier_links(); > > - if (fwnode_has_op(dev->fwnode, add_links)) { > + if (fw_devlink_flags && fwnode_has_op(dev->fwnode, add_links)) { > fw_ret = fwnode_call_int_op(dev->fwnode, add_links, dev); > if (fw_ret == -ENODEV) > device_link_wait_for_mandatory_supplier(dev); > diff --git a/include/linux/fwnode.h b/include/linux/fwnode.h > index 8feeb94b8acc..e0abafbb17f8 100644 > --- a/include/linux/fwnode.h > +++ b/include/linux/fwnode.h > @@ -170,4 +170,6 @@ struct fwnode_operations { > } while (false) > #define get_dev_from_fwnode(fwnode) get_device((fwnode)->dev) > > +extern u32 fw_devlink_get_flags(void); > + > #endif > -- > 2.25.0.265.gbab2e86ba0-goog >
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index dbc22d684627..29985152b66d 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1350,6 +1350,24 @@ can be changed at run time by the max_graph_depth file in the tracefs tracing directory. default: 0 (no limit) + fw_devlink= [KNL] Create device links between consumer and supplier + devices by scanning the firmware to infer the + consumer/supplier relationships. This feature is + especially useful when drivers are loaded as modules as + it ensures proper ordering of tasks like device probing + (suppliers first, then consumers), supplier boot state + clean up (only after all consumers have probed), + suspend/resume & runtime PM (consumers first, then + suppliers). + Format: { off | permissive | on | rpm } + off -- Don't create device links from firmware info. + permissive -- Create device links from firmware info + but use it only for ordering boot state clean + up (sync_state() calls). + on -- Create device links from firmware info and use it + to enforce probe and suspend/resume ordering. + rpm -- Like "on", but also use to order runtime PM. + gamecon.map[2|3]= [HW,JOY] Multisystem joystick and NES/SNES/PSX pad support via parallel port (up to 5 devices per port) diff --git a/drivers/base/core.c b/drivers/base/core.c index d32a3aefff32..aeaca8a3aad9 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -2345,6 +2345,31 @@ static int device_private_init(struct device *dev) return 0; } +u32 fw_devlink_flags; +static int __init fw_devlink_setup(char *arg) +{ + if (!arg) + return -EINVAL; + + if (strcmp(arg, "off") == 0) { + fw_devlink_flags = 0; + } else if (strcmp(arg, "permissive") == 0) { + fw_devlink_flags = DL_FLAG_SYNC_STATE_ONLY; + } else if (strcmp(arg, "on") == 0) { + fw_devlink_flags = DL_FLAG_AUTOPROBE_CONSUMER; + } else if (strcmp(arg, "rpm") == 0) { + fw_devlink_flags = DL_FLAG_AUTOPROBE_CONSUMER | + DL_FLAG_PM_RUNTIME; + } + return 0; +} +early_param("fw_devlink", fw_devlink_setup); + +u32 fw_devlink_get_flags(void) +{ + return fw_devlink_flags; +} + /** * device_add - add device to device hierarchy. * @dev: device. @@ -2493,7 +2518,7 @@ int device_add(struct device *dev) */ device_link_add_missing_supplier_links(); - if (fwnode_has_op(dev->fwnode, add_links)) { + if (fw_devlink_flags && fwnode_has_op(dev->fwnode, add_links)) { fw_ret = fwnode_call_int_op(dev->fwnode, add_links, dev); if (fw_ret == -ENODEV) device_link_wait_for_mandatory_supplier(dev); diff --git a/include/linux/fwnode.h b/include/linux/fwnode.h index 8feeb94b8acc..e0abafbb17f8 100644 --- a/include/linux/fwnode.h +++ b/include/linux/fwnode.h @@ -170,4 +170,6 @@ struct fwnode_operations { } while (false) #define get_dev_from_fwnode(fwnode) get_device((fwnode)->dev) +extern u32 fw_devlink_get_flags(void); + #endif
fwnode_operations.add_links allows creating device links from information provided by firmware. fwnode_operations.add_links is currently implemented only by OF/devicetree code and a specific case of efi. However, there's nothing preventing ACPI or other firmware types from implementing it. The OF implementation is currently controlled by a kernel commandline parameter called of_devlink. Since this feature is generic isn't limited to OF, add a generic fw_devlink kernel commandline parameter to control this feature across firmware types. Signed-off-by: Saravana Kannan <saravanak@google.com> --- .../admin-guide/kernel-parameters.txt | 18 +++++++++++++ drivers/base/core.c | 27 ++++++++++++++++++- include/linux/fwnode.h | 2 ++ 3 files changed, 46 insertions(+), 1 deletion(-)