| Message ID | 20250407145546.270683-12-herve.codina@bootlin.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | lan966x pci device: Add support for SFPs | expand |
On Mon, Apr 07, 2025 at 04:55:40PM +0200, Herve Codina wrote: > PCI drivers can use a device-tree overlay to describe the hardware > available on the PCI board. This is the case, for instance, of the > LAN966x PCI device driver. > > Adding some more nodes in the device-tree overlay adds some more > consumer/supplier relationship between devices instantiated from this > overlay. > > Those fw_node consumer/supplier relationships are handled by fw_devlink > and are created based on the device-tree parsing done by the > of_fwnode_add_links() function. > > Those consumer/supplier links are needed in order to ensure a correct PM > runtime management and a correct removal order between devices. > > For instance, without those links a supplier can be removed before its > consumers is removed leading to all kind of issue if this consumer still > want the use the already removed supplier. > > The support for the usage of an overlay from a PCI driver has been added > on x86 systems in commit 1f340724419ed ("PCI: of: Create device tree PCI > host bridge node"). > > In the past, support for fw_devlink on x86 had been tried but this > support has been removed in commit 4a48b66b3f52 ("of: property: Disable > fw_devlink DT support for X86"). Indeed, this support was breaking some > x86 systems such as OLPC system and the regression was reported in [0]. > > Instead of disabling this support for all x86 system, use a finer grain > and disable this support only for the possible problematic subset of x86 > system mixing ACPI and device-tree at boot time (i.e. OLPC and CE4100). This is incorrect, they never had ACPI to begin with. Also there is third platform that are using DT on x86 core — SpreadTrum based phones. And not sure about AMD stuff (Geode?). > [0] https://lore.kernel.org/lkml/3c1f2473-92ad-bfc4-258e-a5a08ad73dd0@web.de/ Can you make this to be a Link tag? Link: https://lore.kernel.org/lkml/3c1f2473-92ad-bfc4-258e-a5a08ad73dd0@web.de/ [0] > Signed-off-by: Herve Codina <herve.codina@bootlin.com>
diff --git a/drivers/of/property.c b/drivers/of/property.c index c1feb631e383..a4b367d056b8 100644 --- a/drivers/of/property.c +++ b/drivers/of/property.c @@ -1605,7 +1605,7 @@ static int of_fwnode_add_links(struct fwnode_handle *fwnode) const struct property *p; struct device_node *con_np = to_of_node(fwnode); - if (IS_ENABLED(CONFIG_X86)) + if (IS_ENABLED(CONFIG_X86_INTEL_CE) || IS_ENABLED(CONFIG_OLPC)) return 0; if (!con_np)
PCI drivers can use a device-tree overlay to describe the hardware available on the PCI board. This is the case, for instance, of the LAN966x PCI device driver. Adding some more nodes in the device-tree overlay adds some more consumer/supplier relationship between devices instantiated from this overlay. Those fw_node consumer/supplier relationships are handled by fw_devlink and are created based on the device-tree parsing done by the of_fwnode_add_links() function. Those consumer/supplier links are needed in order to ensure a correct PM runtime management and a correct removal order between devices. For instance, without those links a supplier can be removed before its consumers is removed leading to all kind of issue if this consumer still want the use the already removed supplier. The support for the usage of an overlay from a PCI driver has been added on x86 systems in commit 1f340724419ed ("PCI: of: Create device tree PCI host bridge node"). In the past, support for fw_devlink on x86 had been tried but this support has been removed in commit 4a48b66b3f52 ("of: property: Disable fw_devlink DT support for X86"). Indeed, this support was breaking some x86 systems such as OLPC system and the regression was reported in [0]. Instead of disabling this support for all x86 system, use a finer grain and disable this support only for the possible problematic subset of x86 system mixing ACPI and device-tree at boot time (i.e. OLPC and CE4100). [0] https://lore.kernel.org/lkml/3c1f2473-92ad-bfc4-258e-a5a08ad73dd0@web.de/ Signed-off-by: Herve Codina <herve.codina@bootlin.com> --- drivers/of/property.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)