Messages in this thread | | | Date | Fri, 12 Sep 2014 05:00:49 -0500 | From | Suravee Suthikulpanit <> | Subject | Re: [PATCH v10 00/10] Support for creating generic PCI host bridges from DT |
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On 9/12/2014 4:30 AM, Liviu Dudau wrote: > On Fri, Sep 12, 2014 at 09:25:13AM +0100, Suravee Suthikulpanit wrote: >> On 9/8/2014 8:54 AM, Liviu Dudau wrote: >>> This is my version 10 of the attempt at adding support for generic PCI host >>> bridge controllers that make use of device tree information to >>> configure themselves. This version reverses v9's attempt to create one function >>> to drive the whole process of extracting the host bridge ranges, setup the >>> host bridge driver and then scan the root bus behind the host bridge. While it >>> would've been quite user friendly, I agree that it would've caused a lot of pain >>> in the future. >>> >>> I would like to get ACKs for the remaining patches as I would like to integrate >>> this into -next in the following week. >>> >>> This version marks an implementation break with the previous versions as >>> of_create_pci_host_bridge() is now gone. It gets replaced by >>> of_pci_get_host_bridge_resources() that only parses the DT and extracts the >>> relevant ranges and converts them to resources. The updated host bridge drivers >>> will have to follow the guidelines in this example code: >>> >>> static int foohb_probe(struct platform_device *pdev) >>> { >>> struct device_node *dn = pdev->dev.of_node; >>> struct foohb_drv *drv; >>> resource_size_t io_base = 0; /* phys address for start of IO */ >>> struct pci_bus *bus; >>> int err = 0; >>> LIST_HEAD(res); >>> >>> ..... >>> err = of_pci_get_host_bridge_resources(dn, 0, 255, &res, &io_base); >>> if (err) >>> goto err_handling; >>> err = foohb_setup(drv, ...., &res, &io_base); >>> if (err) >>> goto err_handling; > > Hi Suravee, > >> >> My understanding is that the "foohb_setup" above is supposed to be equivalent >> to the "int (*setup)(struct pci_host_bridge *, resource_size_t)" in V9 that was >> passed in as an argument of "of_create_pci_hot_bridge()". > > Correct. Parameters are probably different, but it is internal to your driver so > you can do whatever you want there. > >> >> The problem I have is I need an intermediate step between "pci_create_root_bus()" >> and "pci_scan_child_bus()" in order to update the information such as the "pci_bus->msi" >> before this is propagate down to the child bus during the "pci_scan_child_bus" >> which is also called in the pci_scan_root_bus() function. > > How did that work with my v9 patchset? How does it work for other MSI-aware platforms? > Are they not using pci_scan_child_bus()?
In the of_create_pci_host_bridge of V9, you call the setup function between "pci_create_root_bus()" and "pci_scan_child_bus()". At that point, I can update the "root_bus->msi" to point to my "struct msi_chip" which was created during GICv2m initialization (Please see http://marc.info/?l=linux-kernel&m=141034053331632&w=2). Then, when a child bus is created, it propagate this msi_chip pointer from the parent bus.
Suravee
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