Hi Marek, On Mon, Aug 13, 2018 at 9:46 PM, Marek Vasut <marek.va...@gmail.com> wrote: > On 08/13/2018 04:24 AM, Bin Meng wrote: >> Hi Marek, >> >> On Fri, Aug 10, 2018 at 8:38 PM, Marek Vasut <marek.va...@gmail.com> wrote: >>> On 08/10/2018 02:01 PM, Tom Rini wrote: >>>> On Wed, Aug 08, 2018 at 09:37:25PM +0200, Marek Vasut wrote: >>>>> On 08/08/2018 05:32 PM, Bin Meng wrote: >>>>>> Hi Marek, >>>>>> >>>>>> On Wed, Aug 8, 2018 at 10:33 PM, Marek Vasut <marek.va...@gmail.com> >>>>>> wrote: >>>>>>> On 08/08/2018 03:39 PM, Bin Meng wrote: >>>>>>>> Hi Marek, >>>>>>>> >>>>>>>> On Wed, Aug 8, 2018 at 9:24 PM, Marek Vasut <marek.va...@gmail.com> >>>>>>>> wrote: >>>>>>>>> On 08/08/2018 03:14 PM, Bin Meng wrote: >>>>>>>>>> Hi Marek, >>>>>>>>>> >>>>>>>>>> On Wed, Aug 8, 2018 at 9:03 PM, Marek Vasut <marek.va...@gmail.com> >>>>>>>>>> wrote: >>>>>>>>>>> The PCI controller can have DT subnodes describing extra properties >>>>>>>>>>> of particular PCI devices, ie. a PHY attached to an EHCI controller >>>>>>>>>>> on a PCI bus. This patch parses those DT subnodes and assigns a node >>>>>>>>>>> to the PCI device instance, so that the driver can extract details >>>>>>>>>>> from that node and ie. configure the PHY using the PHY subsystem. >>>>>>>>>>> >>>>>>>>>>> Signed-off-by: Marek Vasut <marek.vasut+rene...@gmail.com> >>>>>>>>>>> Cc: Simon Glass <s...@chromium.org> >>>>>>>>>>> --- >>>>>>>>>>> drivers/pci/pci-uclass.c | 14 ++++++++++++++ >>>>>>>>>>> 1 file changed, 14 insertions(+) >>>>>>>>>>> >>>>>>>>>>> diff --git a/drivers/pci/pci-uclass.c b/drivers/pci/pci-uclass.c >>>>>>>>>>> index 46e9c71bdf..306bea0dbf 100644 >>>>>>>>>>> --- a/drivers/pci/pci-uclass.c >>>>>>>>>>> +++ b/drivers/pci/pci-uclass.c >>>>>>>>>>> @@ -662,6 +662,8 @@ static int pci_find_and_bind_driver(struct >>>>>>>>>>> udevice *parent, >>>>>>>>>>> for (id = entry->match; >>>>>>>>>>> id->vendor || id->subvendor || id->class_mask; >>>>>>>>>>> id++) { >>>>>>>>>>> + ofnode node; >>>>>>>>>>> + >>>>>>>>>>> if (!pci_match_one_id(id, find_id)) >>>>>>>>>>> continue; >>>>>>>>>>> >>>>>>>>>>> @@ -691,6 +693,18 @@ static int pci_find_and_bind_driver(struct >>>>>>>>>>> udevice *parent, >>>>>>>>>>> goto error; >>>>>>>>>>> debug("%s: Match found: %s\n", __func__, >>>>>>>>>>> drv->name); >>>>>>>>>>> dev->driver_data = find_id->driver_data; >>>>>>>>>>> + >>>>>>>>>>> + dev_for_each_subnode(node, parent) { >>>>>>>>>>> + phys_addr_t df, size; >>>>>>>>>>> + df = ofnode_get_addr_size(node, >>>>>>>>>>> "reg", &size); >>>>>>>>>>> + >>>>>>>>>>> + if (PCI_FUNC(df) == PCI_FUNC(bdf) && >>>>>>>>>>> + PCI_DEV(df) == PCI_DEV(bdf)) { >>>>>>>>>>> + dev->node = node; >>>>>>>>>>> + break; >>>>>>>>>>> + } >>>>>>>>>> >>>>>>>>>> The function pci_find_and_bind_driver() is supposed to bind devices >>>>>>>>>> that are NOT in the device tree. Adding device tree access in this >>>>>>>>>> routine is quite odd. You can add the EHCI controller that need such >>>>>>>>>> PHY subnodes in the device tree and there is no need to modify >>>>>>>>>> anything I believe. If you are looking for an example, please check >>>>>>>>>> pciuart0 in arch/x86/dts/crownbay.dts. >>>>>>>>> >>>>>>>>> Well this does not work for me, the EHCI PCI doesn't get a DT node >>>>>>>>> assigned, check r8a7794.dtsi for the PCI devices I use. >>>>>>>>> >>>>>>>> >>>>>>>> I think that's because you don't specify a "compatible" string for >>>>>>>> these two EHCI PCI nodes. >>>>>>> >>>>>>> That's perfectly fine, why should I specify it ? Linux has no problem >>>>>>> with it either. >>>>>>> >>>>>> >>>>>> Without a "compatible" string, DM does not bind any device in the >>>>>> device tree to a driver, hence no device node created. This is not >>>>>> Linux. >>>>> >>>>> DT is NOT Linux specific, it is OS-agnostic, DT describes hardware and >>>>> hardware only. If U-Boot cannot parse DT correctly, U-Boot is broken and >>>>> must be fixed. >>>>> >>>>> This is a fix. If there is a better fix, I am open to it. >>>> >>>> DT should but isn't always OS agnostic. DTS files that reside in the >>>> Linux Kernel are in practice is Linux-centric with the expectation that >>>> even if you could solve a given problem with valid DTS changes you make >>>> whatever is parsing it do additional logic instead. That, >>>> approximately, is what your patch is doing. If you added some HW >>>> description information to the dtsi file everything would work as >>>> expected as your DTS is describing the hardware and U-Boot is reading >>>> that description and figuring out what to do with it. >>> >>> Yes, you need additional logic to match the PCI controller subnode in DT >>> with PCI device BFD, that's expected. You do NOT need extra compatibles, >>> the PCI bus gives you enough information to match a driver on them. In >>> fact, adding a compatible can interfere with this matching. >>> >> >> Please, read U-Boot's doc/driver-model/pci-info.txt. You really don't >> understand current implementation in U-Boot. In short, U-Boot supports >> two scenarios for PCI driver binding: > > That documentation is wrong and needs to be fixed. The compatible is > optional. >
No it is not wrong. The documentation reflects the update-to-date U-Boot support of PCI bus with DM. >> - Declare a PCI device in the device tree. That requires specifying a >> 'compatible' string as well as 'reg' property as defined by the 'PCI >> Bus Binding' spec. DM uses the 'compatible' string to bind the driver >> for the device. >> - Don't declare a PCI device in the device tree. Instead, using >> U_BOOT_PCI_DEVICE() to declare a device and driver mapping. >> >> You can choose either two when you support PCI devices on your board, >> but you cannot mix both support together and make them a mess. In this >> patch, you hacked pci_find_and_bind_driver() which is the 2nd scenario >> to support the 1st scenario. > > Again, the DT contains all the required information to bind the node and > the driver instance. Clearly, we need option 3 for this. > Then that's a new design proposal. Anything that wants to mess up current design is a hack. >>>> The problem here is that in Linux, something that sees the compatible >>>> renesas,pci-r8a7794 or renesas,pci-rcar-gen2 is doing whatever else >>>> needs to be done. Or something else? Please explain how what you want >>>> to have work here in U-Boot is working in the Linux kernel. Thanks! >>> >>> This has nothing to do with a specific controller. iMX6 does the same >>> thing, see ie arch/arm/boot/dts/imx6q-utilite-pro.dts . Regards, Bin _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot