From mboxrd@z Thu Jan 1 00:00:00 1970 From: Simon Glass Date: Mon, 20 Aug 2018 13:29:56 -0600 Subject: [U-Boot] [PATCH] pci: Support parsing PCI controller DT subnodes In-Reply-To: References: <20180810120135.GH29229@bill-the-cat> <972158e3-e0bd-4798-699f-06a97d7100d1@gmail.com> <98561a43-18bf-3c76-d3c6-3320cdafdf4b@gmail.com> <7a1aa6ed-7ddd-551a-f445-171465dbbe46@gmail.com> <92b4b0cc-b3fb-45c8-20f9-a232c2891edf@gmail.com> <20180815112540.GG30947@bill-the-cat> Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi Marek, On 20 August 2018 at 12:42, Marek Vasut wrote: > > On 08/20/2018 06:57 PM, Simon Glass wrote: > > Hi Bin, > > > > On 16 August 2018 at 19:51, Bin Meng wrote: > >> Hi Marek, > >> > >> On Thu, Aug 16, 2018 at 7:47 PM, Marek Vasut wrote: > >>> On 08/15/2018 01:25 PM, Tom Rini wrote: > >>>> On Wed, Aug 15, 2018 at 06:19:25PM +0800, Bin Meng wrote: > >>>>> Hi Marek, > >>>>> > >>>>> On Wed, Aug 15, 2018 at 5:22 PM, Marek Vasut wrote: > >>>>>> On 08/14/2018 11:40 AM, Bin Meng wrote: > >>>>>>> Hi Marek, > >>>>>>> > >>>>>>> On Tue, Aug 14, 2018 at 4:55 PM, Marek Vasut wrote: > >>>>>>>> On 08/14/2018 03:46 AM, Bin Meng wrote: > >>>>>>>>> Hi Marek, > >>>>>>>>> > >>>>>>>>> On Mon, Aug 13, 2018 at 9:46 PM, Marek Vasut wrote: > >>>>>>>>>> On 08/13/2018 04:24 AM, Bin Meng wrote: > >>>>>>>>>>> Hi Marek, > >>>>>>>>>>> > >>>>>>>>>>> On Fri, Aug 10, 2018 at 8:38 PM, Marek Vasut 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 wrote: > >>>>>>>>>>>>>>>> On 08/08/2018 03:39 PM, Bin Meng wrote: > >>>>>>>>>>>>>>>>> Hi Marek, > >>>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>>> On Wed, Aug 8, 2018 at 9:24 PM, Marek Vasut wrote: > >>>>>>>>>>>>>>>>>> On 08/08/2018 03:14 PM, Bin Meng wrote: > >>>>>>>>>>>>>>>>>>> Hi Marek, > >>>>>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>>>>> On Wed, Aug 8, 2018 at 9:03 PM, Marek Vasut 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 > >>>>>>>>>>>>>>>>>>>> Cc: Simon Glass > >>>>>>>>>>>>>>>>>>>> --- > >>>>>>>>>>>>>>>>>>>> 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. > >>>>>>>> > >>>>>>>> Which is incomplete, as it cannot parse subnodes without compatible strings. > >>>>>>>> > >>>>>>> > >>>>>>> No, it's by design, as I said many times. It can support parsing > >>>>>>> subnodes with a "compatible" string existence. > >>>>>> > >>>>>> It can support parsing subnodes with a "compatible" string existence AND > >>>>>> It can NOT support parsing subnodes without a "compatible" string > >>>>>> existence THUS It is incomplete. > >>>>>> > >>>>>>>>>>> - 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. > >>>>>>>> > >>>>>>>> That means every single patch anyone submits is now a hack ? Please ... > >>>>>>>> > >>>>>>> > >>>>>>> I never said "every single patch anyone submits is now a hack". "You > >>>>>>> are inserting words into my mouth and I dislike that." I said your > >>>>>>> current patch is against the design, and mess up current design which > >>>>>>> is a hack. > >>>>>> > >>>>>> But then every patch which changes the behavior is against "the design" > >>>>>> and thus is a hack. Ultimately, most improvements would be considered a > >>>>>> hack. > >>>>> > >>>>> No it depends. For this case, there are two options that DM PCI > >>>>> currently provides. You created a 3rd option that bring option 1 and 2 > >>>>> together in a mixed way, yet without any documenting and additional > >>>>> other changes. If you posted such changes in a series and have all > >>>>> stuff well considered, I would not consider it a hack, but a proposed > >>>>> design change. > >>>> > >>>> Also, the design document is not immutable and can and should be updated > >>>> as needed to match changes in the code. > >>> > >>> So what is the conclusion here ? Patch the design document and apply > >>> this patch as is ? > >>> > >> > >> I think we should see Simon's comments before we move forward. The > >> proposal I made before should come in a series, not just > >> documentation. > > > > This thread is too long :-) > > > > From what I understand, Marek and Bin are discussing whether a > > compatible string is needed to bind a driver. > > > > Generally it is. But with PCI and USB we have a search mechanism which > > can be used instead. > > > > The patch Marek submitted does not seems at all desirable to me. > > Can you explain why ? We already have a compatible string as the standard way to attach drivers to devices. For PCI, we already have PCI_DEVICE() and friends for when we can attach a driver for a PCI device without using a compatible string. Both of these are defined in the DT specification. The patch seems to be a rework of PCI_DEVICE() and I cannot why it is necessary. > > > I would like to see what Bin proposes. > > Me too, so far I only see "not Marek's patch" and no real alternative. Bin, do you have a patch you can share? Regards, Simon