On 08/20/2018 06:57 PM, Simon Glass wrote:
Hi Bin,
On 16 August 2018 at 19:51, Bin Meng bmeng.cn@gmail.com wrote:
Hi Marek,
On Thu, Aug 16, 2018 at 7:47 PM, Marek Vasut marek.vasut@gmail.com 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 marek.vasut@gmail.com wrote:
On 08/14/2018 11:40 AM, Bin Meng wrote: > Hi Marek, > > On Tue, Aug 14, 2018 at 4:55 PM, Marek Vasut marek.vasut@gmail.com wrote: >> On 08/14/2018 03:46 AM, Bin Meng wrote: >>> Hi Marek, >>> >>> On Mon, Aug 13, 2018 at 9:46 PM, Marek Vasut marek.vasut@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.vasut@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.vasut@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.vasut@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.vasut@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+renesas@gmail.com >>>>>>>>>>>>>> Cc: Simon Glass sjg@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. >> >> 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 ?
I would like to see what Bin proposes.
Me too, so far I only see "not Marek's patch" and no real alternative.