On 08/21/2018 05:46 AM, Bin Meng wrote:
Hi Simon,
On Tue, Aug 21, 2018 at 3:29 AM, Simon Glass sjg@chromium.org wrote:
Hi Marek,
On 20 August 2018 at 12:42, Marek Vasut marek.vasut@gmail.com wrote:
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 :-)
Yes, too long discussion :)
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?
No, I don't have any patch series for now, although I offered to work on a series to implement my proposal. I haven't started it as I wanted to hear your thoughts. The proposal I made is to satisfy the requirement that Marek insisted on. Basically Marek thought current DM PCI implementation is wrong to ask for a "compatible" string of a PCI device in the device tree, because he thought adding "compatible" to DT is invalid and Linux does not do that either. While I disagree we have to 100% follow Linux's implementation, I am still open for any possible design changes, if that's the preferable practice in U-Boot (but we have to make it clear and document this officially somewhere).
The proposal I made is:
- Keep pci-uclass driver's post_bind() and child_post_bind() only for
Sandbox configuration
- Keep the call to pci_bus_find_devfn() in pci_bind_bus_devices() only
for Sandbox configuration
- Sandbox is special. We should limit the mechanism of matching PCI
emulation device via "compatible" to sandbox only
The above three points can be done separately and I don't care about this too much.
- Assign the DT node to the bound device in pci_find_and_bind_driver()
if there is a valid PCI "reg" encoding for a specific PCI device in the device tree
This is what this patch does. And in fact, I have real hardware which needs this patch to be useful and on which I can test if this works.
- Create DM PCI test case against the DT node assignment
- Remove all compatible string in U-Boot's PCI device drivers: eg:
ehci_pci_ids[], xhci_pci_ids[], etc. IOW, all PCI device drivers should only use U_BOOT_PCI_DEVICE(), aka the original U-Boot option 2
- Fork a "pci-ns16550" driver to support U_BOOT_PCI_DEVICE(), as
currently PCI ns16550 device driver uses "compatible" string to do the matching, and update crownbay.dts and galileo.dts (so far I only know two boards are using PCI ns16550 serial port)
- Make sure all DM PCI test cases are not broken
- Document all of the above changes in doc/driver-model/pci-info.txt
I think you're just adding completely orthogonal stuff to this 5-liner patch into the list and overly complicate the situation. Sure, if you want to do all this, go ahead, but I don't see how this prevents this particular patch from being applied , except maybe for the documentation tweak.