On Wed, Jul 02, 2025 at 11:19:36AM -0400, Frank Li wrote:

On Wed, Jul 02, 2025 at 08:25:17PM +0530, Manivannan Sadhasivam wrote:

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On Wed, Jul 02, 2025 at 10:40:53AM GMT, Frank Li wrote:

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On Wed, Jul 02, 2025 at 04:30:48PM +0530, Manivannan Sadhasivam wrote:

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On Mon, Jun 09, 2025 at 12:34:13PM GMT, Frank Li wrote:

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Set device ID as 'vfunc_no << 3 | func_no' and use
'device_set_of_node_from_dev()' to set 'of_node' the same as the EPC parent
device.

Currently, EPF 'of_node' is NULL, but many functions depend on 'of_node'
settings, such as DMA, IOMMU, and MSI. At present, all DMA allocation
functions use the EPC's device node, but they should use the EPF one.
For multiple function drivers, IOMMU/MSI should be different for each
function driver.

We don't define OF node for any function, so device_set_of_node_from_dev() also
ends up reusing the EPC node. So how can you make use of it in multi EPF setup?

In mfd devices, children devices reuse parent's of_node
drivers/gpio/gpio-adp5585.c
drivers/input/keyboard/adp5589-keys.c
drivers/pwm/pwm-adp5585.c

multi EPF should be similar to create multi children devices of mfd.

No, they are not similar. MFD are real physical devices, but EPFs are (so far)
software based entities.

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I don't understand.

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If multiple function devices share the same EPC device, there will be
no isolation between them. Setting the ID and 'of_node' prepares for
proper support.

Only share the same of_node.

Actually pci host bridge have similar situation, all pci ep devices reuse
bridge's of node. framework use rid to distringuish it. EPF can use device::id
to do similar things.

Actually iommu face the similar problem. So far, there are not EP device enable
iommu yet, because it needs special mapping.

Prevously, I consider create dymatic of_node for each EPF and copy iommu/msi
information to each children. But when I see adp5585 case, I think direct
use parent's of_node should be simple and good enough.

In future, I suggest add children dt binding for it. For example: EPF provide
a mailbox interface. how other dts node to refer to this mailbox's phandle?

As I said above, EPFs are not real devices. There is currently only one
exception, MHI, which is backed by a hardware entity. So we cannot add
devicetree nodes for EPF, unless each EPF is a hardware entity.

But how resolve this problem, if a DT device need phandle to a EPF? anyway
this is off topic. let go back this doorbell.

It needs an of_node for EPF device, I tried many method before.

Create dymatic of_node for it? MSI framework still go through to parent
of_node to get such information. not big differnece as my view.

Hi, any idea?  how to move forward? we can dynmatic create of_node for it.

Frank

Frank

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- Mani

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