On 4/15/2020 7:04 PM, Lorenzo Pieralisi wrote: > On Wed, Apr 15, 2020 at 06:44:37PM +0300, Laurentiu Tudor wrote: >> >> >> On 4/14/2020 5:32 PM, Lorenzo Pieralisi wrote: >>> On Wed, Mar 25, 2020 at 06:48:55PM +0200, Laurentiu Tudor wrote: >>>> Hi Lorenzo, >>>> >>>> On 3/25/2020 2:51 PM, Lorenzo Pieralisi wrote: >>>>> On Thu, Feb 27, 2020 at 12:05:39PM +0200, laurentiu.tudor@xxxxxxx wrote: >>>>>> From: Laurentiu Tudor <laurentiu.tudor@xxxxxxx> >>>>>> >>>>>> The devices on this bus are not discovered by way of device tree >>>>>> but by queries to the firmware. It makes little sense to trick the >>>>>> generic of layer into thinking that these devices are of related so >>>>>> that we can get our dma configuration. Instead of doing that, add >>>>>> our custom dma configuration implementation. >>>>>> >>>>>> Signed-off-by: Laurentiu Tudor <laurentiu.tudor@xxxxxxx> >>>>>> --- >>>>>> drivers/bus/fsl-mc/fsl-mc-bus.c | 31 ++++++++++++++++++++++++++++++- >>>>>> 1 file changed, 30 insertions(+), 1 deletion(-) >>>>>> >>>>>> diff --git a/drivers/bus/fsl-mc/fsl-mc-bus.c b/drivers/bus/fsl-mc/fsl-mc-bus.c >>>>>> index 36eb25f82c8e..eafaa0e0b906 100644 >>>>>> --- a/drivers/bus/fsl-mc/fsl-mc-bus.c >>>>>> +++ b/drivers/bus/fsl-mc/fsl-mc-bus.c >>>>>> @@ -132,11 +132,40 @@ static int fsl_mc_bus_uevent(struct device *dev, struct kobj_uevent_env *env) >>>>>> static int fsl_mc_dma_configure(struct device *dev) >>>>>> { >>>>>> struct device *dma_dev = dev; >>>>>> + struct iommu_fwspec *fwspec; >>>>>> + const struct iommu_ops *iommu_ops; >>>>>> + struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev); >>>>>> + int ret; >>>>>> + u32 icid; >>>>>> >>>>>> while (dev_is_fsl_mc(dma_dev)) >>>>>> dma_dev = dma_dev->parent; >>>>>> >>>>>> - return of_dma_configure(dev, dma_dev->of_node, 0); >>>>>> + fwspec = dev_iommu_fwspec_get(dma_dev); >>>>>> + if (!fwspec) >>>>>> + return -ENODEV; >>>>>> + iommu_ops = iommu_ops_from_fwnode(fwspec->iommu_fwnode); >>>>>> + if (!iommu_ops) >>>>>> + return -ENODEV; >>>>>> + >>>>>> + ret = iommu_fwspec_init(dev, fwspec->iommu_fwnode, iommu_ops); >>>>>> + if (ret) >>>>>> + return ret; >>>>>> + >>>>>> + icid = mc_dev->icid; >>>>>> + ret = iommu_fwspec_add_ids(dev, &icid, 1); >>>>> >>>>> I see. So with this patch we would use the MC named component only to >>>>> retrieve the iommu_ops >>>> >>>> Right. I'd also add that the implementation tries to follow the existing >>>> standard .dma_configure implementations, e.g. of_dma_configure + >>>> of_iommu_configure. I'd also note that similarly to the ACPI case, this >>>> MC FW device is probed as a platform device in the DT scenario, binding >>>> here [1]. >>>> A similar approach is used for the retrieval of the msi irq domain, see >>>> following patch. >>>> >>>>> - the streamid are injected directly here bypassing OF/IORT bindings translations altogether. >>>> >>>> Actually I've submitted a v2 [2] that calls into .of_xlate() to allow >>>> the smmu driver to do some processing on the raw streamid coming from >>>> the firmware. I have not yet tested this with ACPI but expect it to >>>> work, however, it's debatable how valid is this approach in the context >>>> of ACPI. >>> >>> Actually, what I think you need is of_map_rid() (and an IORT >>> equivalent, that I am going to write - generalizing iort_msi_map_rid()). >>> >>> Would that be enough to enable IORT "normal" mappings in the MC bus >>> named components ? >>> >> >> At a first glance, looks like this could very well fix the ACPI >> scenario, but I have some unclarities on the approach: >> * are we going to rely in DT and ACPI generic layers even if these >> devices are not published / enumerated through DT or ACPI tables? >> * the firmware manages and provides discrete streamids for the devices >> it exposes so there's no translation involved. There's no >> requestor_id / input_id involved but it seems that we would still do >> some kind of translation relying for this on the DT/ACPI functions. >> * MC firmware has its own stream_id (e.g. on some chips 0x4000, others >> 0xf00, so outside the range of stream_ids used for the mc devices) >> while for the devices on this bus, MC allocates stream_ids from a >> range (e.g. 0x17 - 0x3f). Is it possible to describe this in the IORT table? >> * Regarding the of_map_rid() use you mentioned, I was planning to >> decouple the mc bus from the DT layer by dropping the use of >> of_map_rid(), see patch 4. >> I briefly glanced over the iort code and spotted this static function: >> iort_iommu_xlate(). Wouldn't it also help, of course after making it public? > > Guys I have lost you honestly. I don't understand what you really need > to do with DT and ACPI here. Are they needed to describe what you need > or not ? If the MC dma configure function does not need any DT/ACPI > bindings that's fine by me, I don't understand though why you are still > asking how to represent MC in ACPI then, what for. > Sorry for the stress and all this back and forth. Perhaps it's due to my lack of understanding why we would need this translation complexity. We'll return with a proposal in the next spin of the patches so we have something concrete to discuss on. --- Thanks & Best Regards, Laurentiu