On Thu, Jun 08, 2017 at 09:09:28AM +0000, Shameerali Kolothum Thodi wrote: > > > > -----Original Message----- > > From: Lorenzo Pieralisi [mailto:lorenzo.pieralisi@xxxxxxx] > > Sent: Thursday, June 08, 2017 9:49 AM > > To: Shameerali Kolothum Thodi > > Cc: marc.zyngier@xxxxxxx; sudeep.holla@xxxxxxx; will.deacon@xxxxxxx; > > robin.murphy@xxxxxxx; hanjun.guo@xxxxxxxxxx; Gabriele Paoloni; John > > Garry; iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; linux-arm- > > kernel@xxxxxxxxxxxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; devel@xxxxxxxxxx; > > Linuxarm; Wangzhou (B); Guohanjun (Hanjun Guo) > > Subject: Re: [RFCv2 2/2] iommu/arm-smmu-v3:Enable ACPI based HiSilicon > > erratum 161010801 > > > > On Tue, Jun 06, 2017 at 03:01:36PM +0000, Shameerali Kolothum Thodi > > wrote: > > > > [...] > > > > > > > + irq_dom = pci_msi_get_device_domain(to_pci_dev(dev)); > > > > > + if (irq_dom) { > > > > > + int ret; > > > > > + u32 rid; > > > > > + > > > > > + rid = pci_msi_domain_get_msi_rid(irq_dom, > > > > to_pci_dev(dev)); > > > > > + ret = iort_dev_find_its_base(dev, rid, 0, &base); > > > > > > > > Well, here we use ITS id 0 which is fine as long as code in IORT > > > > uses the same policy for getting the irq_domain (ie we want to > > > > reserve the ITS address space that is actually used by the device to > > > > send IRQs not a a different one) it is just a heads-up because I find this > > confusing. > > > > > > Ok. Just to make it clear, 0 is the index into the ITS identifier > > > list. I noted that iort_get_device_domain() uses index 0 while > > > retrieving the ITS identifier. May be use the same approach here as > > > well? ie, remove the index from function call? > > > > > > I am not sure, how we can get the index info though theoretically It > > > is possible for the ITS group node having multiple ITSs. > > > > Actually I think it would make sense to reserve ALL ITS regions a device may > > be mapped to instead of just index 0 (ie in your case it is equivalent); this > > leaves us some leeway as to choose which ITS the device will be actually > > mapped to and this code does not have to care. > > Ok. That make sense. Just a quick one, is it ok to add another helper function in > iort code to retrieve the its->its_count then? While at it, given that the pci API code to retrieve domain and rid falls back to IORT anyway, I would add the whole reservation to IORT (mind, it depends on IOMMU_API) as one function instead of fiddling about with indexes. Side note: why Hilisicon dts upstream (eg hip07.dtsi) report ITS size as 256K ? I was just checking whether the ITS reg map size is system dependent and I bumped into them, I suspect there may be some dts patching needed here. Lorenzo -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
