Hi Marc, Please see my comments inline > -----Original Message----- > From: Marc Zyngier [mailto:marc.zyngier@xxxxxxx] > Sent: Thursday, April 16, 2015 12:37 AM > To: Lian Minghuan-B31939 > Cc: linux-pci@xxxxxxxxxxxxxxx; Arnd Bergmann; Hu Mingkai-B21284; Zang > Roy-R61911; Yoder Stuart-B08248; Bjorn Helgaas; Wood Scott-B07421; linux- > arm-kernel@xxxxxxxxxxxxxxxxxxx; Jason Cooper; Thomas Gleixner > Subject: Re: [PATCH 1/2] irqchip/gicv3-its: Support share device ID > > On Wed, 15 Apr 2015 17:49:23 +0800 > Minghuan Lian <Minghuan.Lian@xxxxxxxxxxxxx> wrote: > > > SMMU of some platforms can only isolate limited device ID. > > This may require that all PCI devices share the same ITS device with > > the fixed device ID. The patch adds function > > arch_msi_share_devid_update used for these platforms to update the > > fixed device ID and maximum MSI interrupts number. > > > > Signed-off-by: Minghuan Lian <Minghuan.Lian@xxxxxxxxxxxxx> > > --- > > drivers/irqchip/irq-gic-v3-its.c | 11 +++++++++++ > > 1 file changed, 11 insertions(+) > > > > diff --git a/drivers/irqchip/irq-gic-v3-its.c > > b/drivers/irqchip/irq-gic-v3-its.c > > index d0374a6..be78d0a 100644 > > --- a/drivers/irqchip/irq-gic-v3-its.c > > +++ b/drivers/irqchip/irq-gic-v3-its.c > > @@ -1169,6 +1169,15 @@ static int its_get_pci_alias(struct pci_dev *pdev, > u16 alias, void *data) > > return 0; > > } > > > > +void __weak > > +arch_msi_share_devid_update(struct pci_dev *pdev, u32 *dev_id, u32 > > +*nvesc) { > > + /* > > + * use PCI_DEVID NOT share device ID as default > > + * so nothing need to do > > + */ > > +} > > + > > NAK. On top of being ugly as sin, this breaks any form of multiplatform > support. No way anything like this is going in. Guys, you really should know > better. > [Minghuan] The current ITS MSI will create an individual ITS device for each PCIe device, and use PCI_DEVID as ITS dev_id However, out platform only supports ITS dev_id 0 -63. A normal PCIe DEVID of 0000:01:00.0 is 256 bigger than 63. Besides, because of the limited dev_id number, all the PCIe device will share the same ITS dev. Our platform provides a hardware module LUT to map PCI DEVID to ITS dev_id. So, when creating ITS device, we need to update dev_id and the nvesc. I may change pci_for_each_dma_alias to add a new flag to use alias_bus and alias_devfn. But I also need to update nvesc which should contains all the PCI device MSI/MSIX nvesc and PCIe PME, aerdrv interrupts. The main difference is that we need a ITS device to service multiple PCIe devices. Could you give me some suggestions how to implement this requirement. > > static int its_msi_prepare(struct irq_domain *domain, struct device *dev, > > int nvec, msi_alloc_info_t *info) { @@ -1185,6 > +1194,8 @@ > > static int its_msi_prepare(struct irq_domain *domain, struct device *dev, > > dev_alias.count = nvec; > > > > pci_for_each_dma_alias(pdev, its_get_pci_alias, &dev_alias); > > + arch_msi_share_devid_update(pdev, &dev_alias.dev_id, > > +&dev_alias.count); > > + > > See the function above? That's where the aliasing should be taken care of. > [Minghuan] The alias will use dma_alias_devfn, but it does not contains alias_bus. I need to translate PCI_DEVID to a fixed ID. > > its = domain->parent->host_data; > > > > its_dev = its_find_device(its, dev_alias.dev_id); > > Thanks, > > M. > -- > Jazz is not dead. It just smells funny. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
