Hi Lorenzo, On Fri, 28 Sep 2018 12:06:40 +0100 <lorenzo.pieralisi@xxxxxxx> wrote: > [+Murali, Marc] > > On Thu, Sep 27, 2018 at 04:44:26PM +0900, Kunihiko Hayashi wrote: > > Hi Lorenzo, Gustavo, > > > > On Wed, 26 Sep 2018 21:31:36 +0900 <hayashi.kunihiko@xxxxxxxxxxxxx> wrote: > > > > > Hi Lorenzo, Gustavo, > > > > > > Thank you for reviewing. > > > > > > On Tue, 25 Sep 2018 18:53:01 +0100 > > > Gustavo Pimentel <gustavo.pimentel@xxxxxxxxxxxx> wrote: > > > > > > > On 25/09/2018 17:14, Lorenzo Pieralisi wrote: > > > > > [+Gustavo, please have a look at INTX/MSI management] > > > > > > > > > > On Thu, Sep 06, 2018 at 06:40:32PM +0900, Kunihiko Hayashi wrote: > > > > >> This introduces specific glue layer for UniPhier platform to support > > > > >> PCIe host controller that is based on the DesignWare PCIe core, and > > > > >> this driver supports Root Complex (host) mode. > > > > > > > > > > Please read this thread and apply it to next versions: > > > > > > > > > > https://urldefense.proofpoint.com/v2/url?u=https-3A__marc.info_-3Fl-3Dlinux-2Dpci-26m-3D150905742808166-26w-3D2&d=DwIBAg&c=DPL6_X_6JkXFx7AXWqB0tg&r=bkWxpLoW-f-E3EdiDCCa0_h0PicsViasSlvIpzZvPxs&m=H8UNDDUGQnQnqfWr4CBios689dJcjxu4qeTTRGulLmU&s=CgcXc_2LThyOpW-4bCriJNo9H1lzROEdy_cG9p-Y5hU&e= > > > > > > I also found this thread in previous linux-pci, and I think it's helpful for me. > > > I'll check it carefully. > > > > [snip] > > > > > > >> + ret = devm_request_irq(dev, pp->irq, uniphier_pcie_irq_handler, > > > > >> + IRQF_SHARED, "pcie", priv); > > > > > > > > > > This is wrong, you should set-up a chained IRQ for INTX. > > > > > > > > > > I *think* that > > > > > > > > > > ks_pcie_setup_interrupts() > > > > > > > > > > is a good example to start with but I wonder whether it is worth > > > > > generalizing the INTX approach to designware as a whole as it was > > > > > done for MSIs. > > > > > > > > > > Thoughts ? > > > > > > > > From what I understood this is for legacy IRQ, right? > > > > > > Yes. For legacy IRQ. > > > > > > > Like you (Lorenzo) said there is 2 drivers (pci-keystone-dw.c and pci-dra7xx.c) > > > > that uses it and can be use as a template for handling this type of interrupts. > > > > > > > > We can try to pass some kind of generic INTX function to the DesignWare host > > > > library to handling this, but this will require some help from keystone and > > > > dra7xx maintainers, since my setup doesn't have legacy IRQ HW support. > > > > > > Now I think it's difficult to make a template for INTX function, > > > and at first, I'll try to re-write this part with reference to pci-keystone-dw.c. > > > > I understand that there are 2 types of interrupt and the drivers. > > > > One like pci-keystone-dw.c is: > > > > - there are 4 interrupts for legacy, > > - invoke handlers for each interrupt, and handle the interrupt, > > - call irq_set_chained_handler_and_data() to make a chain of the interrupts > > when initializing > > > > The other like pci-dra7xx.c is: > > > > - there is 1 IRQ for legacy as a parent, > > - check an interrupt factor register, and handle the interrupt correspond > > to the factor, > > - call request_irq() for the parent IRQ and irq_domain_add_linear() for > > the factor when initializing > > > > The pcie-uniphier.c is the same type as the latter (like pci-dra7xx.c). > > > > However, in pci-dra7xx.c, MSI and legacy IRQ share the same interrupt number, > > so the same handler is called and the handler divides these IRQs. > > (found in dra7xx_pcie_msi_irq_handler()) > > > > In pcie-uniphier.c, MSI and legacy IRQ are independent. > > Therefore it's necessary to prepare the handler for the legacy IRQ. > > > > I think that it's difficult to apply the way of pci-keystone-dw.c, and > > uniphier_pcie_irq_handler() and calling devm_request_irq() are still > > necessary to handle legacy IRQ. > > I do not think it is difficult, the difference is that keystone has > 1 GIC irq line allocated per legacy IRQ, your set-up has one for > all INTX. I read other drivers to handle INTX like pcie-mediatek.c, pcie-altera.c, and so forth, and understood the common way to rewrite it with chained IRQ. Using irq_set_chained_handler_and_data() instead of devm_request_irq() and adding chained_irq_{enter, exit}() to the handler can allow INTX to handle chained IRQ. Now I can rewrite INTX part with the above way in v3, though, I'm not sure whether there is a way to generalize INTX of all dwc drivers, because of the followings: - the handler needs to read SoC-dependent register to check which an IRQ line of {0,1,2,3}, - domain_ops functions are different for each driver (using handle_simple_irq or handle_level_irq, etc.) - the way to get child interrupt-controller node might be different. Anyway I think we need to leave these topics until clarifying keystone's linear irq topic. --- Best Regards, Kunihiko Hayashi
