2015-03-05 9:40 GMT+03:00 Rafał Miłecki <zajec5@xxxxxxxxx>: > On 3 March 2015 at 14:06, Sergey Ryazanov <ryazanov.s.a@xxxxxxxxx> wrote: >> 2015-02-16 10:35 GMT+03:00 Rafał Miłecki <zajec5@xxxxxxxxx>: >>> Once I've hit >>> BUG_ON(in_interrupt()); >>> when hacking PCI drivers locally on MIPS board. I see the problem but >>> don't know the solution. >>> >>> 1) I think "read" and "write" of struct pci_ops should be safe to call >>> in IRQ handler >>> 2) In drivers/bcma/driver_pci_host.c we use ioremap_nocache >>> >>> This causes a problem for boards with 2 PCI(e) cards. The base address >>> for the 2nd card is >>> #define BCMA_SOC_PCI1_CFG 0x44000000U >>> which doesn't allow MIPS to use KSEG1. >>> >>> As the result forwardtrace looks like this: >>> 1) ioremap_nocache >>> 2) __ioremap_mode >>> 3) __ioremap >>> 4) get_vm_area >>> 5) __get_vm_area_node >>> And then we can hit BUG_ON(in_interrupt()); >>> >>> Can you see any solution for this? Currently there isn't any mainline >>> code triggering this problem, but it would be nice to have everything >>> working anyway. >>> >> Why do you need to read the PCI configuration space in the interrupt >> handler? As you wrote, it uncommon that driver tries to do that. >> Usually the PCI configuration read/updated during device >> initialization stage (by the PCI core and by a device driver) and then >> you interact with the I/O memory and not with the configuration space. > > This is what brcmsmac does. I copied this behavior locally to b43 when > debugging some DMA controller problem. > > They do: > request_irq(pdev->irq, brcms_isr, IRQF_SHARED, KBUILD_MODNAME, wl) > > And then the forwardtrace looks like this: > brcms_isr > brcms_c_isr > wlc_intstatus > brcms_deviceremoved > ai_deviceremoved > pci_read_config_dword(sii->pcibus, PCI_VENDOR_ID, &w); > Looks like as some kind of workaround and also marked as cardbus specific in wlc_intstatus(). In any case, Jonas already noted in this thread that this PCI controller driver serves only two devices, so you free to pre-remap I/O mem at the controller initialization stage. -- Sergey
