On Thursday 25 February 2016 13:43:48 Kishon Vijay Abraham I wrote: > Hi Arnd, > > On Wednesday 24 February 2016 02:34 PM, Arnd Bergmann wrote: > > On Wednesday 24 February 2016 11:39:26 Kishon Vijay Abraham I wrote: > >> Hi, > >> > >> On Monday 08 February 2016 05:30 AM, Paul Gortmaker wrote: > >>> In a recent patch series that aimed to remove code related to module > >>> unload for PCI support that was simply non modular, the discussion > >>> led to people wanting to keep the code and push towards taking the > >>> steps needed to support moving it towards tristate instead[1]. > >>> > >>> Here, we take step one, which is simply making the Kconfig change > >>> and then dealing with any build fallout or modpost fallout. What > >>> amounts to essentially a sanity build test. To be clear, these > >>> have not been runtime validated; that will need to be done by those > >>> with access to real hardware. However, the changes are not anything > >>> that should disrupt any existing built-in validation, so real world > >>> users should not be impacted by this change. > >>> > >>> We start with a smaller family of drivers; those that actively select > >>> PCI_DW, as a nice self contained group to test the waters and see if > >>> everyone is still good with this approach before investing more time > >>> on a wider scale to other pci/host/ code blocks. > >>> > >>> As such the drivers here share a dependency on having the same group > >>> of functions exported in order to successfully complete modpost. > >>> > >>> In addition, we have to stray outside drivers/pci to add exports > >>> in two places; once for an ARM fault handler, and once for an OF > >>> variable. > >>> > >>> The pci-keystone-dw.c instance was handled separately because it > >>> consists of two source files that need their own group of driver > >>> specific exports above and beyond the "shared" ones. > >>> > >>> Then we convert the Kconfig for all remaining at once; we could have > >>> done it on a per driver basis for ease of revert if anyone really > >>> objects, but since it would be a one line change, that seemed like > >>> not a real concern. > >>> > >>> Build testing was done on the linux-next tree for arm allmodconfig. > >> > >> I took these patches and gave a test with DRA7xx board. As expected there was > >> no issues when the driver was built-in. However when I tried to rmmod/modprobe > >> I got this error [2]. > > > > Thanks for testing this! > > > >> [2] -> http://pastebin.ubuntu.com/15185894/ > > > > It looks like you are hitting the BUG_ON() in ioremap_pte_range() > > that checks if a virtual address already has a page table entry, > > which in turn is probably a result of dw_pcie_host_init() > > calling pci_remap_iospace() again for the same memory area > > it has called the last time, and no cleanup done inbetween. > > > > Could you try adding a pci_unmap_iospace() and calling that > > in the device remove function? Let me know if you need help > > implementing it. > > That didn't look straight forward to me :-( I'll try to see this next week. Any > help from you will make it simpler for me. I tried writing the function now, and I think it's actually quite easy: void pci_unmap_iospace(const struct resource *res) { #if defined(PCI_IOBASE) && defined(CONFIG_MMU) return iounmap(PCI_IOBASE + res->start); #endif } You just need to pass the same resource in here htat you pass into pci_remap_iospace(). Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
