> -----Original Message----- > From: Arnd Bergmann [mailto:a...@arndb.de] > Sent: Tuesday, October 13, 2015 12:19 PM > To: Gabriele Paoloni > Cc: Wangzhou (B); Bjorn Helgaas; Bjorn Helgaas; jingooh...@gmail.com; > pratyush.an...@gmail.com; li...@arm.linux.org.uk; > thomas.petazz...@free-electrons.com; lorenzo.pieral...@arm.com; > james.mo...@arm.com; liviu.du...@arm.com; ja...@lakedaemon.net; > r...@kernel.org; gabriel.fernan...@linaro.org; > minghuan.l...@freescale.com; linux-...@vger.kernel.org; linux-arm- > ker...@lists.infradead.org; devicet...@vger.kernel.org; linux- > ker...@vger.kernel.org; zhangjukuo; qiuzhenfa; liudongdong (C); > qiujiang; xuwei (O); Liguozhu (Kenneth); Wangkefeng (Kevin); Rob > Herring > Subject: Re: [PATCH v10 4/6] PCI: hisi: Add PCIe host support for > HiSilicon SoC Hip05 > > On Tuesday 13 October 2015 06:58:42 Gabriele Paoloni wrote: > > > > > >> + > > > >> +static int __init hisi_pcie_init(void) > > > >> +{ > > > >> + return platform_driver_probe(&hisi_pcie_driver, > hisi_pcie_probe); > > > >> +} > > > >> +subsys_initcall(hisi_pcie_init); > > > > > > > > Can you use module_platform_driver() or > module_platform_driver_probe() > > > > here instead of the subsys_initcall()? No, I don't really know > what > > > > the difference between module_platform_driver() and > > > > module_platform_driver_probe() is, sorry :) > > module_platform_driver_probe() will only call the probe function once > (and fail in case of -EPROBE_DEFER), while module_platform_driver() > installs the platform driver in a way that the device can be bound > and unbound at any point. > > > > In fact, I used module_platform_driver_probe in previous version, > but > > > A PCIe VGA card of HiSilicon will use Hip05 PCIe host, so we > modified > > > module_platform_driver_probe to subsys_initcall which will be > called > > > before module_platform_driver_probe. > > > > > > We will upstream the driver of above PCIe VGA card soon. > > I don't see a reason why a VGA driver would need the PCI host to be > probed this early, unless it is the only usable console in the system. > > > Hi Bjorn, firstly many thanks for looking at this. > > > > About this last bit the reason why we use subsys_initcall() is that > > our host bridge is embedded in the SoC and as such is not hot- > pluggable > > for instance see: > > http://lxr.free-electrons.com/source/Documentation/driver- > model/platform.txt#L59 > > We should still be able to build the driver as a loadable module, > even if you don't do that on your own kernels.
Hi Arnd, I don't see the point of having loadable KOs for platform devices that are integrated into SoCs (like PCIe Host Controllers...) > > This doesn't mean that it has to be module_platform_driver, > subsys_initcall > will also work in a loadable module, it just won't be as early. However, > we should try to come up with a consistent approach for all PCI host > drivers, > I don't see any reason for hisi to be different from the others here. To me it sounds more appropriate to adopt subsys_initcall() for all the PCI Host Bridge controllers rather than having them as loadable modules... What is your view? Thanks Gab > > > Our approach is also used by Exynos: > > http://lxr.free-electrons.com/source/drivers/pci/host/pci- > exynos.c#L644 > > Maybe we should change that too. > > Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
