Messages in this thread | | | Date | Thu, 7 Apr 2016 16:34:43 +0800 | From | Jisheng Zhang <> | Subject | Re: [PATCH v2] PCI: designware: move remaining rc setup code to dw_pcie_setup_rc() |
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Hi Gabriele,
On Thu, 7 Apr 2016 08:20:28 +0000 Gabriele Paoloni wrote:
> Hi Jisheng > > Thanks for your reply > > > -----Original Message----- > > From: Jisheng Zhang [mailto:jszhang@marvell.com] > > Sent: 07 April 2016 03:38 > > To: Gabriele Paoloni; jingoohan1@gmail.com; pratyush.anand@gmail.com; > > bhelgaas@google.com > > Cc: linux-pci@vger.kernel.org; linux-kernel@vger.kernel.org; linux-arm- > > kernel@lists.infradead.org > > Subject: Re: [PATCH v2] PCI: designware: move remaining rc setup code > > to dw_pcie_setup_rc() > > > > Hi Gabriele, > > > > On Wed, 6 Apr 2016 14:50:29 +0000 Gabriele Paoloni wrote: > > > > > Hi, sorry to be late on this > > > > > > > -----Original Message----- > > > > From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel- > > > > owner@vger.kernel.org] On Behalf Of Jisheng Zhang > > > > Sent: 16 March 2016 11:41 > > > > To: jingoohan1@gmail.com; pratyush.anand@gmail.com; > > bhelgaas@google.com > > > > Cc: linux-pci@vger.kernel.org; linux-kernel@vger.kernel.org; linux- > > arm- > > > > kernel@lists.infradead.org; Jisheng Zhang > > > > Subject: [PATCH v2] PCI: designware: move remaining rc setup code > > to > > > > dw_pcie_setup_rc() > > > > > > > > dw_pcie_setup_rc(), as its name indicates, setups the RC. But > > current > > > > dw_pcie_host_init() also contains some necessary rc setup code. > > > > > > > > Another reason: the host may lost power during suspend to ram, the > > RC > > > > need to be re-setup after resume. The rc can't be correctly resumed > > > > without the rc setup code in dw_pcie_host_init(). > > > > > > > > So this patch moves the code to dw_pcie_setup_rc() to address the > > above > > > > two issues. After this patch, each pcie designware driver users > > could > > > > call dw_pcie_setup_rc() to re-setup rc when resume back. > > > > > > I think this patch breaks the Hisilicon driver... > > > > > > Our driver performs linkup setup in UEFI therefore we do not call > > > dw_pcie_setup_rc(), we only call dw_pcie_host_init(). > > > > Thanks for the information. So pcie-hisi rely on UEFI to do something > > similar > > in dw_pcie_setup_rc(), this comes to a common driver implement > > question: should > > linux device driver rely on bootloader to configure HW device? > > I don't see any issue with this... > > > > > Is it acceptable that pcie-hisi adds a call to dw_pcie_setup_rc() in > > hisi_add_pcie_port()? > > I don't think so...that would try to overwrite what is already set by > the bootloader; so it is wrong in principle and maybe it can lead to > undefined behaviours...
make sense! This commit is intend to re-setup the rc when waken from s2ram (in s2ram state, the host lost power)
I have no good solution but to introduce one function e.g dw_pcie_setup_rc_after_linkup(), then move related code from dw_pcie_host_init to it, then let my host driver resume hook to call.
Hi Pratyush, Jingoo and Bjorn etc.
any suggestions are appreciated!
Thanks, Jisheng
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