From: "Z.q. Hou" <zhiqiang.hou@nxp.com>
To: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
"bhelgaas@google.com" <bhelgaas@google.com>
Cc: "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"robh+dt@kernel.org" <robh+dt@kernel.org>,
"mark.rutland@arm.com" <mark.rutland@arm.com>,
"l.subrahmanya@mobiveil.co.in" <l.subrahmanya@mobiveil.co.in>,
"shawnguo@kernel.org" <shawnguo@kernel.org>,
Leo Li <leoyang.li@nxp.com>,
"catalin.marinas@arm.com" <catalin.marinas@arm.com>,
"will.deacon@arm.com" <will.deacon@arm.com>,
Mingkai Hu <mingkai.hu@nxp.com>,
"M.h. Lian" <minghuan.lian@nxp.com>,
Xiaowei Bao <xiaowei.bao@nxp.com>
Subject: RE: [PATCHv5 16/20] PCI: mobiveil: Add link up condition check
Date: Wed, 12 Jun 2019 11:36:45 +0000 [thread overview]
Message-ID: <AM0PR04MB673830A6DF6FEDFC9155037184EC0@AM0PR04MB6738.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <20190611171733.GB22836@redmoon>
Hi Lorenzo,
Thanks a lot for your comments!
> -----Original Message-----
> From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Sent: 2019年6月12日 1:18
> To: Z.q. Hou <zhiqiang.hou@nxp.com>; bhelgaas@google.com
> Cc: linux-pci@vger.kernel.org; linux-arm-kernel@lists.infradead.org;
> devicetree@vger.kernel.org; linux-kernel@vger.kernel.org;
> robh+dt@kernel.org; mark.rutland@arm.com; l.subrahmanya@mobiveil.co.in;
> shawnguo@kernel.org; Leo Li <leoyang.li@nxp.com>;
> catalin.marinas@arm.com; will.deacon@arm.com; Mingkai Hu
> <mingkai.hu@nxp.com>; M.h. Lian <minghuan.lian@nxp.com>; Xiaowei Bao
> <xiaowei.bao@nxp.com>
> Subject: Re: [PATCHv5 16/20] PCI: mobiveil: Add link up condition check
>
> NB: Please trim the CC list and keep it to concerned maintainers.
>
> On Fri, Apr 12, 2019 at 08:36:48AM +0000, Z.q. Hou wrote:
> > From: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
> >
> > Avoid to issue CFG transactions to link partner when the PCIe link is
> > not up.
> >
> > Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
> > ---
> > V5:
> > - Corrected the subject.
> >
> > drivers/pci/controller/pcie-mobiveil.c | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/drivers/pci/controller/pcie-mobiveil.c
> > b/drivers/pci/controller/pcie-mobiveil.c
> > index 621852078caf..1ee3ea2570c0 100644
> > --- a/drivers/pci/controller/pcie-mobiveil.c
> > +++ b/drivers/pci/controller/pcie-mobiveil.c
> > @@ -283,6 +283,10 @@ static bool mobiveil_pcie_valid_device(struct
> > pci_bus *bus, unsigned int devfn) {
> > struct mobiveil_pcie *pcie = bus->sysdata;
> >
> > + /* If there is no link, then there is no device */
> > + if (bus->number > pcie->root_bus_nr && !mobiveil_pcie_link_up(pcie))
>
> I think Bjorn mentioned this a million times already, eg:
>
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.ke
> rnel.org%2Flinux-pci%2F20190411201535.GS256045%40google.com%2F&am
> p;data=02%7C01%7Czhiqiang.hou%40nxp.com%7Cffb4c8dcebe4493a375908
> d6ee90b471%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C63695
> 8702637973543&sdata=m%2FqV5zohqyBMUDT7zrVjF%2FLtYeJZO36rdY
> eMTPGGbHg%3D&reserved=0
>
> this is racy and gives a false sense of robustness. We have code in the kernel
> that checks the link but adding more seems silly to me, so I am inclined to
> drop this patch.
>
Understand, drop it.
Thanks,
Zhiqiang
> Lorenzo
>
> > + return false;
> > +
> > /* Only one device down on each root port */
> > if ((bus->number == pcie->root_bus_nr) && (devfn > 0))
> > return false;
> > --
> > 2.17.1
> >
next prev parent reply other threads:[~2019-06-12 11:36 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-12 8:35 [PATCHv5 00/20] PCI: mobiveil: fixes for Mobiveil PCIe Host Bridge IP driver Z.q. Hou
2019-04-12 8:35 ` [PATCHv5 01/20] PCI: mobiveil: Unify register accessors Z.q. Hou
2019-04-12 8:35 ` [PATCHv5 02/20] PCI: mobiveil: Format the code without functionality change Z.q. Hou
2019-07-03 15:10 ` Lorenzo Pieralisi
2019-07-04 2:41 ` Z.q. Hou
2019-07-03 15:19 ` Lorenzo Pieralisi
2019-07-03 15:24 ` Lorenzo Pieralisi
2019-07-04 3:00 ` Z.q. Hou
2019-07-04 10:56 ` Lorenzo Pieralisi
2019-07-05 2:24 ` Z.q. Hou
2019-04-12 8:35 ` [PATCHv5 03/20] PCI: mobiveil: Correct the returned error number Z.q. Hou
2019-07-03 14:17 ` Lorenzo Pieralisi
2019-07-04 2:38 ` Z.q. Hou
2019-04-12 8:35 ` [PATCHv5 04/20] PCI: mobiveil: Remove the flag MSI_FLAG_MULTI_PCI_MSI Z.q. Hou
2019-06-11 16:59 ` Lorenzo Pieralisi
2019-06-11 17:29 ` Marc Zyngier
2019-06-12 10:54 ` Lorenzo Pieralisi
2019-06-12 11:22 ` Marc Zyngier
2019-06-12 11:34 ` Z.q. Hou
2019-06-12 13:08 ` Lorenzo Pieralisi
2019-06-15 1:30 ` Z.q. Hou
2019-06-17 9:33 ` Lorenzo Pieralisi
2019-06-17 10:34 ` Z.q. Hou
2019-06-28 11:35 ` Lorenzo Pieralisi
2019-07-01 10:07 ` Z.q. Hou
2019-04-12 8:35 ` [PATCHv5 05/20] PCI: mobiveil: Correct PCI base address in MEM/IO outbound windows Z.q. Hou
2019-04-12 8:35 ` [PATCHv5 06/20] PCI: mobiveil: Replace the resource list iteration function Z.q. Hou
2019-04-12 8:35 ` [PATCHv5 07/20] PCI: mobiveil: Use WIN_NUM_0 explicitly for CFG outbound window Z.q. Hou
2019-06-12 15:13 ` Lorenzo Pieralisi
2019-04-12 8:36 ` [PATCHv5 08/20] PCI: mobiveil: Use the 1st inbound window for MEM inbound transactions Z.q. Hou
2019-06-28 16:02 ` Lorenzo Pieralisi
2019-07-01 10:18 ` Z.q. Hou
2019-04-12 8:36 ` [PATCHv5 09/20] PCI: mobiveil: Correct inbound/outbound window setup routines Z.q. Hou
2019-06-28 16:41 ` Lorenzo Pieralisi
2019-07-01 10:24 ` Z.q. Hou
2019-04-12 8:36 ` [PATCHv5 10/20] PCI: mobiveil: Fix the INTx process errors Z.q. Hou
2019-06-12 15:08 ` Lorenzo Pieralisi
2019-06-14 7:08 ` Karthikeyan Mitran
2019-06-14 10:43 ` Lorenzo Pieralisi
2019-06-19 5:28 ` Karthikeyan Mitran
2019-06-19 7:24 ` Z.q. Hou
2019-06-28 17:05 ` Lorenzo Pieralisi
2019-07-01 10:27 ` Z.q. Hou
2019-04-12 8:36 ` [PATCHv5 11/20] PCI: mobiveil: Correct the fixup of Class Code field Z.q. Hou
2019-04-12 8:36 ` [PATCHv5 12/20] PCI: mobiveil: Move the link up waiting out of mobiveil_host_init() Z.q. Hou
2019-04-12 8:36 ` [PATCHv5 13/20] PCI: mobiveil: Move IRQ chained handler setup out of DT parse Z.q. Hou
2019-04-12 8:36 ` [PATCHv5 14/20] PCI: mobiveil: Initialize Primary/Secondary/Subordinate bus numbers Z.q. Hou
2019-04-12 8:36 ` [PATCHv5 15/20] PCI: mobiveil: Fix the checking of valid device Z.q. Hou
2019-04-12 8:36 ` [PATCHv5 16/20] PCI: mobiveil: Add link up condition check Z.q. Hou
2019-06-11 17:17 ` Lorenzo Pieralisi
2019-06-12 11:36 ` Z.q. Hou [this message]
2019-04-12 8:36 ` [PATCHv5 17/20] PCI: mobiveil: Complete initialization of host even if no PCIe link Z.q. Hou
2019-06-12 14:34 ` Lorenzo Pieralisi
2019-06-15 2:34 ` Z.q. Hou
2019-04-12 8:37 ` [PATCHv5 18/20] PCI: mobiveil: Disable IB and OB windows set by bootloader Z.q. Hou
2019-06-12 16:23 ` Lorenzo Pieralisi
2019-06-15 5:03 ` Z.q. Hou
2019-06-17 9:30 ` Lorenzo Pieralisi
2019-06-17 10:42 ` Z.q. Hou
2019-04-12 8:37 ` [PATCHv5 19/20] PCI: mobiveil: Add 8-bit and 16-bit register accessors Z.q. Hou
2019-06-12 13:54 ` Lorenzo Pieralisi
2019-06-15 1:13 ` Z.q. Hou
2019-06-17 9:29 ` Lorenzo Pieralisi
2019-06-17 10:16 ` Z.q. Hou
2019-04-12 8:37 ` [PATCHv5 20/20] dt-bindings: PCI: mobiveil: Change gpio_slave and apb_csr to optional Z.q. Hou
2019-07-03 10:33 ` [PATCHv5 00/20] PCI: mobiveil: fixes for Mobiveil PCIe Host Bridge IP driver Lorenzo Pieralisi
2019-07-04 2:36 ` Z.q. Hou
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