Linux-PCI Archive on lore.kernel.org
 help / color / Atom feed
From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
To: "Z.q. Hou" <zhiqiang.hou@nxp.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: Tue, 11 Jun 2019 18:17:33 +0100
Message-ID: <20190611171733.GB22836@redmoon> (raw)
In-Reply-To: <20190412083635.33626-17-Zhiqiang.Hou@nxp.com>

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://lore.kernel.org/linux-pci/20190411201535.GS256045@google.com/

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.

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
> 

  reply index

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 [this message]
2019-06-12 11:36     ` Z.q. Hou
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

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190611171733.GB22836@redmoon \
    --to=lorenzo.pieralisi@arm.com \
    --cc=bhelgaas@google.com \
    --cc=catalin.marinas@arm.com \
    --cc=devicetree@vger.kernel.org \
    --cc=l.subrahmanya@mobiveil.co.in \
    --cc=leoyang.li@nxp.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pci@vger.kernel.org \
    --cc=mark.rutland@arm.com \
    --cc=minghuan.lian@nxp.com \
    --cc=mingkai.hu@nxp.com \
    --cc=robh+dt@kernel.org \
    --cc=shawnguo@kernel.org \
    --cc=will.deacon@arm.com \
    --cc=xiaowei.bao@nxp.com \
    --cc=zhiqiang.hou@nxp.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-PCI Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-pci/0 linux-pci/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-pci linux-pci/ https://lore.kernel.org/linux-pci \
		linux-pci@vger.kernel.org linux-pci@archiver.kernel.org
	public-inbox-index linux-pci


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-pci


AGPL code for this site: git clone https://public-inbox.org/ public-inbox