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From: Bjorn Helgaas <helgaas@kernel.org>
To: marek.vasut@gmail.com
Cc: linux-pci@vger.kernel.org,
	Kazufumi Ikeda <kaz-ikeda@xc.jp.nec.com>,
	Gaku Inami <gaku.inami.xw@bp.renesas.com>,
	Marek Vasut <marek.vasut+renesas@gmail.com>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Phil Edworthy <phil.edworthy@renesas.com>,
	Simon Horman <horms+renesas@verge.net.au>,
	Wolfram Sang <wsa@the-dreams.de>,
	linux-renesas-soc@vger.kernel.org
Subject: Re: [PATCH V2] PCI: rcar: Add the initialization of PCIe link in resume_noirq
Date: Thu, 7 Mar 2019 14:50:13 -0600
Message-ID: <20190307205013.GA208051@google.com> (raw)
In-Reply-To: <20190217132441.15139-1-marek.vasut@gmail.com>

On Sun, Feb 17, 2019 at 02:24:41PM +0100, marek.vasut@gmail.com wrote:
> From: Kazufumi Ikeda <kaz-ikeda@xc.jp.nec.com>
> 
> Reestablish the PCIe link very early in the resume process in case it
> went down to prevent PCI accesses from hanging the bus. Such accesses
> can happen early in the PCI resume process, in the resume_noirq, thus
> the link must be reestablished in the resume_noirq callback of the
> driver.
> 
> Signed-off-by: Kazufumi Ikeda <kaz-ikeda@xc.jp.nec.com>
> Signed-off-by: Gaku Inami <gaku.inami.xw@bp.renesas.com>
> Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
> Cc: Geert Uytterhoeven <geert+renesas@glider.be>
> Cc: Phil Edworthy <phil.edworthy@renesas.com>
> Cc: Simon Horman <horms+renesas@verge.net.au>
> Cc: Wolfram Sang <wsa@the-dreams.de>
> Cc: linux-renesas-soc@vger.kernel.org
> ---
> V2: - Use BIT() macro for (1 << n)
>     - Since polling in rcar_pcie_wait_for_dl() uses udelay(), do not
>       add extra changes to this function anymore
>     - Make resume_noirq return early and clean up parenthesis therein
> ---
>  drivers/pci/controller/pcie-rcar.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/drivers/pci/controller/pcie-rcar.c b/drivers/pci/controller/pcie-rcar.c
> index c8febb009454..b8f8fb3bc640 100644
> --- a/drivers/pci/controller/pcie-rcar.c
> +++ b/drivers/pci/controller/pcie-rcar.c
> @@ -46,6 +46,7 @@
>  
>  /* Transfer control */
>  #define PCIETCTLR		0x02000
> +#define  DL_DOWN		BIT(3)
>  #define  CFINIT			1

I saw discussion after the V1 patch about using BIT() and making
similar constants also use BIT() for consistency.  That makes sense to
me, and I think the best way would be:

  1) in *this* patch, use "#define DL_DOWN 8"
  2) in a followup patch, convert them all to BIT()

That way each revision of pcie-rcar.c is self-consistent.

>  #define PCIETSTR		0x02004
>  #define  DATA_LINK_ACTIVE	1
> @@ -1130,6 +1131,7 @@ static int rcar_pcie_probe(struct platform_device *pdev)
>  	pcie = pci_host_bridge_priv(bridge);
>  
>  	pcie->dev = dev;
> +	platform_set_drvdata(pdev, pcie);
>  
>  	err = pci_parse_request_of_pci_ranges(dev, &pcie->resources, NULL);
>  	if (err)
> @@ -1221,10 +1223,28 @@ static int rcar_pcie_probe(struct platform_device *pdev)
>  	return err;
>  }
>  
> +static int rcar_pcie_resume_noirq(struct device *dev)
> +{
> +	struct rcar_pcie *pcie = dev_get_drvdata(dev);
> +
> +	if (rcar_pci_read_reg(pcie, PMSR) &&
> +	    !(rcar_pci_read_reg(pcie, PCIETCTLR) & DL_DOWN))
> +		return 0;
> +
> +	/* Re-establish the PCIe link */
> +	rcar_pci_write_reg(pcie, CFINIT, PCIETCTLR);
> +	return rcar_pcie_wait_for_dl(pcie);
> +}
> +
> +static const struct dev_pm_ops rcar_pcie_pm_ops = {
> +	.resume_noirq = rcar_pcie_resume_noirq,
> +};

I think there's the beginning of a convention to use #ifdef
CONFIG_PM_SLEEP around the ops themselves [1].  Otherwise I think
we'll get a warning about unused code when CONFIG_PM_SLEEP is unset.

>  static struct platform_driver rcar_pcie_driver = {
>  	.driver = {
>  		.name = "rcar-pcie",
>  		.of_match_table = rcar_pcie_of_match,
> +		.pm = &rcar_pcie_pm_ops,
>  		.suppress_bind_attrs = true,
>  	},
>  	.probe = rcar_pcie_probe,
> -- 
> 2.19.2
> 

[1] https://lore.kernel.org/linux-pci/20180531042020.GQ39853@bhelgaas-glaptop.roam.corp.google.com

  parent reply index

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-17 13:24 marek.vasut
2019-02-19 17:24 ` Wolfram Sang
2019-02-25  9:58   ` Simon Horman
2019-03-07 20:50 ` Bjorn Helgaas [this message]
2019-03-07 22:49   ` Marek Vasut
2019-03-08 17:17     ` Bjorn Helgaas
2019-03-08 21:35       ` Marek Vasut
2019-03-11 10:10         ` Rafael J. Wysocki
2019-03-19 16:18       ` Lorenzo Pieralisi
2019-03-22 11:31 ` Lorenzo Pieralisi
2019-03-22 12:09   ` Marek Vasut
2019-03-22 12:18     ` Lorenzo Pieralisi
2019-03-22 12:29       ` Geert Uytterhoeven
2019-03-22 12:33         ` Marek Vasut
2019-03-22 12:42           ` Geert Uytterhoeven
2019-03-22 12:49             ` Marek Vasut
2019-03-25 16:54 ` Lorenzo Pieralisi
2019-03-25 19:44   ` Marek Vasut

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