On Sun, Feb 17, 2019 at 02:24:41PM +0100, marek.vasut@xxxxxxxxx wrote:
> From: Kazufumi Ikeda <kaz-ikeda@xxxxxxxxxxxxx>
>
> 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@xxxxxxxxxxxxx>
> Signed-off-by: Gaku Inami <gaku.inami.xw@xxxxxxxxxxxxxx>
> Signed-off-by: Marek Vasut <marek.vasut+renesas@xxxxxxxxx>
> Cc: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> Cc: Phil Edworthy <phil.edworthy@xxxxxxxxxxx>
> Cc: Simon Horman <horms+renesas@xxxxxxxxxxxx>
> Cc: Wolfram Sang <wsa@xxxxxxxxxxxxx>
> Cc: linux-renesas-soc@xxxxxxxxxxxxxxx
> ---
> 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@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
