Re: [PATCH v11 04/11] PCI: brcmstb: Add suspend and resume pm_ops

Rob Herring
2020-09-10T15:59:17Z

On Mon, Aug 24, 2020 at 03:30:17PM -0400, Jim Quinlan wrote:
> From: Jim Quinlan <jquinlan@broadcom.com>
>
> Broadcom Set-top (BrcmSTB) boards typically support S2, S3, and S5 suspend
> and resume. Now the PCIe driver may do so as well.
>
> Signed-off-by: Jim Quinlan <jquinlan@broadcom.com>
> Acked-by: Florian Fainelli <f.fainelli@gmail.com>
> ---
> drivers/pci/controller/pcie-brcmstb.c | 47 +++++++++++++++++++++++++++
> 1 file changed, 47 insertions(+)
>
> diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
> index c2b3d2946a36..3d588ab7a6dd 100644
> --- a/drivers/pci/controller/pcie-brcmstb.c
> +++ b/drivers/pci/controller/pcie-brcmstb.c
> @@ -978,6 +978,47 @@ static void brcm_pcie_turn_off(struct brcm_pcie *pcie)
> brcm_pcie_bridge_sw_init_set(pcie, 1);
> }
>
> +static int brcm_pcie_suspend(struct device *dev)
> +{
> + struct brcm_pcie *pcie = dev_get_drvdata(dev);
> +
> + brcm_pcie_turn_off(pcie);
> + clk_disable_unprepare(pcie->clk);
> +
> + return 0;
> +}
> +
> +static int brcm_pcie_resume(struct device *dev)
> +{
> + struct brcm_pcie *pcie = dev_get_drvdata(dev);
> + void __iomem *base;
> + u32 tmp;
> + int ret;
> +
> + base = pcie->base;
> + clk_prepare_enable(pcie->clk);
> +
> + /* Take bridge out of reset so we can access the SERDES reg */
> + brcm_pcie_bridge_sw_init_set(pcie, 0);
> +
> + /* SERDES_IDDQ = 0 */
> + tmp = readl(base + PCIE_MISC_HARD_PCIE_HARD_DEBUG);
> + u32p_replace_bits(&tmp, 0, PCIE_MISC_HARD_PCIE_HARD_DEBUG_SERDES_IDDQ_MASK);
> + writel(tmp, base + PCIE_MISC_HARD_PCIE_HARD_DEBUG);
> +
> + /* wait for serdes to be stable */
> + udelay(100);

Really needs to be a spinloop?

> +
> + ret = brcm_pcie_setup(pcie);
> + if (ret)
> + return ret;
> +
> + if (pcie->msi)
> + brcm_msi_set_regs(pcie->msi);
> +
> + return 0;
> +}
> +
> static void __brcm_pcie_remove(struct brcm_pcie *pcie)
> {
> brcm_msi_remove(pcie);
> @@ -1087,12 +1128,18 @@ static int brcm_pcie_probe(struct platform_device *pdev)
>
> MODULE_DEVICE_TABLE(of, brcm_pcie_match);
>
> +static const struct dev_pm_ops brcm_pcie_pm_ops = {
> + .suspend_noirq = brcm_pcie_suspend,
> + .resume_noirq = brcm_pcie_resume,

Why do you need interrupts disabled? There's 39 cases of .suspend_noirq
and 1352 of .suspend in the tree.

Is doing a clk unprepare even safe in .suspend_noirq? IIRC,
prepare/unprepare can sleep.

> +};
> +
> static struct platform_driver brcm_pcie_driver = {
> .probe = brcm_pcie_probe,
> .remove = brcm_pcie_remove,
> .driver = {
> .name = "brcm-pcie",
> .of_match_table = brcm_pcie_match,
> + .pm = &brcm_pcie_pm_ops,
> },
> };
> module_platform_driver(brcm_pcie_driver);
> --
> 2.17.1
>