RE: [PATCH v2] PCI: imx6: Assert i.MX8MM CLKREQ# even if no device present

From: Hongxing Zhu <hongxing.zhu@nxp.com>
To: Hongxing Zhu <hongxing.zhu@nxp.com>,
	"l.stach@pengutronix.de" <l.stach@pengutronix.de>,
	"bhelgaas@google.com" <bhelgaas@google.com>,
	"lorenzo.pieralisi@arm.com" <lorenzo.pieralisi@arm.com>
Cc: "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"kernel@pengutronix.de" <kernel@pengutronix.de>,
	dl-linux-imx <linux-imx@nxp.com>
Subject: RE: [PATCH v2] PCI: imx6: Assert i.MX8MM CLKREQ# even if no device present
Date: Wed, 16 Mar 2022 00:13:49 +0000	[thread overview]
Message-ID: <AS8PR04MB8676DF41D10EB1DDAC6F11A88C119@AS8PR04MB8676.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <1645672013-8949-1-git-send-email-hongxing.zhu@nxp.com>

Hi Lucas:
This patch is pending for a while.
Can you help to take look at it and give the ack if you don't have comments on it?
Thank you in advanced.

Best Regards
Richard Zhu

> -----Original Message-----
> From: Richard Zhu <hongxing.zhu@nxp.com>
> Sent: 2022年2月24日 11:07
> To: l.stach@pengutronix.de; bhelgaas@google.com;
> lorenzo.pieralisi@arm.com
> Cc: linux-pci@vger.kernel.org; linux-arm-kernel@lists.infradead.org;
> linux-kernel@vger.kernel.org; kernel@pengutronix.de; dl-linux-imx
> <linux-imx@nxp.com>; Hongxing Zhu <hongxing.zhu@nxp.com>
> Subject: [PATCH v2] PCI: imx6: Assert i.MX8MM CLKREQ# even if no device
> present
> 
> The CLKREQ# signal is an open drain, active low signal that is driven low by the
> remote Endpoint device. But it might not be driven low if no Endpoint device is
> connected.
> 
> On i.MX8MM PCIe, phy_init() may fail and system boot may hang if no
> Endpoint is connected to assert CLKREQ#.
> 
> Handle this as on i.MX8MQ, where we explicitly assert CLKREQ# so the PHY
> can be initialized.
> 
> Fixes: 178e244cb6e2 ("PCI: imx: Add the imx8mm pcie support")
> Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> ---
>  drivers/pci/controller/dwc/pci-imx6.c | 4 ----
>  1 file changed, 4 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> b/drivers/pci/controller/dwc/pci-imx6.c
> index 78e32a539060..168cb1287ba9 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -447,10 +447,6 @@ static int imx6_pcie_enable_ref_clk(struct imx6_pcie
> *imx6_pcie)
>  	case IMX7D:
>  		break;
>  	case IMX8MM:
> -		ret = clk_prepare_enable(imx6_pcie->pcie_aux);
> -		if (ret)
> -			dev_err(dev, "unable to enable pcie_aux clock\n");
> -		break;
>  	case IMX8MQ:
>  		ret = clk_prepare_enable(imx6_pcie->pcie_aux);
>  		if (ret) {
> --
> 2.25.1