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From: Stanimir Varbanov <svarbanov@mm-sol.com>
To: Marc Gonzalez <marc.w.gonzalez@free.fr>,
	Bjorn Helgaas <bhelgaas@google.com>
Cc: Andy Gross <andy.gross@linaro.org>,
	David Brown <david.brown@linaro.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	PCI <linux-pci@vger.kernel.org>,
	MSM <linux-arm-msm@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Jeffrey Hugo <jhugo@codeaurora.org>
Subject: Re: [RFC PATCH v1] PCI: qcom: Use quirk to override incorrect device class
Date: Tue, 12 Mar 2019 14:42:46 +0200
Message-ID: <65321fe3-ca29-c454-63ae-98a46c2e5158@mm-sol.com> (raw)
In-Reply-To: <94bb3f22-c5a7-1891-9d89-42a520e9a592@free.fr>

Hi Marc,

Thanks for the patch!

On 3/11/19 4:56 PM, Marc Gonzalez wrote:
> Some chips report an incorrect device class. Override the incorrect
> value using a quirk, instead of code in the read function.
> 
> Signed-off-by: Marc Gonzalez <marc.w.gonzalez@free.fr>
> ---
> FWIW, this quirk is no longer required on recent chips:
> msm8996 (tested by Stanimir), msm8998 (tested by me), sdm845 (untested) are unaffected
> apq/ipq8064 is affected => what is the device ID for these chips?
> others?
> 
> Stanimir added: "this will become a real problem (now we use the driver as RC)
> when someone decide to use it as an endpoint"
> ---
>  drivers/pci/controller/dwc/pcie-qcom.c | 14 ++++++--------
>  1 file changed, 6 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
> index 3de5510fd3d5..94da2c9c2ad5 100644
> --- a/drivers/pci/controller/dwc/pcie-qcom.c
> +++ b/drivers/pci/controller/dwc/pcie-qcom.c
> @@ -1136,17 +1136,15 @@ static int qcom_pcie_rd_own_conf(struct pcie_port *pp, int where, int size,
>  {
>  	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>  
> -	/* the device class is not reported correctly from the register */
> -	if (where == PCI_CLASS_REVISION && size == 4) {
> -		*val = readl(pci->dbi_base + PCI_CLASS_REVISION);
> -		*val &= 0xff;	/* keep revision id */
> -		*val |= PCI_CLASS_BRIDGE_PCI << 16;
> -		return PCIBIOS_SUCCESSFUL;
> -	}
> -

once you dropped the above snippet this function becomes absolutely
useless so please delete it at all and also from qcom_pcie_dw_ops.

>  	return dw_pcie_read(pci->dbi_base + where, size, val);
>  }
>  
> +static void qcom_fixup_class(struct pci_dev *dev)
> +{
> +	dev->class = PCI_CLASS_BRIDGE_PCI << 8;
> +}
> +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_QCOM, PCI_ANY_ID, qcom_fixup_class);

I wonder, in case that dw_pcie_setup_rc() already has a write to
PCI_CLASS_DEVICE configuration register to set it as a bridge do we
still need to do the above fixup?

-- 
regards,
Stan

  reply index

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-11 14:56 Marc Gonzalez
2019-03-12 12:42 ` Stanimir Varbanov [this message]
2019-03-12 17:18   ` Marc Gonzalez
2019-03-12 17:34     ` Marc Gonzalez
2019-03-13 11:45       ` [PATCH v2] PCI: qcom: Use default config space read function Marc Gonzalez
2019-03-13 13:13         ` Marc Gonzalez
2019-03-13 18:29         ` Srinivas Kandagatla
2019-03-13 20:39           ` Marc Gonzalez
2019-03-13 21:52             ` Srinivas Kandagatla
2019-03-13 22:26               ` Marc Gonzalez
2019-03-14 11:10                 ` Srinivas Kandagatla
2019-03-14 13:18                   ` Marc Gonzalez
2019-03-18 14:28                     ` [PATCH v3] " Marc Gonzalez
2019-03-18 14:39                       ` Srinivas Kandagatla
2019-03-18 16:35                       ` Stanimir Varbanov
2019-03-18 17:14                         ` [PATCH v4] " Marc Gonzalez
2019-03-25 12:11                           ` Marc Gonzalez
2019-03-25 13:32                             ` Stanimir Varbanov
2019-03-25 15:42                               ` [PATCH v5] " Marc Gonzalez
2019-03-29 13:48                                 ` Marc Gonzalez
2019-03-29 15:55                                 ` Stanimir Varbanov
2019-03-29 16:38                                 ` Lorenzo Pieralisi
2019-04-01 10:39                                   ` Marc Gonzalez
2019-04-01 11:12                                     ` Lorenzo Pieralisi
2019-04-30 14:06       ` [RFC PATCH v1] PCI: qcom: Use quirk to override incorrect device class Lorenzo Pieralisi
2019-05-02  9:42         ` Marc Gonzalez

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