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From:   "Zhao, Haifeng" <haifeng.zhao@intel.com>
To:     Christoph Hellwig <hch@infradead.org>
CC:     "bhelgaas@google.com" <bhelgaas@google.com>,
        "oohall@gmail.com" <oohall@gmail.com>,
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Subject: RE: [PATCH 1/5 V2] PCI: define a function to check and wait till port
 finish DPC handling
Thread-Topic: [PATCH 1/5 V2] PCI: define a function to check and wait till
 port finish DPC handling
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Date:   Sun, 27 Sep 2020 06:43:57 +0000
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 <20200927062359.GA23452@infradead.org>
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Yep, I am think the same question, is there any other files better to put t=
his function ?
How  about pci.c ?

Thanks,
Ethan

-----Original Message-----
From: Christoph Hellwig <hch@infradead.org>=20
Sent: Sunday, September 27, 2020 2:24 PM
To: Zhao, Haifeng <haifeng.zhao@intel.com>
Cc: bhelgaas@google.com; oohall@gmail.com; ruscur@russell.cc; lukas@wunner.=
de; andriy.shevchenko@linux.intel.com; stuart.w.hayes@gmail.com; mr.nuke.me=
@gmail.com; mika.westerberg@linux.intel.com; linux-pci@vger.kernel.org; lin=
ux-kernel@vger.kernel.org; Jia, Pei P <pei.p.jia@intel.com>; ashok.raj@linu=
x.intel.com; Kuppuswamy, Sathyanarayanan <sathyanarayanan.kuppuswamy@intel.=
com>
Subject: Re: [PATCH 1/5 V2] PCI: define a function to check and wait till p=
ort finish DPC handling

> +#ifdef CONFIG_PCIE_DPC
> +static inline bool pci_wait_port_outdpc(struct pci_dev *pdev) {
> +	u16 cap =3D pdev->dpc_cap, status;
> +	u16 loop =3D 0;
> +
> +	if (!cap) {
> +		pci_WARN_ONCE(pdev, !cap, "No DPC capability initiated\n");
> +		return false;
> +	}
> +	pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status);
> +	pci_dbg(pdev, "DPC status %x, cap %x\n", status, cap);
> +	while (status & PCI_EXP_DPC_STATUS_TRIGGER && loop < 100) {
> +		msleep(10);
> +		loop++;
> +		pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status);
> +	}
> +	if (!(status & PCI_EXP_DPC_STATUS_TRIGGER)) {
> +		pci_dbg(pdev, "Out of DPC %x, cost %d ms\n", status, loop*10);
> +		return true;
> +	}
> +	pci_dbg(pdev, "Timeout to wait port out of DPC status\n");
> +	return false;
> +}

I don't think that there is any good reason to have this as an inline funct=
ion.