From mboxrd@z Thu Jan  1 00:00:00 1970
From: "liudongdong (C)" <liudongdong3@huawei.com>
Subject: Re: [PATCH V3 20/21] pci, acpi: Match PCI config space accessors
 against platfrom specific quirks.
Date: Tue, 19 Jan 2016 09:49:40 +0800
Message-ID: <569D9634.3040304@huawei.com>
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To: Tomasz Nowicki <tn@semihalf.com>, Mark Salter <msalter@redhat.com>, bhelgaas@google.com, arnd@arndb.de, will.deacon@arm.com, catalin.marinas@arm.com, rjw@rjwysocki.net, hanjun.guo@linaro.org, Lorenzo.Pieralisi@arm.com, okaya@codeaurora.org, jiang.liu@linux.intel.com, Stefano.Stabellini@eu.citrix.com
Cc: robert.richter@caviumnetworks.com, mw@semihalf.com, Liviu.Dudau@arm.com, ddaney@caviumnetworks.com, tglx@linutronix.de, wangyijing@huawei.com, Suravee.Suthikulpanit@amd.com, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, linaro-acpi@lists.linaro.org, jchandra@broadcom.com, jcm@redhat.com, Zhou Wang <wangzhou1@hisilicon.com>, Gabriele Paoloni <gabriele.paoloni@huawei.com>
List-Id: linux-acpi@vger.kernel.org

Hi Tomasz, Mark

=E5=9C=A8 2016/1/18 20:41, Tomasz Nowicki =E5=86=99=E9=81=93:
> On 14.01.2016 16:36, Mark Salter wrote:
>>> +extern struct pci_mcfg_fixup __start_acpi_mcfg_fixups[];
>>> >+extern struct pci_mcfg_fixup __end_acpi_mcfg_fixups[];
>>> >+
>>> >+static struct pci_ops *pci_mcfg_check_quirks(struct acpi_pci_root=
 *root)
>>> >+{
>>> >+    struct pci_mcfg_fixup *f;
>>> >+    int bus_num =3D root->secondary.start;
>>> >+    int domain =3D root->segment;
>>> >+
>>> >+    /*
>>> >+     * First match against PCI topology <domain:bus> then use DMI=
 or
>>> >+     * custom match handler.
>>> >+     */
>>> >+    for (f =3D __start_acpi_mcfg_fixups; f < __end_acpi_mcfg_fixu=
ps; f++) {
>>> >+        if ((f->domain =3D=3D domain || f->domain =3D=3D PCI_MCFG=
_DOMAIN_ANY) &&
>>> >+            (f->bus_num =3D=3D bus_num || f->bus_num =3D=3D PCI_M=
CFG_BUS_ANY) &&
>>> >+            (f->system ? dmi_check_system(f->system) : 0 ||
>>> >+             f->match ? f->match(f, root) : 0))
>>> >+            return f->ops;
>> I think this would be better as:
>>
>>             (f->system ? dmi_check_system(f->system) : 1 &&
>>              f->match ? f->match(f, root) : 1))
>>             return f->ops;
>>
>> Otherwise, one has to call dmi_check_system() from f->match() if
>> access to root is needed.
>

Non-DMI, we need not to call dmi_check_system() from f->match(),
we can use _HID to decide to hook the pci_ops or not.

Device (PCI1)
{
         Name (_HID, "HISI0080") // PCI Express Root Bridge
         Name (_CID, "PNP0A03") // Compatible PCI Root Bridge
	...
}

static const struct acpi_device_id hisi_pcie_ids[] =3D {
     {"HISI0080", 0},
     {"", 0},
};

static int hisi_pcie_match(struct pci_mcfg_fixup *fixup, struct acpi_pc=
i_root *root)
{
     int ret;
     struct acpi_device *device;

     device =3D root->device;
     ret =3D acpi_match_device_ids(device, hisi_pcie_ids);
     if (ret)
         return 0;
     ......
     return 1;
}

static struct pci_ops hisi_ecam_pci_ops =3D {
     .map_bus =3D pci_mcfg_dev_base,
     .read =3D hisi_pci_read,
     .write =3D hisi_pci_write,
};

DECLARE_ACPI_MCFG_FIXUP(NULL, hisi_pcie_match, &hisi_ecam_pci_ops,
     PCI_MCFG_DOMAIN_ANY, PCI_MCFG_BUS_ANY);

Thanks
Dongdong
> Makes a lot of sense to me, I will modify as you suggested.
>
> Tomasz
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