[PATCH v2 3/4] PCI/ACPI: Add Broadcom bcm2711 MCFG quirk
Florian Fainelli
f.fainelli at gmail.com
Wed Aug 25 09:23:47 PDT 2021
On 8/24/2021 11:39 PM, Jeremy Linton wrote:
> Hi,
>
> On 8/22/21 3:53 AM, Florian Fainelli wrote:
>>
>>
>> On 8/19/2021 11:56 PM, Jeremy Linton wrote:
>>> Now that there is a bcm2711 quirk, it needs to be enabled when the
>>> MCFG is missing. Use an ACPI namespace _DSD property
>>> "linux-ecam-quirk-id" as an alternative to the MCFG OEM.
>>>
>>> Signed-off-by: Jeremy Linton <jeremy.linton at arm.com>
>>> ---
>>> drivers/acpi/pci_mcfg.c | 13 +++++++++++++
>>> 1 file changed, 13 insertions(+)
>>>
>>> diff --git a/drivers/acpi/pci_mcfg.c b/drivers/acpi/pci_mcfg.c
>>> index 53cab975f612..4b991ee5c66c 100644
>>> --- a/drivers/acpi/pci_mcfg.c
>>> +++ b/drivers/acpi/pci_mcfg.c
>>> @@ -169,6 +169,9 @@ static struct mcfg_fixup mcfg_quirks[] = {
>>> ALTRA_ECAM_QUIRK(1, 13),
>>> ALTRA_ECAM_QUIRK(1, 14),
>>> ALTRA_ECAM_QUIRK(1, 15),
>>> +
>>> + { "bcm2711", "", 0, 0, MCFG_BUS_ANY, &bcm2711_pcie_ops,
>>> + DEFINE_RES_MEM(0xFD500000, 0xA000) },
>>> };
>>> static char mcfg_oem_id[ACPI_OEM_ID_SIZE];
>>> @@ -198,8 +201,18 @@ static void pci_mcfg_apply_quirks(struct
>>> acpi_pci_root *root,
>>> u16 segment = root->segment;
>>> struct resource *bus_range = &root->secondary;
>>> struct mcfg_fixup *f;
>>> + const char *soc;
>>> int i;
>>> + /*
>>> + * This may be a machine with a PCI/SMC conduit, which means it
>>> doesn't
>>> + * have an MCFG. Use an ACPI namespace definition instead.
>>> + */
>>> + if (!fwnode_property_read_string(acpi_fwnode_handle(root->device),
>>> + "linux-ecam-quirk-id", &soc)) {
>>> + memcpy(mcfg_oem_id, soc, ACPI_OEM_ID_SIZE);
>>
>> Being super paranoid here, can we use one of the "safe" string copy
>> routines here just in case?
>
> Hmm, I went around with this a bit when I first wrote it, because the
> OEM fields in the ACPI tables are fixed len and don't have null
> termination. Maybe the right thing to do here is verify the string size
> is at least as long as the OEM_ID_SIZE and then continue to use the memcpy.
Sure, sounds entirely reasonable to me.
--
Florian
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