Re: [Linaro-acpi] [PATCH V6 12/13] pci, pci-thunder-ecam: Add ACPI support for ThunderX ECAM.

[Tomasz Nowicki <tn@semihalf.com>]

On 19.04.2016 13:12, Graeme Gregory wrote:
> On Tue, Apr 19, 2016 at 11:41:29AM +0100, G Gregory wrote:
>> On 19 April 2016 at 11:26, Tomasz Nowicki <tn@semihalf.com> wrote:
>>> On 15.04.2016 19:06, Tomasz Nowicki wrote:
>>>>
>>>> Passes 1.x miss PCI enhanced allocation (EA) header for fixed-BARs,
>>>> thus these passes should use Cavium-specific config access functions
>>>> that synthesize the missing EA capabilities.
>>>>
>>>> We already have DT driver which addresses errata requirements and
>>>> allows to use special PCI config accessors. Currently this driver uses
>>>> compatible = "cavium,pci-host-thunder-ecam" to mach against the errata.
>>>> For ACPI case we need explicit errata number and corresponding
>>>> DECLARE_ACPI_MCFG_FIXUP fixup code.
>>>>
>>>> Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
>>>> ---
>>>>    arch/arm64/Kconfig                  | 14 ++++++++++++++
>>>>    arch/arm64/include/asm/cpufeature.h |  3 ++-
>>>>    arch/arm64/kernel/cpu_errata.c      |  8 ++++++++
>>>>    drivers/pci/host/pci-thunder-ecam.c | 35
>>>> +++++++++++++++++++++++++++++++++++
>>>>    4 files changed, 59 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
>>>> index 1bded87..b7614b8 100644
>>>> --- a/arch/arm64/Kconfig
>>>> +++ b/arch/arm64/Kconfig
>>>> @@ -445,6 +445,20 @@ config CAVIUM_ERRATUM_27456
>>>>
>>>>            If unsure, say Y.
>>>>
>>>> +config CAVIUM_ERRATUM_24575
>>>> +       bool "Cavium erratum 24575: Enhanced Allocation (EA) emualaion"
>>>> +       default y
>>>> +       help
>>>> +         Enable workaround for erratum 24575.
>>>> +
>>>> +         Early versions of the Cavium Thunder CN88XX processor are
>>>> missing
>>>> +         Enhanced Allocation (EA) capabilities for the fixed BAR
>>>> addresses used
>>>> +         by the on-SoC hardware blocks. The erratum adds config access
>>>> +         functions that synthesize the missing EA capabilities for
>>>> versions
>>>> +         that are missing that information.
>>>> +
>>>> +         If unsure, say Y.
>>>> +
>>>>    endmenu
>>>>
>>>>
>>>> diff --git a/arch/arm64/include/asm/cpufeature.h
>>>> b/arch/arm64/include/asm/cpufeature.h
>>>> index b9b6494..a78364e 100644
>>>> --- a/arch/arm64/include/asm/cpufeature.h
>>>> +++ b/arch/arm64/include/asm/cpufeature.h
>>>> @@ -35,8 +35,9 @@
>>>>    #define ARM64_ALT_PAN_NOT_UAO                 10
>>>>    #define ARM64_HAS_VIRT_HOST_EXTN              11
>>>>    #define ARM64_WORKAROUND_CAVIUM_27456         12
>>>> +#define ARM64_WORKAROUND_CAVIUM_24575          13
>>>>
>>>> -#define ARM64_NCAPS                            13
>>>> +#define ARM64_NCAPS                            14
>>>>
>>>>    #ifndef __ASSEMBLY__
>>>>
>>>> diff --git a/arch/arm64/kernel/cpu_errata.c
>>>> b/arch/arm64/kernel/cpu_errata.c
>>>> index 06afd04..89c13d7 100644
>>>> --- a/arch/arm64/kernel/cpu_errata.c
>>>> +++ b/arch/arm64/kernel/cpu_errata.c
>>>> @@ -97,6 +97,14 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
>>>>                             (1 << MIDR_VARIANT_SHIFT) | 1),
>>>>          },
>>>>    #endif
>>>> +#ifdef CONFIG_CAVIUM_ERRATUM_24575
>>>> +       {
>>>> +       /* Cavium ThunderX, pass 1.x */
>>>> +               .desc = "Cavium erratum 24575",
>>>> +               .capability = ARM64_WORKAROUND_CAVIUM_24575,
>>>> +               MIDR_RANGE(MIDR_THUNDERX, 0x00, 0x01),
>>>> +       },
>>>> +#endif
>>>>          {
>>>>          }
>>>>    };
>>>> diff --git a/drivers/pci/host/pci-thunder-ecam.c
>>>> b/drivers/pci/host/pci-thunder-ecam.c
>>>> index f67c6d7..01de697 100644
>>>> --- a/drivers/pci/host/pci-thunder-ecam.c
>>>> +++ b/drivers/pci/host/pci-thunder-ecam.c
>>>> @@ -11,10 +11,14 @@
>>>>    #include <linux/ioport.h>
>>>>    #include <linux/of_pci.h>
>>>>    #include <linux/of.h>
>>>> +#include <linux/pci-acpi.h>
>>>>    #include <linux/platform_device.h>
>>>>
>>>> +#include <asm/virt.h>
>>>> +
>>>>    #include "../ecam.h"
>>>>
>>>> +
>>>>    static void set_val(u32 v, int where, int size, u32 *val)
>>>>    {
>>>>          int shift = (where & 3) * 8;
>>>> @@ -376,5 +380,36 @@ static struct platform_driver thunder_ecam_driver = {
>>>>    };
>>>>    module_platform_driver(thunder_ecam_driver);
>>>>
>>>> +#ifdef CONFIG_ACPI
>>>> +
>>>> +static bool needs_cavium_erratum_24575(struct pci_cfg_fixup *fixup,
>>>> +                                     struct acpi_pci_root *root)
>>>> +{
>>>> +       /*
>>>> +        * We must match errata code and be hypervisor, quirk does not
>>>> apply
>>>> +        * for virtual machines.
>>>> +        */
>>>> +       return cpus_have_cap(ARM64_WORKAROUND_CAVIUM_24575) &&
>>>> +              is_hyp_mode_available();
>>>> +}
>>>> +
>>>> +DECLARE_ACPI_MCFG_FIXUP(NULL, needs_cavium_erratum_24575,
>>>> &pci_thunder_ecam_ops,
>>>> +                       0, PCI_MCFG_BUS_ANY);
>>>> +DECLARE_ACPI_MCFG_FIXUP(NULL, needs_cavium_erratum_24575,
>>>> &pci_thunder_ecam_ops,
>>>> +                       1, PCI_MCFG_BUS_ANY);
>>>> +DECLARE_ACPI_MCFG_FIXUP(NULL, needs_cavium_erratum_24575,
>>>> &pci_thunder_ecam_ops,
>>>> +                       2, PCI_MCFG_BUS_ANY);
>>>> +DECLARE_ACPI_MCFG_FIXUP(NULL, needs_cavium_erratum_24575,
>>>> &pci_thunder_ecam_ops,
>>>> +                       3, PCI_MCFG_BUS_ANY);
>>>> +DECLARE_ACPI_MCFG_FIXUP(NULL, needs_cavium_erratum_24575,
>>>> &pci_thunder_ecam_ops,
>>>> +                       10, PCI_MCFG_BUS_ANY);
>>>> +DECLARE_ACPI_MCFG_FIXUP(NULL, needs_cavium_erratum_24575,
>>>> &pci_thunder_ecam_ops,
>>>> +                       11, PCI_MCFG_BUS_ANY);
>>>> +DECLARE_ACPI_MCFG_FIXUP(NULL, needs_cavium_erratum_24575,
>>>> &pci_thunder_ecam_ops,
>>>> +                       12, PCI_MCFG_BUS_ANY);
>>>> +DECLARE_ACPI_MCFG_FIXUP(NULL, needs_cavium_erratum_24575,
>>>> &pci_thunder_ecam_ops,
>>>> +                       13, PCI_MCFG_BUS_ANY);
>>>> +#endif
>>>> +
>>>
>>>
>>> I wonder if we can identify quirk based on _DSD properties, like that:
>>>
>>> Name (_DSD, Package () {
>>>          ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
>>>          Package () {
>>>                  Package (2) {"cavium,pci-host-thunder-ecam", 1},
>>>          }
>>> })
>>>
>>> similar for PEM driver:
>>>
>>> Name (_DSD, Package () {
>>>          ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
>>>          Package () {
>>>                  Package (2) {"cavium,pci-host-thunder-pem", 1},
>>>          }
>>> })
>>>
>>> Do you think it is right thing to do?
>>>
>>
>> Well if your adding new properties why not add a Cavium specific _CID?
>>
>
> For clarity what I mean is something like this allowed.
>
> Device (PCI0)
> {
>      Name (_HID, EisaId ("PNP0A08"))
>      Name (_CID, EisaId ("PNP0A03"))
>      Name (_HID, "CAV0666")) // Cavium Quirky Hardware
>
>      ....
>
> }
>

Rafael, Bjorn, what do you think?

Tomasz