Re: [edk2-devel] [PATCH 2/3] Platform/RaspberryPi/Acpitables: Add eMMC2 device and tweak Arasan

["Jeremy Linton" <jeremy.linton@arm.com>]

Hi,

On 1/9/21 8:09 AM, Mark Kettenis via groups.io wrote:
> On Fri, Jan 8, 2021 at 05:27 PM, Jeremy Linton wrote:
> 
>>
>> Hi,
>>
>> On 1/8/21 2:28 AM, Ard Biesheuvel wrote:
>>
>>> On 1/8/21 7:16 AM, Jeremy Linton wrote:
>>>
>>>> The primarly problem with the rpi Arasan controller working
>>>> with a default SDHCI driver is the lack of a meaningful
>>>> capabilities register. As such if we add a _DSD entry
>>>> to provide that information, we can then bind it to
>>>> the linux sdhci_iproc driver which already
>>>> hardcodes the remaining controller bugs.
>>>>
>>>> Further we have gotten BRCME88C approved as the HID
>>>> for the newer eMMC2 controller. So lets define an
>>>> ACPI object to describe it.
>>>>
>>>> Of course both devices are sharing an interrupt so
>>>> we should also indicate that in the table as well.
>>>>
>>>> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
>>>> ---
>>>> Platform/RaspberryPi/AcpiTables/Dsdt.asl | 2 +
>>>> Platform/RaspberryPi/AcpiTables/Sdhc.asl | 86
>>>> +++++++++++++++++++++++++++++++-
>>>> 2 files changed, 86 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/Platform/RaspberryPi/AcpiTables/Dsdt.asl
>>>> b/Platform/RaspberryPi/AcpiTables/Dsdt.asl
>>>> index d116f965e1..cca08c0539 100644
>>>> --- a/Platform/RaspberryPi/AcpiTables/Dsdt.asl
>>>> +++ b/Platform/RaspberryPi/AcpiTables/Dsdt.asl
>>>> @@ -150,6 +150,7 @@ DefinitionBlock ("Dsdt.aml", "DSDT", 5, "RPIFDN",
>>>> "RPI", 2)
>>>> QWORDMEMORYBUF(23)
>>>> QWORDMEMORYBUF(24)
>>>> QWORDMEMORYBUF(25)
>>>> + QWORDMEMORYBUF(26)
>>>> })
>>>>
>>>> // USB
>>>> @@ -196,6 +197,7 @@ DefinitionBlock ("Dsdt.aml", "DSDT", 5, "RPIFDN",
>>>> "RPI", 2)
>>>> // SDC
>>>> QWORDMEMORYSET(24, MMCHS1_OFFSET, MMCHS1_LENGTH)
>>>> QWORDMEMORYSET(25, SDHOST_OFFSET, SDHOST_LENGTH)
>>>> + QWORDMEMORYSET(26, MMCHS2_OFFSET, MMCHS2_LENGTH)
>>>>
>>>> Return (RBUF)
>>>> }
>>>> diff --git a/Platform/RaspberryPi/AcpiTables/Sdhc.asl
>>>> b/Platform/RaspberryPi/AcpiTables/Sdhc.asl
>>>> index 0ab1ba27f2..a7ac831066 100644
>>>> --- a/Platform/RaspberryPi/AcpiTables/Sdhc.asl
>>>> +++ b/Platform/RaspberryPi/AcpiTables/Sdhc.asl
>>>> @@ -19,7 +19,7 @@
>>>> // Note: UEFI can use either SDHost or Arasan. We expose both to the OS.
>>>> //
>>>>
>>>> -// ArasanSD 3.0 SD Host Controller.
>>>> +// ArasanSD 3.0 SD Host Controller. (brcm,bcm2835-sdhci)
>>>> Device (SDC1)
>>>> {
>>>> Name (_HID, "BCM2847")
>>>> @@ -37,7 +37,7 @@ Device (SDC1)
>>>> Name (RBUF, ResourceTemplate ()
>>>> {
>>>> MEMORY32FIXED (ReadWrite, 0, MMCHS1_LENGTH, RMEM)
>>>> - Interrupt (ResourceConsumer, Level, ActiveHigh, Exclusive) {
>>>> BCM2836_MMCHS1_INTERRUPT }
>>>> + Interrupt (ResourceConsumer, Level, ActiveHigh, Shared) {
>>>> BCM2836_MMCHS1_INTERRUPT }
>>>> })
>>>> Method (_CRS, 0x0, Serialized)
>>>> {
>>>> @@ -45,6 +45,86 @@ Device (SDC1)
>>>> Return (^RBUF)
>>>> }
>>>>
>>>> + // The standard CAPs registers on this controller
>>>> + // appear to be 0, lets set some minimal defaults
>>>> + // Since this cap doesn't indicate DMA capability
>>>> + // we don't need a _DMA()
>>>> + Name (_DSD, Package () {
>>>> + ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
>>>> + Package () {
>>>> + Package () { "sdhci-caps", 0x0100fa81 },
>>>> + }
>>>> + })
>>>> +
>>>> +
>>>> + //
>>>> + // A child device that represents the
>>>> + // sd card, which is marked as non-removable.
>>>> + //
>>>> + Device (SDMM)
>>>> + {
>>>> + Method (_ADR)
>>>> + {
>>>> + Return (0)
>>>> + }
>>>> + Method (_RMV) // Is removable
>>>> + {
>>>> + Return (0) // 0 - fixed
>>>> + }
>>>> + }
>>>> +}
>>>> +
>>>> +#if (RPI_MODEL == 4)
>>>> +// emmc2 Host Controller. (brcm,bcm2711-emmc2)
>>>> +Device (SDC3)
>>>> +{
>>>> + Name (_HID, "BRCME88C")
>>>> + Name (_UID, 0x1)
>>>> + Name (_CCA, 0x0)
>>>> + Name (_S1D, 0x1)
>>>> + Name (_S2D, 0x1)
>>>> + Name (_S3D, 0x1)
>>>> + Name (_S4D, 0x1)
>>>> + Method (_STA)
>>>> + {
>>>> + Return(0xf)
>>>> + }
>>>> + Name (RBUF, ResourceTemplate ()
>>>> + {
>>>> + MEMORY32FIXED (ReadWrite, 0, MMCHS2_LENGTH, RMEM)
>>>> + Interrupt (ResourceConsumer, Level, ActiveHigh, Shared) {
>>>> BCM2836_MMCHS1_INTERRUPT }
>>>> + })
>>>> + Method (_CRS, 0x0, Serialized)
>>>> + {
>>>> + MEMORY32SETBASE (RBUF, RMEM, RBAS, MMCHS2_OFFSET)
>>>> + Return (^RBUF)
>>>> + }
>>>> +
>>>> + // forceably limit to 1G
>>>> + Name (_DMA, ResourceTemplate() {
>>>> + QWordMemory (ResourceConsumer,
>>>> + ,
>>>> + MinFixed,
>>>> + MaxFixed,
>>>> + NonCacheable,
>>>> + ReadWrite,
>>>> + 0x0,
>>>> + 0x0, // MIN
>>>> + 0x3fffffff, // MAX
>>>> + 0x0, // TRA
>>>> + 0x40000000, // LEN
>>>> + ,
>>>> + ,
>>>> + )
>>>> + })
>>>> +
>>>
>>> Shouldn't the _DMA method be on a container object instead of on the
>>> device object itself?
>>
>> Pained cough... There is a _DMA on the gpu devs container of which this
>> device belongs. That doesn't make the DMA work. The spec says that _DMA
>> is to exist on the bus device, and I think what is happening here is
>> that the "device" is the SDMM (which isn't directly visible because of
>> the way diff broke this patch up) contained in the "SDC3 mmc bus".
> 
> The Linux device tree has the following comment:
> 
> /*
> * emmc2 has different DMA constraints based on SoC revisions. It was
> * moved into its own bus, so as for RPi4's firmware to update them.
> * The firmware will find whether the emmc2bus alias is defined, and if
> * so, it'll edit the dma-ranges property below accordingly.
> *
> 
> And the dma-ranges property it references is:
> 
> dma-ranges = <0x0 0xc0000000  0x0 0x00000000  0x40000000>;
> 
> Not sure how the firmware will adjust this, but it does imply that there is actual translation
> going on here and it doesn't match the _DMA property you added.
> 
>>
>> Frankly, I could be wrong, but what I do know is that without that bit
>> of ugliness DMA doesn't work in linux on this controller. I just
>> stripped it out again to verify the failure with 4.11. It does the same
>> thing, the controller itself seems to be working but the block device
>> associated with it can't be read. There are few other possibilities
>> (like maybe this controller shouldn't be a gpudevs child) and i'm fixing
>> a bug I created..I had kernel instrumentation in 5.9 tracking the dma
>> mask propagation, and I was fairly confident in this a couple months
>> ago, less so now.
>>
> 
> One question I have is whether _DMA methods should be applied recursively or
> not. If you have a bus that provides a translating _DMA method that is behind a
> bus that also has a _DMA method, should the translation specified in that first _DMA
> method be applied or not? The text in the ACPI spec is far for clear her...


First, thanks for looking at this!

The way I understand the spec, one does have to honor nested translations.

> 
> If I read the Linux code in drivers/acpi/scan.c correctly, Linux would not apply
> the translation in this case. Since the _DMA method you add does not specify any
> translation, I think that means the required address translation isn't happening
> which means that DMA transactions would fail. I suspect the block device behind
> the controller would still be detected, but any actual I/O would fail since the right
> memory isn't addressed.
> 
> So I think the best thing to do would be to have a separate ACPI0004 container
> with a translating _DMA method and but the emmc2 device below that.

I think if you look at the rpi's Dsdt, you will see an ACPI0004 
container, which includes the GpuDevs, of which Sdhc.asl is child. That 
container has a _DMA method which specifies the 1G translation+limit 
which matches what you would expect based on the DT.

So this further _DMA should be layering on it and re-enforcing only the 
DMA limit, not a new translation.

> 
>>
>>
>>>
>>>> + Name (_DSD, Package () {
>>>> + ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
>>>> + Package () {
>>>> + Package () { "sdhci-caps-mask", 0x0000000000080000 },
>>>> + }
>>>> + })
>>>> +
>>>> //
>>>> // A child device that represents the
>>>> // sd card, which is marked as non-removable.
>>>> @@ -62,6 +142,7 @@ Device (SDC1)
>>>> }
>>>> }
>>>>
>>>> +#else // !RPI4
>>>>
>>>> // Broadcom SDHost 2.0 SD Host Controller
>>>> Device (SDC2)
>>>> @@ -105,3 +186,4 @@ Device (SDC2)
>>>> }
>>>> }
>>>> }
>>>> +#endif // !RPI4
>>>
>>>
>>
>>
> 
> 
> 
> 
> 
>