Re: [PATCH 1/6] usb: dwc3: Support Synopsys USB 3.1 IP

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On 10/1/2015 7:03 PM, Felipe Balbi wrote:
> Hi,
> 
> On Fri, Sep 04, 2015 at 07:15:10PM -0700, John Youn wrote:
>> This patch allows the dwc3 driver to run on the new Synopsys USB 3.1
>> IP core, albeit in USB 3.0 mode only.
>>
>> The Synopsys USB 3.1 IP (DWC_usb31) retains mostly the same register
>> interface and programming model as the existing USB 3.0 controller IP
>> (DWC_usb3). However, the underlying IP is different and the GSNPSID
>> and version numbers are different.
>>
>> The DWC_usb31 version register is actually lower in value than the
>> full GSNPSID of the DWC_usb3 IP. So if we are on DWC_usb3 IP just
>> store the lower word of the GSNPSID instead of the full register. Then
>> adjust the revision constants to match. This will allow existing
>> revision checks to continue to work when running on the new IP.
> 
> I would rather not touch those constants at all. We can have the driver
> set a is_dwc31 flag and use if !is_dwc31 && rev < XYZ for the revision checks.
> 
> It's more work, but it seems better IMO.

I initially did it like that but it got really messy and it would
make it harder to port back to stable kernels...

> 
>> Finally add a documentation note about the revision numbering and
>> checking with regards to the old and new IP. Because these are
>> different IPs which will both continue to be supported, feature sets
>> and revisions checks may not sync-up across future versions.
> 
> and this is why I prefer to have the flag :-) We can run different revision
> check methods depending if we're running on dwc3 or dwc31.

All of the existing checks apply to both. The mismatch condition
will be the exception.


> 
>> From now, any check based on a revision (for STARS, workarounds, and
>> new features) should take into consideration how it applies to both
>> the 3.1/3.0 IP and make the check accordingly.
>>
>> Cc: <stable@xxxxxxxxxxxxxxx> # v3.18+
> 
> I really fail to how any of these patches in this series apply for stable. Care
> to explain ?

We have some prototyping products that are stuck on 3.18 stable
kernels and will continue to ship with that for some time. We'd
like to run the USB 3.1 controller on those platforms. Without
these version id and version number updates dwc3 will not work
with the USB 3.1 IP.

I think the plan is to update those platforms to 4.2 eventually.
So even then it will still need this patch.

Also it will help out any customers stuck on earlier kernels.

How would you advise we handle this, with the version id and
number changes?

I can make the changes as you suggest but it might be a pain
to apply it to stable kernels.

The other patches in this series tagged for stable are to
support these same platforms on 3.18+. Either so that they
can work at all (such as missing PCI IDs) or to pass some
compliance tests (LPM flags in platform data, enblslpm quirk).



> 
>> Signed-off-by: John Youn <johnyoun@xxxxxxxxxxxx>
>> ---
>>  drivers/usb/dwc3/core.c |  9 ++++++--
>>  drivers/usb/dwc3/core.h | 56 +++++++++++++++++++++++++++++++------------------
>>  2 files changed, 43 insertions(+), 22 deletions(-)
>>
>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
>> index c72c8c5..566cca1 100644
>> --- a/drivers/usb/dwc3/core.c
>> +++ b/drivers/usb/dwc3/core.c
>> @@ -534,12 +534,17 @@ static int dwc3_core_init(struct dwc3 *dwc)
>>  
>>  	reg = dwc3_readl(dwc->regs, DWC3_GSNPSID);
>>  	/* This should read as U3 followed by revision number */
>> -	if ((reg & DWC3_GSNPSID_MASK) != 0x55330000) {
>> +	if ((reg & DWC3_GSNPSID_MASK) == 0x55330000) {
>> +		/* Detected DWC_usb3 IP */
>> +		dwc->revision = reg & DWC3_GSNPSREV_MASK;
> 
> leave the mask out of it and ...
> 
>> +	} else if ((reg & DWC3_GSNPSID_MASK) == 0x33310000) {
>> +		/* Detected DWC_usb31 IP */
>> +		dwc->revision = dwc3_readl(dwc->regs, DWC3_VER_NUMBER);
> 
> set a dwc->is_dwc31 = true flag here.
> 
>> +	} else {
>>  		dev_err(dwc->dev, "this is not a DesignWare USB3 DRD Core\n");
>>  		ret = -ENODEV;
>>  		goto err0;
>>  	}
>> -	dwc->revision = reg;
>>  
>>  	/*
>>  	 * Write Linux Version Code to our GUID register so it's easy to figure
>> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
>> index 9188745..7446467 100644
>> --- a/drivers/usb/dwc3/core.h
>> +++ b/drivers/usb/dwc3/core.h
>> @@ -108,6 +108,9 @@
>>  #define DWC3_GPRTBIMAP_FS0	0xc188
>>  #define DWC3_GPRTBIMAP_FS1	0xc18c
>>  
>> +#define DWC3_VER_NUMBER		0xc1a0
>> +#define DWC3_VER_TYPE		0xc1a4
> 
> what is this VER_TYPE register ?

It gives the release type, EA, GA, etc. It's not used so I can
leave it out if you want.


> 
>> @@ -661,7 +664,8 @@ struct dwc3_scratchpad_array {
>>   * @num_event_buffers: calculated number of event buffers
>>   * @u1u2: only used on revisions <1.83a for workaround
>>   * @maximum_speed: maximum speed requested (mainly for testing purposes)
>> - * @revision: revision register contents
>> + * @revision: the core revision. the contents will depend on the whether
>> + *            this is a usb3 or usb31 core.
>>   * @dr_mode: requested mode of operation
>>   * @usb2_phy: pointer to USB2 PHY
>>   * @usb3_phy: pointer to USB3 PHY
>> @@ -771,27 +775,39 @@ struct dwc3 {
>>  	u32			num_event_buffers;
>>  	u32			u1u2;
>>  	u32			maximum_speed;
>> +
>> +	/*
>> +	 * All 3.1 IP version constants are greater than the 3.0 IP
>> +	 * version constants. This works for most version checks in
>> +	 * dwc3. However, in the future, this may not apply as
>> +	 * features may be developed on newer versions of the 3.0 IP
>> +	 * that are not in the 3.1 IP.
>> +	 */
>>  	u32			revision;
>>  
>> -#define DWC3_REVISION_173A	0x5533173a
>> -#define DWC3_REVISION_175A	0x5533175a
>> -#define DWC3_REVISION_180A	0x5533180a
>> -#define DWC3_REVISION_183A	0x5533183a
>> -#define DWC3_REVISION_185A	0x5533185a
>> -#define DWC3_REVISION_187A	0x5533187a
>> -#define DWC3_REVISION_188A	0x5533188a
>> -#define DWC3_REVISION_190A	0x5533190a
>> -#define DWC3_REVISION_194A	0x5533194a
>> -#define DWC3_REVISION_200A	0x5533200a
>> -#define DWC3_REVISION_202A	0x5533202a
>> -#define DWC3_REVISION_210A	0x5533210a
>> -#define DWC3_REVISION_220A	0x5533220a
>> -#define DWC3_REVISION_230A	0x5533230a
>> -#define DWC3_REVISION_240A	0x5533240a
>> -#define DWC3_REVISION_250A	0x5533250a
>> -#define DWC3_REVISION_260A	0x5533260a
>> -#define DWC3_REVISION_270A	0x5533270a
>> -#define DWC3_REVISION_280A	0x5533280a
> 
> yeah, I'd rather not do all this.
> 
>> +/* DWC_usb3 revisions */
>> +#define DWC3_REVISION_173A	0x173a
>> +#define DWC3_REVISION_175A	0x175a
>> +#define DWC3_REVISION_180A	0x180a
>> +#define DWC3_REVISION_183A	0x183a
>> +#define DWC3_REVISION_185A	0x185a
>> +#define DWC3_REVISION_187A	0x187a
>> +#define DWC3_REVISION_188A	0x188a
>> +#define DWC3_REVISION_190A	0x190a
>> +#define DWC3_REVISION_194A	0x194a
>> +#define DWC3_REVISION_200A	0x200a
>> +#define DWC3_REVISION_202A	0x202a
>> +#define DWC3_REVISION_210A	0x210a
>> +#define DWC3_REVISION_220A	0x220a
>> +#define DWC3_REVISION_230A	0x230a
>> +#define DWC3_REVISION_240A	0x240a
>> +#define DWC3_REVISION_250A	0x250a
>> +#define DWC3_REVISION_260A	0x260a
>> +#define DWC3_REVISION_270A	0x270a
>> +#define DWC3_REVISION_280A	0x280a
>> +
>> +/* DWC_usb31 revisions */
>> +#define DWC3_USB31_REVISION_110A	0x3131302a
> 
> are you sure you tested this ? Above you check for 0x33310000 but here you use
> 0x3131 ? What gives ? Also, it seems odd that revision 1.10a is actually 3.02a
> in HW, is this really correct ?
> 

The one in the source file is wrong. I did run it but not sure
how it was working... maybe wrong bitfile. I'll look into it
and fix it.

The version value is actually ASCII using all 4
bytes: "110*". The last 'a' is replaced with '*' in the register
as that indicates a documentation only change with no IP changes.

John





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