From: Ran Wang <ran.wang_1@nxp.com>
To: Felipe Balbi <balbi@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"open list:DESIGNWARE USB3 DRD IP DRIVER"
<linux-usb@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>,
Rob Herring <robh+dt@kernel.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
Leo Li <leoyang.li@nxp.com>
Subject: RE: [PATCH] usb: dwc3: Enable the USB snooping
Date: Mon, 3 Jun 2019 02:33:15 +0000 [thread overview]
Message-ID: <AM5PR0402MB2865D0F0E2B4F65C86D051F8F1140@AM5PR0402MB2865.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <AM5PR0402MB2865F3735D808E1BC9F67968F1180@AM5PR0402MB2865.eurprd04.prod.outlook.com>
Hi Felipe,
On Thursday, May 30, 2019 17:09, Ran Wang wrote:
>
> <snip>
> > >> >> > /* Global Debug Queue/FIFO Space Available Register */
> > >> >> > #define DWC3_GDBGFIFOSPACE_NUM(n) ((n) & 0x1f)
> > >> >> > #define DWC3_GDBGFIFOSPACE_TYPE(n) (((n) << 5) & 0x1e0)
> > >> >> > @@ -859,6 +867,7 @@ struct dwc3_scratchpad_array {
> > >> >> > * 3 - Reserved
> > >> >> > * @imod_interval: set the interrupt moderation interval in 250ns
> > >> >> > * increments or 0 to disable.
> > >> >> > + * @dma_coherent: set if enable dma-coherent.
> > >> >>
> > >> >> you're not enabling dma coherency, you're enabling cache snooping.
> > >> >> And this property should describe that. Also, keep in mind that
> > >> >> different devices may want different cache types for each of
> > >> >> those fields, so your property would have to be a lot more
> > >> >> complex. Something
> > like:
> > >> >>
> > >> >> snps,cache-type = <foobar "cacheable">, <baz "cacheable">, ...
> > >> >>
> > >> >> Then driver would have to parse this properly to setup GSBUSCFG0.
> > >
> > > According to the DesignWare Cores SuperSpeed USB 3.0 Controller
> > > Databook (v2.60a), it has described Type Bit Assignments for all
> > > supported
> > master bus type:
> > > AHB, AXI3, AXI4 and Native. I found the bit definition are different
> > > among
> > them.
> > > So, for the example you gave above, feel a little bit confused.
> > > Did you mean:
> > > snps,cache-type = <DATA_RD "write allocate">, <DESC_RD
> > > "cacheable">, <DATA_WR "bufferable">, <DESC_WR "read allocate">
> >
> > yeah, something like that.
>
> I think DATA_RD should be a macro, right? So, where I can put its define?
> Create a dwc3.h in include/dt-bindings/usb/ ?
Could you please give me some advice here? I'd like to prepare next version patch after
getting this settled.
> Another question about this remain open is: DWC3 data book's Table 6-5 Cache
> Type Bit Assignments show that bits definition will differ per MBUS_TYPEs as
> below:
> ----------------------------------------------------------------
> MBUS_TYPE| bit[3] |bit[2] |bit[1] |bit[0]
> ----------------------------------------------------------------
> AHB |Cacheable |Bufferable |Privilegge |Data
> AXI3 |Write Allocate|Read Allocate|Cacheable |Bufferable
> AXI4 |Allocate Other|Allocate |Modifiable |Bufferable
> AXI4 |Other Allocate|Allocate |Modifiable |Bufferable
> Native |Same as AXI |Same as AXI |Same as AXI|Same as AXI
> ----------------------------------------------------------------
> Note: The AHB, AXI3, AXI4, and PCIe busses use different names for certain
> signals, which have the same meaning:
> Bufferable = Posted
> Cacheable = Modifiable = Snoop (negation of No Snoop)
>
> For Layerscape SoCs, MBUS_TYPE is AXI3. So I am not sure how to use
> snps,cache-type = <DATA_RD "write allocate">, to cover all MBUS_TYPE?
> (you can notice that AHB and AXI3's cacheable are on different bit) Or I just need
> to handle AXI3 case?
Also on this open. Thank you in advance.
Regards,
Ran
next prev parent reply other threads:[~2019-06-03 2:33 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20171115060459.45375-1-ran.wang_1@nxp.com>
[not found] ` <87ineb9b5v.fsf@linux.intel.com>
[not found] ` <VI1PR04MB1504776EF3D4D8C374F0C069F1290@VI1PR04MB1504.eurprd04.prod.outlook.com>
[not found] ` <87shdfet90.fsf@linux.intel.com>
2019-05-28 10:02 ` [PATCH] usb: dwc3: Enable the USB snooping Ran Wang
2019-05-28 10:19 ` Felipe Balbi
2019-05-29 10:12 ` Ran Wang
2019-05-29 10:24 ` Felipe Balbi
2019-05-30 2:17 ` Ran Wang
2019-05-30 9:08 ` Ran Wang
2019-06-03 2:33 ` Ran Wang [this message]
2019-06-17 12:52 ` Felipe Balbi
2019-06-24 1:45 ` Ran Wang
2019-06-24 5:58 ` Felipe Balbi
2019-07-09 7:55 ` Ran Wang
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