Messages in this thread | | | Subject | Re: [PATCHv1 3/4] dt-bindings: fpga: add authenticate-fpga-config property | From | Richard Gong <> | Date | Tue, 17 Nov 2020 09:39:55 -0600 |
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On 11/16/20 8:24 PM, Xu Yilun wrote: > On Mon, Nov 16, 2020 at 08:14:52AM -0600, Richard Gong wrote: >> >> Hi Yilun, >> >> On 11/15/20 8:47 PM, Xu Yilun wrote: >>> On Sun, Nov 15, 2020 at 11:21:06AM -0800, Moritz Fischer wrote: >>>> Hi Richard, >>>> >>>> On Thu, Nov 12, 2020 at 12:06:42PM -0600, richard.gong@linux.intel.com wrote: >>>>> From: Richard Gong <richard.gong@intel.com> >>>>> >>>>> Add authenticate-fpga-config property for FPGA bitstream authentication. >>>>> >>>>> Signed-off-by: Richard Gong <richard.gong@intel.com> >>>>> --- >>>>> Documentation/devicetree/bindings/fpga/fpga-region.txt | 1 + >>>>> 1 file changed, 1 insertion(+) >>>>> >>>>> diff --git a/Documentation/devicetree/bindings/fpga/fpga-region.txt b/Documentation/devicetree/bindings/fpga/fpga-region.txt >>>>> index e811cf8..7a512bc 100644 >>>>> --- a/Documentation/devicetree/bindings/fpga/fpga-region.txt >>>>> +++ b/Documentation/devicetree/bindings/fpga/fpga-region.txt >>>>> @@ -187,6 +187,7 @@ Optional properties: >>>>> - external-fpga-config : boolean, set if the FPGA has already been configured >>>>> prior to OS boot up. >>>>> - encrypted-fpga-config : boolean, set if the bitstream is encrypted >>>>> +- authenticate-fpga-config : boolean, set if do bitstream authentication >>>> It is unclear to me from the description whether this entails >>>> authentication + reconfiguration or just authentication. >>>> >>>> If the latter is the case this should probably be described as such. >>> >>> If it is just authentication, do we still need to disable bridges in >>> fpga_region_program_fpga? >>> >> >> Yes. >> >> Except for the actual configuration of the device, the authentication >> feature is the same as FPGA configuration. > > FPGA Bridges gate bus signals between a host and FPGA. So the FPGA > region could not be accessed by host when doing configuration. But for > this authentication, we are just writing the flash, we don't actually > touch the FPGA soft logic. The host should still be able to operate on > the old logic before reboot, is it? > Yes, it's feasible in theory but doesn't make much sense in practice. I prefer to keep fpga_region_program_fpga() unchanged.
Regards, Richard
> Thanks, > Yilun > >> >> Regards, >> Richard >> >>> I'm wondering if the FPGA functionalities could still be working when >>> the authenticating is ongoing, or when the authenticating is failed. >>> >> >> >> >>> Thanks, >>> Yilun >>> >>>> >>>>> - region-unfreeze-timeout-us : The maximum time in microseconds to wait for >>>>> bridges to successfully become enabled after the region has been >>>>> programmed. >>>>> -- >>>>> 2.7.4 >>>>> >>>> >>>> Thanks
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