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From: Georges Savoundararadj <gsavoundararadj-svHpOmPGTvqcqzYg7KEe8g@public.gmane.org>
To: Alexander.Steffen-d0qZbvYSIPpWk0Htik3J/w@public.gmane.org,
	tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
Subject: Re: About the SLB9670 TPM 2.0 driver status
Date: Thu, 27 Apr 2017 16:36:12 -0700	[thread overview]
Message-ID: <2e7a5267-5ead-c46a-cc30-b4159ce026a7@witekio.us> (raw)
In-Reply-To: <4b9a97a8d4164d0b9fa8d8c99618b7fc-nFblLGNE8XKJSz+rYg/bSJowlv4uC7bZ@public.gmane.org>

Hi Alexander,

On 04/27/2017 08:40 AM, Alexander.Steffen-d0qZbvYSIPpWk0Htik3J/w@public.gmane.org wrote:
>> Hi Alexander,
>>
>>
>> On 04/26/2017 09:04 AM, Alexander.Steffen-d0qZbvYSIPpWk0Htik3J/w@public.gmane.org wrote:
>>>> I am working with on Infineon SLB9670 TPM 2.0 on SPI.
>>>>
>>>> How well is this chip supported in the mainline kernel?
>>> Unfortunately, due to some small bugs, tpm_tis_spi in mainline is not yet
>> compatible with this device. Starting with 4.12 it should be properly
>> supported.
>> Sounds good!
>>>> I am currently using the linux-socfpga kernel (version 4.8.0; branch
>>>> socfpga-4.8) [1]
>>>> on which I applied the following patches from patchwork:
>>>>
>>>> aacabbe0d5ec tpm_tis_spi: Add small delay after last transfer [2]
>>>> a4a011be786f tpm_tis_spi: Remove limitation of transfers to
>>>> MAX_SPI_FRAMESIZE bytes [3] 840157e08b2f tpm_tis_spi: Check correct
>>>> byte for wait state indicator [4]
>>>> 10cb31aec536 tpm_tis_spi: Abort transfer when too many wait states
>>>> are signaled [5] 3ad7d9172a8c tpm_tis_spi: Use single function to
>>>> transfer data [6] 4a809ec34a0f tpm_tis_core: Choose appropriate
>>>> timeout for reading burstcount [7]
>>>>
>>>> With these patches, I can read the Vendor ID properly.
>>> Those are all the patches that I needed on a Raspberry Pi 2 for the device to
>> work correctly. I did not use 4.8 though, but worked with 4.10.
>>>> But, the driver initialization fails in the tpm2_probe function.
>>> Could you be more specific? What exactly fails? What data is transferred
>> to/from the TPM when it fails?
>> I tried again on the 4.11-rc8 kernel with the latest patches from linux-tpmdd
>> to be integrated in 4.12 (between tpmdd-next-20170220 and
>> tpmdd-next-20170425) and I got the same failure.
>>
>> The following function calls fails
>> * tpm2_probe
>> ** tpm_transmit_cmd
>> *** tpm_transmit
>> **** chips->ops->send/tpm_tis_send
>> ***** tpm_tis_send_main
>> ****** tpm_tis_send_data
>>
>> tpm_tis_send_data fails at this moment when it checks the status:
>>
>>       status = tpm_tis_status(chip);
>>       if (!itpm && (status & TPM_STS_DATA_EXPECT) != 0) {
>>           rc = -EIO;
>>           goto out_err;
>>       }
> Sounds like a communication problem then. The TPM claims to have received less data than necessary for that command, so it did not see some of the bytes that the driver sent.
>
> The difference between this transfer that fails and the others that you say are successful is the amount of data transferred in a single SPI frame. You could force the driver to split up the data into smaller frames by replacing "burstcnt = min_t(...)" in tpm_tis_send_data with "burstcnt = 1" and see whether this makes a difference. Changing the SPI clock speed might also be worth a try.
>
> Do you have any other device that can talk to the TPM (maybe a Raspberry Pi 2, since I know those to work)? If so, you can use it first to rule out a general problem with your TPM and then to compare the SPI signals on the line with your other system. We had the problem with a Raspberry Pi 2, that its SPI master under some circumstances generated incorrect signals that the TPM (correctly) did not understand (hence the need for https://patchwork.kernel.org/patch/9600213/).
The driver is now initializing correctly. The problem was related to the 
SPI Slave Select signal.

I am using the SLB9670 TPM 2.0 on a Altera Cyclone V-based board which 
relies for the SPI communication on the  DesignWare SPI controller 
(drivers/spi/spi-dw.c).
According to the commit 80b444e57948ea4bd5a89fb1f8c404ddab6c1973, this 
controller requires the GPIO Slave Select to be used with the internal 
chip select.

To fix the issue, I had to configure the SPIM0_SS pin as GPIO 
(GENERALIO12(0xFFD084B0)=0) and to add in the device tree the property 
"cs-gpios" as follow:

&spi0 {
         status = "okay";
         cs-gpios = <&portc 2 0>; /* SPI_SS */

         tpm0@0 {
                 reg = <0>;
                 compatible = "infineon,slb9670";
                 spi-max-frequency = <10000000>;
         };
};

Thanks,

Georges


>> The data transferred is the command defined in the tpm2_probe function.
>>
>> Thanks,
>>
>> Georges
>>> Alexander

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      parent reply	other threads:[~2017-04-27 23:36 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-26  2:12 About the SLB9670 TPM 2.0 driver status Georges Savoundararadj
     [not found] ` <e7ee0491-3f29-5578-7cc4-af9c0a73dcb3-svHpOmPGTvqcqzYg7KEe8g@public.gmane.org>
2017-04-26 10:37   ` Jarkko Sakkinen
2017-04-26 16:04   ` Alexander.Steffen-d0qZbvYSIPpWk0Htik3J/w
     [not found]     ` <a5616ca471a64e5ab4809a231966987b-nFblLGNE8XKJSz+rYg/bSJowlv4uC7bZ@public.gmane.org>
2017-04-26 18:47       ` Georges Savoundararadj
     [not found]         ` <39067149-b6e1-04e2-7677-5dc054475140-svHpOmPGTvqcqzYg7KEe8g@public.gmane.org>
2017-04-27 15:40           ` Alexander.Steffen-d0qZbvYSIPpWk0Htik3J/w
     [not found]             ` <4b9a97a8d4164d0b9fa8d8c99618b7fc-nFblLGNE8XKJSz+rYg/bSJowlv4uC7bZ@public.gmane.org>
2017-04-27 23:36               ` Georges Savoundararadj [this message]

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