Hi Elena,
Elena Unix elenaunix01@gmail.com wrote on Mon, 17 Jun 2019 15:46:29 +0200:
Hi Miquèl,
Thank you for your answer.
Miquel Raynal miquel.raynal@bootlin.com wrote on Mon, 17 Jun 2019 10:44:52 +0200:
Hi Elena,
Elena Unix elenaunix01@gmail.com wrote on Fri, 14 Jun 2019 09:43:46 +0200:
Hello,
I am trying to enable the TPM 2.0 SLB9670 in U-Boot for a Raspberry Pi 3 B+. More precisely, the TPM is on an add-on board, the IRIDIUM SLB9670. The communication between the RPI and the TPM is ensured by SPI so I enabled the software spi driver (spi-gpio) in U-Boot because the bcm28x spi driver is not available in U-Boot.
CONFIG_SPI=y CONFIG_DM_SPI=y CONFIG_SOFT_SPI=y
Are you sure the SPI bus is correctly driven? Can you connect anything else and ensure it works? You may also probe all the GPIO lines (using an oscilloscope) and check each of them is clocked correctly.
I simply checked by doing a loopback test, i.e connecting MISO and MOSI by a cable and it worked. I will test with an oscilloscope when I have one and keep you up to date.
Then, I enabled the TPM support in U-Boot.
CONFIG_CMD_TPM_V2=y CONFIG_CMD_TPM=y
If you use TPM V2, CMD_TPM is not needed. But that's not your problem.
CONFIG_TPM_V2=y CONFIG_TPM2_TIS_SPI=y CONFIG_TPM=y
Looks fine.
Finally, I updated my Device Tree. /dts-v1/ / { ... aliases { spi0 = &soft_spi; };
soft_spi: soft-spi { compatible = "spi-gpio"; pinctrl-names = "default"; pinctrl-0 = <&spi0_gpio7>; status = "okay"; gpio-sck = <&gpio 11 0>; gpio-mosi = <&gpio 10 0>; gpio-miso = <&gpio 9 0>; cs-gpios = <&gpio 7 1>; #address-cells = <1>; #size-cells = <0>;
slb9670: slb9670@0 { compatible = "tis,tpm2-spi"; reg = <1>; #address-cells = <1>; #size-cells = <0>; spi-max-frequency = <32000000>;You might want to slow down a bit this frequency, try it with 1MHz, just for testing (and see something meaningful with the scope).
I tried to lower the frequency to 1MHZ but without success.
status = "okay"; };};
spio0_gpio7: spio0_gpio7 { brcm,pins = <7 8 9 10 11>; brcm,function = <4>;
If you bit-bang the SPI bus, I suppose you must use the GPIO function on each pin, is <4> the GPIO function or the SPI function?
No the <4> function is the SPI function, thank you it was a mistake. I changed it to GPIO function but I have the same errors when executing tpm2 commands in U-Boot.
}; ... };
But, when I try to execute the following command : U-Boot> tpm2 init
I have the following response :
tpm_tis_spi_probe : missing reset GPIO
This is indeed harmless, just a warning.
tpm_tis_spi_request_locality : Timeout getting locality : -2
This usually means you cannot talk to the chip.
tpm_tis_spi_probe : could not request locality 0 Could not find TPM (ret=-2)
The Iridium board contains a reset circuit on board, which pulls the reset line of the TPM to GND after VCC becomes available, so the reset GPIO is not needed I think.
I don’t see what is wrong with my setup, a little help would be very appreciated.
Thank you in advance, Elena ___________
Good luck, Miquèl
Moreover, I commented out the tpm_tis_spi_request_locality() function in the TPM driver just to perform a test by executing the U-Boot> tpm2 init I then had the following response : tpm_tis_spi_probe() SPI TPMv2.0 found (vid:15d1, did:001b, rid:10)
Right, so it seems that the communication works.
Back to debugging then, you may dump the bytes read/written in your SPI driver's read/write callbacks. Once you'll have a working solution, it would be very appreciated if you could contribute it back. Good luck!
Thanks, Miquèl