On 17.08.2015 15:10, Heiner Kallweit wrote: > Am 17.08.2015 um 02:19 schrieb Krzysztof Kozlowski: >> 2015-08-16 20:18 GMT+09:00 Heiner Kallweit <hkallweit1@xxxxxxxxx>: >>> Am 15.08.2015 um 13:19 schrieb Heiner Kallweit: >>>> I'm having issues making the hardware RNG work on a Samsung Exynos 5422 (Odroid XU4) with kernel 4.2rc6. >>>> No random number generation is started if I write the appropriate value (0x18) to the hash control register. >>>> >>>> What I did so far: >>>> Splitted the sss DT node in exynos5420.dtsi into one for the s5p-sss driver and one for the exynos-rng driver. >>>> (s5p-sss doesn't seem to need the hash registers from offset 0x400) >>>> >>>> sss: sss@10830000 { >>>> icompatible = "samsung,exynos4210-secss"; >>>> reg = <0x10830000 0x400>; >>>> interrupts = <0 112 0>; >>>> clocks = <&clock CLK_SSS>; >>>> clock-names = "secss"; >>>> }; >>>> >>>> rng: rng@10830400 { >>>> compatible = "samsung,exynosrng-secss"; >>>> reg = <0x10830400 0x300>; >>>> clocks = <&clock CLK_SSS>; >>>> clock-names = "secss"; >>>> }; >>>> >>>> The DT binding is just for testing and after adding some DT glue logic (of_device_id table) to the exynos-rng driver >>>> it binds to the rng platform device. >>>> The clock also seems to be ok with a rate of 266 MHz. >>>> As is the driver hangs in a loop because the PRNG_DONE in the status register bit never gets set. >>>> >>>> I traced it back to the hash control register not accepting value 0x8 (or 0x18 incl. the start bit) for the PRNG. >>>> Writing a value and reading it back works for values from 0 to 5 only. >>>> As I have no SSS datasheet my only other reference is drivers/crypto/ace_sha.h in the uboot source code >>>> which also uses the HW RNG. >>>> >>>> Any hint would be appreciated. >>>> >>> After some more testing it seems like SSS in general has problems on Exynos 5422. >>> Also the AES implementation in s5p-sss doesn't work. dmesg output: >>> >>> [ 7.116739] alg: skcipher: encryption failed on chunk test 1 for ecb-aes-s5p: ret=22 >>> [ 7.123673] s5p-sss driver registered >> >> Have you tried or looked at vendor code for Samsung mobile devices? >> The code can be downloaded from opensource.samsung.com. I think the >> model with Exynos5422 is SM-G900H. >> >> I don't have any other hints... >> >> Best regards, >> Krzysztof >> . >> > Thanks for your feedback. > > I now took a look at the kernel code Odroid provides, especially the ACE crypto driver. > It's a 3.10.82 kernel with a lot of Samsung code which is not (yet) upstreamed. > > There seem to be different revisions of SSS (ACE driver mentions v.4, v.5, v.6, and Slim SSS). > The vendor kernel uses Slim SSS and the HW AES encryption works. > The code there looks like Exynos 5422 should support also v.5, but it's disabled. > > I didn't test all SSS registers but for the ones I tested I can change the value. > Having said that access to SSS registers is not forbidden. > > Then I changed the memory mapped region to 0x10900000, offset 0x800. According to the > vendor kernel code there should be the registers for hash functions under Slim SSS. > > Not much luck either .. Maybe because Slim SSS uses another clock. > The Slim SSS clock is defined in include/dt-bindings/clock/exynos5420.h already. > I added a clock definition based on the one in the vendor kernel and changed the DT node to use it. > > GATE(CLK_SSS, "sss", "aclk266_g2d", GATE_IP_G2D, 2, 0, 0), > + GATE(CLK_SLIM_SSS, "slimsss", "aclk266_g2d", GATE_IP_G2D, 12, 0, 0), > > But this didn't do the trick yet. Try booting with "clk_ignore_unused" in command line to reduce the chance that wrong clock-hierarchy causes some important clocks to be gated. The clock hierarchy for SSS in mainline is not fully implemented. Beside multiple SSS clocks in GATE_IP_G2D and other places, there are also SSS bus clocks in GATE_BUS_G2D. By default (after reset) they are not gated but who knows what bootloader does with them? Best regards, Krzysztof -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html