On Wed, Sep 22, 2021 at 4:12 AM Joel Stanley [off-list ref] wrote:

On Tue, 21 Sept 2021 at 21:47, Emmanuel Gil Peyrot
[off-list ref] wrote:

quoted

This engine implements AES in CBC mode, using 128-bit keys only.  It is
present on both the Wii and the Wii U, and is apparently identical in
both consoles.

The hardware is capable of firing an interrupt when the operation is
done, but this driver currently uses a busy loop, I’m not too sure
whether it would be preferable to switch, nor how to achieve that.

It also supports a mode where no operation is done, and thus could be
used as a DMA copy engine, but I don’t know how to expose that to the
kernel or whether it would even be useful.

In my testing, on a Wii U, this driver reaches 80.7 MiB/s, while the
aes-generic driver only reaches 30.9 MiB/s, so it is a quite welcome
speedup.

This driver was written based on reversed documentation, see:
https://wiibrew.org/wiki/Hardware/AES

Signed-off-by: Emmanuel Gil Peyrot <redacted>
Tested-by: Emmanuel Gil Peyrot <redacted>  # on Wii U
---
 drivers/crypto/Kconfig        |  11 ++
 drivers/crypto/Makefile       |   1 +
 drivers/crypto/nintendo-aes.c | 273 ++++++++++++++++++++++++++++++++++
 3 files changed, 285 insertions(+)
 create mode 100644 drivers/crypto/nintendo-aes.c

diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig
index 9a4c275a1335..adc94ad7462d 100644
--- a/drivers/crypto/Kconfig
+++ b/drivers/crypto/Kconfig

@@ -871,4 +871,15 @@ config CRYPTO_DEV_SA2UL

 source "drivers/crypto/keembay/Kconfig"

+config CRYPTO_DEV_NINTENDO
+       tristate "Support for the Nintendo Wii U AES engine"
+       depends on WII || WIIU || COMPILE_TEST

This current seteup will allow the driver to be compile tested for
non-powerpc, which will fail on the dcbf instructions.

Perhaps use this instead:

       depends on WII || WIIU || (COMPILE_TEST && PPC)

Or:

    depends on PPC
    depends on WII || WIIU || COMPILE_TEST

to distinguish between hard and soft dependencies.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds