[EXT] Re: [PATCH v4 5/5] firmware: imx: adds miscdev

[Pankaj Gupta]

> -----Original Message-----
> From: Randy Dunlap <rdunlap at infradead.org>
> Sent: Saturday, July 6, 2024 2:17 AM
> To: Pankaj Gupta <pankaj.gupta at nxp.com>; Jonathan Corbet
> <corbet at lwn.net>; Rob Herring <robh at kernel.org>; Krzysztof Kozlowski
> <krzk+dt at kernel.org>; Conor Dooley <conor+dt at kernel.org>; Shawn Guo
> <shawnguo at kernel.org>; Sascha Hauer <s.hauer at pengutronix.de>;
> Pengutronix Kernel Team <kernel at pengutronix.de>; Fabio Estevam
> <festevam at gmail.com>; Rob Herring <robh+dt at kernel.org>; Krzysztof
> Kozlowski <krzysztof.kozlowski+dt at linaro.org>
> Cc: linux-doc at vger.kernel.org; linux-kernel at vger.kernel.org;
> devicetree at vger.kernel.org; imx at lists.linux.dev; linux-arm-
> kernel at lists.infradead.org
> Subject: [EXT] Re: [PATCH v4 5/5] firmware: imx: adds miscdev
> 
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> 
> On 7/5/24 6:52 AM, Pankaj Gupta wrote:
> > diff --git a/Documentation/ABI/testing/se-cdev
> b/Documentation/ABI/testing/se-cdev
> > new file mode 100644
> > index 000000000000..97a5b2ca115d
> > --- /dev/null
> > +++ b/Documentation/ABI/testing/se-cdev
> > @@ -0,0 +1,43 @@
> > +What:                /dev/<se>_mu[0-9]+_ch[0-9]+
> > +Date:                May 2024
> > +KernelVersion:       6.8
> > +Contact:     linux-imx at nxp.com, pankaj.gupta at nxp.com
> > +Description:
> > +             NXP offers multiple hardware IP(s) for  secure enclaves like EdgeLock-
> 
>                                                      ^^^ one space only

Will replace "for  secure enclaves", with "for secure enclaves"


> 
> > +             Enclave(ELE), SECO. The character device file descriptors
> > +             /dev/<se>_mu*_ch* are the interface between user-space NXP's
> secure-
> 
> Please use "userspace" or "user space".

Accepted.
> 
> > +             enclave shared library and the kernel driver.
> > +
> > +             The ioctl(2)-based ABI is defined and documented in
> > +             [include]<linux/firmware/imx/ele_mu_ioctl.h>
> 
> End the line above with a period.

Accepted.

> 
> > +              ioctl(s) are used primarily for:
> > +                     - shared memory management
> > +                     - allocation of I/O buffers
> > +                     - getting mu info
> > +                     - setting a dev-ctx as receiver to receive all the commands from
> FW
> > +                     - getting SoC info
> > +                     - send command and receive command response
> > +
> > +             The following file operations are supported:
> > +
> > +             open(2)
> > +               Currently the only useful flags are O_RDWR.
> > +
> > +             read(2)
> > +               Every read() from the opened character device context is waiting on
> > +               wait_event_interruptible, that gets set by the registered mailbox
> callback
> > +               function, indicating a message received from the firmware on
> message-
> > +               unit.
> > +
> > +             write(2)
> > +               Every write() to the opened character device context needs to
> acquire
> > +               mailbox_lock before sending message on to the message unit.
> > +
> > +             close(2)
> > +               Stops and frees up the I/O contexts that were associated
> > +               with the file descriptor.
> > +
> > +Users:
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithu
> b.com%2Fnxp-imx%2Fimx-secure-
> enclave.git&data=05%7C02%7Cpankaj.gupta%40nxp.com%7Cce675eed648
> 24848da5308dc9d33ae7f%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0
> %7C0%7C638558092493138985%7CUnknown%7CTWFpbGZsb3d8eyJWIjoi
> MC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0
> %7C%7C%7C&sdata=fJ97U1mUja7gSpb%2FE1GOx6JdsYpfAUf9rnTuul4TOHs
> %3D&reserved=0,
> > +
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithu
> b.com%2Fnxp-imx%2Fimx-
> smw.git&data=05%7C02%7Cpankaj.gupta%40nxp.com%7Cce675eed648248
> 48da5308dc9d33ae7f%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C
> 0%7C638558092493147090%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4
> wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C
> %7C%7C&sdata=oH0zIc2YQeERpc8lDXuyvQsGMtKjKZSp46t6X9irntU%3D&re
> served=0
> > +             crypto/skcipher,
> > +             drivers/nvmem/imx-ocotp-ele.c
> 
> --
> ~Randy