mmc: core: Add mmc CMD+ACMD passthrough ioctl

Allows appropriately-privileged applications to send CMD (normal) and ACMD
(application-specific; preceded with CMD55) commands to cards/devices on
the mmc bus.  This is primarily useful for enabling the security
functionality built in to every SD card.

It can also be used as a generic passthrough (e.g. to enable virtual
machines to control mmc bus devices directly).  However, this use case has
not been tested rigorously.  Generic passthrough testing was only conducted
for a few non-security opcodes to prove the feasibility of the passthrough.

Since any opcode can be sent using this passthrough, it is very possible to
render the card/device unusable.  Applications that use this ioctl must
have CAP_SYS_RAWIO.

Security commands tested on TI PCIxx12 (SDHCI), Sigma Designs SMP8652 SoC,
TI OMAP3621/OMAP3630 SoC, Samsung S5PC110 SoC, Qualcomm MSM7200A SoC.

Signed-off-by: John Calixto <[email protected]>
Reviewed-by: Andrei Warkentin <[email protected]>
Reviewed-by: Arnd Bergmann <[email protected]>
Signed-off-by: Chris Ball <[email protected]>

0 files changed, 0 insertions, 0 deletions