rockchip: efuse: add (misc) driver for RK3399 non-secure efuse block
This adds a simple driver for reading the efuse block of the RK3399.
It should be easy enough to add drivers for other devices (e.g. the
RK3328, RK3368, etc.) by passing the device details via driver_data.
Unlike the kernel driver (using the nvmem subsystem), we don't expose
the efuse as multiple named cells, but rather as a linear memory that
can be read using misc_read(...).
The primary use case (as of today) is the generation of a 'serial#'
(and a 'cpuid#') environment variable for the RK3399-Q7 (Puma)
system-on-module.
Note that this adds a debug-only (i.e. only if DEBUG is defined)
command 'rk3399_dump_efuses' that dumps the efuse block's content.
N.B.: The name 'rk3399_dump_efuses' was intentionally chosen to
include a SoC-name (together with a comment in the function) to
remind whoever adds support for additional SoCs that this
function currently makes assumptions regarding the size of the
fuse-box based on the RK3399. The hope is that the function is
adjusted to reflect any changes resulting from generalising the
driver for multiple SoCs and is then renamed.
Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index ecca159..92f348f 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -20,6 +20,19 @@
Select this to enable a sysid for Altera devices. Please find
details on the "Embedded Peripherals IP User Guide" of Altera.
+config ROCKCHIP_EFUSE
+ bool "Rockchip e-fuse support"
+ depends on MISC
+ help
+ Enable (read-only) access for the e-fuse block found in Rockchip
+ SoCs: accesses can either be made using byte addressing and a length
+ or through child-nodes that are generated based on the e-fuse map
+ retrieved from the DTS.
+
+ This driver currently supports the RK3399 only, but can easily be
+ extended (by porting the read function from the Linux kernel sources)
+ to support other recent Rockchip devices.
+
config CMD_CROS_EC
bool "Enable crosec command"
depends on CROS_EC