This implements a driver for the pin multiplexer as present in the ESP32
SoCs.
All APIs are supported.
Jira: ZEP-2297
Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>
The first stage bootloader, part of the ESP32 ROM, already sets up
a stack that's sufficient to execute C programs. So, instead of
implementing __stack() in assembly, do it in C to simplify things
slightly.
This ESP32-specific initialization will perform the following:
- Disable the watchdog timer that's enabled by the bootloader
- Move exception handlers to IRAM
- Disable normal interrupts
- Disable the second CPU
- Zero out the BSS segment
Things that might be performed in the future include setting up the
CPU frequency, memory protection regions, and enabling the flash
cache.
Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>
This is a minimal driver enabling console output during the port
bringup. While the driver works, only one of the three UART devices
are supported, and there isn't any way to change any parameters or
use interrupts. This will most likely be superceded by a proper
driver after the port has matured.
Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>
Leandro Pereira