Deep sleep: Any source named rtc_wake_stub* is linked as RTC wake stub code
Also move esp_deepsleep.h documentation out to docs/deep-sleep-stub.rst
See merge request !142
Fix spi_flash_write regression and nvs error recovery
In the previous set of changes related to spi_flash, new alignment checks were added. One of these checks, word alignment of `src` buffer in `nvs_flas_write`, was unnecessary. ROM `SPIWrite` function can handle unaligned source buffers.
This change caused an error to be returned to nvs for some legitimate write operations. Due to a bug in nvs, further write operations were possible, while the internal state of `Page` instance was broken. In WiFi functional tests, this inflicted havoc on the nvs partition, creating multiple duplicate items in the affected page. Because multiple duplicate items per page were never supposed to be handled during page load, duplicates were not removed. Thankfully this caused an assert at a later point in the loading process, otherwise this bug would be very difficult to detect.
This change set fixes the original spi_flash regression, handling of `INVALID` state of `nvs::Page`, and handling of duplicate items.
See merge request !161
Feature/tw8155 optimize tx flow control
1. Remove TX flow control in LWIP
2. Make the return value of esp_wifi_internal_tx consistent with LWIP error code
See merge request !164
API reference, first batch
This includes fixes to documentation formats in header files, some standalone doc fixes, necessary files for readthedocs, and instructions for documenting the code.
See merge request !162
146f5962 - Make the return value of esp_wifi_internal_tx consistent with LWIP error code so that
the up-layer can detect the out-of-memory error and take action accordingly, such do flow control.
1. Add a ring buffer for UART TX.
If the buffer size is set to zero, driver will not use a buffer. But we need a task to send data from buffer to fifo. I tried directly copy data in ISR, but the code looked too long for ISR.
2. Modify the format in uart.h
