uart_tx_wait_idle: fix issue with last character not transmitted

- ROM function uart_tx_wait_idle may have a bug which causes the function to return before the final character is fully transmitted.
  This replaces uart_tx_wait_idle declaration with a static inline definition which fixes the issue.
- Also replaces the use of uart_tx_flush with uart_tx_wait_idle in esp_restart, to remove garbage in console output on restart.
- rtc_printf is temporary replaced with a no-op, pending a new release of librtc.a. Current release assumes that UART0 is used for output,
  and switches UART0 baud rate while doing frequency changes and printing some log output. This doesn’t work if a different UART is used for output.

diff --git a/components/esp32/include/rom/uart.h b/components/esp32/include/rom/uart.h
index aa3cf5921793284db816b89dffe479c787458929..81fa26c23887d5e6ae282ac7fc7605827a71aff4 100644 (file)
--- a/components/esp32/include/rom/uart.h
+++ b/components/esp32/include/rom/uart.h
@@ -18,6 +18,8 @@
 #include "esp_types.h"
 #include "esp_attr.h"
 #include "ets_sys.h"
+#include "soc/soc.h"
+#include "soc/uart_reg.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -260,11 +262,16 @@ void uart_tx_flush(uint8_t uart_no);
 /**
   * @brief Wait until uart tx full empty and the last char send ok.
   *
-  * @param  uint8_t uart_no : 0 for UART0, 1 for UART1.
+  * @param  uart_no : 0 for UART0, 1 for UART1, 2 for UART2
   *
-  * @return None.
+  * The function defined in ROM code has a bug, so we define the correct version
+  * here for compatibility.
   */
-void uart_tx_wait_idle(uint8_t uart_no);
+static inline void uart_tx_wait_idle(uint8_t uart_no) {
+    while(REG_GET_FIELD(UART_STATUS_REG(uart_no), UART_ST_UTX_OUT)) {
+        ;
+    }
+}
 
 /**
   * @brief Get an input char from message channel.

diff --git a/components/esp32/lib_printf.c b/components/esp32/lib_printf.c
index a2aff4cf56bc9fbe54ca6a2b39423583579f2862..417e71bdf752b24259d81307006c060454dfe947 100644 (file)
--- a/components/esp32/lib_printf.c
+++ b/components/esp32/lib_printf.c
@@ -62,11 +62,8 @@ int phy_printf(const char* format, ...)
 
 int rtc_printf(const char* format, ...)
 {
-    va_list arg;
-    va_start(arg, format);
-    int res = lib_printf("rtc", format, arg);
-    va_end(arg);
-    return res;
+    // librtc.a printf temporary disabled due to UART baud rate switching bug.
+    return 0;
 }
 
 int wpa_printf(const char* format, ...)

diff --git a/components/esp32/system_api.c b/components/esp32/system_api.c
index 36a5f806da87aaea802bcc2518bdebed4c945d66..e8013441b14cab59b1fcd2144f8461cccfce0d38 100644 (file)
--- a/components/esp32/system_api.c
+++ b/components/esp32/system_api.c
@@ -105,10 +105,10 @@ void IRAM_ATTR esp_restart(void)
     Cache_Read_Disable(0);
     Cache_Read_Disable(1);
 
-    // Flush any data left in UART FIFO
-    uart_tx_flush(0);
-    uart_tx_flush(1);
-    uart_tx_flush(2);
+    // Flush any data left in UART FIFOs
+    uart_tx_wait_idle(0);
+    uart_tx_wait_idle(1);
+    uart_tx_wait_idle(2);
 
     // Reset wifi/bluetooth (bb/mac)
     SET_PERI_REG_MASK(DPORT_WIFI_RST_EN_REG, 0x1f);