From 43191db63e9f4132a29c10160a32742d8165ec76 Mon Sep 17 00:00:00 2001
From: Deomid Ryabkov <rojer@cesanta.com>
Date: Wed, 11 Apr 2018 18:31:26 +0100
Subject: [PATCH] Fix boot loader UART baud rate on soft reboot
Also remove `-O3` optimization flasg, it negates `-Os`. Saves ~400 bytes.
CL: none
PUBLISHED_FROM=f40f42e4f54a8e0e003ab65ec8f5838c2d932876
---
.../platforms/esp8266/rboot/rboot/rboot.c | 20 ++++++++++++++++---
.../platforms/esp8266/rboot/rboot/rboot.mk | 2 +-
2 files changed, 18 insertions(+), 4 deletions(-)
diff --git a/src/common/platforms/esp8266/rboot/rboot/rboot.c b/src/common/platforms/esp8266/rboot/rboot/rboot.c
index 4ac5df18b..6f7521423 100644
--- a/src/common/platforms/esp8266/rboot/rboot/rboot.c
+++ b/src/common/platforms/esp8266/rboot/rboot/rboot.c
@@ -160,7 +160,8 @@ static uint8 calc_chksum(uint8 *start, uint8 *end) {
}
#endif
-#define UART_CLKDIV_26MHZ(B) (52000000 + B / 2) / B
+#define UART_CLKDIV_80MHZ(B) (80000000 + B / 2) / B
+#define UART_CLKDIV_52MHZ(B) (52000000 + B / 2) / B
// prevent this function being placed inline with main
// to keep main's stack size as small as possible
@@ -182,10 +183,23 @@ uint32 NOINLINE find_image(void) {
// delay to slow boot (help see messages when debugging)
//ets_delay_us(2000000);
- uart_div_modify(0, UART_CLKDIV_26MHZ(115200));
+ /*
+ * UART divider depends on the APB frequency. Cold boot starts with 52MHz APB,
+ * SDK configures PLL, sets it to 80 and it persists across soft reset
+ * so on soft reset a different divider should be used. What we really want to
+ * know is if the PLL is running but since that is completely undocumented
+ * we use CPU frequency bit as a workaround: mos sets CPU to 160 MHz on startup
+ * so we assume that if frequency is preserved, then it's soft reset, PLL is
+ * running and APB is at 80 MHz.
+ */
+ if (READ_PERI_REG(0x3ff00014) & 1) {
+ uart_div_modify(0, UART_CLKDIV_80MHZ(115200));
+ } else {
+ uart_div_modify(0, UART_CLKDIV_52MHZ(115200));
+ }
ets_delay_us(1000);
- ets_printf("\r\nrBoot v1.2.1 - richardaburton@gmail.com\r\n");
+ ets_printf("\r\nrBoot v1.2.1-cesanta1 - richardaburton@gmail.com\r\n");
// read rom header
SPIRead(0, header, sizeof(rom_header));
diff --git a/src/common/platforms/esp8266/rboot/rboot/rboot.mk b/src/common/platforms/esp8266/rboot/rboot/rboot.mk
index f7f398784..419ba5a8d 100644
--- a/src/common/platforms/esp8266/rboot/rboot/rboot.mk
+++ b/src/common/platforms/esp8266/rboot/rboot/rboot.mk
@@ -23,7 +23,7 @@ LD := $(addprefix $(XTENSA_BINDIR)/,xtensa-lx106-elf-gcc)
endif
CC_WRAPPER ?=
-CFLAGS = -Os -O3 -Wpointer-arith -Wundef -Werror -Wl,-EL \
+CFLAGS = -Os -Wpointer-arith -Wundef -Werror -Wl,-EL \
-fno-inline-functions -nostdlib -mlongcalls -mtext-section-literals \
-D__ets__ -DIRAM='__attribute__((section(".fast.text")))' \
-DNOINSTR='__attribute__((no_instrument_function))' \
--
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