feat: support riscv32

targets/esp32c2.memory.ld

@@ -0,0 +1,33 @@
+# See "System Structure and Address Mapping" figure at
+# https://www.espressif.com/sites/default/files/documentation/esp8684_technical_reference_manual_en.pdf
+
+ICACHE_SIZE = 0x4000;
+# Skip possible ICACHE area
+IRAM_START_ADDRESS = 0x4037C000 + ICACHE_SIZE;
+IRAM_LEN = 0x40000 - ICACHE_SIZE;
+
+DRAM_START_ADDRESS = 0x3FCA0000;
+DRAM_LEN = 0x40000;
+
+# Docs say that:
+# The default console baud rate on ESP32-C2:
+#  - 115200 when a 40 MHz XTAL is used
+#  - 74880 when a 26 MHz XTAL is used
+#
+# It seems something wrong with CPU_FREQUENCY and UART0_BAUD definitions,
+# but UART0_CLKDIV_VAL == 173 gives expected baud rate 74880 on 26 MHz XTAL.
+CPU_FREQUENCY = 20000000;
+UART0_BAUD = 115200;
+
+UART0_CLKDIV_REG = 0x60000014;
+UART0_CLKDIV_VAL = CPU_FREQUENCY / UART0_BAUD;
+UART0_STATUS = 0x6000001C;
+UART0_TX_ADDR = 0x60000000;
+
+MEMORY
+{
+  iram_seg  (RX) : org = IRAM_START_ADDRESS, len = IRAM_LEN
+  dram_seg  (RW) : org = DRAM_START_ADDRESS, len = DRAM_LEN
+}
+
+INCLUDE "targets/esp32-riscv.app.elf.ld";