Chitu variant for disk-based update (#18264)

buildroot/share/PlatformIO/variants/CHITU_F103/wirish/boards.cpp

@@ -0,0 +1,225 @@
+/******************************************************************************
+ * The MIT License
+ *
+ * Copyright (c) 2010 Perry Hung.
+ * Copyright (c) 2011, 2012 LeafLabs, LLC.
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy,
+ * modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *****************************************************************************/
+
+/**
+ * @file wirish/boards.cpp
+ * @brief init() and board routines.
+ *
+ * This file is mostly interesting for the init() function, which
+ * configures Flash, the core clocks, and a variety of other available
+ * peripherals on the board so the rest of Wirish doesn't have to turn
+ * things on before using them.
+ *
+ * Prior to returning, init() calls boardInit(), which allows boards
+ * to perform any initialization they need to. This file includes a
+ * weak no-op definition of boardInit(), so boards that don't need any
+ * special initialization don't have to define their own.
+ *
+ * How init() works is chip-specific. See the boards_setup.cpp files
+ * under e.g. wirish/stm32f1/, wirish/stmf32f2 for the details, but be
+ * advised: their contents are unstable, and can/will change without
+ * notice.
+ */
+
+#include <boards.h>
+#include <libmaple/libmaple_types.h>
+#include <libmaple/flash.h>
+#include <libmaple/nvic.h>
+#include <libmaple/systick.h>
+#include "boards_private.h"
+
+static void setup_flash(void);
+static void setup_clocks(void);
+static void setup_nvic(void);
+static void setup_adcs(void);
+static void setup_timers(void);
+
+/*
+ * Exported functions
+ */
+
+void init(void) {
+    setup_flash();
+    setup_clocks();
+    setup_nvic();
+    systick_init(SYSTICK_RELOAD_VAL);
+    wirish::priv::board_setup_gpio();
+    setup_adcs();
+    setup_timers();
+    wirish::priv::board_setup_usb();
+    wirish::priv::series_init();
+    boardInit();
+}
+
+/* Provide a default no-op boardInit(). */
+__weak void boardInit(void) {
+}
+
+/* You could farm this out to the files in boards/ if e.g. it takes
+ * too long to test on boards with lots of pins. */
+bool boardUsesPin(uint8 pin) {
+    for (int i = 0; i < BOARD_NR_USED_PINS; i++) {
+        if (pin == boardUsedPins[i]) {
+            return true;
+        }
+    }
+    return false;
+}
+
+/*
+ * Auxiliary routines
+ */
+
+static void setup_flash(void) {
+    // Turn on as many Flash "go faster" features as
+    // possible. flash_enable_features() just ignores any flags it
+    // can't support.
+    flash_enable_features(FLASH_PREFETCH | FLASH_ICACHE | FLASH_DCACHE);
+    // Configure the wait states, assuming we're operating at "close
+    // enough" to 3.3V.
+    flash_set_latency(FLASH_SAFE_WAIT_STATES);
+}
+
+static void setup_clocks(void) {
+    // Turn on HSI. We'll switch to and run off of this while we're
+    // setting up the main PLL.
+    rcc_turn_on_clk(RCC_CLK_HSI);
+
+    // Turn off and reset the clock subsystems we'll be using, as well
+    // as the clock security subsystem (CSS). Note that resetting CFGR
+    // to its default value of 0 implies a switch to HSI for SYSCLK.
+    RCC_BASE->CFGR = 0x00000000;
+    rcc_disable_css();
+    rcc_turn_off_clk(RCC_CLK_PLL);
+    rcc_turn_off_clk(RCC_CLK_HSE);
+    wirish::priv::board_reset_pll();
+    // Clear clock readiness interrupt flags and turn off clock
+    // readiness interrupts.
+    RCC_BASE->CIR = 0x00000000;
+#if !USE_HSI_CLOCK
+    // Enable HSE, and wait until it's ready.
+    rcc_turn_on_clk(RCC_CLK_HSE);
+    while (!rcc_is_clk_ready(RCC_CLK_HSE))
+        ;
+#endif
+    // Configure AHBx, APBx, etc. prescalers and the main PLL.
+    wirish::priv::board_setup_clock_prescalers();
+    rcc_configure_pll(&wirish::priv::w_board_pll_cfg);
+
+    // Enable the PLL, and wait until it's ready.
+    rcc_turn_on_clk(RCC_CLK_PLL);
+    while(!rcc_is_clk_ready(RCC_CLK_PLL))
+        ;
+
+    // Finally, switch to the now-ready PLL as the main clock source.
+    rcc_switch_sysclk(RCC_CLKSRC_PLL);
+}
+
+/*
+ * These addresses are where usercode starts when a bootloader is
+ * present. If no bootloader is present, the user NVIC usually starts
+ * at the Flash base address, 0x08000000.
+ */
+#if defined(BOOTLOADER_maple)
+	#define USER_ADDR_ROM 0x08005000
+#else
+	#define USER_ADDR_ROM 0x08000000
+#endif
+#define USER_ADDR_RAM 0x20000C00
+extern char __text_start__;
+
+static void setup_nvic(void) {
+
+nvic_init((uint32)VECT_TAB_ADDR, 0);
+
+/* Roger Clark. We now control nvic vector table in boards.txt using the build.vect paramater
+#ifdef VECT_TAB_FLASH
+    nvic_init(USER_ADDR_ROM, 0);
+#elif defined VECT_TAB_RAM
+    nvic_init(USER_ADDR_RAM, 0);
+#elif defined VECT_TAB_BASE
+    nvic_init((uint32)0x08000000, 0);
+#elif defined VECT_TAB_ADDR
+    // A numerically supplied value
+    nvic_init((uint32)VECT_TAB_ADDR, 0);
+#else
+    // Use the __text_start__ value from the linker script; this
+    // should be the start of the vector table.
+    nvic_init((uint32)&__text_start__, 0);
+#endif
+
+*/
+}
+
+static void adc_default_config(adc_dev *dev) {
+    adc_enable_single_swstart(dev);
+    adc_set_sample_rate(dev, wirish::priv::w_adc_smp);
+}
+
+static void setup_adcs(void) {
+    adc_set_prescaler(wirish::priv::w_adc_pre);
+    adc_foreach(adc_default_config);
+}
+
+static void timer_default_config(timer_dev *dev) {
+    timer_adv_reg_map *regs = (dev->regs).adv;
+    const uint16 full_overflow = 0xFFFF;
+    const uint16 half_duty = 0x8FFF;
+
+    timer_init(dev);
+    timer_pause(dev);
+
+    regs->CR1 = TIMER_CR1_ARPE;
+    regs->PSC = 1;
+    regs->SR = 0;
+    regs->DIER = 0;
+    regs->EGR = TIMER_EGR_UG;
+    switch (dev->type) {
+    case TIMER_ADVANCED:
+        regs->BDTR = TIMER_BDTR_MOE | TIMER_BDTR_LOCK_OFF;
+        // fall-through
+    case TIMER_GENERAL:
+        timer_set_reload(dev, full_overflow);
+        for (uint8 channel = 1; channel <= 4; channel++) {
+            if (timer_has_cc_channel(dev, channel)) {
+                timer_set_compare(dev, channel, half_duty);
+                timer_oc_set_mode(dev, channel, TIMER_OC_MODE_PWM_1,
+                                  TIMER_OC_PE);
+            }
+        }
+        // fall-through
+    case TIMER_BASIC:
+        break;
+    }
+
+    timer_generate_update(dev);
+    timer_resume(dev);
+}
+
+static void setup_timers(void) {
+    timer_foreach(timer_default_config);
+}

buildroot/share/PlatformIO/variants/CHITU_F103/wirish/boards_setup.cpp

@@ -0,0 +1,123 @@
+/******************************************************************************
+ * The MIT License
+ *
+ * Copyright (c) 2012 LeafLabs, LLC.
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy,
+ * modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+*****************************************************************************/
+
+/**
+ * @file wirish/stm32f1/boards_setup.cpp
+ * @author Marti Bolivar <mbolivar@leaflabs.com>
+ * @brief STM32F1 chip setup.
+ *
+ * This file controls how init() behaves on the STM32F1. Be very
+ * careful when changing anything here. Many of these values depend
+ * upon each other.
+ */
+
+#include "boards_private.h"
+
+#include <libmaple/gpio.h>
+#include <libmaple/timer.h>
+
+#include <boards.h>
+#include <usb_serial.h>
+
+// Allow boards to provide a PLL multiplier. This is useful for
+// e.g. STM32F100 value line MCUs, which use slower multipliers.
+// (We're leaving the default to RCC_PLLMUL_9 for now, since that
+// works for F103 performance line MCUs, which is all that LeafLabs
+// currently officially supports).
+#ifndef BOARD_RCC_PLLMUL
+  #if !USE_HSI_CLOCK
+  #if F_CPU==128000000
+    #define BOARD_RCC_PLLMUL RCC_PLLMUL_16
+  #elif F_CPU==72000000
+    #define BOARD_RCC_PLLMUL RCC_PLLMUL_9
+  #elif F_CPU==48000000
+    #define BOARD_RCC_PLLMUL RCC_PLLMUL_6
+  #elif F_CPU==16000000
+    #define BOARD_RCC_PLLMUL RCC_PLLMUL_2
+  #endif
+  #else
+  #define BOARD_RCC_PLLMUL RCC_PLLMUL_16
+  #endif
+#endif
+
+namespace wirish {
+    namespace priv {
+
+        static stm32f1_rcc_pll_data pll_data = {BOARD_RCC_PLLMUL};
+#if !USE_HSI_CLOCK
+        __weak rcc_pll_cfg w_board_pll_cfg = {RCC_PLLSRC_HSE, &pll_data};
+#else
+        __weak rcc_pll_cfg w_board_pll_cfg = {RCC_PLLSRC_HSI_DIV_2, &pll_data};
+#endif
+        __weak adc_prescaler w_adc_pre = ADC_PRE_PCLK2_DIV_6;
+        __weak adc_smp_rate w_adc_smp = ADC_SMPR_55_5;
+
+        __weak void board_reset_pll(void) {
+            // TODO
+        }
+
+        __weak void board_setup_clock_prescalers(void) {
+            rcc_set_prescaler(RCC_PRESCALER_AHB, RCC_AHB_SYSCLK_DIV_1);
+            rcc_set_prescaler(RCC_PRESCALER_APB1, RCC_APB1_HCLK_DIV_2);
+            rcc_set_prescaler(RCC_PRESCALER_APB2, RCC_APB2_HCLK_DIV_1);
+      rcc_clk_disable(RCC_USB);
+      #if F_CPU == 72000000
+      rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);
+      #elif F_CPU == 48000000
+      rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1);     
+      #endif  
+        }
+
+        __weak void board_setup_gpio(void) {
+            gpio_init_all();
+        }
+
+        __weak void board_setup_usb(void) {
+      
+
+  
+#ifdef SERIAL_USB 
+#ifdef GENERIC_BOOTLOADER     
+      //Reset the USB interface on generic boards - developed by Victor PV
+      gpio_set_mode(PIN_MAP[PA12].gpio_device, PIN_MAP[PA12].gpio_bit, GPIO_OUTPUT_PP);
+      gpio_write_bit(PIN_MAP[PA12].gpio_device, PIN_MAP[PA12].gpio_bit,0);
+      
+      for(volatile unsigned int i=0;i<512;i++);// Only small delay seems to be needed, and USB pins will get configured in Serial.begin
+      gpio_set_mode(PIN_MAP[PA12].gpio_device, PIN_MAP[PA12].gpio_bit, GPIO_INPUT_FLOATING);
+#endif  
+
+      Serial.begin();// Roger Clark. Changed SerialUSB to Serial for Arduino sketch compatibility
+#endif
+        }
+
+        __weak void series_init(void) {
+            // Initialize AFIO here, too, so peripheral remaps and external
+            // interrupts work out of the box.
+            afio_init();
+        }
+
+    }
+}

buildroot/share/PlatformIO/variants/CHITU_F103/wirish/start.S

@@ -0,0 +1,57 @@
+/******************************************************************************
+ * The MIT License
+ *
+ * Copyright (c) 2011 LeafLabs, LLC.
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy,
+ * modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *****************************************************************************/
+
+/*
+ * This file is a modified version of a file obtained from
+ * CodeSourcery Inc. (now part of Mentor Graphics Corp.), in which the
+ * following text appeared:
+ *
+ * The authors hereby grant permission to use, copy, modify, distribute,
+ * and license this software and its documentation for any purpose, provided
+ * that existing copyright notices are retained in all copies and that this
+ * notice is included verbatim in any distributions. No written agreement,
+ * license, or royalty fee is required for any of the authorized uses.
+ * Modifications to this software may be copyrighted by their authors
+ * and need not follow the licensing terms described here, provided that
+ * the new terms are clearly indicated on the first page of each file where
+ * they apply.
+ */
+
+        .text
+        .code 16
+        .thumb_func
+
+        .globl __start__
+        .type __start__, %function
+__start__:
+        .fnstart
+        ldr r1,=__msp_init
+        mov sp,r1
+        ldr r1,=start_c
+        bx r1
+        .pool
+        .cantunwind
+        .fnend

buildroot/share/PlatformIO/variants/CHITU_F103/wirish/start_c.c

@@ -0,0 +1,144 @@
+/******************************************************************************
+ * The MIT License
+ *
+ * Copyright (c) 2011 LeafLabs, LLC.
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy,
+ * modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *****************************************************************************/
+
+/*
+ * This file is a modified version of a file obtained from
+ * CodeSourcery Inc. (now part of Mentor Graphics Corp.), in which the
+ * following text appeared:
+ *
+ * Copyright (c) 2006, 2007 CodeSourcery Inc
+ *
+ * The authors hereby grant permission to use, copy, modify, distribute,
+ * and license this software and its documentation for any purpose, provided
+ * that existing copyright notices are retained in all copies and that this
+ * notice is included verbatim in any distributions. No written agreement,
+ * license, or royalty fee is required for any of the authorized uses.
+ * Modifications to this software may be copyrighted by their authors
+ * and need not follow the licensing terms described here, provided that
+ * the new terms are clearly indicated on the first page of each file where
+ * they apply.
+ */
+
+#include <stddef.h>
+
+#include <libmaple/rcc.h>
+#include <libmaple/libmaple.h>
+#include <libmaple/bitband.h>
+
+#include "rcc_private.h"
+
+#include <libmaple/usart.h>
+#include <libmaple/gpio.h>
+#include "usart_private.h"
+
+#include <libmaple/sdio.h>
+#include <string.h>
+
+extern void __libc_init_array(void);
+
+extern int main(int, char**, char**);
+
+extern void exit(int) __attribute__((noreturn, weak));
+
+/* The linker must ensure that these are at least 4-byte aligned. */
+extern char __data_start__, __data_end__;
+extern char __bss_start__, __bss_end__;
+
+struct rom_img_cfg {
+    int *img_start;
+};
+
+extern char _lm_rom_img_cfgp;
+extern void __lm_error();
+extern void timer_disable_all();
+
+    /* Turn off ADC */
+extern void adc_disable_all();
+
+    /* Turn off all USARTs */
+extern void usart_disable_all();
+extern void DisableEverything();
+
+void __attribute__((noreturn)) start_c(void) {
+    struct rom_img_cfg *img_cfg = (struct rom_img_cfg*)&_lm_rom_img_cfgp;
+    int *src = img_cfg->img_start;
+    int *dst = (int*)&__data_start__;
+    int exit_code;
+
+    asm("CPSID I");
+    /* Reset the RCC clock configuration to the default reset state(for debug purpose) */
+    /* Set HSION bit */
+    RCC_BASE->CR |= 0x00000001U;
+
+    /* Reset SW, HPRE, PPRE1, PPRE2, ADCPRE and MCO bits */
+    RCC_BASE->CFGR &= 0xF0FF0000U;
+
+    /* Reset HSEON, CSSON and PLLON bits */
+    RCC_BASE->CR &= 0xFEF6FFFFU;
+
+    /* Reset HSEBYP bit */
+    RCC_BASE->CR &= 0xFFFBFFFFU;
+
+    /* Reset PLLSRC, PLLXTPRE, PLLMUL and USBPRE/OTGFSPRE bits */
+    RCC_BASE->CFGR &= 0xFF80FFFFU;
+
+    /* Disable all interrupts and clear pending bits  */
+    RCC_BASE->CIR = 0x009F0000U;
+
+    USART1_BASE->CR1 = 0;
+    USART1_BASE->CR2 = 0;
+    USART1_BASE->CR3 = 0;
+
+    memset(SDIO_BASE, 0, sizeof(sdio_reg_map));
+    asm("CPSIE I");
+
+    /* Initialize .data, if necessary. */
+    if (src != dst) {
+        int *end = (int*)&__data_end__;
+        while (dst < end) {
+            *dst++ = *src++;
+        }
+    }
+
+    /* Zero .bss. */
+    dst = (int*)&__bss_start__;
+    while (dst < (int*)&__bss_end__) {
+        *dst++ = 0;
+    }
+
+    /* Run initializers. */
+    __libc_init_array();
+
+    /* Jump to main. */
+    exit_code = main(0, 0, 0);
+    if (exit) {
+        exit(exit_code);
+    }
+
+    /* If exit is NULL, make sure we don't return. */
+    for (;;)
+        continue;
+}

buildroot/share/PlatformIO/variants/CHITU_F103/wirish/syscalls.c

@@ -0,0 +1,176 @@
+/******************************************************************************
+ * The MIT License
+ *
+ * Copyright (c) 2010 Perry Hung.
+ * Copyright (c) 2011, 2012 LeafLabs, LLC.
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy,
+ * modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *****************************************************************************/
+
+/**
+ * @file wirish/syscalls.c
+ * @brief newlib stubs
+ *
+ * Low level system routines used by newlib for basic I/O and memory
+ * allocation. You can override most of these.
+ */
+
+#include <libmaple/libmaple.h>
+
+#include <sys/stat.h>
+#include <errno.h>
+#include <stddef.h>
+
+/* If CONFIG_HEAP_START (or CONFIG_HEAP_END) isn't defined, then
+ * assume _lm_heap_start (resp. _lm_heap_end) is appropriately set by
+ * the linker */
+#ifndef CONFIG_HEAP_START
+extern char _lm_heap_start;
+#define CONFIG_HEAP_START               ((void *)&_lm_heap_start)
+#endif
+#ifndef CONFIG_HEAP_END
+extern char _lm_heap_end;
+#define CONFIG_HEAP_END                 ((void *)&_lm_heap_end)
+#endif
+
+/*
+ * _sbrk -- Increment the program break.
+ *
+ * Get incr bytes more RAM (for use by the heap).  malloc() and
+ * friends call this function behind the scenes.
+ */
+void *_sbrk(int incr) {
+    static void * pbreak = NULL; /* current program break */
+    void * ret;
+
+    if (pbreak == NULL) {
+        pbreak = CONFIG_HEAP_START;
+    }
+
+    if ((CONFIG_HEAP_END - pbreak < incr) ||
+        (pbreak - CONFIG_HEAP_START < -incr)) {
+        errno = ENOMEM;
+        return (void *)-1;
+    }
+
+    ret = pbreak;
+    pbreak += incr;
+    return ret;
+}
+
+__weak int _open(const char *path __attribute__((unused)), int flags __attribute__((unused)), ...) {
+    return 1;
+}
+
+__weak int _close(int fd __attribute__((unused))) {
+    return 0;
+}
+
+__weak int _fstat(int fd __attribute__((unused)), struct stat *st) {
+    st->st_mode = S_IFCHR;
+    return 0;
+}
+
+__weak int _isatty(int fd __attribute__((unused))) {
+    return 1;
+}
+
+__weak int isatty(int fd __attribute__((unused))) {
+    return 1;
+}
+
+__weak int _lseek(int fd __attribute__((unused)), off_t pos __attribute__((unused)), int whence __attribute__((unused))) {
+    return -1;
+}
+
+__weak unsigned char getch(void) {
+    return 0;
+}
+
+
+__weak int _read(int fd __attribute__((unused)), char *buf, size_t cnt __attribute__((unused))) {
+    *buf = getch();
+
+    return 1;
+}
+
+__weak void putch(unsigned char c __attribute__((unused))) {
+}
+
+__weak void cgets(char *s, int bufsize) {
+    char *p;
+    int c;
+    int i;
+
+    for (i = 0; i < bufsize; i++) {
+        *(s+i) = 0;
+    }
+//    memset(s, 0, bufsize);
+
+    p = s;
+
+    for (p = s; p < s + bufsize-1;) {
+        c = getch();
+        switch (c) {
+        case '\r' :
+        case '\n' :
+            putch('\r');
+            putch('\n');
+            *p = '\n';
+            return;
+
+        case '\b' :
+            if (p > s) {
+                *p-- = 0;
+                putch('\b');
+                putch(' ');
+                putch('\b');
+            }
+            break;
+
+        default :
+            putch(c);
+            *p++ = c;
+            break;
+        }
+    }
+    return;
+}
+
+__weak int _write(int fd __attribute__((unused)), const char *buf, size_t cnt) {
+    int i;
+
+    for (i = 0; i < cnt; i++)
+        putch(buf[i]);
+
+    return cnt;
+}
+
+/* Override fgets() in newlib with a version that does line editing */
+__weak char *fgets(char *s, int bufsize, void *f __attribute__((unused))) {
+    cgets(s, bufsize);
+    return s;
+}
+
+__weak void _exit(int exitcode __attribute__((unused))) {
+    while (1)
+        ;
+}