stm32: Initial support for stm32g0

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

src/stm32/Kconfig

@@ -6,9 +6,9 @@ config STM32_SELECT
     bool
     default y
     select HAVE_GPIO
-    select HAVE_GPIO_ADC
+    select HAVE_GPIO_ADC if !MACH_STM32G0
-    select HAVE_GPIO_I2C if !(MACH_STM32F031 || MACH_STM32H7)
+    select HAVE_GPIO_I2C if !(MACH_STM32F031 || MACH_STM32G0 || MACH_STM32H7)
-    select HAVE_GPIO_SPI if !MACH_STM32F031
+    select HAVE_GPIO_SPI if !(MACH_STM32F031 || MACH_STM32G0)
     select HAVE_GPIO_HARD_PWM if MACH_STM32F1 || MACH_STM32F4 || MACH_STM32H7
     select HAVE_GPIO_BITBANGING if !MACH_STM32F031
     select HAVE_STRICT_TIMING
@@ -64,6 +64,9 @@ choice
         bool "STM32F072"
         select MACH_STM32F0
         select MACH_STM32F0x2
+    config MACH_STM32G0B1
+        bool "STM32G0B1"
+        select MACH_STM32G0
     config MACH_STM32H743
         bool "STM32H743"
         select MACH_STM32H7
@@ -80,6 +83,8 @@ config MACH_STM32F2
     bool
 config MACH_STM32F4
     bool
+config MACH_STM32G0
+    bool
 config MACH_STM32H7
     bool
 config MACH_STM32F0x2 # F042, F072 series
@@ -109,6 +114,7 @@ config MCU
     default "stm32f407xx" if MACH_STM32F407
     default "stm32f429xx" if MACH_STM32F429
     default "stm32f446xx" if MACH_STM32F446
+    default "stm32g0b1xx" if MACH_STM32G0B1
     default "stm32h743xx" if MACH_STM32H743
     default "stm32h750xx" if MACH_STM32H750
 
@@ -121,6 +127,7 @@ config CLOCK_FREQ
     default 84000000 if MACH_STM32F401
     default 168000000 if MACH_STM32F4x5
     default 180000000 if MACH_STM32F446
+    default 64000000 if MACH_STM32G0
     default 400000000 if MACH_STM32H7 # 400Mhz is max Klipper currently supports
 
 config FLASH_SIZE
@@ -131,6 +138,7 @@ config FLASH_SIZE
     default 0x10000 if MACH_STM32F103 # Flash size of stm32f103x8 (64KiB)
     default 0x40000 if MACH_STM32F2 || MACH_STM32F401
     default 0x80000 if MACH_STM32F4x5 || MACH_STM32F446
+    default 0x20000 if MACH_STM32G0B1
     default 0x20000 if MACH_STM32H750
     default 0x200000 if MACH_STM32H743
 
@@ -148,6 +156,7 @@ config RAM_SIZE
     default 0x20000 if MACH_STM32F207
     default 0x10000 if MACH_STM32F401
     default 0x20000 if MACH_STM32F4x5 || MACH_STM32F446
+    default 0x24000 if MACH_STM32G0B1
     default 0x20000 if MACH_STM32H750
     default 0x80000 if MACH_STM32H743
 
@@ -171,9 +180,9 @@ config STM32F103GD_DISABLE_SWD
 ######################################################################
 
 choice
-    prompt "Bootloader offset" if MACH_STM32F1 || MACH_STM32F2 || MACH_STM32F4 || MACH_STM32F070 || MACH_STM32H743
+    prompt "Bootloader offset"
     config STM32_FLASH_START_2000
-        bool "8KiB bootloader (stm32duino)" if MACH_STM32F103 || MACH_STM32F070
+        bool "8KiB bootloader" if MACH_STM32F103 || MACH_STM32F070 || MACH_STM32G0
     config STM32_FLASH_START_5000
         bool "20KiB bootloader" if MACH_STM32F103
     config STM32_FLASH_START_7000

src/stm32/Makefile

@@ -8,6 +8,7 @@ dirs-$(CONFIG_MACH_STM32F0) += lib/stm32f0
 dirs-$(CONFIG_MACH_STM32F1) += lib/stm32f1
 dirs-$(CONFIG_MACH_STM32F2) += lib/stm32f2
 dirs-$(CONFIG_MACH_STM32F4) += lib/stm32f4
+dirs-$(CONFIG_MACH_STM32G0) += lib/stm32g0
 dirs-$(CONFIG_MACH_STM32H7) += lib/stm32h7
 
 MCU := $(shell echo $(CONFIG_MCU))
@@ -17,6 +18,7 @@ CFLAGS-$(CONFIG_MACH_STM32F0) += -mcpu=cortex-m0 -Ilib/stm32f0/include
 CFLAGS-$(CONFIG_MACH_STM32F1) += -mcpu=cortex-m3 -Ilib/stm32f1/include
 CFLAGS-$(CONFIG_MACH_STM32F2) += -mcpu=cortex-m3 -Ilib/stm32f2/include
 CFLAGS-$(CONFIG_MACH_STM32F4) += -mcpu=cortex-m4 -Ilib/stm32f4/include
+CFLAGS-$(CONFIG_MACH_STM32G0) += -mcpu=cortex-m0plus -Ilib/stm32g0/include
 CFLAGS-$(CONFIG_MACH_STM32H7) += -mcpu=cortex-m7 -Ilib/stm32h7/include
 CFLAGS += $(CFLAGS-y) -D$(MCU_UPPER) -mthumb -Ilib/cmsis-core -Ilib/fast-hash
 
@@ -40,6 +42,8 @@ src-$(CONFIG_MACH_STM32F2) += stm32/gpioperiph.c stm32/adc.c stm32/i2c.c
 src-$(CONFIG_MACH_STM32F4) += ../lib/stm32f4/system_stm32f4xx.c
 src-$(CONFIG_MACH_STM32F4) += stm32/stm32f4.c generic/armcm_timer.c
 src-$(CONFIG_MACH_STM32F4) += stm32/gpioperiph.c stm32/adc.c stm32/i2c.c
+src-$(CONFIG_MACH_STM32G0) += generic/timer_irq.c stm32/stm32f0_timer.c
+src-$(CONFIG_MACH_STM32G0) += stm32/stm32g0.c stm32/gpioperiph.c
 src-$(CONFIG_MACH_STM32H7) += ../lib/stm32h7/system_stm32h7xx.c
 src-$(CONFIG_MACH_STM32H7) += stm32/stm32h7.c generic/armcm_timer.c
 src-$(CONFIG_MACH_STM32H7) += stm32/gpioperiph.c stm32/stm32h7_adc.c
@@ -51,6 +55,7 @@ usb-src-$(CONFIG_HAVE_STM32_USBOTG) := stm32/usbotg.c
 src-$(CONFIG_USBSERIAL) += $(usb-src-y) stm32/chipid.c generic/usb_cdc.c
 serial-src-y := stm32/serial.c
 serial-src-$(CONFIG_MACH_STM32F0) := stm32/stm32f0_serial.c
+serial-src-$(CONFIG_MACH_STM32G0) := stm32/stm32f0_serial.c
 serial-src-$(CONFIG_MACH_STM32H7) := stm32/stm32h7_serial.c
 src-$(CONFIG_SERIAL) += $(serial-src-y) generic/serial_irq.c
 src-$(CONFIG_CANSERIAL) += stm32/can.c ../lib/fast-hash/fasthash.c

src/stm32/gpioperiph.c

@@ -31,6 +31,7 @@ gpio_peripheral(uint32_t gpio, uint32_t mode, int pullup)
     // stm32f0 is ~10Mhz at 50pF
     // stm32f2 is ~25Mhz at 40pF
     // stm32f4 is ~50Mhz at 40pF
+    // stm32g0 is ~30Mhz at 50pF
     // stm32h7 is ~85Mhz at 50pF
     uint32_t ospeed = CONFIG_MACH_STM32F0 ? 0x01 : 0x02;
     regs->OSPEEDR = (regs->OSPEEDR & ~m_msk) | (ospeed << m_shift);

src/stm32/internal.h

@@ -12,6 +12,8 @@
 #include "stm32f2xx.h"
 #elif CONFIG_MACH_STM32F4
 #include "stm32f4xx.h"
+#elif CONFIG_MACH_STM32G0
+#include "stm32g0xx.h"
 #elif CONFIG_MACH_STM32H7
 #include "stm32h7xx.h"
 #endif

src/stm32/stm32f0_serial.c

@@ -48,6 +48,17 @@
   #define USART2_IRQn USART1_IRQn
 #endif
 
+#if CONFIG_MACH_STM32G0
+  // The stm32g0 has slightly different register names
+  #define USART2_IRQn USART2_LPUART2_IRQn
+  #define USART_CR1_RXNEIE USART_CR1_RXNEIE_RXFNEIE
+  #define USART_CR1_TXEIE USART_CR1_TXEIE_TXFNFIE
+  #define USART_ISR_RXNE USART_ISR_RXNE_RXFNE
+  #define USART_ISR_TXE USART_ISR_TXE_TXFNF
+  #define USART_BRR_DIV_MANTISSA_Pos 4
+  #define USART_BRR_DIV_FRACTION_Pos 0
+#endif
+
 #define CR1_FLAGS (USART_CR1_UE | USART_CR1_RE | USART_CR1_TE   \
                    | USART_CR1_RXNEIE)
 

src/stm32/stm32g0.c

@@ -0,0 +1,217 @@
+// Code to setup clocks on stm32g0
+//
+// Copyright (C) 2019-2021  Kevin O'Connor <kevin@koconnor.net>
+//
+// This file may be distributed under the terms of the GNU GPLv3 license.
+
+#include "autoconf.h" // CONFIG_CLOCK_REF_FREQ
+#include "board/armcm_boot.h" // armcm_main
+#include "board/irq.h" // irq_disable
+#include "command.h" // DECL_CONSTANT_STR
+#include "internal.h" // enable_pclock
+#include "sched.h" // sched_main
+
+
+/****************************************************************
+ * Clock setup
+ ****************************************************************/
+
+#define FREQ_PERIPH 64000000
+#define FREQ_USB 48000000
+
+// Map an APB peripheral address to an enable bit
+static int
+lookup_apb_bit(uint32_t periph_base)
+{
+    if (periph_base == USB_BASE)
+        return 13;
+    if (periph_base == CRS_BASE)
+        return 16;
+    if (periph_base == SPI1_BASE)
+        return 32 + 12;
+    if (periph_base == USART1_BASE)
+        return 32 + 14;
+    if (periph_base == ADC1_BASE)
+        return 32 + 20;
+    return (periph_base - APBPERIPH_BASE) / 0x400;
+}
+
+// Enable a peripheral clock
+void
+enable_pclock(uint32_t periph_base)
+{
+    if (periph_base >= IOPORT_BASE) {
+        uint32_t pos = (periph_base - IOPORT_BASE) / 0x400;
+        RCC->IOPENR |= 1 << pos;
+        RCC->IOPENR;
+        RCC->IOPRSTR |= (1<<pos);
+        RCC->IOPRSTR &= ~(1<<pos);
+    } else if (periph_base >= AHBPERIPH_BASE) {
+        uint32_t pos = (periph_base - AHBPERIPH_BASE) / 0x400;
+        RCC->AHBENR |= 1 << pos;
+        RCC->AHBENR;
+        RCC->AHBRSTR |= (1<<pos);
+        RCC->AHBRSTR &= ~(1<<pos);
+    } else {
+        uint32_t pos = lookup_apb_bit(periph_base);
+        if (pos < 32) {
+            RCC->APBENR1 |= 1 << pos;
+            RCC->APBENR1;
+            RCC->APBRSTR1 |= (1 << pos);
+            RCC->APBRSTR1 &= ~(1 << pos);
+        } else {
+            RCC->APBENR2 |= 1 << (pos - 32);
+            RCC->APBENR2;
+            RCC->APBRSTR2 |= (1 << (pos - 32));
+            RCC->APBRSTR2 &= ~(1 << (pos - 32));
+        }
+    }
+}
+
+// Check if a peripheral clock has been enabled
+int
+is_enabled_pclock(uint32_t periph_base)
+{
+    if (periph_base >= IOPORT_BASE) {
+        uint32_t pos = (periph_base - IOPORT_BASE) / 0x400;
+        return RCC->IOPENR & (1 << pos);
+    } else if (periph_base >= AHBPERIPH_BASE) {
+        uint32_t pos = (periph_base - AHBPERIPH_BASE) / 0x400;
+        return RCC->AHBENR & (1 << pos);
+    } else {
+        uint32_t pos = lookup_apb_bit(periph_base);
+        if (pos < 32)
+            return RCC->APBENR1 & (1 << pos);
+        return RCC->APBENR2 & (1 << (pos - 32));
+    }
+}
+
+// Return the frequency of the given peripheral clock
+uint32_t
+get_pclock_frequency(uint32_t periph_base)
+{
+    return FREQ_PERIPH;
+}
+
+// Enable a GPIO peripheral clock
+void
+gpio_clock_enable(GPIO_TypeDef *regs)
+{
+    uint32_t rcc_pos = ((uint32_t)regs - IOPORT_BASE) / 0x400;
+    RCC->IOPENR |= 1 << rcc_pos;
+    RCC->IOPENR;
+}
+
+#if !CONFIG_STM32_CLOCK_REF_INTERNAL
+DECL_CONSTANT_STR("RESERVE_PINS_crystal", "PF0,PF1");
+#endif
+
+// Configure and enable the PLL as clock source
+static void
+clock_setup(void)
+{
+    uint32_t pll_base = 4000000, pll_freq = 192000000, pllcfgr;
+    if (!CONFIG_STM32_CLOCK_REF_INTERNAL) {
+        // Configure PLL from external crystal (HSE)
+        uint32_t div = CONFIG_CLOCK_REF_FREQ / pll_base;
+        RCC->CR |= RCC_CR_HSEON;
+        pllcfgr = RCC_PLLCFGR_PLLSRC_HSE | ((div - 1) << RCC_PLLCFGR_PLLM_Pos);
+    } else {
+        // Configure PLL from internal 16Mhz oscillator (HSI)
+        uint32_t div = 16000000 / pll_base;
+        pllcfgr = RCC_PLLCFGR_PLLSRC_HSI | ((div - 1) << RCC_PLLCFGR_PLLM_Pos);
+    }
+    pllcfgr |= (pll_freq/pll_base) << RCC_PLLCFGR_PLLN_Pos;
+    pllcfgr |= (pll_freq/CONFIG_CLOCK_FREQ - 1) << RCC_PLLCFGR_PLLR_Pos;
+    RCC->PLLCFGR = pllcfgr | RCC_PLLCFGR_PLLREN;
+    RCC->CR |= RCC_CR_PLLON;
+
+    // Wait for PLL lock
+    while (!(RCC->CR & RCC_CR_PLLRDY))
+        ;
+
+    // Switch system clock to PLL
+    RCC->CFGR = (2 << RCC_CFGR_SW_Pos);
+    while ((RCC->CFGR & RCC_CFGR_SWS_Msk) != (2 << RCC_CFGR_SWS_Pos))
+        ;
+
+    // Enable USB clock
+    if (CONFIG_USBSERIAL) {
+        RCC->CR |= RCC_CR_HSI48ON;
+        while (!(RCC->CR & RCC_CR_HSI48RDY))
+            ;
+        enable_pclock(CRS_BASE);
+        CRS->CR |= CRS_CR_AUTOTRIMEN | CRS_CR_CEN;
+    }
+}
+
+
+/****************************************************************
+ * USB bootloader
+ ****************************************************************/
+
+#define USB_BOOT_FLAG_ADDR (CONFIG_RAM_START + CONFIG_RAM_SIZE - 1024)
+#define USB_BOOT_FLAG 0x55534220424f4f54 // "USB BOOT"
+
+// Flag that bootloader is desired and reboot
+static void
+usb_reboot_for_dfu_bootloader(void)
+{
+    irq_disable();
+    *(uint64_t*)USB_BOOT_FLAG_ADDR = USB_BOOT_FLAG;
+    NVIC_SystemReset();
+}
+
+// Check if rebooting into system DFU Bootloader
+static void
+check_usb_dfu_bootloader(void)
+{
+    if (!CONFIG_USBSERIAL || *(uint64_t*)USB_BOOT_FLAG_ADDR != USB_BOOT_FLAG)
+        return;
+    *(uint64_t*)USB_BOOT_FLAG_ADDR = 0;
+    uint32_t *sysbase = (uint32_t*)0x1fff0000;
+    asm volatile("mov sp, %0\n bx %1"
+                 : : "r"(sysbase[0]), "r"(sysbase[1]));
+}
+
+// Handle USB reboot requests
+void
+usb_request_bootloader(void)
+{
+    usb_reboot_for_dfu_bootloader();
+}
+
+
+/****************************************************************
+ * Startup
+ ****************************************************************/
+
+// Main entry point - called from armcm_boot.c:ResetHandler()
+void
+armcm_main(void)
+{
+    check_usb_dfu_bootloader();
+    SCB->VTOR = (uint32_t)VectorTable;
+
+    // Reset clock registers (in case bootloader has changed them)
+    RCC->CR |= RCC_CR_HSION;
+    while (!(RCC->CR & RCC_CR_HSIRDY))
+        ;
+    RCC->CFGR = 0x00000000;
+    RCC->CR = RCC_CR_HSION;
+    while (RCC->CR & RCC_CR_PLLRDY)
+        ;
+    RCC->PLLCFGR = 0x00001000;
+    RCC->IOPENR = 0x00000000;
+    RCC->AHBENR = 0x00000100;
+    RCC->APBENR1 = 0x00000000;
+    RCC->APBENR2 = 0x00000000;
+
+    // Set flash latency
+    FLASH->ACR = (2<<FLASH_ACR_LATENCY_Pos) | FLASH_ACR_ICEN | FLASH_ACR_PRFTEN;
+
+    // Configure main clock
+    clock_setup();
+
+    sched_main();
+}