stm32: Add support for STM32N6xx MCUs.

This commit adds preliminary support for ST's new STM32N6xx MCUs.

Supported features of this MCU so far are:
- basic clock tree initialisation, running at 800MHz
- fully working USB
- XSPI in memory-mapped mode
- machine.Pin
- machine.UART
- RTC and deepsleep support
- SD card
- filesystem
- ROMFS
- WiFi and BLE via cyw43-driver (SDIO backend)

Note that the N6 does not have internal flash, and has some tricky boot
sequence, so using a custom bootloader (mboot) is almost a necessity.

Signed-off-by: Damien George <damien@micropython.org>

1 files changed, 25 insertions, 5 deletions

diff --git a/ports/stm32/sdio.c b/ports/stm32/sdio.c
index 99d05a515..de82ceadc 100644
--- a/ports/stm32/sdio.c
+++ b/ports/stm32/sdio.c
@@ -77,7 +77,11 @@ static volatile uint8_t *sdmmc_buf_top;
 #define SDMMC_IRQHandler        SDMMC2_IRQHandler
 #define SDMMC_CLK_ENABLE()      __HAL_RCC_SDMMC2_CLK_ENABLE()
 #define SDMMC_CLK_DISABLE()     __HAL_RCC_SDMMC2_CLK_DISABLE()
+#if defined(STM32N6)
+#define SDMMC_IS_CLK_DISABLED() (!__HAL_RCC_SDMMC2_IS_CLK_ENABLED())
+#else
 #define SDMMC_IS_CLK_DISABLED() __HAL_RCC_SDMMC2_IS_CLK_DISABLED()
+#endif
 #define STATIC_AF_SDMMC_CK      STATIC_AF_SDMMC2_CK
 #define STATIC_AF_SDMMC_CMD     STATIC_AF_SDMMC2_CMD
 #define STATIC_AF_SDMMC_D0      STATIC_AF_SDMMC2_D0
@@ -96,9 +100,17 @@ static volatile uint8_t *sdmmc_buf_top;
 #define MICROPY_HW_SDIO_CMD     (pin_D2)
 #endif
 
-#if defined(STM32H7)
+#if defined(STM32H7) || defined(STM32N6)
 static uint32_t safe_divide(uint32_t denom) {
+    #if defined(STM32N6)
+    #if MICROPY_HW_SDIO_SDMMC == 1
+    uint32_t num = LL_RCC_GetSDMMCClockFreq(LL_RCC_SDMMC1_CLKSOURCE);
+    #else
+    uint32_t num = LL_RCC_GetSDMMCClockFreq(LL_RCC_SDMMC2_CLKSOURCE);
+    #endif
+    #else
     uint32_t num = HAL_RCCEx_GetPeriphCLKFreq(RCC_PERIPHCLK_SDMMC);
+    #endif
     uint32_t divres;
 
     divres = num / (2U * denom);
@@ -119,11 +131,15 @@ void sdio_init(uint32_t irq_pri) {
     mp_hal_pin_config_alt_static(MICROPY_HW_SDIO_CMD, MP_HAL_PIN_MODE_ALT, MP_HAL_PIN_PULL_UP, STATIC_AF_SDMMC_CMD);
 
     SDMMC_CLK_ENABLE(); // enable SDIO peripheral
+    #if defined(STM32N6)
+    LL_AHB5_GRP1_EnableClockLowPower(LL_AHB5_GRP1_PERIPH_SDMMC1);
+    LL_AHB5_GRP1_EnableClockLowPower(LL_AHB5_GRP1_PERIPH_SDMMC2);
+    #endif
 
     SDMMC_TypeDef *SDIO = SDMMC;
     #if defined(STM32F7)
     SDIO->CLKCR = SDMMC_CLKCR_HWFC_EN | SDMMC_CLKCR_PWRSAV | (120 - 2); // 1-bit, 400kHz
-    #elif defined(STM32H7)
+    #elif defined(STM32H7) || defined(STM32N6)
     SDIO->CLKCR = SDMMC_CLKCR_HWFC_EN | SDMMC_CLKCR_PWRSAV | safe_divide(400000U); // 1-bit, 400kHz
     #else
     SDIO->CLKCR = SDMMC_CLKCR_HWFC_EN | SDMMC_CLKCR_PWRSAV | (120 / 2); // 1-bit, 400kHz
@@ -172,7 +188,7 @@ void sdio_enable_high_speed_4bit(void) {
     mp_hal_delay_us(10);
     #if defined(STM32F7)
     SDIO->CLKCR = SDMMC_CLKCR_HWFC_EN | SDMMC_CLKCR_WIDBUS_0 | SDMMC_CLKCR_BYPASS /*| SDMMC_CLKCR_PWRSAV*/; // 4-bit, 48MHz
-    #elif defined(STM32H7)
+    #elif defined(STM32H7) || defined(STM32N6)
     SDIO->CLKCR = SDMMC_CLKCR_HWFC_EN | SDMMC_CLKCR_WIDBUS_0 | safe_divide(48000000U); // 4-bit, 48MHz
     #else
     SDIO->CLKCR = SDMMC_CLKCR_HWFC_EN | SDMMC_CLKCR_WIDBUS_0; // 4-bit, 48MHz
@@ -199,7 +215,7 @@ void SDMMC_IRQHandler(void) {
             sdmmc_irq_state = SDMMC_IRQ_STATE_DONE;
             return;
         }
-        #if defined(STM32H7)
+        #if defined(STM32H7) || defined(STM32N6)
         if (!sdmmc_dma) {
             while (sdmmc_buf_cur < sdmmc_buf_top && (SDMMC->STA & SDMMC_STA_DPSMACT) && !(SDMMC->STA & SDMMC_STA_RXFIFOE)) {
                 *(uint32_t *)sdmmc_buf_cur = SDMMC->FIFO;
@@ -413,11 +429,15 @@ int sdio_transfer_cmd53(bool write, uint32_t block_size, uint32_t arg, size_t le
         dma_nohal_init(&dma_SDIO_0, dma_config);
         dma_nohal_start(&dma_SDIO_0, dma_src, dma_dest, dma_len);
         #else
+        #if defined(STM32N6)
+        SDMMC->IDMABASER = (uint32_t)buf;
+        #else
         SDMMC->IDMABASE0 = (uint32_t)buf;
+        #endif
         SDMMC->IDMACTRL = SDMMC_IDMA_IDMAEN;
         #endif
     } else {
-        #if defined(STM32H7)
+        #if defined(STM32H7) || defined(STM32N6)
         SDMMC->IDMACTRL = 0;
         #endif
     }