By default the SDIO (F4) or SDMMC1 (L4, F7) is used as the SD card
peripheral, but if a board config defines MICROPY_HW_SDMMC2_CK and other
pins then the SD card driver will use SDMMC2.
Current version of HAL drivers optimize IRQ handler by using precalculated
DMA register address and stream bitshift instead of calculating it on every interrupt.
Since we skip call to `HAL_DMA_Init` on reused DMA, fields StreamBaseAddress and StreamIndex
of DMA handle are not initialized and thus leads to SegFault in `DMA_IRQHandler`.
HAL_DMA_Init is a big routine and we do not need to call it on each use of DMA
(ex.: series of I2C operations) and DMA_CalcBaseAndBitshift is really small and
releasing it increases code size by only 8 bytes.
The DMA state is always HAL_DMA_STATE_RESET because of the memset clearing
all the data, so prior to this patch HAL_DMA_DeInit was never called. Now
it is always called to make sure the DMA is properly reset.
The main thing is to change the DMA code in a way that the structure
DMA_Stream_TypeDef (which is similar to DMA_Channel_TypeDef on stm32l4)
is no longer used outside of dma.c, as this structure only exists for the
F4 series. Therefore I introduced a new structure (dma_descr_t) which
handles all DMA specific stuff for configuration. Further the periphery
(spi, i2c, sdcard, dac) does not need to know the internals of the dma.
Adds a lot of code, makes IRQs a bit less efficient, but is very useful
for debugging. Usage: pyb.irq_stats() returns a memory view that can be
read and written, eg:
list(pyb.irq_stats())
pyb.irq_stats()[0]
pyb.irq_stats()[0] = 0
The patch provides general IRQ_ENTER() and IRQ_EXIT() macros that can be
modified to provide further IRQ statistics if desired.
Turning on each DMA block increases the current consumption
by about 8 mA. This code adds an idle timer for each DMA
block and turns off the clocks when no streams are in use
for 128 msec. Having a small timeout allows for improved
performance when back-to-back transfers are being performed.
The 128 msec is basically a guess.
This removes hard-coded DMA init params from dma_init(), instead defining
these parameters in a DMA_InitTypeDef struct that gets passed as an
argument to dma_init()
This makes dma_init more generic so it can be used for I2S and SD Card,
which require different initialization parameters.
