As implmented, dma_resume assumed that transfers widths were 1 byte and
that the memory address incrmenting was always on and periphial address
incrementing always off. This resulted in memory corruption anytime
these assumptions were not true and a dma was resumed. The DMA module
allows intitiating transfers that did not meet these assumption.
This patch adds proper handling inside dma_resume to safely resume any
transfer. Clearifications and errors are added/fixed in the module's
header file. Also, a few constants are removed from the gobal namespace.
As it was, the calculation of DMA2's IRQ number was inccrorect for some
STM families. The implmentation alocates streams numbers 0 to 7 for the
first DMA controller and 8 and up for the second DMA controller. This
offset of +8 was not accounted for when IRQ's of the second DMA
controller was calculated. This patch corrects this.
This commit adds two new functions to the DMA peripheral code for the
stm32. The setup function allows for a one-time setup of peripheral
config. The prepare function does the per-transfer setup. This allows
for a single setup call during the peripheral lock step and a
per-transfer call to the prepare function.
This commit removes a number of assert statements that should already
have been hit before. This is the reason that the assert in the
acquire function is left.
The FCR register content might change during mem-to-mem DMA transfers,
Forcing it back in the acquire should be sufficient to ensure proper
operations.
