The normal bring up process:
- Establish the QSPI_REF_CLK (PMC clock controller)
- Release the reset
- Set the baud-rate divisor (QSPI divider)
- Configure the controller
- Enable interrupts
- Set PIO or DMA mode
- Enable the controller
- Issue controller command
- PIO operating mode
- Read/write data via TX/RXFIFOs
- Issue controller commands
- Monitor FIFOs in interrupt handler
- DMA operating mode
- Configure and launch the DMA transfer
- Program DMA controller
- Program interrupts
- Send SPI command to flash device using controller commands sent to the command FIFO
- Initiate DMA transfer
- Wait for the DMA done interrupt [DONE] to be generated
- Configure and launch the DMA transfer