We are developping a device based on IMX6S. The driver of eCSPI in the BSP does not support DMA transfer, so we have written a driver that support DMA. We write a test program that transmit data to SPI, but we found that no value was sent from the DMA to the Tx FIFO of the SPI.
We set the register as shown below.
- Initialize ECSPI2.
- ECSPI2_CONREG (0x01F0E2F9)
BURST_LENGTH = 31
CHANNEL_SELECT = 0 (CS0)
DRCTL = 0
PRE_DIVIDER = 14
POST_DIVIDER = 2
CHANNEL_MODE = 15 (ALL CS Master)
SMC = 1
XCH = 0
HT = 0
EN = 1
- ECSPI2_CONFIGREG (0x00000100)
HT_LENGTH =0
SCLK_CTL = 0
DATA_CTL = 0
SS_POL = 0
SS_CTL = 1 (SS_CTL_CS0)
SCLK_POL = 0
SCLK_PHA = 0
- ECSPI2_INTREG (0x0)
: not setting
- ECSPI2_DMAREG (0xA09F0080)
RXTDEN = 1
RX_DMA_LENGTH = 32
RXDEN = 1
RX_THRESHOLD = 31
TEDEN = 1
TX_THRESHOLD = 0
- ECSPI2_STATREG (0x3)
: not setting
TDR = 1
TE =1
- ECSPI2_TESTREG (0x80000000)
LBC = 1
-------------------------------------------------
- prepare DMA.
- 32 byte tx/rx buffer
- Script addr
tx : mcu2app, rx : app2mcu
Buffer Descriptor Mode
Interrupt + Warp + Done
- 4byte buswidth
- burstsize = 32
- set callback function
- event number
tx : 6, rx : 5
TX DMA : chan=0x2, mode=0xb0020, peripAddr=0x200c004
RX DMA : chan=0x3, mode=0xb0020, peripAddr=0x200c000
-------------------------------------------------
- set CS0
gpio set to high.
-------------------------------------------------
- start DMA.
write (1 << tx_channel) to SDMA_HSTART(0x0C)
write (1 << rx_channel) to SDMA_HSTART(0x0C)
-------------------------------------------------
I tried to check sdma function in loopback mode.
Just write to 32bit data to ECSPI2_TXDATA(Transmit Data Register). then tx dma callback function indicated.
Do you have any idea where is the problem?
