How to make work (M)DMA pool in SRAM on custom SOM with STM32MP151/7C
We try to configure the (M)DMA in Linux device-tree for our System on Module board based on STM32MP151/7C but it always said us that it cannot configure it so we had to disable dma for memory (QSPI Nor/NAND and FMC Nand) which cause performance issue.
If we do not set
/delete-property/dmas;
/delete-property/dma-names;
in device-tree for qspi, the qspi try to use DMA and do not detect chip on the bus.... (there no more logs for qspi in dmesg).
Here are the logs I have at Linux kernel boot :
[ 0.424027] stm32-dma 48000000.dma-controller: no dma pool: can't use MDMA: 0
[ 0.425335] stm32-dma 48000000.dma-controller: STM32 DMA driver registered
[ 0.425784] stm32-dma 48001000.dma-controller: no dma pool: can't use MDMA: 0
[ 0.427082] stm32-dma 48001000.dma-controller: STM32 DMA driver registered
How can I configure correctly the DMA pool ?
N.B: We also use OPTEE which is located in SRAM too but the two memory reservation are not overlapped so I do not understand why it does not want to be initialized.
What can be the correct dma-pool configuration for dma to work as expected ?