MPC512x SPI very high cpu load
Hi,
we're using the latest denx tree on an mpc512x, and we have a touchscreen on the spi which is talking at 100kHz.
The polling frequency is 5ms and we transmit around 20 bytes per poll.
If we keep the touchscreen pressed, cpu utilization goes to 70% for the spi task. This is quite strange, since I thought the mpc512x would be using DMA to feed the PSC FIFOs.
Has anyone found the same problem? Should I lower the spi bandwidth?
Thank you,
Matteo
Quoted 6 lines · Matteo Fortini
Hi,
we're using the latest denx tree on an mpc512x, and we have a touchscreen on the spi which is talking at 100kHz.The polling frequency is 5ms and we transmit around 20 bytes per poll.
If we keep the touchscreen pressed, cpu utilization goes to 70% for the spi task. This is quite strange, since I thought the mpc512x would be using DMA to feed the PSC FIFOs.
If the SPI driver isn't using DMA then, it's not using DMA.
Signature · 2 lines
Matt Sealey <[email protected]> Genesi, Manager, Developer Relations