On Sun, 25 Feb 2007 20:51:12 +0100 DI BACCO ANTONIO - technolabs wrote: > Hi Melinda, > > the problem in my case was caused by the following instructions to > allocate the buffers for SPI controller tx and rx: > > rxbuffer = (u8*)m8xx_cpm_hostalloc(SPI_MAX_BUFFER_SIZE); > txbuffer = (u8*)m8xx_cpm_hostalloc(SPI_MAX_BUFFER_SIZE); > // Set the bd's rx and tx buffer address pointers > rbdf->cbd_bufaddr = virt_to_bus((void > *)rxbuffer); tbdf->cbd_bufaddr = virt_to_bus((void *)txbuffer); > > I don't know why (I'm asking an opinion to Vitaly Bordug), I replaced > the allocation of rx and tx buffers with: > > ...->cbd_bufaddr = __pa(__get_free_page(GFP_KERNEL | GFP_DMA)) > Well this is just evil... even if it works :)
> but it will better to use dma_alloc_coherent. > In my case the use of m8xx_cpm_hostalloc led to an immediate kernel > hang after giving the start command to the spi controller. > Heh, this case you'lll have to use dpram for the buffers I guess iiuc. dma_* stuff might work too but I'm not sure. Moreover, it didn't work for me in case of powerpc, where m8xx_cpm_hostalloc made as a placeholder for dma_alloc_coherent... _______________________________________________ Linuxppc-embedded mailing list [email protected] https://ozlabs.org/mailman/listinfo/linuxppc-embedded
