On 4 May 2016 at 18:42, Jan Dąbroś jsd@semihalf.com wrote:
Hi Ard,
I am working on support for AHCI controller for my ARMv8 platform and I decide to use PciEmulation approach. I was able to run XHCI via PciEmulation without problems, but unfortunately with AHCI it isn't working.
Controller is compatible with AHCI specification. It isn't dma-coherent and I think that problem lies here. Initialization timeouts in below part of code:
// // Enable FIS Receive DMA engine for the first D2H FIS. // Offset = EFI_AHCI_PORT_START + Port * EFI_AHCI_PORT_REG_WIDTH +EFI_AHCI_PORT_CMD; AhciOrReg (PciIo, Offset, EFI_AHCI_PORT_CMD_FRE); Status = AhciWaitMmioSet ( PciIo, Offset, EFI_AHCI_PORT_CMD_FR, EFI_AHCI_PORT_CMD_FR, EFI_AHCI_PORT_CMD_FR_CLEAR_TIMEOUT ); if (EFI_ERROR (Status)) { continue; }
Where do you think may be problem? Do you have any tips what should I try to do?
Are you using DmaLib? If you are, it is simply a matter of using ArmDmaLib, which uses uncached memory and/or explicit cache maintenance to perform non-coherent DMA. Basically, you need to implement the Allocate, free, map and unmap functions in the PCI I/O protocol using DmaLib methods, so you can use either coherent or non-coherent DMA depending on which version of the library you bind your driver to.