Re: [PATCH] ide: New libata driver for OCTEON SOC Compact Flash interface.

[Sergei Shtylyov <sshtylyov@ru.mvista.com>]

Hello.

David Daney wrote:

> As part of our efforts to get the Cavium OCTEON processor support
> merged (see: http://marc.info/?l=linux-mips&m=122704699515601), we
> have this CF driver for your consideration.
>
> Most OCTEON variants have *no* DMA or interrupt support on the CF
> interface so for these, only PIO is supported.  Although if DMA is
> available, we do take advantage of it.
>
> The register definitions are part of the chip support patch set
> mentioned above, and are not included here.
>
> At this point I would like to get feedback on the patch and would
> expect that it would merge via the linux-mips tree along with the rest
> of the chip support.
>
> Thanks,
>
> Signed-off-by: David Daney <ddaney@caviumnetworks.com>
[...]
> diff --git a/drivers/ata/pata_octeon_cf.c b/drivers/ata/pata_octeon_cf.c
> new file mode 100644
> index 0000000..e8712c0
> --- /dev/null
> +++ b/drivers/ata/pata_octeon_cf.c
> @@ -0,0 +1,942 @@
[...]
> +/**
> + * Get the status of the DMA engine. The results of this function
> + * must emulate the BMDMA engine expected by libata.
> + *
> + * @ap:     ATA port to check status on
> + *
> + * Returns BMDMA status bits
> + */
> +static uint8_t octeon_cf_bmdma_status(struct ata_port *ap)
> +{
> +    struct octeon_cf_data *ocd = ap->dev->platform_data;
> +    cvmx_mio_boot_dma_intx_t mio_boot_dma_int;
> +    cvmx_mio_boot_dma_cfgx_t mio_boot_dma_cfg;
> +    uint8_t result = 0;
> +
> +    mio_boot_dma_int.u64 =
> +        cvmx_read_csr(CVMX_MIO_BOOT_DMA_INTX(ocd->dma_engine));
> +    if (mio_boot_dma_int.s.done)
> +        result |= ATA_DMA_INTR;

   But if you're saying that there is only DMA completion inetrrupt, you 
*cannot* completely emulate SFF-8038i BMDMA since its interrupt status 
is the (delayed) IDE INTRQ status. I suggest that you move away from the 
emulation -- Alan has said it's possible.

MBR, Sergei