Re: [PATCH] [libata] Set proper ATA UDMA mode for bf548 according to system clock.

[Sonic Zhang]

Any comment?

Thanks

Sonic

On Nov 27, 2007 12:47 PM, sonic zhang <sonic.adi@xxxxxxxxx> wrote:
> UDMA Mode - Frequency compatibility
>
> UDMA5 - 100 MB/s   - SCLK  = 133 MHz
> UDMA4 - 66 MB/s    - SCLK >=  80 MHz
> UDMA3 - 44.4 MB/s  - SCLK >=  50 MHz
> UDMA2 - 33 MB/s    - SCLK >=  40 MHz
>
>
> Signed-off-by: Sonic Zhang <sonic.zhang@xxxxxxxxxx>
> ---
>  drivers/ata/pata_bf54x.c |    7 +++++++
>  1 files changed, 7 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/ata/pata_bf54x.c b/drivers/ata/pata_bf54x.c
> index 81db405..088a41f 100644
> --- a/drivers/ata/pata_bf54x.c
> +++ b/drivers/ata/pata_bf54x.c
> @@ -1489,6 +1489,8 @@ static int __devinit bfin_atapi_probe(st
>         int board_idx = 0;
>         struct resource *res;
>         struct ata_host *host;
> +       unsigned int fsclk = get_sclk();
> +       int udma_mode = 5;
>         const struct ata_port_info *ppi[] =
>                 { &bfin_port_info[board_idx], NULL };
>
> @@ -1507,6 +1509,11 @@ static int __devinit bfin_atapi_probe(st
>         if (res == NULL)
>                 return -EINVAL;
>
> +       while (bfin_port_info[board_idx].udma_mask>0 && udma_fsclk[udma_mode] > fsclk) {
> +               udma_mode--;
> +               bfin_port_info[board_idx].udma_mask >>= 1;
> +       }
> +
>         /*
>          * Now that that's out of the way, wire up the port..
>          */
> --
> 1.4.3.4
>
>
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