Hi,
On Wednesday, November 09, 2016 02:56:37 AM Vladimir Zapolskiy wrote:
> The controller is capable to operate in up to PIO4 mode, however
> before the change the driver relies on timing settings done by
> a bootloader for PIO0 mode only. The change adds more flexibility
> in PIO mode selection at runtime and makes the driver to work even if
> bootloader does not preset ATA timings.
>
> Signed-off-by: Vladimir Zapolskiy <vz@xxxxxxxxx>
> ---
> drivers/ata/pata_imx.c | 47 ++++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 46 insertions(+), 1 deletion(-)
[...]
> +static void pata_imx_set_timing(struct ata_device *adev,
> + struct pata_imx_priv *priv)
> +{
> + struct ata_timing timing;
> + unsigned long clkrate;
> + u32 T, mode;
> +
> + clkrate = clk_get_rate(priv->clk);
> +
> + if (adev->pio_mode < XFER_PIO_0 || adev->pio_mode > XFER_PIO_4 ||
> + !clkrate)
No need check for adev->pio_mode < XFER_PIO_0 || adev->pio_mode > XFER_PIO_4
as the libata core code guarantees that these conditions will never happen.
Also you should at least print an error on !clkrate condition. [ IMHO it
is actually better to BUG_ON() on this condition as the further operations
may be risky for the data integrity (wrong PIO timings may be used). ]
> + return;
> +
> + T = 1000000000 / clkrate;
> + ata_timing_compute(adev, adev->pio_mode, &timing, T * 1000, 0);
> +
> + mode = adev->pio_mode - XFER_PIO_0;
> +
> + writeb(3, priv->host_regs + PATA_IMX_ATA_TIME_OFF);
> + writeb(3, priv->host_regs + PATA_IMX_ATA_TIME_ON);
> + writeb(timing.setup, priv->host_regs + PATA_IMX_ATA_TIME_1);
> + writeb(timing.act8b, priv->host_regs + PATA_IMX_ATA_TIME_2W);
> + writeb(timing.act8b, priv->host_regs + PATA_IMX_ATA_TIME_2R);
> + writeb(1, priv->host_regs + PATA_IMX_ATA_TIME_PIO_RDX);
> +
> + writeb(pio_t4[mode] / T + 1, priv->host_regs + PATA_IMX_ATA_TIME_4);
> + writeb(pio_t9[mode] / T + 1, priv->host_regs + PATA_IMX_ATA_TIME_9);
> + writeb(pio_tA[mode] / T + 1, priv->host_regs + PATA_IMX_ATA_TIME_AX);
> +}
Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics
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