* Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx> wrote:
> > Hiding essentially an early udelay() implementation in an early-printk driver is
> > ugly and counterproductive.
>
> Sure. How about below change?
>
> diff --git a/drivers/usb/early/xhci-dbc.c b/drivers/usb/early/xhci-dbc.c
> index d3f0c84..940989e 100644
> --- a/drivers/usb/early/xhci-dbc.c
> +++ b/drivers/usb/early/xhci-dbc.c
> @@ -587,6 +587,35 @@ static int xdbc_bulk_transfer(void *data, int size, bool read)
> return size;
> }
>
> +static void __init xdbc_udelay_calibration(void)
> +{
> + unsigned long lpj = 0;
> + unsigned int tsc_khz, cpu_khz;
> +
> + if (!boot_cpu_has(X86_FEATURE_TSC))
> + goto calibration_out;
> +
> + cpu_khz = x86_platform.calibrate_cpu();
> + tsc_khz = x86_platform.calibrate_tsc();
> +
> + if (tsc_khz == 0)
> + tsc_khz = cpu_khz;
> + else if (abs(cpu_khz - tsc_khz) * 10 > tsc_khz)
> + cpu_khz = tsc_khz;
> +
> + if (!tsc_khz)
> + goto calibration_out;
> +
> + lpj = tsc_khz * 1000;
> + do_div(lpj, HZ);
> +
> +calibration_out:
> + if (!lpj)
> + lpj = 1 << 22;
> +
> + loops_per_jiffy = lpj;
> +}
> +
> static int __init xdbc_early_setup(void)
> {
> int ret;
> @@ -686,6 +715,8 @@ int __init early_xdbc_parse_parameter(char *s)
> }
> xdbc.xdbc_reg = (struct xdbc_regs __iomem *)(xdbc.xhci_base + offset);
>
> + xdbc_udelay_calibration();
> +
> return 0;
> }
Yeah - so could we do this in a more generic fashion, not in the early-printk
driver but in core x86 code?
Thanks,
Ingo
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