Re: AW: AW: AW: [PATCH] x86: HPET force enable for Soekris net6501

Thomas Gleixner
2014-09-09T14:54:46Z

On Tue, 9 Sep 2014, Eric Sesterhenn wrote:
> On 02/14/2014 07:28 PM, Conrad Kostecki wrote:
> This patch enables a quirk for the Soekris net6501 HPET if
> pciquirks=soekris_e6xx" is supplied at the kernel commandline,
> Without these patches the clocksource defaults to jiffies, which
> is unstable.
>
> Signed-off-by: Eric Sesterhenn <eric.sesterhenn@lsexperts.de>
>
> diff --git a/arch/x86/kernel/quirks.c b/arch/x86/kernel/quirks.c
> index ff898bb..7c3faf5 100644
> --- a/arch/x86/kernel/quirks.c
> +++ b/arch/x86/kernel/quirks.c
> @@ -6,6 +6,25 @@
>
> #include <asm/hpet.h>
>
> +static int pciquirk_soekris;
> +
> +static int __init parse_pciquirks(char *str)
> +{
> +
> + while (str) {
> + char *next = strchr(str, ',');
> +
> + if (next)
> + *next++ = 0;
> + if (!strncmp("soekris_e6xx", str, 12))
> + pciquirk_soekris = 1;
> + str = next;
> + }
> + return 1;
> +}
> +__setup("pciquirks=", parse_pciquirks);

Eew. No, we really can do without random new quirk interfaces.

> #if defined(CONFIG_X86_IO_APIC) && defined(CONFIG_SMP) && defined(CONFIG_PCI)
>
> static void quirk_intel_irqbalance(struct pci_dev *dev)
> @@ -498,6 +517,28 @@ void force_hpet_resume(void)
> }
>
> /*
> + * Soekris net6501, based on Atom E6xx series, does not have ACPI.
> + * HPET should be force enabled on such platforms.
> + */
> +static void e6xx_force_enable_hpet(struct pci_dev *dev)
> +{
> + if (hpet_address || force_hpet_address)
> + return;
> +
> + if (pciquirk_soekris != 1)
> + return;

Thinking more about it, this is really not necessary.

@hpa: You asked whether this might affect any other e6xx devices.

According to the atom e6xx-series datasheet the HPET is non optional
and always memory mapped to 0xfed00000. I don't see how that would
harm any machine which has the hpet proper advertised via ACPI.

Thanks,

tglx

> +
> + force_hpet_address = 0xFED00000;
> + force_hpet_resume_type = NONE_FORCE_HPET_RESUME;
> + dev_printk(KERN_DEBUG, &dev->dev, "Force enabled HPET at "
> + "0x%lx\n", force_hpet_address);
> + return;
> +}
> +
> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_E6XX_CU,
> + e6xx_force_enable_hpet);