svn commit: r273598 - in head: include sys/dev/acpica
Andriy Gapon
avg at FreeBSD.org
Fri Oct 24 19:06:06 UTC 2014
On 24/10/2014 21:39, Rui Paulo wrote:
> Author: rpaulo
> Date: Fri Oct 24 18:39:15 2014
> New Revision: 273598
> URL: https://svnweb.freebsd.org/changeset/base/273598
>
> Log:
> HPET: create /dev/hpetN as a way to access HPET from userland.
>
> In some cases, TSC is broken and special applications might benefit
> from memory mapping HPET and reading the registers to count time.
> Most often the main HPET counter is 32-bit only[1], so this only gives
> the application a 300 second window based on the default HPET
> interval.
> Other applications, such as Intel's DPDK, expect /dev/hpet to be
> present and use it to count time as well.
Does this device attempt to play nice with eventtimer infrastructure that may
use the same timer?
> Although we have an almost userland version of gettimeofday() which
> uses rdtsc in userland, it's not always possible to use it, depending
> on how broken the multi-socket hardware is.
>
> Install the acpi_hpet.h so that applications can use the HPET register
> definitions.
>
> [1] I haven't found a system where HPET's main counter uses more than
> 32 bit. There seems to be a discrepancy in the Intel documentation
> (claiming it's a 64-bit counter) and the actual implementation (a
> 32-bit counter in a 64-bit memory area).
>
> MFC after: 1 week
> Relnotes: yes
>
> Modified:
> head/include/Makefile
> head/sys/dev/acpica/acpi_hpet.c
>
> Modified: head/include/Makefile
> ==============================================================================
> --- head/include/Makefile Fri Oct 24 17:40:32 2014 (r273597)
> +++ head/include/Makefile Fri Oct 24 18:39:15 2014 (r273598)
> @@ -159,6 +159,8 @@ copies:
> cd ${.CURDIR}/../sys/dev/acpica; \
> ${INSTALL} -C -o ${BINOWN} -g ${BINGRP} -m 444 acpiio.h \
> ${DESTDIR}${INCLUDEDIR}/dev/acpica
> + ${INSTALL} -C -o ${BINOWN} -g ${BINGRP} -m 444 acpi_hpet.h \
> + ${DESTDIR}${INCLUDEDIR}/dev/acpica
> cd ${.CURDIR}/../sys/dev/agp; \
> ${INSTALL} -C -o ${BINOWN} -g ${BINGRP} -m 444 agpreg.h \
> ${DESTDIR}${INCLUDEDIR}/dev/agp
> @@ -243,7 +245,7 @@ symlinks:
> done
> .endfor
> cd ${.CURDIR}/../sys/dev/acpica; \
> - for h in acpiio.h; do \
> + for h in acpiio.h acpi_hpet.h; do \
> ln -fs ../../../../sys/dev/acpica/$$h \
> ${DESTDIR}${INCLUDEDIR}/dev/acpica; \
> done
>
> Modified: head/sys/dev/acpica/acpi_hpet.c
> ==============================================================================
> --- head/sys/dev/acpica/acpi_hpet.c Fri Oct 24 17:40:32 2014 (r273597)
> +++ head/sys/dev/acpica/acpi_hpet.c Fri Oct 24 18:39:15 2014 (r273598)
> @@ -35,11 +35,13 @@ __FBSDID("$FreeBSD$");
> #include "opt_apic.h"
> #endif
> #include <sys/param.h>
> +#include <sys/conf.h>
> #include <sys/bus.h>
> #include <sys/kernel.h>
> #include <sys/module.h>
> #include <sys/proc.h>
> #include <sys/rman.h>
> +#include <sys/mman.h>
> #include <sys/time.h>
> #include <sys/smp.h>
> #include <sys/sysctl.h>
> @@ -106,6 +108,23 @@ struct hpet_softc {
> char name[8];
> } t[32];
> int num_timers;
> + struct cdev *pdev;
> + int mmap_allow;
> + int mmap_allow_write;
> + int devinuse;
> +};
> +
> +static d_open_t hpet_open;
> +static d_close_t hpet_close;
> +static d_mmap_t hpet_mmap;
> +
> +static struct cdevsw hpet_cdevsw = {
> + .d_version = D_VERSION,
> + .d_flags = D_TRACKCLOSE,
> + .d_name = "hpet",
> + .d_open = hpet_open,
> + .d_close = hpet_close,
> + .d_mmap = hpet_mmap,
> };
>
> static u_int hpet_get_timecount(struct timecounter *tc);
> @@ -317,6 +336,47 @@ hpet_find_irq_rid(device_t dev, u_long s
> }
> }
>
> +static int
> +hpet_open(struct cdev *cdev, int oflags, int devtype, struct thread *td)
> +{
> + struct hpet_softc *sc;
> +
> + sc = cdev->si_drv1;
> + if (!sc->mmap_allow)
> + return (EPERM);
> + if (atomic_cmpset_32(&sc->devinuse, 0, 1) == 0)
> + return (EBUSY);
> + else
> + return (0);
> +}
> +
> +static int
> +hpet_close(struct cdev *cdev, int fflag, int devtype, struct thread *td)
> +{
> + struct hpet_softc *sc;
> +
> + sc = cdev->si_drv1;
> + sc->devinuse = 0;
> +
> + return (0);
> +}
> +
> +static int
> +hpet_mmap(struct cdev *cdev, vm_ooffset_t offset, vm_paddr_t *paddr,
> + int nprot, vm_memattr_t *memattr)
> +{
> + struct hpet_softc *sc;
> +
> + sc = cdev->si_drv1;
> + if (offset > rman_get_size(sc->mem_res))
> + return (EINVAL);
> + if (!sc->mmap_allow_write && (nprot & PROT_WRITE))
> + return (EPERM);
> + *paddr = rman_get_start(sc->mem_res) + offset;
> +
> + return (0);
> +}
> +
> /* Discover the HPET via the ACPI table of the same name. */
> static void
> hpet_identify(driver_t *driver, device_t parent)
> @@ -701,6 +761,26 @@ hpet_attach(device_t dev)
> maxhpetet++;
> }
> }
> +
> + sc->pdev = make_dev(&hpet_cdevsw, 0, UID_ROOT, GID_WHEEL,
> + 0600, "hpet%d", device_get_unit(dev));
> + if (sc->pdev) {
> + sc->pdev->si_drv1 = sc;
> + sc->mmap_allow = 1;
> + TUNABLE_INT_FETCH("hw.acpi.hpet.mmap_allow",
> + &sc->mmap_allow);
> + sc->mmap_allow_write = 1;
> + TUNABLE_INT_FETCH("hw.acpi.hpet.mmap_allow_write",
> + &sc->mmap_allow_write);
> + SYSCTL_ADD_INT(device_get_sysctl_ctx(dev),
> + SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
> + OID_AUTO, "mmap_allow",
> + CTLFLAG_RW, &sc->mmap_allow, 0,
> + "Allow userland to memory map HPET");
> + } else
> + device_printf(dev, "could not create /dev/hpet%d\n",
> + device_get_unit(dev));
> +
> return (0);
> }
>
>
--
Andriy Gapon
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