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    SubjectRe: [PATCH 3/3] omap: add hwspinlock device
    On Tue, Oct 19, 2010 at 11:03 AM, Kevin Hilman
    <khilman@deeprootsystems.com> wrote:
    > Ohad Ben-Cohen <ohad@wizery.com> writes:
    >
    >> From: Simon Que <sque@ti.com>
    >>
    >> Build and register an hwspinlock platform device.
    >>
    >> Although only OMAP4 supports the hardware spinlock module (for now),
    >> it is still safe to run this initcall on all omaps, because hwmod lookup
    >> will simply fail on hwspinlock-less platforms.
    >>
    >> Signed-off-by: Simon Que <sque@ti.com>
    >> Signed-off-by: Hari Kanigeri <h-kanigeri2@ti.com>
    >> Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
    >> Cc: Benoit Cousson <b-cousson@ti.com>
    >> ---
    >>  arch/arm/mach-omap2/Makefile     |    1 +
    >>  arch/arm/mach-omap2/hwspinlock.c |   67 ++++++++++++++++++++++++++++++++++++++
    >>  2 files changed, 68 insertions(+), 0 deletions(-)
    >>  create mode 100644 arch/arm/mach-omap2/hwspinlock.c
    >>
    >> diff --git a/arch/arm/mach-omap2/Makefile b/arch/arm/mach-omap2/Makefile
    >> index 7352412..e55d1c5 100644
    >> --- a/arch/arm/mach-omap2/Makefile
    >> +++ b/arch/arm/mach-omap2/Makefile
    >> @@ -190,3 +190,4 @@ obj-y                                     += $(smc91x-m) $(smc91x-y)
    >>
    >>  smsc911x-$(CONFIG_SMSC911X)          := gpmc-smsc911x.o
    >>  obj-y                                        += $(smsc911x-m) $(smsc911x-y)
    >> +obj-$(CONFIG_ARCH_OMAP4)             += hwspinlock.o
    >> diff --git a/arch/arm/mach-omap2/hwspinlock.c b/arch/arm/mach-omap2/hwspinlock.c
    >> new file mode 100644
    >> index 0000000..641a6d4
    >> --- /dev/null
    >> +++ b/arch/arm/mach-omap2/hwspinlock.c
    >> @@ -0,0 +1,67 @@
    >> +/*
    >> + * OMAP hardware spinlock device initialization
    >> + *
    >> + * Copyright (C) 2010 Texas Instruments. All rights reserved.
    >> + *
    >> + * Contact: Simon Que <sque@ti.com>
    >> + *          Hari Kanigeri <h-kanigeri2@ti.com>
    >> + *
    >> + * This program is free software; you can redistribute it and/or
    >> + * modify it under the terms of the GNU General Public License
    >> + * version 2 as published by the Free Software Foundation.
    >> + *
    >> + * This program is distributed in the hope that it will be useful, but
    >> + * WITHOUT ANY WARRANTY; without even the implied warranty of
    >> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    >> + * General Public License for more details.
    >> + *
    >> + * You should have received a copy of the GNU General Public License
    >> + * along with this program; if not, write to the Free Software
    >> + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
    >> + * 02110-1301 USA
    >> + */
    >> +
    >> +#include <linux/kernel.h>
    >> +#include <linux/init.h>
    >> +#include <linux/err.h>
    >> +
    >> +#include <plat/omap_hwmod.h>
    >> +#include <plat/omap_device.h>
    >> +
    >> +struct omap_device_pm_latency omap_spinlock_latency[] = {
    >> +     {
    >> +             .deactivate_func = omap_device_idle_hwmods,
    >> +             .activate_func   = omap_device_enable_hwmods,
    >> +             .flags = OMAP_DEVICE_LATENCY_AUTO_ADJUST,
    >> +     }
    >> +};
    >> +
    >> +int __init hwspinlocks_init(void)
    >> +{
    >> +     int retval = 0;
    >> +     struct omap_hwmod *oh;
    >> +     struct omap_device *od;
    >> +     const char *oh_name = "spinlock";
    >> +     const char *dev_name = "omap_hwspinlock";
    >> +
    >> +     /*
    >> +      * Hwmod lookup will fail in case our platform doesn't support the
    >> +      * hardware spinlock module, so it is safe to run this initcall
    >> +      * on all omaps
    >> +      */
    >> +     oh = omap_hwmod_lookup(oh_name);
    >> +     if (oh == NULL)
    >> +             return -EINVAL;
    >> +
    >> +     od = omap_device_build(dev_name, 0, oh, NULL, 0,
    >> +                             omap_spinlock_latency,
    >> +                             ARRAY_SIZE(omap_spinlock_latency), false);
    >> +     if (IS_ERR(od)) {
    >> +             pr_err("Can't build omap_device for %s:%s\n", dev_name,
    >> +                                                             oh_name);
    >> +             retval = PTR_ERR(od);
    >> +     }
    >> +
    >> +     return retval;
    >> +}
    >> +postcore_initcall(hwspinlocks_init);
    >
    > Any reason this needs to be a postcore_initcall?  Are there users of
    > hwspinlocks this early in boot?  Probaly subsys or even device_initcall
    > is more appropriate here.
    >
    > I would've suspected that any users of hwspinlocks will be dependent on
    > drivers for the other cores (e.g. syslink) which would likely be
    > initialized much later.

    On that note, is there any reason why this file cannot be selected as a module?

    g.

    --
    Grant Likely, B.Sc., P.Eng.
    Secret Lab Technologies Ltd.
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