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    Subject[PATCH v4 08/14] m68k: hp300: Convert to clocksource API
    Date
    Add a platform clocksource by adapting the existing arch_gettimeoffset
    implementation.

    Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
    Acked-by: Linus Walleij <linus.walleij@linaro.org>
    ---
    Changed since v1:
    - Moved clk_total access to within the irq lock.
    - Use type u32 for tick counter.
    ---
    arch/m68k/hp300/time.c | 37 ++++++++++++++++++++++++++++++-------
    1 file changed, 30 insertions(+), 7 deletions(-)

    diff --git a/arch/m68k/hp300/time.c b/arch/m68k/hp300/time.c
    index d30b03ea93a2..90982803a629 100644
    --- a/arch/m68k/hp300/time.c
    +++ b/arch/m68k/hp300/time.c
    @@ -8,6 +8,7 @@
    */

    #include <asm/ptrace.h>
    +#include <linux/clocksource.h>
    #include <linux/types.h>
    #include <linux/init.h>
    #include <linux/sched.h>
    @@ -19,6 +20,18 @@
    #include <asm/traps.h>
    #include <asm/blinken.h>

    +static u64 hp300_read_clk(struct clocksource *cs);
    +
    +static struct clocksource hp300_clk = {
    + .name = "timer",
    + .rating = 250,
    + .read = hp300_read_clk,
    + .mask = CLOCKSOURCE_MASK(32),
    + .flags = CLOCK_SOURCE_IS_CONTINUOUS,
    +};
    +
    +static u32 clk_total;
    +
    /* Clock hardware definitions */

    #define CLOCKBASE 0xf05f8000
    @@ -32,9 +45,10 @@
    #define CLKMSB3 0xD

    /* This is for machines which generate the exact clock. */
    -#define USECS_PER_JIFFY (1000000/HZ)

    -#define INTVAL ((10000 / 4) - 1)
    +#define HP300_TIMER_CLOCK_FREQ 250000
    +#define HP300_TIMER_CYCLES (HP300_TIMER_CLOCK_FREQ / HZ)
    +#define INTVAL (HP300_TIMER_CYCLES - 1)

    static irqreturn_t hp300_tick(int irq, void *dev_id)
    {
    @@ -45,6 +59,7 @@ static irqreturn_t hp300_tick(int irq, void *dev_id)
    local_irq_save(flags);
    in_8(CLOCKBASE + CLKSR);
    asm volatile ("movpw %1@(5),%0" : "=d" (tmp) : "a" (CLOCKBASE));
    + clk_total += INTVAL;
    timer_routine(0, NULL);
    local_irq_restore(flags);

    @@ -53,20 +68,26 @@ static irqreturn_t hp300_tick(int irq, void *dev_id)
    return IRQ_HANDLED;
    }

    -u32 hp300_gettimeoffset(void)
    +static u64 hp300_read_clk(struct clocksource *cs)
    {
    - /* Read current timer 1 value */
    + unsigned long flags;
    unsigned char lsb, msb1, msb2;
    - unsigned short ticks;
    + u32 ticks;

    + local_irq_save(flags);
    + /* Read current timer 1 value */
    msb1 = in_8(CLOCKBASE + 5);
    lsb = in_8(CLOCKBASE + 7);
    msb2 = in_8(CLOCKBASE + 5);
    if (msb1 != msb2)
    /* A carry happened while we were reading. Read it again */
    lsb = in_8(CLOCKBASE + 7);
    +
    ticks = INTVAL - ((msb2 << 8) | lsb);
    - return ((USECS_PER_JIFFY * ticks) / INTVAL) * 1000;
    + ticks += clk_total;
    + local_irq_restore(flags);
    +
    + return ticks;
    }

    void __init hp300_sched_init(irq_handler_t vector)
    @@ -76,9 +97,11 @@ void __init hp300_sched_init(irq_handler_t vector)

    asm volatile(" movpw %0,%1@(5)" : : "d" (INTVAL), "a" (CLOCKBASE));

    - if (request_irq(IRQ_AUTO_6, hp300_tick, 0, "timer tick", vector))
    + if (request_irq(IRQ_AUTO_6, hp300_tick, IRQF_TIMER, "timer tick", vector))
    pr_err("Couldn't register timer interrupt\n");

    out_8(CLOCKBASE + CLKCR2, 0x1); /* select CR1 */
    out_8(CLOCKBASE + CLKCR1, 0x40); /* enable irq */
    +
    + clocksource_register_hz(&hp300_clk, HP300_TIMER_CLOCK_FREQ);
    }
    --
    2.18.1
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