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m68k: hp300: Convert to clocksource API 

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>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
This commit is contained in:
Finn Thain 2018-12-01 11:53:10 +11:00 committed by Geert Uytterhoeven
parent 3384df06c1
commit 2ed16626f5
1 changed files with 30 additions and 7 deletions
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37
arch/m68k/hp300/time.c
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@ -8,6 +8,7 @@
*/ */
#include <asm/ptrace.h> #include <asm/ptrace.h>
#include <linux/clocksource.h>
#include <linux/types.h> #include <linux/types.h>
#include <linux/init.h> #include <linux/init.h>
#include <linux/sched.h> #include <linux/sched.h>
@ -19,6 +20,18 @@
#include <asm/traps.h> #include <asm/traps.h>
#include <asm/blinken.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 */ /* Clock hardware definitions */
#define CLOCKBASE 0xf05f8000 #define CLOCKBASE 0xf05f8000
@ -32,9 +45,10 @@
#define CLKMSB3 0xD #define CLKMSB3 0xD
/* This is for machines which generate the exact clock. */ /* 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) 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); local_irq_save(flags);
in_8(CLOCKBASE + CLKSR); in_8(CLOCKBASE + CLKSR);
asm volatile ("movpw %1@(5),%0" : "=d" (tmp) : "a" (CLOCKBASE)); asm volatile ("movpw %1@(5),%0" : "=d" (tmp) : "a" (CLOCKBASE));
clk_total += INTVAL;
timer_routine(0, NULL); timer_routine(0, NULL);
local_irq_restore(flags); local_irq_restore(flags);
@ -53,20 +68,26 @@ static irqreturn_t hp300_tick(int irq, void *dev_id)
return IRQ_HANDLED; 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 char lsb, msb1, msb2;
unsigned short ticks; u32 ticks;
local_irq_save(flags);
/* Read current timer 1 value */
msb1 = in_8(CLOCKBASE + 5); msb1 = in_8(CLOCKBASE + 5);
lsb = in_8(CLOCKBASE + 7); lsb = in_8(CLOCKBASE + 7);
msb2 = in_8(CLOCKBASE + 5); msb2 = in_8(CLOCKBASE + 5);
if (msb1 != msb2) if (msb1 != msb2)
/* A carry happened while we were reading. Read it again */ /* A carry happened while we were reading. Read it again */
lsb = in_8(CLOCKBASE + 7); lsb = in_8(CLOCKBASE + 7);
ticks = INTVAL - ((msb2 << 8) | lsb); 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) 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)); 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"); pr_err("Couldn't register timer interrupt\n");
out_8(CLOCKBASE + CLKCR2, 0x1); /* select CR1 */ out_8(CLOCKBASE + CLKCR2, 0x1); /* select CR1 */
out_8(CLOCKBASE + CLKCR1, 0x40); /* enable irq */ out_8(CLOCKBASE + CLKCR1, 0x40); /* enable irq */
clocksource_register_hz(&hp300_clk, HP300_TIMER_CLOCK_FREQ);
} }