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m68k: mac: 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>
Tested-by: Stan Johnson <userm57@yahoo.com>
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 4be2ba93cf
commit 481fa139b8
1 changed files with 36 additions and 9 deletions
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45
arch/m68k/mac/via.c
View File

@ -23,6 +23,7 @@
*
*/
#include <linux/clocksource.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/mm.h>
@ -577,16 +578,39 @@ EXPORT_SYMBOL(via2_scsi_drq_pending);
/* timer and clock source */
#define VIA_CLOCK_FREQ 783360 /* VIA "phase 2" clock in Hz */
#define VIA_TIMER_INTERVAL (1000000 / HZ) /* microseconds per jiffy */
#define VIA_TIMER_CYCLES (VIA_CLOCK_FREQ / HZ) /* clock cycles per jiffy */
#define VIA_TC (VIA_TIMER_CYCLES - 2) /* including 0 and -1 */
#define VIA_TC_LOW (VIA_TC & 0xFF)
#define VIA_TC_HIGH (VIA_TC >> 8)
static u64 mac_read_clk(struct clocksource *cs);
static struct clocksource mac_clk = {
.name = "via1",
.rating = 250,
.read = mac_read_clk,
.mask = CLOCKSOURCE_MASK(32),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
static u32 clk_total, clk_offset;
static irqreturn_t via_timer_handler(int irq, void *dev_id)
{
irq_handler_t timer_routine = dev_id;
clk_total += VIA_TIMER_CYCLES;
clk_offset = 0;
timer_routine(0, NULL);
return IRQ_HANDLED;
}
void __init via_init_clock(irq_handler_t timer_routine)
{
if (request_irq(IRQ_MAC_TIMER_1, timer_routine, 0, "timer", NULL)) {
if (request_irq(IRQ_MAC_TIMER_1, via_timer_handler, IRQF_TIMER, "timer",
timer_routine)) {
pr_err("Couldn't register %s interrupt\n", "timer");
return;
}
@ -596,13 +620,16 @@ void __init via_init_clock(irq_handler_t timer_routine)
via1[vT1CL] = VIA_TC_LOW;
via1[vT1CH] = VIA_TC_HIGH;
via1[vACR] |= 0x40;
clocksource_register_hz(&mac_clk, VIA_CLOCK_FREQ);
}
u32 mac_gettimeoffset(void)
static u64 mac_read_clk(struct clocksource *cs)
{
unsigned long flags;
u8 count_high;
u16 count, offset = 0;
u16 count;
u32 ticks;
/*
* Timer counter wrap-around is detected with the timer interrupt flag
@ -618,11 +645,11 @@ u32 mac_gettimeoffset(void)
if (count_high == 0xFF)
count_high = 0;
if (count_high > 0 && (via1[vIFR] & VIA_TIMER_1_INT))
offset = VIA_TIMER_CYCLES;
clk_offset = VIA_TIMER_CYCLES;
count = count_high << 8;
ticks = VIA_TIMER_CYCLES - count;
ticks += clk_offset + clk_total;
local_irq_restore(flags);
count = count_high << 8;
count = VIA_TIMER_CYCLES - count + offset;
return ((count * VIA_TIMER_INTERVAL) / VIA_TIMER_CYCLES) * 1000;
return ticks;
}