Add a platform clocksource by adapting the existing arch_gettimeoffset implementation.
Signed-off-by: Finn Thain <fth...@telegraphics.com.au> Acked-by: Linus Walleij <linus.wall...@linaro.org> Tested-by: Stan Johnson <user...@yahoo.com> --- Changed since v3: - Use clk_offset variable to track the offset when the irq check is skipped. Changed since v2: - Drop 'clk_offset' variable. Changed since v1: - Moved clk_total access to within the irq lock. - Use type u32 for tick counter. --- arch/m68k/mac/via.c | 45 ++++++++++++++++++++++++++++++++++++--------- 1 file changed, 36 insertions(+), 9 deletions(-) diff --git a/arch/m68k/mac/via.c b/arch/m68k/mac/via.c index 65aca12a8694..31cccc79cb7a 100644 --- a/arch/m68k/mac/via.c +++ b/arch/m68k/mac/via.c @@ -23,6 +23,7 @@ * */ +#include <linux/clocksource.h> #include <linux/types.h> #include <linux/kernel.h> #include <linux/mm.h> @@ -573,16 +574,39 @@ 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; } @@ -592,13 +616,16 @@ 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 @@ -614,11 +641,11 @@ 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; - local_irq_restore(flags); - + clk_offset = VIA_TIMER_CYCLES; count = count_high << 8; - count = VIA_TIMER_CYCLES - count + offset; + ticks = VIA_TIMER_CYCLES - count; + ticks += clk_offset + clk_total; + local_irq_restore(flags); - return ((count * VIA_TIMER_INTERVAL) / VIA_TIMER_CYCLES) * 1000; + return ticks; } -- 2.18.1