lkml.org 
[lkml]   [2018]   [Nov]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[RFC PATCH v2 10/14] m68k: mac: 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>
Tested-by: Stan Johnson <userm57@yahoo.com>
---
Changed since v1:
- Moved clk_total access to within the irq lock.
- Use type u32 for tick counter.
---
arch/m68k/mac/via.c | 46 ++++++++++++++++++++++++++++++++++++---------
1 file changed, 37 insertions(+), 9 deletions(-)

diff --git a/arch/m68k/mac/via.c b/arch/m68k/mac/via.c
index d1dbf9017300..de59a5cb4250 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 +574,40 @@ 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;
+static u32 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 +617,16 @@ 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
@@ -617,11 +645,11 @@ u32 mac_gettimeoffset(void)
/* spin */;
}
if (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
\
 
 \ /
  Last update: 2018-11-19 02:22    [W:0.137 / U:0.112 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site