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Date: Tue, 9 Jun 2015 17:18:15 +0530
From: Vineet Gupta <Vineet.Gupta1@...opsys.com>
To: <linux-arch@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC: <arnd@...db.de>, <arc-linux-dev@...opsys.com>,
Vineet Gupta <Vineet.Gupta1@...opsys.com>,
Daniel Lezcano <daniel.lezcano@...aro.org>,
"Thomas Gleixner" <tglx@...utronix.de>
Subject: [PATCH 15/28] ARCv2: SMP: clocksource: Enable Global Real Time counter
Cc: Daniel Lezcano <daniel.lezcano@...aro.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Vineet Gupta <vgupta@...opsys.com>
---
arch/arc/Kconfig | 5 +++++
arch/arc/include/asm/mcip.h | 3 +++
arch/arc/kernel/mcip.c | 3 +++
arch/arc/kernel/time.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 56 insertions(+)
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index ef5ca5969eaf..1b684595e258 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -384,6 +384,11 @@ config ARC_HAS_RTC
default n
depends on !SMP
+config ARC_HAS_GRTC
+ bool "SMP synchronized 64-bit cycle counter"
+ default y
+ depends on SMP
+
config ARC_NUMBER_OF_INTERRUPTS
int "Number of interrupts"
range 8 240
diff --git a/arch/arc/include/asm/mcip.h b/arch/arc/include/asm/mcip.h
index 31f9bac77a27..52c11f0bb0e5 100644
--- a/arch/arc/include/asm/mcip.h
+++ b/arch/arc/include/asm/mcip.h
@@ -39,6 +39,9 @@ struct mcip_cmd {
#define CMD_DEBUG_SET_MASK 0x34
#define CMD_DEBUG_SET_SELECT 0x36
+#define CMD_GRTC_READ_LO 0x42
+#define CMD_GRTC_READ_HI 0x43
+
#define CMD_IDU_ENABLE 0x71
#define CMD_IDU_DISABLE 0x72
#define CMD_IDU_SET_MODE 0x74
diff --git a/arch/arc/kernel/mcip.c b/arch/arc/kernel/mcip.c
index 35921c3ab394..ad7e90b97f6e 100644
--- a/arch/arc/kernel/mcip.c
+++ b/arch/arc/kernel/mcip.c
@@ -154,4 +154,7 @@ void mcip_init_early_smp(void)
__mcip_cmd_data(CMD_DEBUG_SET_SELECT, 0, 0xf);
__mcip_cmd_data(CMD_DEBUG_SET_MASK, 0xf, 0xf);
}
+
+ if (IS_ENABLED(CONFIG_ARC_HAS_GRTC) && !mp.grtc)
+ panic("kernel trying to use non-existent GRTC\n");
}
diff --git a/arch/arc/kernel/time.c b/arch/arc/kernel/time.c
index da495478a40b..3364d2bbc515 100644
--- a/arch/arc/kernel/time.c
+++ b/arch/arc/kernel/time.c
@@ -45,6 +45,8 @@
#include <asm/clk.h>
#include <asm/mach_desc.h>
+#include <asm/mcip.h>
+
/* Timer related Aux registers */
#define ARC_REG_TIMER0_LIMIT 0x23 /* timer 0 limit */
#define ARC_REG_TIMER0_CTRL 0x22 /* timer 0 control */
@@ -60,6 +62,48 @@
/********** Clock Source Device *********/
+#ifdef CONFIG_ARC_HAS_GRTC
+
+static int arc_counter_setup(void)
+{
+ return 1;
+}
+
+static cycle_t arc_counter_read(struct clocksource *cs)
+{
+ unsigned long flags;
+ union {
+#ifdef CONFIG_CPU_BIG_ENDIAN
+ struct { u32 h, l; };
+#else
+ struct { u32 l, h; };
+#endif
+ cycle_t full;
+ } stamp;
+
+ local_irq_save(flags);
+
+ __mcip_cmd(CMD_GRTC_READ_LO, 0);
+ stamp.l = read_aux_reg(ARC_REG_MCIP_READBACK);
+
+ __mcip_cmd(CMD_GRTC_READ_HI, 0);
+ stamp.h = read_aux_reg(ARC_REG_MCIP_READBACK);
+
+ local_irq_restore(flags);
+
+ return stamp.full;
+}
+
+static struct clocksource arc_counter = {
+ .name = "ARConnect GRTC",
+ .rating = 400,
+ .read = arc_counter_read,
+ .mask = CLOCKSOURCE_MASK(64),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+#else
+
#ifdef CONFIG_ARC_HAS_RTC
#define AUX_RTC_CTRL 0x103
@@ -135,6 +179,7 @@ static struct clocksource arc_counter = {
};
#endif
+#endif
/********** Clock Event Device *********/
--
1.9.1
--
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