[PATCH v4 0/3] Add clockevet for timer-nps driver to NPS400 SoC

[PATCH v4 0/3] Add clockevet for timer-nps driver to NPS400 SoC

[Noam Camus]

From: Noam Camus <noamca@mellanox.com>

Change log
---
V3 --> V4
Main changes are [Thanks for the review]:
Fix many typos at log [Daniel]
Add handling for bad return values [Daniel and Thomas]
Replace use of internal irqchip pointers with existing IRQ API [Thomas]
Provide interrupt handler (percpu) with dev_id equal to evt [Thomas]
Fix passing *clk by reference to nps_get_timer_clk() [Daniel]

V2 --> V3
Apply Rob Herring comment about backword compatibility

V1 --> V2
Apply Daniel Lezcano comments:
	CLOCKSOURCE_OF_DECLARE return value
	update hotplug callbacks usage
	squash of 2 first commits.
In this version I created new commit to serve as preperation for adding clockevents.
This way the last patch is more readable with clockevent content.
---

In first version of this driver we supported clocksource for the NPS400.
The support for clockevent was taken from Synopsys ARC timer driver.
This was good for working with our simulator of NPS400.
However in NPS400 ASIC the timers behave differently than simulation.
The timers in ASIC are shared between all threads whithin a core
and hence need different driver to support this behaviour.

The idea of this design is that we got 16 HW threads per core
each represented at bimask in a shared register in this core.
So when thread wants that next clockevent expiration will produce
timer interrupt to itself the correspondance bit in this register
should be set.
So theoretically if all 16 bits are set then all HW threads will get
timer interrupt on next expiration of timer 0.

Note that we use Synopsys ARC design naming convention for the timers
where:
timer0 is used for clockevents
timer1 is used for clocksource.

Noam Camus (3):
  soc: Support for NPS HW scheduling
  clocksource: update "fn" at CLOCKSOURCE_OF_DECLARE() of nps400 timer
  clocksource: Add clockevent support to NPS400 driver

 .../bindings/timer/ezchip,nps400-timer.txt         |   15 --
 .../bindings/timer/ezchip,nps400-timer0.txt        |   17 ++
 .../bindings/timer/ezchip,nps400-timer1.txt        |   15 ++
 arch/arc/plat-eznps/include/plat/ctop.h            |    2 -
 drivers/clocksource/timer-nps.c                    |  264 ++++++++++++++++++--
 include/soc/nps/mtm.h                              |   59 +++++
 6 files changed, 335 insertions(+), 37 deletions(-)
 delete mode 100644 Documentation/devicetree/bindings/timer/ezchip,nps400-timer.txt
 create mode 100644 Documentation/devicetree/bindings/timer/ezchip,nps400-timer0.txt
 create mode 100644 Documentation/devicetree/bindings/timer/ezchip,nps400-timer1.txt
 create mode 100644 include/soc/nps/mtm.h

[PATCH v4 1/3] soc: Support for NPS HW scheduling

[Noam Camus]

From: Noam Camus <noamca@mellanox.com>

This new header file is for NPS400 SoC (part of ARC architecture).
The header file includes macros for save/restore of HW scheduling.
The control of HW scheduling is achieved by writing core registers.
This code was moved from arc/plat-eznps so it can be used
from drivers/clocksource/, available only for CONFIG_EZNPS_MTM_EXT.

Signed-off-by: Noam Camus <noamca@mellanox.com>
---
 arch/arc/plat-eznps/include/plat/ctop.h |    2 -
 include/soc/nps/mtm.h                   |   59 +++++++++++++++++++++++++++++++
 2 files changed, 59 insertions(+), 2 deletions(-)
 create mode 100644 include/soc/nps/mtm.h

diff --git a/arch/arc/plat-eznps/include/plat/ctop.h b/arch/arc/plat-eznps/include/plat/ctop.h
index 9d6718c..ee2e32d 100644
--- a/arch/arc/plat-eznps/include/plat/ctop.h
+++ b/arch/arc/plat-eznps/include/plat/ctop.h
@@ -46,9 +46,7 @@
 #define CTOP_AUX_UDMC				(CTOP_AUX_BASE + 0x300)
 
 /* EZchip core instructions */
-#define CTOP_INST_HWSCHD_OFF_R3			0x3B6F00BF
 #define CTOP_INST_HWSCHD_OFF_R4			0x3C6F00BF
-#define CTOP_INST_HWSCHD_RESTORE_R3		0x3E6F70C3
 #define CTOP_INST_HWSCHD_RESTORE_R4		0x3E6F7103
 #define CTOP_INST_SCHD_RW			0x3E6F7004
 #define CTOP_INST_SCHD_RD			0x3E6F7084
diff --git a/include/soc/nps/mtm.h b/include/soc/nps/mtm.h
new file mode 100644
index 0000000..d2f5e7e
--- /dev/null
+++ b/include/soc/nps/mtm.h
@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 2016, Mellanox Technologies. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#ifndef SOC_NPS_MTM_H
+#define SOC_NPS_MTM_H
+
+#define CTOP_INST_HWSCHD_OFF_R3                 0x3B6F00BF
+#define CTOP_INST_HWSCHD_RESTORE_R3             0x3E6F70C3
+
+static inline void hw_schd_save(unsigned int *flags)
+{
+	__asm__ __volatile__(
+	"       .word %1\n"
+	"       st r3,[%0]\n"
+	:
+	: "r"(flags), "i"(CTOP_INST_HWSCHD_OFF_R3)
+	: "r3", "memory");
+}
+
+static inline void hw_schd_restore(unsigned int flags)
+{
+	__asm__ __volatile__(
+	"       mov r3, %0\n"
+	"       .word %1\n"
+	:
+	: "r"(flags), "i"(CTOP_INST_HWSCHD_RESTORE_R3)
+	: "r3");
+}
+
+#endif /* SOC_NPS_MTM_H */
-- 
1.7.1

[PATCH v4 2/3] clocksource: update "fn" at CLOCKSOURCE_OF_DECLARE() of nps400 timer

[Noam Camus]

From: Noam Camus <noamca@mellanox.com>

nps_setup_clocksource() should take node as only argument i.e.:
replace
int __init nps_setup_clocksource(struct device_node *node, struct clk *clk)
with
int __init nps_setup_clocksource(struct device_node *node)

This is also serve as preperation for next patch which adds support
for clockevents to nps400.
Specifically we add new function nps_get_timer_clk() to serve clocksource
and later clockevent registration.

Signed-off-by: Noam Camus <noamca@mellanox.com>
---
 drivers/clocksource/timer-nps.c |   63 +++++++++++++++++++++++----------------
 1 files changed, 37 insertions(+), 26 deletions(-)

diff --git a/drivers/clocksource/timer-nps.c b/drivers/clocksource/timer-nps.c
index 70c149a..1533349 100644
--- a/drivers/clocksource/timer-nps.c
+++ b/drivers/clocksource/timer-nps.c
@@ -46,7 +46,33 @@
 /* This array is per cluster of CPUs (Each NPS400 cluster got 256 CPUs) */
 static void *nps_msu_reg_low_addr[NPS_CLUSTER_NUM] __read_mostly;
 
-static unsigned long nps_timer_rate;
+static int nps_get_timer_clk(struct device_node *node,
+			     unsigned long *timer_freq,
+			     struct clk **clk)
+{
+	int ret;
+
+	*clk = of_clk_get(node, 0);
+	if (IS_ERR(*clk)) {
+		pr_err("timer missing clk");
+		return PTR_ERR(*clk);
+	}
+
+	ret = clk_prepare_enable(*clk);
+	if (ret) {
+		pr_err("Couldn't enable parent clk\n");
+		return ret;
+	}
+
+	*timer_freq = clk_get_rate(*clk);
+	if (!(*timer_freq)) {
+		pr_err("Couldn't clk get rate\n");
+		clk_disable_unprepare(*clk);
+		return *timer_freq;
+	}
+
+	return 0;
+}
 
 static cycle_t nps_clksrc_read(struct clocksource *clksrc)
 {
@@ -55,26 +81,24 @@ static cycle_t nps_clksrc_read(struct clocksource *clksrc)
 	return (cycle_t)ioread32be(nps_msu_reg_low_addr[cluster]);
 }
 
-static int __init nps_setup_clocksource(struct device_node *node,
-					struct clk *clk)
+static int __init nps_setup_clocksource(struct device_node *node)
 {
 	int ret, cluster;
+	struct clk *clk;
+	unsigned long nps_timer1_freq;
+
 
 	for (cluster = 0; cluster < NPS_CLUSTER_NUM; cluster++)
 		nps_msu_reg_low_addr[cluster] =
 			nps_host_reg((cluster << NPS_CLUSTER_OFFSET),
-				 NPS_MSU_BLKID, NPS_MSU_TICK_LOW);
+				     NPS_MSU_BLKID, NPS_MSU_TICK_LOW);
 
-	ret = clk_prepare_enable(clk);
-	if (ret) {
-		pr_err("Couldn't enable parent clock\n");
+	ret = nps_get_timer_clk(node, &nps_timer1_freq, &clk);
+	if (ret)
 		return ret;
-	}
 
-	nps_timer_rate = clk_get_rate(clk);
-
-	ret = clocksource_mmio_init(nps_msu_reg_low_addr, "EZnps-tick",
-				    nps_timer_rate, 301, 32, nps_clksrc_read);
+	ret = clocksource_mmio_init(nps_msu_reg_low_addr, "nps-tick",
+				    nps_timer1_freq, 301, 32, nps_clksrc_read);
 	if (ret) {
 		pr_err("Couldn't register clock source.\n");
 		clk_disable_unprepare(clk);
@@ -83,18 +107,5 @@ static int __init nps_setup_clocksource(struct device_node *node,
 	return ret;
 }
 
-static int __init nps_timer_init(struct device_node *node)
-{
-	struct clk *clk;
-
-	clk = of_clk_get(node, 0);
-	if (IS_ERR(clk)) {
-		pr_err("Can't get timer clock.\n");
-		return PTR_ERR(clk);
-	}
-
-	return nps_setup_clocksource(node, clk);
-}
-
 CLOCKSOURCE_OF_DECLARE(ezchip_nps400_clksrc, "ezchip,nps400-timer",
-		       nps_timer_init);
+		       nps_setup_clocksource);
-- 
1.7.1

[PATCH v4 3/3] clocksource: Add clockevent support to NPS400 driver

[Noam Camus]

From: Noam Camus <noamca@mellanox.com>

Till now we used clockevent from generic ARC driver.
This was enough as long as we worked with simple multicore SoC.
When we are working with multithread SoC each HW thread can be
scheduled to receive timer interrupt using timer mask register.
This patch will provide a way to control clock events per HW thread.

The design idea is that for each core there is dedicated regirtser
(TSI) serving all 16 HW threads.
The register is a bitmask with one bit for each HW thread.
When HW thread wants that next expiration of timer interrupt will
hit it then the proper bit should be set in this dedicated register.
When timer expires all HW threads within this core which their bit
is set at the TSI register will be interrupted.

Driver can be used from device tree by:
compatible = "ezchip,nps400-timer0" <-- for clocksource
compatible = "ezchip,nps400-timer1" <-- for clockevent

Note that name convention for timer0/timer1 was taken from legacy
ARC design. This design is our base before adding HW threads.
For backward compatibility we keep "ezchip,nps400-timer" for clocksource

Signed-off-by: Noam Camus <noamca@mellanox.com>
---
 .../bindings/timer/ezchip,nps400-timer.txt         |   15 --
 .../bindings/timer/ezchip,nps400-timer0.txt        |   17 ++
 .../bindings/timer/ezchip,nps400-timer1.txt        |   15 ++
 drivers/clocksource/timer-nps.c                    |  213 ++++++++++++++++++++
 4 files changed, 245 insertions(+), 15 deletions(-)
 delete mode 100644 Documentation/devicetree/bindings/timer/ezchip,nps400-timer.txt
 create mode 100644 Documentation/devicetree/bindings/timer/ezchip,nps400-timer0.txt
 create mode 100644 Documentation/devicetree/bindings/timer/ezchip,nps400-timer1.txt

diff --git a/Documentation/devicetree/bindings/timer/ezchip,nps400-timer.txt b/Documentation/devicetree/bindings/timer/ezchip,nps400-timer.txt
deleted file mode 100644
index c8c03d7..0000000
--- a/Documentation/devicetree/bindings/timer/ezchip,nps400-timer.txt
+++ /dev/null
@@ -1,15 +0,0 @@
-NPS Network Processor
-
-Required properties:
-
-- compatible :	should be "ezchip,nps400-timer"
-
-Clocks required for compatible = "ezchip,nps400-timer":
-- clocks : Must contain a single entry describing the clock input
-
-Example:
-
-timer {
-	compatible = "ezchip,nps400-timer";
-	clocks = <&sysclk>;
-};
diff --git a/Documentation/devicetree/bindings/timer/ezchip,nps400-timer0.txt b/Documentation/devicetree/bindings/timer/ezchip,nps400-timer0.txt
new file mode 100644
index 0000000..e3cfce8
--- /dev/null
+++ b/Documentation/devicetree/bindings/timer/ezchip,nps400-timer0.txt
@@ -0,0 +1,17 @@
+NPS Network Processor
+
+Required properties:
+
+- compatible :	should be "ezchip,nps400-timer0"
+
+Clocks required for compatible = "ezchip,nps400-timer0":
+- interrupts : The interrupt of the first timer
+- clocks : Must contain a single entry describing the clock input
+
+Example:
+
+timer {
+	compatible = "ezchip,nps400-timer0";
+	interrupts = <3>;
+	clocks = <&sysclk>;
+};
diff --git a/Documentation/devicetree/bindings/timer/ezchip,nps400-timer1.txt b/Documentation/devicetree/bindings/timer/ezchip,nps400-timer1.txt
new file mode 100644
index 0000000..c0ab419
--- /dev/null
+++ b/Documentation/devicetree/bindings/timer/ezchip,nps400-timer1.txt
@@ -0,0 +1,15 @@
+NPS Network Processor
+
+Required properties:
+
+- compatible :	should be "ezchip,nps400-timer1"
+
+Clocks required for compatible = "ezchip,nps400-timer1":
+- clocks : Must contain a single entry describing the clock input
+
+Example:
+
+timer {
+	compatible = "ezchip,nps400-timer1";
+	clocks = <&sysclk>;
+};
diff --git a/drivers/clocksource/timer-nps.c b/drivers/clocksource/timer-nps.c
index 1533349..1097ad6 100644
--- a/drivers/clocksource/timer-nps.c
+++ b/drivers/clocksource/timer-nps.c
@@ -109,3 +109,216 @@ static int __init nps_setup_clocksource(struct device_node *node)
 
 CLOCKSOURCE_OF_DECLARE(ezchip_nps400_clksrc, "ezchip,nps400-timer",
 		       nps_setup_clocksource);
+CLOCKSOURCE_OF_DECLARE(ezchip_nps400_clk_src, "ezchip,nps400-timer1",
+		       nps_setup_clocksource);
+
+#ifdef CONFIG_EZNPS_MTM_EXT
+#include <soc/nps/mtm.h>
+
+/* Timer related Aux registers */
+#define NPS_REG_TIMER0_TSI	0xFFFFF850
+#define NPS_REG_TIMER0_LIMIT	0x23
+#define NPS_REG_TIMER0_CTRL	0x22
+#define NPS_REG_TIMER0_CNT	0x21
+
+/*
+ * Interrupt Enabled (IE) - re-arm the timer
+ * Not Halted (NH) - is cleared when working with JTAG (for debug)
+ */
+#define TIMER0_CTRL_IE		BIT(0)
+#define TIMER0_CTRL_NH		BIT(1)
+
+static unsigned long nps_timer0_freq;
+static unsigned long nps_timer0_irq;
+
+/*
+ * Arm the timer to interrupt after @cycles
+ */
+static void nps_clkevent_timer_event_setup(unsigned int cycles)
+{
+	write_aux_reg(NPS_REG_TIMER0_LIMIT, cycles);
+	write_aux_reg(NPS_REG_TIMER0_CNT, 0);
+
+	write_aux_reg(NPS_REG_TIMER0_CTRL, TIMER0_CTRL_IE | TIMER0_CTRL_NH);
+}
+
+/*
+ * Clear from TSI the bit for this thread (if not in periodic mode)
+ * If still there are pending HW treads set next timer event
+ */
+static void nps_clkevent_rm_thread(bool remove_thread)
+{
+	unsigned int cflags;
+	unsigned int enabled_threads = 0;
+	int thread;
+
+	hw_schd_save(&cflags);
+
+	enabled_threads = read_aux_reg(NPS_REG_TIMER0_TSI);
+
+	/* remove thread from TSI1 */
+	if (remove_thread) {
+		thread = read_aux_reg(CTOP_AUX_THREAD_ID);
+		enabled_threads &= ~(1 << thread);
+		write_aux_reg(NPS_REG_TIMER0_TSI, enabled_threads);
+	}
+
+	/* Re-arm the timer if needed */
+	if (!enabled_threads)
+		write_aux_reg(NPS_REG_TIMER0_CTRL, TIMER0_CTRL_NH);
+	else
+		write_aux_reg(NPS_REG_TIMER0_CTRL,
+			      TIMER0_CTRL_IE | TIMER0_CTRL_NH);
+
+	hw_schd_restore(cflags);
+}
+
+static void nps_clkevent_add_thread(bool set_event)
+{
+	int thread;
+	unsigned int cflags, enabled_threads;
+
+	hw_schd_save(&cflags);
+
+	/* add thread to TSI1 */
+	thread = read_aux_reg(CTOP_AUX_THREAD_ID);
+	enabled_threads = read_aux_reg(NPS_REG_TIMER0_TSI);
+	enabled_threads |= (1 << thread);
+	write_aux_reg(NPS_REG_TIMER0_TSI, enabled_threads);
+
+	/* set next timer event */
+	if (set_event)
+		write_aux_reg(NPS_REG_TIMER0_CTRL,
+			      TIMER0_CTRL_IE | TIMER0_CTRL_NH);
+
+	hw_schd_restore(cflags);
+}
+
+static int nps_clkevent_set_next_event(unsigned long delta,
+				       struct clock_event_device *dev)
+{
+	nps_clkevent_add_thread(true);
+	enable_percpu_irq(nps_timer0_irq, IRQ_TYPE_NONE);
+
+	return 0;
+}
+
+/*
+ * Whenever anyone tries to change modes, we just mask interrupts
+ * and wait for the next event to get set.
+ */
+static int nps_clkevent_timer_shutdown(struct clock_event_device *dev)
+{
+	disable_percpu_irq(nps_timer0_irq);
+
+	return 0;
+}
+
+/*
+ * For each HW thread set its relevant bit at the TSI register
+ * To arm the timer only thread 0 is needed since it is shared
+ * by all HW threads within same core.
+ */
+static int nps_clkevent_set_periodic(struct clock_event_device *dev)
+{
+	nps_clkevent_add_thread(false);
+	if (read_aux_reg(CTOP_AUX_THREAD_ID) == 0)
+		nps_clkevent_timer_event_setup(nps_timer0_freq / HZ);
+
+	return 0;
+}
+
+static int nps_clkevent_set_oneshot(struct clock_event_device *dev)
+{
+	nps_clkevent_rm_thread(true);
+	nps_clkevent_timer_shutdown(dev);
+
+	return 0;
+}
+
+static DEFINE_PER_CPU(struct clock_event_device, nps_clockevent_device) = {
+	.name				=	"NPS Timer0",
+	.features			=	CLOCK_EVT_FEAT_ONESHOT |
+						CLOCK_EVT_FEAT_PERIODIC,
+	.rating				=	300,
+	.set_next_event			=	nps_clkevent_set_next_event,
+	.set_state_periodic		=	nps_clkevent_set_periodic,
+	.set_state_oneshot		=	nps_clkevent_set_oneshot,
+	.set_state_oneshot_stopped	=	nps_clkevent_timer_shutdown,
+	.set_state_shutdown		=	nps_clkevent_timer_shutdown,
+	.tick_resume			=	nps_clkevent_timer_shutdown,
+};
+
+static irqreturn_t timer_irq_handler(int irq, void *dev_id)
+{
+	struct clock_event_device *evt = dev_id;
+	int irq_reenable = clockevent_state_periodic(evt);
+
+	/* Remove HW thread from TSI only if NOT in periodic state */
+	nps_clkevent_rm_thread(!irq_reenable);
+
+	evt->event_handler(evt);
+
+	return IRQ_HANDLED;
+}
+
+static int nps_timer_starting_cpu(unsigned int cpu)
+{
+	struct clock_event_device *evt = this_cpu_ptr(&nps_clockevent_device);
+
+	evt->cpumask = cpumask_of(smp_processor_id());
+
+	clockevents_config_and_register(evt, nps_timer0_freq, 0, ULONG_MAX);
+	enable_percpu_irq(nps_timer0_irq, IRQ_TYPE_NONE);
+
+	return 0;
+}
+
+static int nps_timer_dying_cpu(unsigned int cpu)
+{
+	disable_percpu_irq(nps_timer0_irq);
+	return 0;
+}
+
+static int __init nps_setup_clockevent(struct device_node *node)
+{
+	struct clk *clk;
+	int ret;
+
+	nps_timer0_irq = irq_of_parse_and_map(node, 0);
+	if (nps_timer0_irq <= 0) {
+		pr_err("clockevent: missing irq");
+		return -EINVAL;
+	}
+
+	ret = nps_get_timer_clk(node, &nps_timer0_freq, &clk);
+	if (ret)
+		return ret;
+
+	/* Needs apriori irq_set_percpu_devid() done in intc map function */
+	ret = request_percpu_irq(nps_timer0_irq, timer_irq_handler,
+				 "Timer0 (per-cpu-tick)",
+				 &nps_clockevent_device);
+	if (ret) {
+		pr_err("Couldn't request irq\n");
+		clk_disable_unprepare(clk);
+		return ret;
+	}
+
+	ret = cpuhp_setup_state(CPUHP_AP_ARC_TIMER_STARTING,
+				"clockevents/nps:starting",
+				nps_timer_starting_cpu,
+				nps_timer_dying_cpu);
+	if (ret) {
+		pr_err("Failed to setup hotplug state");
+		clk_disable_unprepare(clk);
+		free_percpu_irq(nps_timer0_irq, &nps_clockevent_device);
+		return ret;
+	}
+
+	return 0;
+}
+
+CLOCKSOURCE_OF_DECLARE(ezchip_nps400_clk_evt, "ezchip,nps400-timer0",
+		       nps_setup_clockevent);
+#endif /* CONFIG_EZNPS_MTM_EXT */
-- 
1.7.1

Re: [PATCH v4 2/3] clocksource: update "fn" at CLOCKSOURCE_OF_DECLARE() of nps400 timer

[Daniel Lezcano]

On Sun, Nov 06, 2016 at 07:44:57PM +0200, Noam Camus wrote:
> From: Noam Camus <noamca@mellanox.com>
> 
> nps_setup_clocksource() should take node as only argument i.e.:
> replace
> int __init nps_setup_clocksource(struct device_node *node, struct clk *clk)
> with
> int __init nps_setup_clocksource(struct device_node *node)
> 
> This is also serve as preperation for next patch which adds support
> for clockevents to nps400.
> Specifically we add new function nps_get_timer_clk() to serve clocksource
> and later clockevent registration.
> 
> Signed-off-by: Noam Camus <noamca@mellanox.com>
> ---
>  drivers/clocksource/timer-nps.c |   63 +++++++++++++++++++++++----------------
>  1 files changed, 37 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/clocksource/timer-nps.c b/drivers/clocksource/timer-nps.c
> index 70c149a..1533349 100644
> --- a/drivers/clocksource/timer-nps.c
> +++ b/drivers/clocksource/timer-nps.c
> @@ -46,7 +46,33 @@
>  /* This array is per cluster of CPUs (Each NPS400 cluster got 256 CPUs) */
>  static void *nps_msu_reg_low_addr[NPS_CLUSTER_NUM] __read_mostly;
>  
> -static unsigned long nps_timer_rate;
> +static int nps_get_timer_clk(struct device_node *node,
> +			     unsigned long *timer_freq,
> +			     struct clk **clk)

	__init

> +{
> +	int ret;
> +
> +	*clk = of_clk_get(node, 0);
> +	if (IS_ERR(*clk)) {
> +		pr_err("timer missing clk");
> +		return PTR_ERR(*clk);
> +	}
> +
> +	ret = clk_prepare_enable(*clk);
> +	if (ret) {
> +		pr_err("Couldn't enable parent clk\n");
> +		return ret;
> +	}
> +
> +	*timer_freq = clk_get_rate(*clk);
> +	if (!(*timer_freq)) {
> +		pr_err("Couldn't clk get rate\n");
> +		clk_disable_unprepare(*clk);
> +		return *timer_freq;

		^^^^^^^^^^^^^^^^^^
return unsigned long and as zero.



> +	}
> +
> +	return 0;
> +}
>  
>  static cycle_t nps_clksrc_read(struct clocksource *clksrc)
>  {
> @@ -55,26 +81,24 @@ static cycle_t nps_clksrc_read(struct clocksource *clksrc)
>  	return (cycle_t)ioread32be(nps_msu_reg_low_addr[cluster]);
>  }
>  
> -static int __init nps_setup_clocksource(struct device_node *node,
> -					struct clk *clk)
> +static int __init nps_setup_clocksource(struct device_node *node)
>  {
>  	int ret, cluster;
> +	struct clk *clk;
> +	unsigned long nps_timer1_freq;
> +
>  
>  	for (cluster = 0; cluster < NPS_CLUSTER_NUM; cluster++)
>  		nps_msu_reg_low_addr[cluster] =
>  			nps_host_reg((cluster << NPS_CLUSTER_OFFSET),
> -				 NPS_MSU_BLKID, NPS_MSU_TICK_LOW);
> +				     NPS_MSU_BLKID, NPS_MSU_TICK_LOW);
>  
> -	ret = clk_prepare_enable(clk);
> -	if (ret) {
> -		pr_err("Couldn't enable parent clock\n");
> +	ret = nps_get_timer_clk(node, &nps_timer1_freq, &clk);
> +	if (ret)
>  		return ret;
> -	}
>  
> -	nps_timer_rate = clk_get_rate(clk);
> -
> -	ret = clocksource_mmio_init(nps_msu_reg_low_addr, "EZnps-tick",
> -				    nps_timer_rate, 301, 32, nps_clksrc_read);
> +	ret = clocksource_mmio_init(nps_msu_reg_low_addr, "nps-tick",
> +				    nps_timer1_freq, 301, 32, nps_clksrc_read);

301 ?

>  	if (ret) {
>  		pr_err("Couldn't register clock source.\n");
>  		clk_disable_unprepare(clk);
> @@ -83,18 +107,5 @@ static int __init nps_setup_clocksource(struct device_node *node,
>  	return ret;
>  }
>  
> -static int __init nps_timer_init(struct device_node *node)
> -{
> -	struct clk *clk;
> -
> -	clk = of_clk_get(node, 0);
> -	if (IS_ERR(clk)) {
> -		pr_err("Can't get timer clock.\n");
> -		return PTR_ERR(clk);
> -	}
> -
> -	return nps_setup_clocksource(node, clk);
> -}
> -
>  CLOCKSOURCE_OF_DECLARE(ezchip_nps400_clksrc, "ezchip,nps400-timer",
> -		       nps_timer_init);
> +		       nps_setup_clocksource);
> -- 
> 1.7.1
> 

-- 

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