[v8,2/3] clocksource: Add NPS400 timers driver
diff mbox

Message ID 1459707299-31564-3-git-send-email-noamca@mellanox.com
State New
Headers show

Commit Message

Noam Camus April 3, 2016, 6:14 p.m. UTC
From: Noam Camus <noamc@ezchip.com>

Add internal tick generator which is shared by all cores.
Each cluster of cores view it through dedicated address.
This is used for SMP system where all CPUs synced by same
clock source.

Signed-off-by: Noam Camus <noamc@ezchip.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Vineet Gupta <vgupta@synopsys.com>
---
v8:
Change macro name from IPI_IRQ to NPS_IPI_IRQ.
This was needed due to build warning when building for parsic.

v7:
Rebased on latest HEAD (4.6-rc1)

v6:
Files headers changed to start with:
Copyright (c) 2016, Mellanox Technologies
...

This is due to the acquisition of EZchip made by Mellanox.
One can still find "EZchip" used in tree, and this is ok.

This patch set is a requierement before I can insert new platform to ARC,
one that supports the NPS400 SoC.

v5:
Clocksource, irqchip - Fix gracefull return.
				replace call to panic() with pr_err() and proper return value.

v4:
clocksource -- Apply all Daniel comments (Thanks)
				Handle gracefull return and also using clocksoure mmio driver at init

v3:
irqchip - Fix ARM build failure by adding missing include of linux/irq.h
clocksource -- Avoid 64bit arch's to build driver by adding new dependency !PHYS_ADDR_T_64BIT
				This is since we use explicit io access of 32 bit. So for test coverage we allow
				not only build for ARC, but restrict it to 32 bit arch's.
irqchip - Apply all Thomas comments (Thank you)

v2:
Add header file include/soc/nps/common.h.
Now to build we do not depend on ARC subtree.

General summay:
Both drivers are now apart of previous basic patch set of new platform for ARC.
The rest is now can be seen at ARC srctree:
https://git.kernel.org/cgit/linux/kernel/git/vgupta/arc.git/

Now ARC is supporting DT for clockevents and the interrupt controller ARC
uses irq domain handling.

Compare to last version now clocksource driver do not include clockevent registration
since NPS400 can use ARC generic driver.

Compare to last version now irqchip driver sets domain as default since it is the root domain.
Also mapping of IPI is done in this driver.

Last thing is that drivers can be build cleanly for i386 (still runs only for ARC)
Note: in order to build we need to merge drivers into srctree which includes new header:
soc/nps/common.h
This header is part of patch set applied to ARC srctree.

Regards,
Noam Camus
---
 .../bindings/timer/ezchip,nps400-timer.txt         |   15 +++
 drivers/clocksource/Kconfig                        |   10 ++
 drivers/clocksource/Makefile                       |    1 +
 drivers/clocksource/timer-nps.c                    |   98 ++++++++++++++++++++
 4 files changed, 124 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/timer/ezchip,nps400-timer.txt
 create mode 100644 drivers/clocksource/timer-nps.c

Comments

Daniel Lezcano April 7, 2016, 4:57 p.m. UTC | #1
On Sun, Apr 03, 2016 at 09:14:58PM +0300, Noam Camus wrote:
> From: Noam Camus <noamc@ezchip.com>
> 
> Add internal tick generator which is shared by all cores.
> Each cluster of cores view it through dedicated address.
> This is used for SMP system where all CPUs synced by same
> clock source.
> 
> Signed-off-by: Noam Camus <noamc@ezchip.com>
> Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: John Stultz <john.stultz@linaro.org>
> Cc: Vineet Gupta <vgupta@synopsys.com>
> ---

Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Noam Camus April 8, 2016, 8:58 a.m. UTC | #2
>From: Daniel Lezcano <daniel.lezcano@linaro.org>
>Sent: Thursday, April 7, 2016 7:57 PM

>> Add internal tick generator which is shared by all cores.
>> Each cluster of cores view it through dedicated address.
>> This is used for SMP system where all CPUs synced by same
>> clock source.

>Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>

Thank you Daniel, could you review accompanied header at SOC directory.
This header is at previous patch on same set of this one.
https://lkml.org/lkml/2016/4/3/187

Regards,
Noam

Patch
diff mbox

diff --git a/Documentation/devicetree/bindings/timer/ezchip,nps400-timer.txt b/Documentation/devicetree/bindings/timer/ezchip,nps400-timer.txt
new file mode 100644
index 0000000..c8c03d7
--- /dev/null
+++ b/Documentation/devicetree/bindings/timer/ezchip,nps400-timer.txt
@@ -0,0 +1,15 @@ 
+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/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index c346be6..3932d09 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -181,6 +181,16 @@  config CLKSRC_TI_32K
 	  This option enables support for Texas Instruments 32.768 Hz clocksource
 	  available on many OMAP-like platforms.
 
+config CLKSRC_NPS
+	bool "NPS400 clocksource driver" if COMPILE_TEST
+	depends on !PHYS_ADDR_T_64BIT
+	select CLKSRC_MMIO
+	select CLKSRC_OF if OF
+	help
+	  NPS400 clocksource support.
+	  Got 64 bit counter with update rate up to 1000MHz.
+	  This counter is accessed via couple of 32 bit memory mapped registers.
+
 config CLKSRC_STM32
 	bool "Clocksource for STM32 SoCs" if !ARCH_STM32
 	depends on OF && ARM && (ARCH_STM32 || COMPILE_TEST)
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index dc2b899..0b0a4b5 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -46,6 +46,7 @@  obj-$(CONFIG_CLKSRC_QCOM)	+= qcom-timer.o
 obj-$(CONFIG_MTK_TIMER)		+= mtk_timer.o
 obj-$(CONFIG_CLKSRC_PISTACHIO)	+= time-pistachio.o
 obj-$(CONFIG_CLKSRC_TI_32K)	+= timer-ti-32k.o
+obj-$(CONFIG_CLKSRC_NPS)	+= timer-nps.o
 
 obj-$(CONFIG_ARM_ARCH_TIMER)		+= arm_arch_timer.o
 obj-$(CONFIG_ARM_GLOBAL_TIMER)		+= arm_global_timer.o
diff --git a/drivers/clocksource/timer-nps.c b/drivers/clocksource/timer-nps.c
new file mode 100644
index 0000000..d461089
--- /dev/null
+++ b/drivers/clocksource/timer-nps.c
@@ -0,0 +1,98 @@ 
+/*
+ * 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.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/clk.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/cpu.h>
+#include <soc/nps/common.h>
+
+#define NPS_MSU_TICK_LOW	0xC8
+#define NPS_CLUSTER_OFFSET	8
+#define NPS_CLUSTER_NUM		16
+
+/* 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 cycle_t nps_clksrc_read(struct clocksource *clksrc)
+{
+	int cluster = raw_smp_processor_id() >> NPS_CLUSTER_OFFSET;
+
+	return (cycle_t)ioread32be(nps_msu_reg_low_addr[cluster]);
+}
+
+static void __init nps_setup_clocksource(struct device_node *node,
+					 struct clk *clk)
+{
+	int ret, cluster;
+
+	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);
+
+	ret = clk_prepare_enable(clk);
+	if (ret) {
+		pr_err("Couldn't enable parent clock\n");
+		return;
+	}
+
+	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);
+	if (ret) {
+		pr_err("Couldn't register clock source.\n");
+		clk_disable_unprepare(clk);
+	}
+}
+
+static void __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;
+	}
+
+	nps_setup_clocksource(node, clk);
+}
+
+CLOCKSOURCE_OF_DECLARE(ezchip_nps400_clksrc, "ezchip,nps400-timer",
+		       nps_timer_init);