[GIT PULL] clockevents for 4.11

[GIT PULL] clockevents for 4.11

[Daniel Lezcano]

Hi Thomas,

these are the changes for 4.11:

 - Add the new timer renesas ostm (Chris Brandt)

 - Add a clkevt-of macro like the clksrc-of (Daniel Lezcano)

 - Use the 32 bits tcb as the sched_clock (David Engraf)

 - Handle errata for the arm architected timer (Ding Tianhong)

 - Move Cortina Gemini to the drivers directory (Linus Walleij)

Thanks !

  -- Daniel

The following changes since commit 668802c25729a8e3423015c33c05f1c3be3858e9:

  tick/broadcast: Reduce lock cacheline contention (2017-02-04 08:54:46 +0100)

are available in the git repository at:

  https://git.linaro.org/people/daniel.lezcano/linux.git clockevents/4.11

for you to fetch changes up to bb42ca47401010fc02901b5e8f79e40a26f208cb:

  clocksource/drivers/arm_arch_timer: Work around Hisilicon erratum 161010101 (2017-02-08 00:14:04 +0100)

----------------------------------------------------------------
Chris Brandt (2):
      clocksource/drivers/ostm: Document renesas-ostm timer DT bindings
      clocksource/drivers/ostm: Add renesas-ostm timer driver

Daniel Lezcano (1):
      clockevents: Add a clkevt-of mechanism like clksrc-of

David Engraf (1):
      clocksource/drivers/tcb_clksrc: Use 32 bit tcb as sched_clock

Ding Tianhong (4):
      clocksource/drivers/arm_arch_timer: Add dt binding for hisilicon-161010101 erratum
      clocksource/drivers/arm_arch_timer: Remove fsl-a008585 parameter
      clocksource/drivers/arm_arch_timer: Introduce generic errata handling infrastructure
      clocksource/drivers/arm_arch_timer: Work around Hisilicon erratum 161010101

Linus Walleij (2):
      clocksource: add DT bindings for Cortina Gemini
      clocksource/drivers/gemini: Add driver for the Cortina Gemini

 Documentation/admin-guide/kernel-parameters.txt    |   9 -
 .../devicetree/bindings/arm/arch_timer.txt         |   6 +
 .../bindings/timer/cortina,gemini-timer.txt        |  22 ++
 .../devicetree/bindings/timer/renesas,ostm.txt     |  30 +++
 arch/arm/mach-shmobile/Kconfig                     |   1 +
 arch/arm64/include/asm/arch_timer.h                |  38 +--
 drivers/clocksource/Kconfig                        |  38 +++
 drivers/clocksource/Makefile                       |   3 +
 drivers/clocksource/arm_arch_timer.c               | 151 ++++++++---
 drivers/clocksource/clkevt-probe.c                 |  56 +++++
 drivers/clocksource/renesas-ostm.c                 | 265 ++++++++++++++++++++
 drivers/clocksource/tcb_clksrc.c                   |  16 +-
 drivers/clocksource/timer-gemini.c                 | 277 +++++++++++++++++++++
 include/linux/clockchips.h                         |   9 +
 14 files changed, 845 insertions(+), 76 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/timer/cortina,gemini-timer.txt
 create mode 100644 Documentation/devicetree/bindings/timer/renesas,ostm.txt
 create mode 100644 drivers/clocksource/clkevt-probe.c
 create mode 100644 drivers/clocksource/renesas-ostm.c
 create mode 100644 drivers/clocksource/timer-gemini.c


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[PATCH 01/10] clockevents: Add a clkevt-of mechanism like clksrc-of

[Daniel Lezcano]

The current code uses the CLOCKSOURCE_OF_DECLARE macro to fill the clksrc
table with a t-uple (name, init_function).

Unfortunately it ends up to the clockevent and the clocksource being
both initialized with this macro. It is not a problem by itself but there
is not a clear distinction between a clockevent and a clocksource in the
code initialization path. Somebody can argue there are the same IP block
and the same DT node. But conceptually from the software side, there are
two distincts entities and as is they should be initialized separetely.
Some drivers which do not have a clocksource end up by using the
CLOCKSOURCE_OF_DECLARE macro to declare a clockevent.

Another result is the fuzzy organization in the clocksource directory,
where the clockevents are implemented in the same file than the
clocksources or file labelled timer-something implementing a clocksource.

This patch provides another macro to specifically declare a clockevent in
the same way than the clocksource and gives the opportunity to write two
separate drivers, one for the clocksource and another for the clockevents.

Hopefully, that can help to do some housework in the directory, perhaps
split the drivers in to entities, for example:
	- clksrc-rockchip.c
	- clkevt-rockchip.c

Also, it gives the possibility to declare clocksources separately in the
DT and then use a clocksource from IP block while while clockevents are
used from another IP block.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 drivers/clocksource/Kconfig        |  7 +++++
 drivers/clocksource/Makefile       |  1 +
 drivers/clocksource/clkevt-probe.c | 56 ++++++++++++++++++++++++++++++++++++++
 include/linux/clockchips.h         |  9 ++++++
 4 files changed, 73 insertions(+)
 create mode 100644 drivers/clocksource/clkevt-probe.c

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 4866f7a..3dc06f0 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -5,6 +5,10 @@ config CLKSRC_OF
 	bool
 	select CLKSRC_PROBE
 
+config CLKEVT_OF
+	bool
+	select CLKEVT_PROBE
+
 config CLKSRC_ACPI
 	bool
 	select CLKSRC_PROBE
@@ -12,6 +16,9 @@ config CLKSRC_ACPI
 config CLKSRC_PROBE
 	bool
 
+config CLKEVT_PROBE
+	bool
+
 config CLKSRC_I8253
 	bool
 
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index a14111e..4b7e9a2 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -1,4 +1,5 @@
 obj-$(CONFIG_CLKSRC_PROBE)	+= clksrc-probe.o
+obj-$(CONFIG_CLKEVT_PROBE)	+= clkevt-probe.o
 obj-$(CONFIG_ATMEL_PIT)		+= timer-atmel-pit.o
 obj-$(CONFIG_ATMEL_ST)		+= timer-atmel-st.o
 obj-$(CONFIG_ATMEL_TCB_CLKSRC)	+= tcb_clksrc.o
diff --git a/drivers/clocksource/clkevt-probe.c b/drivers/clocksource/clkevt-probe.c
new file mode 100644
index 0000000..8c30fec
--- /dev/null
+++ b/drivers/clocksource/clkevt-probe.c
@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2016, Linaro Ltd.  All rights reserved.
+ * Daniel Lezcano <daniel.lezcano@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/init.h>
+#include <linux/of.h>
+#include <linux/clockchip.h>
+
+extern struct of_device_id __clkevt_of_table[];
+
+static const struct of_device_id __clkevt_of_table_sentinel
+	__used __section(__clkevt_of_table_end);
+
+int __init clockevent_probe(void)
+{
+	struct device_node *np;
+	const struct of_device_id *match;
+	of_init_fn_1_ret init_func;
+	int ret, clockevents = 0;
+
+	for_each_matching_node_and_match(np, __clkevt_of_table, &match) {
+		if (!of_device_is_available(np))
+			continue;
+
+		init_func = match->data;
+
+		ret = init_func(np);
+		if (ret) {
+			pr_warn("Failed to initialize '%s' (%d)\n",
+				np->name, ret);
+			continue;
+		}
+
+		clockevents++;
+	}
+
+	if (!clockevents) {
+		pr_crit("%s: no matching clockevent found\n", __func__);
+		return -ENODEV;
+	}
+
+	return 0;
+}
diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h
index 0d442e3..5d3053c 100644
--- a/include/linux/clockchips.h
+++ b/include/linux/clockchips.h
@@ -224,4 +224,13 @@ static inline void tick_setup_hrtimer_broadcast(void) { }
 
 #endif /* !CONFIG_GENERIC_CLOCKEVENTS */
 
+#define CLOCKEVENT_OF_DECLARE(name, compat, fn) \
+	OF_DECLARE_1_RET(clkevt, name, compat, fn)
+
+#ifdef CONFIG_CLKEVT_PROBE
+extern int clockevent_probe(void);
+#els
+static inline int clockevent_probe(void) { return 0; }
+#endif
+
 #endif /* _LINUX_CLOCKCHIPS_H */
-- 
2.7.4

[PATCH 02/10] clocksource: add DT bindings for Cortina Gemini

[Daniel Lezcano]

From: Linus Walleij <linus.walleij@linaro.org>

This adds device tree bindings for the Cortina Systems Gemini
timer block used in these SoCs.

Cc: Janos Laube <janos.dev@gmail.com>
Cc: Paulius Zaleckas <paulius.zaleckas@gmail.com>
Cc: Hans Ulli Kroll <ulli.kroll@googlemail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: devicetree@vger.kernel.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 .../bindings/timer/cortina,gemini-timer.txt        | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/timer/cortina,gemini-timer.txt

diff --git a/Documentation/devicetree/bindings/timer/cortina,gemini-timer.txt b/Documentation/devicetree/bindings/timer/cortina,gemini-timer.txt
new file mode 100644
index 0000000..16ea1d3
--- /dev/null
+++ b/Documentation/devicetree/bindings/timer/cortina,gemini-timer.txt
@@ -0,0 +1,22 @@
+Cortina Systems Gemini timer
+
+This timer is embedded in the Cortina Systems Gemini SoCs.
+
+Required properties:
+
+- compatible : Must be "cortina,gemini-timer"
+- reg : Should contain registers location and length
+- interrupts : Should contain the three timer interrupts with
+  flags for rising edge
+- syscon : a phandle to the global Gemini system controller
+
+Example:
+
+timer@43000000 {
+	compatible = "cortina,gemini-timer";
+	reg = <0x43000000 0x1000>;
+	interrupts = <14 IRQ_TYPE_EDGE_RISING>, /* Timer 1 */
+		   <15 IRQ_TYPE_EDGE_RISING>, /* Timer 2 */
+		   <16 IRQ_TYPE_EDGE_RISING>; /* Timer 3 */
+	syscon = <&syscon>;
+};
-- 
2.7.4

[PATCH 02/10] clocksource: add DT bindings for Cortina Gemini

[Daniel Lezcano]

From: Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>

This adds device tree bindings for the Cortina Systems Gemini
timer block used in these SoCs.

Cc: Janos Laube <janos.dev-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Paulius Zaleckas <paulius.zaleckas-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Hans Ulli Kroll <ulli.kroll-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org>
Cc: Florian Fainelli <f.fainelli-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Signed-off-by: Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Acked-by: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
---
 .../bindings/timer/cortina,gemini-timer.txt        | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/timer/cortina,gemini-timer.txt

diff --git a/Documentation/devicetree/bindings/timer/cortina,gemini-timer.txt b/Documentation/devicetree/bindings/timer/cortina,gemini-timer.txt
new file mode 100644
index 0000000..16ea1d3
--- /dev/null
+++ b/Documentation/devicetree/bindings/timer/cortina,gemini-timer.txt
@@ -0,0 +1,22 @@
+Cortina Systems Gemini timer
+
+This timer is embedded in the Cortina Systems Gemini SoCs.
+
+Required properties:
+
+- compatible : Must be "cortina,gemini-timer"
+- reg : Should contain registers location and length
+- interrupts : Should contain the three timer interrupts with
+  flags for rising edge
+- syscon : a phandle to the global Gemini system controller
+
+Example:
+
+timer@43000000 {
+	compatible = "cortina,gemini-timer";
+	reg = <0x43000000 0x1000>;
+	interrupts = <14 IRQ_TYPE_EDGE_RISING>, /* Timer 1 */
+		   <15 IRQ_TYPE_EDGE_RISING>, /* Timer 2 */
+		   <16 IRQ_TYPE_EDGE_RISING>; /* Timer 3 */
+	syscon = <&syscon>;
+};
-- 
2.7.4

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[PATCH 03/10] clocksource/drivers/gemini: Add driver for the Cortina Gemini

[Daniel Lezcano]

From: Linus Walleij <linus.walleij@linaro.org>

This is a rewrite of the Gemini timer
driver in arch/arm/mach-gemini/timer.c trying to do everything
the device tree way:

- Make every IO-access relative to a base address and dynamic
  so we can do a dynamic ioremap and get going.
- Do not poke around directly in the global syscon registers,
  access them using the syscon regmap style design pattern for
  the one register we need to check.
- Find register range and interrupt from the device tree.

Cc: Janos Laube <janos.dev@gmail.com>
Cc: Paulius Zaleckas <paulius.zaleckas@gmail.com>
Cc: Hans Ulli Kroll <ulli.kroll@googlemail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 drivers/clocksource/Kconfig        |  10 ++
 drivers/clocksource/Makefile       |   1 +
 drivers/clocksource/timer-gemini.c | 277 +++++++++++++++++++++++++++++++++++++
 3 files changed, 288 insertions(+)
 create mode 100644 drivers/clocksource/timer-gemini.c

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 3dc06f0..afef0e8 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -67,6 +67,16 @@ config DW_APB_TIMER_OF
 	select DW_APB_TIMER
 	select CLKSRC_OF
 
+config GEMINI_TIMER
+	bool "Cortina Gemini timer driver" if COMPILE_TEST
+	depends on GENERIC_CLOCKEVENTS
+	depends on HAS_IOMEM
+	select CLKSRC_MMIO
+	select CLKSRC_OF
+	select MFD_SYSCON
+	help
+	  Enables support for the Gemini timer
+
 config ROCKCHIP_TIMER
 	bool "Rockchip timer driver" if COMPILE_TEST
 	depends on ARM || ARM64
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 4b7e9a2..dbbee80 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -16,6 +16,7 @@ obj-$(CONFIG_CLKSRC_MMIO)	+= mmio.o
 obj-$(CONFIG_DIGICOLOR_TIMER)	+= timer-digicolor.o
 obj-$(CONFIG_DW_APB_TIMER)	+= dw_apb_timer.o
 obj-$(CONFIG_DW_APB_TIMER_OF)	+= dw_apb_timer_of.o
+obj-$(CONFIG_GEMINI_TIMER)	+= timer-gemini.o
 obj-$(CONFIG_ROCKCHIP_TIMER)      += rockchip_timer.o
 obj-$(CONFIG_CLKSRC_NOMADIK_MTU)	+= nomadik-mtu.o
 obj-$(CONFIG_CLKSRC_DBX500_PRCMU)	+= clksrc-dbx500-prcmu.o
diff --git a/drivers/clocksource/timer-gemini.c b/drivers/clocksource/timer-gemini.c
new file mode 100644
index 0000000..dda27b7
--- /dev/null
+++ b/drivers/clocksource/timer-gemini.c
@@ -0,0 +1,277 @@
+/*
+ * Gemini timer driver
+ * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
+ *
+ * Based on a rewrite of arch/arm/mach-gemini/timer.c:
+ * Copyright (C) 2001-2006 Storlink, Corp.
+ * Copyright (C) 2008-2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
+ */
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/sched_clock.h>
+
+/*
+ * Relevant registers in the global syscon
+ */
+#define GLOBAL_STATUS		0x04
+#define CPU_AHB_RATIO_MASK	(0x3 << 18)
+#define CPU_AHB_1_1		(0x0 << 18)
+#define CPU_AHB_3_2		(0x1 << 18)
+#define CPU_AHB_24_13		(0x2 << 18)
+#define CPU_AHB_2_1		(0x3 << 18)
+#define REG_TO_AHB_SPEED(reg)	((((reg) >> 15) & 0x7) * 10 + 130)
+
+/*
+ * Register definitions for the timers
+ */
+#define TIMER1_COUNT		(0x00)
+#define TIMER1_LOAD		(0x04)
+#define TIMER1_MATCH1		(0x08)
+#define TIMER1_MATCH2		(0x0c)
+#define TIMER2_COUNT		(0x10)
+#define TIMER2_LOAD		(0x14)
+#define TIMER2_MATCH1		(0x18)
+#define TIMER2_MATCH2		(0x1c)
+#define TIMER3_COUNT		(0x20)
+#define TIMER3_LOAD		(0x24)
+#define TIMER3_MATCH1		(0x28)
+#define TIMER3_MATCH2		(0x2c)
+#define TIMER_CR		(0x30)
+#define TIMER_INTR_STATE	(0x34)
+#define TIMER_INTR_MASK		(0x38)
+
+#define TIMER_1_CR_ENABLE	(1 << 0)
+#define TIMER_1_CR_CLOCK	(1 << 1)
+#define TIMER_1_CR_INT		(1 << 2)
+#define TIMER_2_CR_ENABLE	(1 << 3)
+#define TIMER_2_CR_CLOCK	(1 << 4)
+#define TIMER_2_CR_INT		(1 << 5)
+#define TIMER_3_CR_ENABLE	(1 << 6)
+#define TIMER_3_CR_CLOCK	(1 << 7)
+#define TIMER_3_CR_INT		(1 << 8)
+#define TIMER_1_CR_UPDOWN	(1 << 9)
+#define TIMER_2_CR_UPDOWN	(1 << 10)
+#define TIMER_3_CR_UPDOWN	(1 << 11)
+#define TIMER_DEFAULT_FLAGS	(TIMER_1_CR_UPDOWN | \
+				 TIMER_3_CR_ENABLE | \
+				 TIMER_3_CR_UPDOWN)
+
+#define TIMER_1_INT_MATCH1	(1 << 0)
+#define TIMER_1_INT_MATCH2	(1 << 1)
+#define TIMER_1_INT_OVERFLOW	(1 << 2)
+#define TIMER_2_INT_MATCH1	(1 << 3)
+#define TIMER_2_INT_MATCH2	(1 << 4)
+#define TIMER_2_INT_OVERFLOW	(1 << 5)
+#define TIMER_3_INT_MATCH1	(1 << 6)
+#define TIMER_3_INT_MATCH2	(1 << 7)
+#define TIMER_3_INT_OVERFLOW	(1 << 8)
+#define TIMER_INT_ALL_MASK	0x1ff
+
+static unsigned int tick_rate;
+static void __iomem *base;
+
+static u64 notrace gemini_read_sched_clock(void)
+{
+	return readl(base + TIMER3_COUNT);
+}
+
+static int gemini_timer_set_next_event(unsigned long cycles,
+				       struct clock_event_device *evt)
+{
+	u32 cr;
+
+	/* Setup the match register */
+	cr = readl(base + TIMER1_COUNT);
+	writel(cr + cycles, base + TIMER1_MATCH1);
+	if (readl(base + TIMER1_COUNT) - cr > cycles)
+		return -ETIME;
+
+	return 0;
+}
+
+static int gemini_timer_shutdown(struct clock_event_device *evt)
+{
+	u32 cr;
+
+	/*
+	 * Disable also for oneshot: the set_next() call will arm the timer
+	 * instead.
+	 */
+	/* Stop timer and interrupt. */
+	cr = readl(base + TIMER_CR);
+	cr &= ~(TIMER_1_CR_ENABLE | TIMER_1_CR_INT);
+	writel(cr, base + TIMER_CR);
+
+	/* Setup counter start from 0 */
+	writel(0, base + TIMER1_COUNT);
+	writel(0, base + TIMER1_LOAD);
+
+	/* enable interrupt */
+	cr = readl(base + TIMER_INTR_MASK);
+	cr &= ~(TIMER_1_INT_OVERFLOW | TIMER_1_INT_MATCH2);
+	cr |= TIMER_1_INT_MATCH1;
+	writel(cr, base + TIMER_INTR_MASK);
+
+	/* start the timer */
+	cr = readl(base + TIMER_CR);
+	cr |= TIMER_1_CR_ENABLE;
+	writel(cr, base + TIMER_CR);
+
+	return 0;
+}
+
+static int gemini_timer_set_periodic(struct clock_event_device *evt)
+{
+	u32 period = DIV_ROUND_CLOSEST(tick_rate, HZ);
+	u32 cr;
+
+	/* Stop timer and interrupt */
+	cr = readl(base + TIMER_CR);
+	cr &= ~(TIMER_1_CR_ENABLE | TIMER_1_CR_INT);
+	writel(cr, base + TIMER_CR);
+
+	/* Setup timer to fire at 1/HT intervals. */
+	cr = 0xffffffff - (period - 1);
+	writel(cr, base + TIMER1_COUNT);
+	writel(cr, base + TIMER1_LOAD);
+
+	/* enable interrupt on overflow */
+	cr = readl(base + TIMER_INTR_MASK);
+	cr &= ~(TIMER_1_INT_MATCH1 | TIMER_1_INT_MATCH2);
+	cr |= TIMER_1_INT_OVERFLOW;
+	writel(cr, base + TIMER_INTR_MASK);
+
+	/* Start the timer */
+	cr = readl(base + TIMER_CR);
+	cr |= TIMER_1_CR_ENABLE;
+	cr |= TIMER_1_CR_INT;
+	writel(cr, base + TIMER_CR);
+
+	return 0;
+}
+
+/* Use TIMER1 as clock event */
+static struct clock_event_device gemini_clockevent = {
+	.name			= "TIMER1",
+	/* Reasonably fast and accurate clock event */
+	.rating			= 300,
+	.shift                  = 32,
+	.features		= CLOCK_EVT_FEAT_PERIODIC |
+				  CLOCK_EVT_FEAT_ONESHOT,
+	.set_next_event		= gemini_timer_set_next_event,
+	.set_state_shutdown	= gemini_timer_shutdown,
+	.set_state_periodic	= gemini_timer_set_periodic,
+	.set_state_oneshot	= gemini_timer_shutdown,
+	.tick_resume		= gemini_timer_shutdown,
+};
+
+/*
+ * IRQ handler for the timer
+ */
+static irqreturn_t gemini_timer_interrupt(int irq, void *dev_id)
+{
+	struct clock_event_device *evt = &gemini_clockevent;
+
+	evt->event_handler(evt);
+	return IRQ_HANDLED;
+}
+
+static struct irqaction gemini_timer_irq = {
+	.name		= "Gemini Timer Tick",
+	.flags		= IRQF_TIMER,
+	.handler	= gemini_timer_interrupt,
+};
+
+static int __init gemini_timer_of_init(struct device_node *np)
+{
+	static struct regmap *map;
+	int irq;
+	int ret;
+	u32 val;
+
+	map = syscon_regmap_lookup_by_phandle(np, "syscon");
+	if (IS_ERR(map)) {
+		pr_err("Can't get regmap for syscon handle");
+		return -ENODEV;
+	}
+	ret = regmap_read(map, GLOBAL_STATUS, &val);
+	if (ret) {
+		pr_err("Can't read syscon status register");
+		return -ENXIO;
+	}
+
+	base = of_iomap(np, 0);
+	if (!base) {
+		pr_err("Can't remap registers");
+		return -ENXIO;
+	}
+	/* IRQ for timer 1 */
+	irq = irq_of_parse_and_map(np, 0);
+	if (irq <= 0) {
+		pr_err("Can't parse IRQ");
+		return -EINVAL;
+	}
+
+	tick_rate = REG_TO_AHB_SPEED(val) * 1000000;
+	printk(KERN_INFO "Bus: %dMHz", tick_rate / 1000000);
+
+	tick_rate /= 6;		/* APB bus run AHB*(1/6) */
+
+	switch (val & CPU_AHB_RATIO_MASK) {
+	case CPU_AHB_1_1:
+		printk(KERN_CONT "(1/1)\n");
+		break;
+	case CPU_AHB_3_2:
+		printk(KERN_CONT "(3/2)\n");
+		break;
+	case CPU_AHB_24_13:
+		printk(KERN_CONT "(24/13)\n");
+		break;
+	case CPU_AHB_2_1:
+		printk(KERN_CONT "(2/1)\n");
+		break;
+	}
+
+	/*
+	 * Reset the interrupt mask and status
+	 */
+	writel(TIMER_INT_ALL_MASK, base + TIMER_INTR_MASK);
+	writel(0, base + TIMER_INTR_STATE);
+	writel(TIMER_DEFAULT_FLAGS, base + TIMER_CR);
+
+	/*
+	 * Setup free-running clocksource timer (interrupts
+	 * disabled.)
+	 */
+	writel(0, base + TIMER3_COUNT);
+	writel(0, base + TIMER3_LOAD);
+	writel(0, base + TIMER3_MATCH1);
+	writel(0, base + TIMER3_MATCH2);
+	clocksource_mmio_init(base + TIMER3_COUNT,
+			      "gemini_clocksource", tick_rate,
+			      300, 32, clocksource_mmio_readl_up);
+	sched_clock_register(gemini_read_sched_clock, 32, tick_rate);
+
+	/*
+	 * Setup clockevent timer (interrupt-driven.)
+	 */
+	writel(0, base + TIMER1_COUNT);
+	writel(0, base + TIMER1_LOAD);
+	writel(0, base + TIMER1_MATCH1);
+	writel(0, base + TIMER1_MATCH2);
+	setup_irq(irq, &gemini_timer_irq);
+	gemini_clockevent.cpumask = cpumask_of(0);
+	clockevents_config_and_register(&gemini_clockevent, tick_rate,
+					1, 0xffffffff);
+
+	return 0;
+}
+CLOCKSOURCE_OF_DECLARE(nomadik_mtu, "cortina,gemini-timer",
+		       gemini_timer_of_init);
-- 
2.7.4

[PATCH 04/10] clocksource/drivers/tcb_clksrc: Use 32 bit tcb as sched_clock

[Daniel Lezcano]

From: David Engraf <david.engraf@sysgo.com>

On newer boards the TC can be read as single 32 bit value without locking.
Thus the clock can be used as reference for sched_clock which is much more
accurate than the jiffies implementation.

Tested on a Atmel SAMA5D2 board.

Signed-off-by: David Engraf <david.engraf@sysgo.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 drivers/clocksource/tcb_clksrc.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/clocksource/tcb_clksrc.c b/drivers/clocksource/tcb_clksrc.c
index d4ca996..745844e 100644
--- a/drivers/clocksource/tcb_clksrc.c
+++ b/drivers/clocksource/tcb_clksrc.c
@@ -10,6 +10,7 @@
 #include <linux/io.h>
 #include <linux/platform_device.h>
 #include <linux/atmel_tc.h>
+#include <linux/sched_clock.h>
 
 
 /*
@@ -56,11 +57,16 @@ static u64 tc_get_cycles(struct clocksource *cs)
 	return (upper << 16) | lower;
 }
 
-static u64 tc_get_cycles32(struct clocksource *cs)
+static u32 tc_get_cv32(void)
 {
 	return __raw_readl(tcaddr + ATMEL_TC_REG(0, CV));
 }
 
+static u64 tc_get_cycles32(struct clocksource *cs)
+{
+	return tc_get_cv32();
+}
+
 static struct clocksource clksrc = {
 	.name           = "tcb_clksrc",
 	.rating         = 200,
@@ -69,6 +75,11 @@ static struct clocksource clksrc = {
 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
+static u64 notrace tc_read_sched_clock(void)
+{
+	return tc_get_cv32();
+}
+
 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 
 struct tc_clkevt_device {
@@ -339,6 +350,9 @@ static int __init tcb_clksrc_init(void)
 		clksrc.read = tc_get_cycles32;
 		/* setup ony channel 0 */
 		tcb_setup_single_chan(tc, best_divisor_idx);
+
+		/* register sched_clock on chips with single 32 bit counter */
+		sched_clock_register(tc_read_sched_clock, 32, divided_rate);
 	} else {
 		/* tclib will give us three clocks no matter what the
 		 * underlying platform supports.
-- 
2.7.4

[PATCH 04/10] clocksource/drivers/tcb_clksrc: Use 32 bit tcb as sched_clock

[Daniel Lezcano]

From: David Engraf <david.engraf@sysgo.com>

On newer boards the TC can be read as single 32 bit value without locking.
Thus the clock can be used as reference for sched_clock which is much more
accurate than the jiffies implementation.

Tested on a Atmel SAMA5D2 board.

Signed-off-by: David Engraf <david.engraf@sysgo.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 drivers/clocksource/tcb_clksrc.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/clocksource/tcb_clksrc.c b/drivers/clocksource/tcb_clksrc.c
index d4ca996..745844e 100644
--- a/drivers/clocksource/tcb_clksrc.c
+++ b/drivers/clocksource/tcb_clksrc.c
@@ -10,6 +10,7 @@
 #include <linux/io.h>
 #include <linux/platform_device.h>
 #include <linux/atmel_tc.h>
+#include <linux/sched_clock.h>
 
 
 /*
@@ -56,11 +57,16 @@ static u64 tc_get_cycles(struct clocksource *cs)
 	return (upper << 16) | lower;
 }
 
-static u64 tc_get_cycles32(struct clocksource *cs)
+static u32 tc_get_cv32(void)
 {
 	return __raw_readl(tcaddr + ATMEL_TC_REG(0, CV));
 }
 
+static u64 tc_get_cycles32(struct clocksource *cs)
+{
+	return tc_get_cv32();
+}
+
 static struct clocksource clksrc = {
 	.name           = "tcb_clksrc",
 	.rating         = 200,
@@ -69,6 +75,11 @@ static struct clocksource clksrc = {
 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
+static u64 notrace tc_read_sched_clock(void)
+{
+	return tc_get_cv32();
+}
+
 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 
 struct tc_clkevt_device {
@@ -339,6 +350,9 @@ static int __init tcb_clksrc_init(void)
 		clksrc.read = tc_get_cycles32;
 		/* setup ony channel 0 */
 		tcb_setup_single_chan(tc, best_divisor_idx);
+
+		/* register sched_clock on chips with single 32 bit counter */
+		sched_clock_register(tc_read_sched_clock, 32, divided_rate);
 	} else {
 		/* tclib will give us three clocks no matter what the
 		 * underlying platform supports.
-- 
2.7.4

[PATCH 05/10] clocksource/drivers/ostm: Document renesas-ostm timer DT bindings

[Daniel Lezcano]

From: Chris Brandt <chris.brandt@renesas.com>

Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 .../devicetree/bindings/timer/renesas,ostm.txt     | 30 ++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/timer/renesas,ostm.txt

diff --git a/Documentation/devicetree/bindings/timer/renesas,ostm.txt b/Documentation/devicetree/bindings/timer/renesas,ostm.txt
new file mode 100644
index 0000000..be3ae0f
--- /dev/null
+++ b/Documentation/devicetree/bindings/timer/renesas,ostm.txt
@@ -0,0 +1,30 @@
+* Renesas OS Timer (OSTM)
+
+The OSTM is a multi-channel 32-bit timer/counter with fixed clock
+source that can operate in either interval count down timer or free-running
+compare match mode.
+
+Channels are independent from each other.
+
+Required Properties:
+
+  - compatible: must be one or more of the following:
+    - "renesas,r7s72100-ostm" for the r7s72100 OSTM
+    - "renesas,ostm" for any OSTM
+		This is a fallback for the above renesas,*-ostm entries
+
+  - reg: base address and length of the register block for a timer channel.
+
+  - interrupts: interrupt specifier for the timer channel.
+
+  - clocks: clock specifier for the timer channel.
+
+Example: R7S72100 (RZ/A1H) OSTM node
+
+	ostm0: timer@fcfec000 {
+		compatible = "renesas,r7s72100-ostm", "renesas,ostm";
+		reg = <0xfcfec000 0x30>;
+		interrupts = <GIC_SPI 102 IRQ_TYPE_EDGE_RISING>;
+		clocks = <&mstp5_clks R7S72100_CLK_OSTM0>;
+		power-domains = <&cpg_clocks>;
+	};
-- 
2.7.4

[PATCH 05/10] clocksource/drivers/ostm: Document renesas-ostm timer DT bindings

[Daniel Lezcano]

From: Chris Brandt <chris.brandt@renesas.com>

Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 .../devicetree/bindings/timer/renesas,ostm.txt     | 30 ++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/timer/renesas,ostm.txt

diff --git a/Documentation/devicetree/bindings/timer/renesas,ostm.txt b/Documentation/devicetree/bindings/timer/renesas,ostm.txt
new file mode 100644
index 0000000..be3ae0f
--- /dev/null
+++ b/Documentation/devicetree/bindings/timer/renesas,ostm.txt
@@ -0,0 +1,30 @@
+* Renesas OS Timer (OSTM)
+
+The OSTM is a multi-channel 32-bit timer/counter with fixed clock
+source that can operate in either interval count down timer or free-running
+compare match mode.
+
+Channels are independent from each other.
+
+Required Properties:
+
+  - compatible: must be one or more of the following:
+    - "renesas,r7s72100-ostm" for the r7s72100 OSTM
+    - "renesas,ostm" for any OSTM
+		This is a fallback for the above renesas,*-ostm entries
+
+  - reg: base address and length of the register block for a timer channel.
+
+  - interrupts: interrupt specifier for the timer channel.
+
+  - clocks: clock specifier for the timer channel.
+
+Example: R7S72100 (RZ/A1H) OSTM node
+
+	ostm0: timer@fcfec000 {
+		compatible = "renesas,r7s72100-ostm", "renesas,ostm";
+		reg = <0xfcfec000 0x30>;
+		interrupts = <GIC_SPI 102 IRQ_TYPE_EDGE_RISING>;
+		clocks = <&mstp5_clks R7S72100_CLK_OSTM0>;
+		power-domains = <&cpg_clocks>;
+	};
-- 
2.7.4

[PATCH 06/10] clocksource/drivers/ostm: Add renesas-ostm timer driver

[Daniel Lezcano]

From: Chris Brandt <chris.brandt@renesas.com>

This patch adds a OSTM driver for the Renesas architecture.
The OS Timer (OSTM) has independent channels that can be
used as a freerun or interval times.
This driver uses the first probed device as a clocksource
and then any additional devices as clock events.

Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 arch/arm/mach-shmobile/Kconfig     |   1 +
 drivers/clocksource/Kconfig        |   7 +
 drivers/clocksource/Makefile       |   1 +
 drivers/clocksource/renesas-ostm.c | 265 +++++++++++++++++++++++++++++++++++++
 4 files changed, 274 insertions(+)
 create mode 100644 drivers/clocksource/renesas-ostm.c

diff --git a/arch/arm/mach-shmobile/Kconfig b/arch/arm/mach-shmobile/Kconfig
index 2bb4b09..ad7d604 100644
--- a/arch/arm/mach-shmobile/Kconfig
+++ b/arch/arm/mach-shmobile/Kconfig
@@ -57,6 +57,7 @@ config ARCH_R7S72100
 	select PM
 	select PM_GENERIC_DOMAINS
 	select SYS_SUPPORTS_SH_MTU2
+	select RENESAS_OSTM
 
 config ARCH_R8A73A4
 	bool "R-Mobile APE6 (R8A73A40)"
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index afef0e8..4002d6d 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -484,6 +484,13 @@ config SH_TIMER_MTU2
 	  Timer Pulse Unit 2 (MTU2) hardware available on SoCs from Renesas.
 	  This hardware comes with 16 bit-timer registers.
 
+config RENESAS_OSTM
+	bool "Renesas OSTM timer driver" if COMPILE_TEST
+	depends on GENERIC_CLOCKEVENTS
+	select CLKSRC_MMIO
+	help
+	  Enables the support for the Renesas OSTM.
+
 config SH_TIMER_TMU
 	bool "Renesas TMU timer driver" if COMPILE_TEST
 	depends on GENERIC_CLOCKEVENTS
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index dbbee80..d227d13 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_CS5535_CLOCK_EVENT_SRC)	+= cs5535-clockevt.o
 obj-$(CONFIG_CLKSRC_JCORE_PIT)		+= jcore-pit.o
 obj-$(CONFIG_SH_TIMER_CMT)	+= sh_cmt.o
 obj-$(CONFIG_SH_TIMER_MTU2)	+= sh_mtu2.o
+obj-$(CONFIG_RENESAS_OSTM)	+= renesas-ostm.o
 obj-$(CONFIG_SH_TIMER_TMU)	+= sh_tmu.o
 obj-$(CONFIG_EM_TIMER_STI)	+= em_sti.o
 obj-$(CONFIG_CLKBLD_I8253)	+= i8253.o
diff --git a/drivers/clocksource/renesas-ostm.c b/drivers/clocksource/renesas-ostm.c
new file mode 100644
index 0000000..c76f576
--- /dev/null
+++ b/drivers/clocksource/renesas-ostm.c
@@ -0,0 +1,265 @@
+/*
+ * Renesas Timer Support - OSTM
+ *
+ * Copyright (C) 2017 Renesas Electronics America, Inc.
+ * Copyright (C) 2017 Chris Brandt
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/interrupt.h>
+#include <linux/sched_clock.h>
+#include <linux/slab.h>
+
+/*
+ * The OSTM contains independent channels.
+ * The first OSTM channel probed will be set up as a free running
+ * clocksource. Additionally we will use this clocksource for the system
+ * schedule timer sched_clock().
+ *
+ * The second (or more) channel probed will be set up as an interrupt
+ * driven clock event.
+ */
+
+struct ostm_device {
+	void __iomem *base;
+	unsigned long ticks_per_jiffy;
+	struct clock_event_device ced;
+};
+
+static void __iomem *system_clock;	/* For sched_clock() */
+
+/* OSTM REGISTERS */
+#define	OSTM_CMP		0x000	/* RW,32 */
+#define	OSTM_CNT		0x004	/* R,32 */
+#define	OSTM_TE			0x010	/* R,8 */
+#define	OSTM_TS			0x014	/* W,8 */
+#define	OSTM_TT			0x018	/* W,8 */
+#define	OSTM_CTL		0x020	/* RW,8 */
+
+#define	TE			0x01
+#define	TS			0x01
+#define	TT			0x01
+#define	CTL_PERIODIC		0x00
+#define	CTL_ONESHOT		0x02
+#define	CTL_FREERUN		0x02
+
+static struct ostm_device *ced_to_ostm(struct clock_event_device *ced)
+{
+	return container_of(ced, struct ostm_device, ced);
+}
+
+static void ostm_timer_stop(struct ostm_device *ostm)
+{
+	if (readb(ostm->base + OSTM_TE) & TE) {
+		writeb(TT, ostm->base + OSTM_TT);
+
+		/*
+		 * Read back the register simply to confirm the write operation
+		 * has completed since I/O writes can sometimes get queued by
+		 * the bus architecture.
+		 */
+		while (readb(ostm->base + OSTM_TE) & TE)
+			;
+	}
+}
+
+static int __init ostm_init_clksrc(struct ostm_device *ostm, unsigned long rate)
+{
+	/*
+	 * irq not used (clock sources don't use interrupts)
+	 */
+
+	ostm_timer_stop(ostm);
+
+	writel(0, ostm->base + OSTM_CMP);
+	writeb(CTL_FREERUN, ostm->base + OSTM_CTL);
+	writeb(TS, ostm->base + OSTM_TS);
+
+	return clocksource_mmio_init(ostm->base + OSTM_CNT,
+			"ostm", rate,
+			300, 32, clocksource_mmio_readl_up);
+}
+
+static u64 notrace ostm_read_sched_clock(void)
+{
+	return readl(system_clock);
+}
+
+static void __init ostm_init_sched_clock(struct ostm_device *ostm,
+			unsigned long rate)
+{
+	system_clock = ostm->base + OSTM_CNT;
+	sched_clock_register(ostm_read_sched_clock, 32, rate);
+}
+
+static int ostm_clock_event_next(unsigned long delta,
+				     struct clock_event_device *ced)
+{
+	struct ostm_device *ostm = ced_to_ostm(ced);
+
+	ostm_timer_stop(ostm);
+
+	writel(delta, ostm->base + OSTM_CMP);
+	writeb(CTL_ONESHOT, ostm->base + OSTM_CTL);
+	writeb(TS, ostm->base + OSTM_TS);
+
+	return 0;
+}
+
+static int ostm_shutdown(struct clock_event_device *ced)
+{
+	struct ostm_device *ostm = ced_to_ostm(ced);
+
+	ostm_timer_stop(ostm);
+
+	return 0;
+}
+static int ostm_set_periodic(struct clock_event_device *ced)
+{
+	struct ostm_device *ostm = ced_to_ostm(ced);
+
+	if (clockevent_state_oneshot(ced) || clockevent_state_periodic(ced))
+		ostm_timer_stop(ostm);
+
+	writel(ostm->ticks_per_jiffy - 1, ostm->base + OSTM_CMP);
+	writeb(CTL_PERIODIC, ostm->base + OSTM_CTL);
+	writeb(TS, ostm->base + OSTM_TS);
+
+	return 0;
+}
+
+static int ostm_set_oneshot(struct clock_event_device *ced)
+{
+	struct ostm_device *ostm = ced_to_ostm(ced);
+
+	ostm_timer_stop(ostm);
+
+	return 0;
+}
+
+static irqreturn_t ostm_timer_interrupt(int irq, void *dev_id)
+{
+	struct ostm_device *ostm = dev_id;
+
+	if (clockevent_state_oneshot(&ostm->ced))
+		ostm_timer_stop(ostm);
+
+	/* notify clockevent layer */
+	if (ostm->ced.event_handler)
+		ostm->ced.event_handler(&ostm->ced);
+
+	return IRQ_HANDLED;
+}
+
+static int __init ostm_init_clkevt(struct ostm_device *ostm, int irq,
+			unsigned long rate)
+{
+	struct clock_event_device *ced = &ostm->ced;
+	int ret = -ENXIO;
+
+	ret = request_irq(irq, ostm_timer_interrupt,
+			  IRQF_TIMER | IRQF_IRQPOLL,
+			  "ostm", ostm);
+	if (ret) {
+		pr_err("ostm: failed to request irq\n");
+		return ret;
+	}
+
+	ced->name = "ostm";
+	ced->features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC;
+	ced->set_state_shutdown = ostm_shutdown;
+	ced->set_state_periodic = ostm_set_periodic;
+	ced->set_state_oneshot = ostm_set_oneshot;
+	ced->set_next_event = ostm_clock_event_next;
+	ced->shift = 32;
+	ced->rating = 300;
+	ced->cpumask = cpumask_of(0);
+	clockevents_config_and_register(ced, rate, 0xf, 0xffffffff);
+
+	return 0;
+}
+
+static int __init ostm_init(struct device_node *np)
+{
+	struct ostm_device *ostm;
+	int ret = -EFAULT;
+	struct clk *ostm_clk = NULL;
+	int irq;
+	unsigned long rate;
+
+	ostm = kzalloc(sizeof(*ostm), GFP_KERNEL);
+	if (!ostm)
+		return -ENOMEM;
+
+	ostm->base = of_iomap(np, 0);
+	if (!ostm->base) {
+		pr_err("ostm: failed to remap I/O memory\n");
+		goto err;
+	}
+
+	irq = irq_of_parse_and_map(np, 0);
+	if (irq < 0) {
+		pr_err("ostm: Failed to get irq\n");
+		goto err;
+	}
+
+	ostm_clk = of_clk_get(np, 0);
+	if (IS_ERR(ostm_clk)) {
+		pr_err("ostm: Failed to get clock\n");
+		ostm_clk = NULL;
+		goto err;
+	}
+
+	ret = clk_prepare_enable(ostm_clk);
+	if (ret) {
+		pr_err("ostm: Failed to enable clock\n");
+		goto err;
+	}
+
+	rate = clk_get_rate(ostm_clk);
+	ostm->ticks_per_jiffy = (rate + HZ / 2) / HZ;
+
+	/*
+	 * First probed device will be used as system clocksource. Any
+	 * additional devices will be used as clock events.
+	 */
+	if (!system_clock) {
+		ret = ostm_init_clksrc(ostm, rate);
+
+		if (!ret) {
+			ostm_init_sched_clock(ostm, rate);
+			pr_info("ostm: used for clocksource\n");
+		}
+
+	} else {
+		ret = ostm_init_clkevt(ostm, irq, rate);
+
+		if (!ret)
+			pr_info("ostm: used for clock events\n");
+	}
+
+err:
+	if (ret) {
+		clk_disable_unprepare(ostm_clk);
+		iounmap(ostm->base);
+		kfree(ostm);
+		return ret;
+	}
+
+	return 0;
+}
+
+CLOCKSOURCE_OF_DECLARE(ostm, "renesas,ostm", ostm_init);
-- 
2.7.4

[PATCH 06/10] clocksource/drivers/ostm: Add renesas-ostm timer driver

[Daniel Lezcano]

From: Chris Brandt <chris.brandt@renesas.com>

This patch adds a OSTM driver for the Renesas architecture.
The OS Timer (OSTM) has independent channels that can be
used as a freerun or interval times.
This driver uses the first probed device as a clocksource
and then any additional devices as clock events.

Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 arch/arm/mach-shmobile/Kconfig     |   1 +
 drivers/clocksource/Kconfig        |   7 +
 drivers/clocksource/Makefile       |   1 +
 drivers/clocksource/renesas-ostm.c | 265 +++++++++++++++++++++++++++++++++++++
 4 files changed, 274 insertions(+)
 create mode 100644 drivers/clocksource/renesas-ostm.c

diff --git a/arch/arm/mach-shmobile/Kconfig b/arch/arm/mach-shmobile/Kconfig
index 2bb4b09..ad7d604 100644
--- a/arch/arm/mach-shmobile/Kconfig
+++ b/arch/arm/mach-shmobile/Kconfig
@@ -57,6 +57,7 @@ config ARCH_R7S72100
 	select PM
 	select PM_GENERIC_DOMAINS
 	select SYS_SUPPORTS_SH_MTU2
+	select RENESAS_OSTM
 
 config ARCH_R8A73A4
 	bool "R-Mobile APE6 (R8A73A40)"
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index afef0e8..4002d6d 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -484,6 +484,13 @@ config SH_TIMER_MTU2
 	  Timer Pulse Unit 2 (MTU2) hardware available on SoCs from Renesas.
 	  This hardware comes with 16 bit-timer registers.
 
+config RENESAS_OSTM
+	bool "Renesas OSTM timer driver" if COMPILE_TEST
+	depends on GENERIC_CLOCKEVENTS
+	select CLKSRC_MMIO
+	help
+	  Enables the support for the Renesas OSTM.
+
 config SH_TIMER_TMU
 	bool "Renesas TMU timer driver" if COMPILE_TEST
 	depends on GENERIC_CLOCKEVENTS
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index dbbee80..d227d13 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_CS5535_CLOCK_EVENT_SRC)	+= cs5535-clockevt.o
 obj-$(CONFIG_CLKSRC_JCORE_PIT)		+= jcore-pit.o
 obj-$(CONFIG_SH_TIMER_CMT)	+= sh_cmt.o
 obj-$(CONFIG_SH_TIMER_MTU2)	+= sh_mtu2.o
+obj-$(CONFIG_RENESAS_OSTM)	+= renesas-ostm.o
 obj-$(CONFIG_SH_TIMER_TMU)	+= sh_tmu.o
 obj-$(CONFIG_EM_TIMER_STI)	+= em_sti.o
 obj-$(CONFIG_CLKBLD_I8253)	+= i8253.o
diff --git a/drivers/clocksource/renesas-ostm.c b/drivers/clocksource/renesas-ostm.c
new file mode 100644
index 0000000..c76f576
--- /dev/null
+++ b/drivers/clocksource/renesas-ostm.c
@@ -0,0 +1,265 @@
+/*
+ * Renesas Timer Support - OSTM
+ *
+ * Copyright (C) 2017 Renesas Electronics America, Inc.
+ * Copyright (C) 2017 Chris Brandt
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/interrupt.h>
+#include <linux/sched_clock.h>
+#include <linux/slab.h>
+
+/*
+ * The OSTM contains independent channels.
+ * The first OSTM channel probed will be set up as a free running
+ * clocksource. Additionally we will use this clocksource for the system
+ * schedule timer sched_clock().
+ *
+ * The second (or more) channel probed will be set up as an interrupt
+ * driven clock event.
+ */
+
+struct ostm_device {
+	void __iomem *base;
+	unsigned long ticks_per_jiffy;
+	struct clock_event_device ced;
+};
+
+static void __iomem *system_clock;	/* For sched_clock() */
+
+/* OSTM REGISTERS */
+#define	OSTM_CMP		0x000	/* RW,32 */
+#define	OSTM_CNT		0x004	/* R,32 */
+#define	OSTM_TE			0x010	/* R,8 */
+#define	OSTM_TS			0x014	/* W,8 */
+#define	OSTM_TT			0x018	/* W,8 */
+#define	OSTM_CTL		0x020	/* RW,8 */
+
+#define	TE			0x01
+#define	TS			0x01
+#define	TT			0x01
+#define	CTL_PERIODIC		0x00
+#define	CTL_ONESHOT		0x02
+#define	CTL_FREERUN		0x02
+
+static struct ostm_device *ced_to_ostm(struct clock_event_device *ced)
+{
+	return container_of(ced, struct ostm_device, ced);
+}
+
+static void ostm_timer_stop(struct ostm_device *ostm)
+{
+	if (readb(ostm->base + OSTM_TE) & TE) {
+		writeb(TT, ostm->base + OSTM_TT);
+
+		/*
+		 * Read back the register simply to confirm the write operation
+		 * has completed since I/O writes can sometimes get queued by
+		 * the bus architecture.
+		 */
+		while (readb(ostm->base + OSTM_TE) & TE)
+			;
+	}
+}
+
+static int __init ostm_init_clksrc(struct ostm_device *ostm, unsigned long rate)
+{
+	/*
+	 * irq not used (clock sources don't use interrupts)
+	 */
+
+	ostm_timer_stop(ostm);
+
+	writel(0, ostm->base + OSTM_CMP);
+	writeb(CTL_FREERUN, ostm->base + OSTM_CTL);
+	writeb(TS, ostm->base + OSTM_TS);
+
+	return clocksource_mmio_init(ostm->base + OSTM_CNT,
+			"ostm", rate,
+			300, 32, clocksource_mmio_readl_up);
+}
+
+static u64 notrace ostm_read_sched_clock(void)
+{
+	return readl(system_clock);
+}
+
+static void __init ostm_init_sched_clock(struct ostm_device *ostm,
+			unsigned long rate)
+{
+	system_clock = ostm->base + OSTM_CNT;
+	sched_clock_register(ostm_read_sched_clock, 32, rate);
+}
+
+static int ostm_clock_event_next(unsigned long delta,
+				     struct clock_event_device *ced)
+{
+	struct ostm_device *ostm = ced_to_ostm(ced);
+
+	ostm_timer_stop(ostm);
+
+	writel(delta, ostm->base + OSTM_CMP);
+	writeb(CTL_ONESHOT, ostm->base + OSTM_CTL);
+	writeb(TS, ostm->base + OSTM_TS);
+
+	return 0;
+}
+
+static int ostm_shutdown(struct clock_event_device *ced)
+{
+	struct ostm_device *ostm = ced_to_ostm(ced);
+
+	ostm_timer_stop(ostm);
+
+	return 0;
+}
+static int ostm_set_periodic(struct clock_event_device *ced)
+{
+	struct ostm_device *ostm = ced_to_ostm(ced);
+
+	if (clockevent_state_oneshot(ced) || clockevent_state_periodic(ced))
+		ostm_timer_stop(ostm);
+
+	writel(ostm->ticks_per_jiffy - 1, ostm->base + OSTM_CMP);
+	writeb(CTL_PERIODIC, ostm->base + OSTM_CTL);
+	writeb(TS, ostm->base + OSTM_TS);
+
+	return 0;
+}
+
+static int ostm_set_oneshot(struct clock_event_device *ced)
+{
+	struct ostm_device *ostm = ced_to_ostm(ced);
+
+	ostm_timer_stop(ostm);
+
+	return 0;
+}
+
+static irqreturn_t ostm_timer_interrupt(int irq, void *dev_id)
+{
+	struct ostm_device *ostm = dev_id;
+
+	if (clockevent_state_oneshot(&ostm->ced))
+		ostm_timer_stop(ostm);
+
+	/* notify clockevent layer */
+	if (ostm->ced.event_handler)
+		ostm->ced.event_handler(&ostm->ced);
+
+	return IRQ_HANDLED;
+}
+
+static int __init ostm_init_clkevt(struct ostm_device *ostm, int irq,
+			unsigned long rate)
+{
+	struct clock_event_device *ced = &ostm->ced;
+	int ret = -ENXIO;
+
+	ret = request_irq(irq, ostm_timer_interrupt,
+			  IRQF_TIMER | IRQF_IRQPOLL,
+			  "ostm", ostm);
+	if (ret) {
+		pr_err("ostm: failed to request irq\n");
+		return ret;
+	}
+
+	ced->name = "ostm";
+	ced->features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC;
+	ced->set_state_shutdown = ostm_shutdown;
+	ced->set_state_periodic = ostm_set_periodic;
+	ced->set_state_oneshot = ostm_set_oneshot;
+	ced->set_next_event = ostm_clock_event_next;
+	ced->shift = 32;
+	ced->rating = 300;
+	ced->cpumask = cpumask_of(0);
+	clockevents_config_and_register(ced, rate, 0xf, 0xffffffff);
+
+	return 0;
+}
+
+static int __init ostm_init(struct device_node *np)
+{
+	struct ostm_device *ostm;
+	int ret = -EFAULT;
+	struct clk *ostm_clk = NULL;
+	int irq;
+	unsigned long rate;
+
+	ostm = kzalloc(sizeof(*ostm), GFP_KERNEL);
+	if (!ostm)
+		return -ENOMEM;
+
+	ostm->base = of_iomap(np, 0);
+	if (!ostm->base) {
+		pr_err("ostm: failed to remap I/O memory\n");
+		goto err;
+	}
+
+	irq = irq_of_parse_and_map(np, 0);
+	if (irq < 0) {
+		pr_err("ostm: Failed to get irq\n");
+		goto err;
+	}
+
+	ostm_clk = of_clk_get(np, 0);
+	if (IS_ERR(ostm_clk)) {
+		pr_err("ostm: Failed to get clock\n");
+		ostm_clk = NULL;
+		goto err;
+	}
+
+	ret = clk_prepare_enable(ostm_clk);
+	if (ret) {
+		pr_err("ostm: Failed to enable clock\n");
+		goto err;
+	}
+
+	rate = clk_get_rate(ostm_clk);
+	ostm->ticks_per_jiffy = (rate + HZ / 2) / HZ;
+
+	/*
+	 * First probed device will be used as system clocksource. Any
+	 * additional devices will be used as clock events.
+	 */
+	if (!system_clock) {
+		ret = ostm_init_clksrc(ostm, rate);
+
+		if (!ret) {
+			ostm_init_sched_clock(ostm, rate);
+			pr_info("ostm: used for clocksource\n");
+		}
+
+	} else {
+		ret = ostm_init_clkevt(ostm, irq, rate);
+
+		if (!ret)
+			pr_info("ostm: used for clock events\n");
+	}
+
+err:
+	if (ret) {
+		clk_disable_unprepare(ostm_clk);
+		iounmap(ostm->base);
+		kfree(ostm);
+		return ret;
+	}
+
+	return 0;
+}
+
+CLOCKSOURCE_OF_DECLARE(ostm, "renesas,ostm", ostm_init);
-- 
2.7.4

[PATCH 07/10] clocksource/drivers/arm_arch_timer: Add dt binding for hisilicon-161010101 erratum

[Daniel Lezcano]

From: Ding Tianhong <dingtianhong@huawei.com>

This erratum describes a bug in logic outside the core, so MIDR can't be
used to identify its presence, and reading an SoC-specific revision
register from common arch timer code would be awkward.  So, describe it
in the device tree.

Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 Documentation/devicetree/bindings/arm/arch_timer.txt | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/arm/arch_timer.txt b/Documentation/devicetree/bindings/arm/arch_timer.txt
index ad440a2..e926aea 100644
--- a/Documentation/devicetree/bindings/arm/arch_timer.txt
+++ b/Documentation/devicetree/bindings/arm/arch_timer.txt
@@ -31,6 +31,12 @@ to deliver its interrupts via SPIs.
   This also affects writes to the tval register, due to the implicit
   counter read.
 
+- hisilicon,erratum-161010101 : A boolean property. Indicates the
+  presence of Hisilicon erratum 161010101, which says that reading the
+  counters is unreliable in some cases, and reads may return a value 32
+  beyond the correct value. This also affects writes to the tval
+  registers, due to the implicit counter read.
+
 ** Optional properties:
 
 - arm,cpu-registers-not-fw-configured : Firmware does not initialize
-- 
2.7.4

[PATCH 07/10] clocksource/drivers/arm_arch_timer: Add dt binding for hisilicon-161010101 erratum

[Daniel Lezcano]

From: Ding Tianhong <dingtianhong@huawei.com>

This erratum describes a bug in logic outside the core, so MIDR can't be
used to identify its presence, and reading an SoC-specific revision
register from common arch timer code would be awkward.  So, describe it
in the device tree.

Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 Documentation/devicetree/bindings/arm/arch_timer.txt | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/arm/arch_timer.txt b/Documentation/devicetree/bindings/arm/arch_timer.txt
index ad440a2..e926aea 100644
--- a/Documentation/devicetree/bindings/arm/arch_timer.txt
+++ b/Documentation/devicetree/bindings/arm/arch_timer.txt
@@ -31,6 +31,12 @@ to deliver its interrupts via SPIs.
   This also affects writes to the tval register, due to the implicit
   counter read.
 
+- hisilicon,erratum-161010101 : A boolean property. Indicates the
+  presence of Hisilicon erratum 161010101, which says that reading the
+  counters is unreliable in some cases, and reads may return a value 32
+  beyond the correct value. This also affects writes to the tval
+  registers, due to the implicit counter read.
+
 ** Optional properties:
 
 - arm,cpu-registers-not-fw-configured : Firmware does not initialize
-- 
2.7.4

[PATCH 08/10] clocksource/drivers/arm_arch_timer: Remove fsl-a008585 parameter

[Daniel Lezcano]

From: Ding Tianhong <dingtianhong@huawei.com>

Having a command line option to flip the errata handling for a
particular erratum is a little bit unusual, and it's vastly superior to
pass this in the DT. By common consensus, it's best to kill off the
command line parameter.

Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
[Mark: split patch, reword commit message]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 Documentation/admin-guide/kernel-parameters.txt |  9 ---------
 drivers/clocksource/arm_arch_timer.c            | 14 --------------
 2 files changed, 23 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index be7c0d9..d8fc55a 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -549,15 +549,6 @@
 			loops can be debugged more effectively on production
 			systems.
 
-	clocksource.arm_arch_timer.fsl-a008585=
-			[ARM64]
-			Format: <bool>
-			Enable/disable the workaround of Freescale/NXP
-			erratum A-008585.  This can be useful for KVM
-			guests, if the guest device tree doesn't show the
-			erratum.  If unspecified, the workaround is
-			enabled based on the device tree.
-
 	clearcpuid=BITNUM [X86]
 			Disable CPUID feature X for the kernel. See
 			arch/x86/include/asm/cpufeatures.h for the valid bit
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 4c8c3fb..6a9d031 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -101,20 +101,6 @@ EXPORT_SYMBOL_GPL(arch_timer_read_ool_enabled);
 
 static int fsl_a008585_enable = -1;
 
-static int __init early_fsl_a008585_cfg(char *buf)
-{
-	int ret;
-	bool val;
-
-	ret = strtobool(buf, &val);
-	if (ret)
-		return ret;
-
-	fsl_a008585_enable = val;
-	return 0;
-}
-early_param("clocksource.arm_arch_timer.fsl-a008585", early_fsl_a008585_cfg);
-
 u32 __fsl_a008585_read_cntp_tval_el0(void)
 {
 	return __fsl_a008585_read_reg(cntp_tval_el0);
-- 
2.7.4

[PATCH 08/10] clocksource/drivers/arm_arch_timer: Remove fsl-a008585 parameter

[Daniel Lezcano]

From: Ding Tianhong <dingtianhong@huawei.com>

Having a command line option to flip the errata handling for a
particular erratum is a little bit unusual, and it's vastly superior to
pass this in the DT. By common consensus, it's best to kill off the
command line parameter.

Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
[Mark: split patch, reword commit message]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 Documentation/admin-guide/kernel-parameters.txt |  9 ---------
 drivers/clocksource/arm_arch_timer.c            | 14 --------------
 2 files changed, 23 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index be7c0d9..d8fc55a 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -549,15 +549,6 @@
 			loops can be debugged more effectively on production
 			systems.
 
-	clocksource.arm_arch_timer.fsl-a008585=
-			[ARM64]
-			Format: <bool>
-			Enable/disable the workaround of Freescale/NXP
-			erratum A-008585.  This can be useful for KVM
-			guests, if the guest device tree doesn't show the
-			erratum.  If unspecified, the workaround is
-			enabled based on the device tree.
-
 	clearcpuid=BITNUM [X86]
 			Disable CPUID feature X for the kernel. See
 			arch/x86/include/asm/cpufeatures.h for the valid bit
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 4c8c3fb..6a9d031 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -101,20 +101,6 @@ EXPORT_SYMBOL_GPL(arch_timer_read_ool_enabled);
 
 static int fsl_a008585_enable = -1;
 
-static int __init early_fsl_a008585_cfg(char *buf)
-{
-	int ret;
-	bool val;
-
-	ret = strtobool(buf, &val);
-	if (ret)
-		return ret;
-
-	fsl_a008585_enable = val;
-	return 0;
-}
-early_param("clocksource.arm_arch_timer.fsl-a008585", early_fsl_a008585_cfg);
-
 u32 __fsl_a008585_read_cntp_tval_el0(void)
 {
 	return __fsl_a008585_read_reg(cntp_tval_el0);
-- 
2.7.4

[PATCH 09/10] clocksource/drivers/arm_arch_timer: Introduce generic errata handling infrastructure

[Daniel Lezcano]

From: Ding Tianhong <dingtianhong@huawei.com>

Currently we have code inline in the arch timer probe path to cater for
Freescale erratum A-008585, complete with ifdeffery. This is a little
ugly, and will get worse as we try to add more errata handling.

This patch refactors the handling of Freescale erratum A-008585. Now the
erratum is described in a generic arch_timer_erratum_workaround
structure, and the probe path can iterate over these to detect errata
and enable workarounds.

This will simplify the addition and maintenance of code handling
Hisilicon erratum 161010101.

Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
[Mark: split patch, correct Kconfig, reword commit message]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 arch/arm64/include/asm/arch_timer.h  | 38 +++++----------
 drivers/clocksource/Kconfig          |  4 ++
 drivers/clocksource/arm_arch_timer.c | 92 ++++++++++++++++++++++++------------
 3 files changed, 80 insertions(+), 54 deletions(-)

diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h
index eaa5bbe..b4b3400 100644
--- a/arch/arm64/include/asm/arch_timer.h
+++ b/arch/arm64/include/asm/arch_timer.h
@@ -29,41 +29,29 @@
 
 #include <clocksource/arm_arch_timer.h>
 
-#if IS_ENABLED(CONFIG_FSL_ERRATUM_A008585)
+#if IS_ENABLED(CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND)
 extern struct static_key_false arch_timer_read_ool_enabled;
-#define needs_fsl_a008585_workaround() \
+#define needs_unstable_timer_counter_workaround() \
 	static_branch_unlikely(&arch_timer_read_ool_enabled)
 #else
-#define needs_fsl_a008585_workaround()  false
+#define needs_unstable_timer_counter_workaround()  false
 #endif
 
-u32 __fsl_a008585_read_cntp_tval_el0(void);
-u32 __fsl_a008585_read_cntv_tval_el0(void);
-u64 __fsl_a008585_read_cntvct_el0(void);
 
-/*
- * The number of retries is an arbitrary value well beyond the highest number
- * of iterations the loop has been observed to take.
- */
-#define __fsl_a008585_read_reg(reg) ({			\
-	u64 _old, _new;					\
-	int _retries = 200;				\
-							\
-	do {						\
-		_old = read_sysreg(reg);		\
-		_new = read_sysreg(reg);		\
-		_retries--;				\
-	} while (unlikely(_old != _new) && _retries);	\
-							\
-	WARN_ON_ONCE(!_retries);			\
-	_new;						\
-})
+struct arch_timer_erratum_workaround {
+	const char *id;		/* Indicate the Erratum ID */
+	u32 (*read_cntp_tval_el0)(void);
+	u32 (*read_cntv_tval_el0)(void);
+	u64 (*read_cntvct_el0)(void);
+};
+
+extern const struct arch_timer_erratum_workaround *timer_unstable_counter_workaround;
 
 #define arch_timer_reg_read_stable(reg) 		\
 ({							\
 	u64 _val;					\
-	if (needs_fsl_a008585_workaround())		\
-		_val = __fsl_a008585_read_##reg();	\
+	if (needs_unstable_timer_counter_workaround())		\
+		_val = timer_unstable_counter_workaround->read_##reg();\
 	else						\
 		_val = read_sysreg(reg);		\
 	_val;						\
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 4002d6d..1945af2 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -342,10 +342,14 @@ config ARM_ARCH_TIMER_EVTSTREAM
 	  This must be disabled for hardware validation purposes to detect any
 	  hardware anomalies of missing events.
 
+config ARM_ARCH_TIMER_OOL_WORKAROUND
+	bool
+
 config FSL_ERRATUM_A008585
 	bool "Workaround for Freescale/NXP Erratum A-008585"
 	default y
 	depends on ARM_ARCH_TIMER && ARM64
+	select ARM_ARCH_TIMER_OOL_WORKAROUND
 	help
 	  This option enables a workaround for Freescale/NXP Erratum
 	  A-008585 ("ARM generic timer may contain an erroneous
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 6a9d031..2af0739 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -96,27 +96,58 @@ early_param("clocksource.arm_arch_timer.evtstrm", early_evtstrm_cfg);
  */
 
 #ifdef CONFIG_FSL_ERRATUM_A008585
-DEFINE_STATIC_KEY_FALSE(arch_timer_read_ool_enabled);
-EXPORT_SYMBOL_GPL(arch_timer_read_ool_enabled);
-
-static int fsl_a008585_enable = -1;
-
-u32 __fsl_a008585_read_cntp_tval_el0(void)
+/*
+ * The number of retries is an arbitrary value well beyond the highest number
+ * of iterations the loop has been observed to take.
+ */
+#define __fsl_a008585_read_reg(reg) ({			\
+	u64 _old, _new;					\
+	int _retries = 200;				\
+							\
+	do {						\
+		_old = read_sysreg(reg);		\
+		_new = read_sysreg(reg);		\
+		_retries--;				\
+	} while (unlikely(_old != _new) && _retries);	\
+							\
+	WARN_ON_ONCE(!_retries);			\
+	_new;						\
+})
+
+static u32 notrace fsl_a008585_read_cntp_tval_el0(void)
 {
 	return __fsl_a008585_read_reg(cntp_tval_el0);
 }
 
-u32 __fsl_a008585_read_cntv_tval_el0(void)
+static u32 notrace fsl_a008585_read_cntv_tval_el0(void)
 {
 	return __fsl_a008585_read_reg(cntv_tval_el0);
 }
 
-u64 __fsl_a008585_read_cntvct_el0(void)
+static u64 notrace fsl_a008585_read_cntvct_el0(void)
 {
 	return __fsl_a008585_read_reg(cntvct_el0);
 }
-EXPORT_SYMBOL(__fsl_a008585_read_cntvct_el0);
-#endif /* CONFIG_FSL_ERRATUM_A008585 */
+#endif
+
+#ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
+const struct arch_timer_erratum_workaround *timer_unstable_counter_workaround = NULL;
+EXPORT_SYMBOL_GPL(timer_unstable_counter_workaround);
+
+DEFINE_STATIC_KEY_FALSE(arch_timer_read_ool_enabled);
+EXPORT_SYMBOL_GPL(arch_timer_read_ool_enabled);
+
+static const struct arch_timer_erratum_workaround ool_workarounds[] = {
+#ifdef CONFIG_FSL_ERRATUM_A008585
+	{
+		.id = "fsl,erratum-a008585",
+		.read_cntp_tval_el0 = fsl_a008585_read_cntp_tval_el0,
+		.read_cntv_tval_el0 = fsl_a008585_read_cntv_tval_el0,
+		.read_cntvct_el0 = fsl_a008585_read_cntvct_el0,
+	},
+#endif
+};
+#endif /* CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND */
 
 static __always_inline
 void arch_timer_reg_write(int access, enum arch_timer_reg reg, u32 val,
@@ -267,8 +298,8 @@ static __always_inline void set_next_event(const int access, unsigned long evt,
 	arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
 }
 
-#ifdef CONFIG_FSL_ERRATUM_A008585
-static __always_inline void fsl_a008585_set_next_event(const int access,
+#ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
+static __always_inline void erratum_set_next_event_generic(const int access,
 		unsigned long evt, struct clock_event_device *clk)
 {
 	unsigned long ctrl;
@@ -286,20 +317,20 @@ static __always_inline void fsl_a008585_set_next_event(const int access,
 	arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
 }
 
-static int fsl_a008585_set_next_event_virt(unsigned long evt,
+static int erratum_set_next_event_virt(unsigned long evt,
 					   struct clock_event_device *clk)
 {
-	fsl_a008585_set_next_event(ARCH_TIMER_VIRT_ACCESS, evt, clk);
+	erratum_set_next_event_generic(ARCH_TIMER_VIRT_ACCESS, evt, clk);
 	return 0;
 }
 
-static int fsl_a008585_set_next_event_phys(unsigned long evt,
+static int erratum_set_next_event_phys(unsigned long evt,
 					   struct clock_event_device *clk)
 {
-	fsl_a008585_set_next_event(ARCH_TIMER_PHYS_ACCESS, evt, clk);
+	erratum_set_next_event_generic(ARCH_TIMER_PHYS_ACCESS, evt, clk);
 	return 0;
 }
-#endif /* CONFIG_FSL_ERRATUM_A008585 */
+#endif /* CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND */
 
 static int arch_timer_set_next_event_virt(unsigned long evt,
 					  struct clock_event_device *clk)
@@ -329,16 +360,16 @@ static int arch_timer_set_next_event_phys_mem(unsigned long evt,
 	return 0;
 }
 
-static void fsl_a008585_set_sne(struct clock_event_device *clk)
+static void erratum_workaround_set_sne(struct clock_event_device *clk)
 {
-#ifdef CONFIG_FSL_ERRATUM_A008585
+#ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
 	if (!static_branch_unlikely(&arch_timer_read_ool_enabled))
 		return;
 
 	if (arch_timer_uses_ppi == VIRT_PPI)
-		clk->set_next_event = fsl_a008585_set_next_event_virt;
+		clk->set_next_event = erratum_set_next_event_virt;
 	else
-		clk->set_next_event = fsl_a008585_set_next_event_phys;
+		clk->set_next_event = erratum_set_next_event_phys;
 #endif
 }
 
@@ -371,7 +402,7 @@ static void __arch_timer_setup(unsigned type,
 			BUG();
 		}
 
-		fsl_a008585_set_sne(clk);
+		erratum_workaround_set_sne(clk);
 	} else {
 		clk->features |= CLOCK_EVT_FEAT_DYNIRQ;
 		clk->name = "arch_mem_timer";
@@ -591,7 +622,7 @@ static void __init arch_counter_register(unsigned type)
 
 		clocksource_counter.archdata.vdso_direct = true;
 
-#ifdef CONFIG_FSL_ERRATUM_A008585
+#ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
 		/*
 		 * Don't use the vdso fastpath if errata require using
 		 * the out-of-line counter accessor.
@@ -879,12 +910,15 @@ static int __init arch_timer_of_init(struct device_node *np)
 
 	arch_timer_c3stop = !of_property_read_bool(np, "always-on");
 
-#ifdef CONFIG_FSL_ERRATUM_A008585
-	if (fsl_a008585_enable < 0)
-		fsl_a008585_enable = of_property_read_bool(np, "fsl,erratum-a008585");
-	if (fsl_a008585_enable) {
-		static_branch_enable(&arch_timer_read_ool_enabled);
-		pr_info("Enabling workaround for FSL erratum A-008585\n");
+#ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
+	for (i = 0; i < ARRAY_SIZE(ool_workarounds); i++) {
+		if (of_property_read_bool(np, ool_workarounds[i].id)) {
+			timer_unstable_counter_workaround = &ool_workarounds[i];
+			static_branch_enable(&arch_timer_read_ool_enabled);
+			pr_info("arch_timer: Enabling workaround for %s\n",
+				timer_unstable_counter_workaround->id);
+			break;
+		}
 	}
 #endif
 
-- 
2.7.4

[PATCH 09/10] clocksource/drivers/arm_arch_timer: Introduce generic errata handling infrastructure

[Daniel Lezcano]

From: Ding Tianhong <dingtianhong@huawei.com>

Currently we have code inline in the arch timer probe path to cater for
Freescale erratum A-008585, complete with ifdeffery. This is a little
ugly, and will get worse as we try to add more errata handling.

This patch refactors the handling of Freescale erratum A-008585. Now the
erratum is described in a generic arch_timer_erratum_workaround
structure, and the probe path can iterate over these to detect errata
and enable workarounds.

This will simplify the addition and maintenance of code handling
Hisilicon erratum 161010101.

Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
[Mark: split patch, correct Kconfig, reword commit message]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 arch/arm64/include/asm/arch_timer.h  | 38 +++++----------
 drivers/clocksource/Kconfig          |  4 ++
 drivers/clocksource/arm_arch_timer.c | 92 ++++++++++++++++++++++++------------
 3 files changed, 80 insertions(+), 54 deletions(-)

diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h
index eaa5bbe..b4b3400 100644
--- a/arch/arm64/include/asm/arch_timer.h
+++ b/arch/arm64/include/asm/arch_timer.h
@@ -29,41 +29,29 @@
 
 #include <clocksource/arm_arch_timer.h>
 
-#if IS_ENABLED(CONFIG_FSL_ERRATUM_A008585)
+#if IS_ENABLED(CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND)
 extern struct static_key_false arch_timer_read_ool_enabled;
-#define needs_fsl_a008585_workaround() \
+#define needs_unstable_timer_counter_workaround() \
 	static_branch_unlikely(&arch_timer_read_ool_enabled)
 #else
-#define needs_fsl_a008585_workaround()  false
+#define needs_unstable_timer_counter_workaround()  false
 #endif
 
-u32 __fsl_a008585_read_cntp_tval_el0(void);
-u32 __fsl_a008585_read_cntv_tval_el0(void);
-u64 __fsl_a008585_read_cntvct_el0(void);
 
-/*
- * The number of retries is an arbitrary value well beyond the highest number
- * of iterations the loop has been observed to take.
- */
-#define __fsl_a008585_read_reg(reg) ({			\
-	u64 _old, _new;					\
-	int _retries = 200;				\
-							\
-	do {						\
-		_old = read_sysreg(reg);		\
-		_new = read_sysreg(reg);		\
-		_retries--;				\
-	} while (unlikely(_old != _new) && _retries);	\
-							\
-	WARN_ON_ONCE(!_retries);			\
-	_new;						\
-})
+struct arch_timer_erratum_workaround {
+	const char *id;		/* Indicate the Erratum ID */
+	u32 (*read_cntp_tval_el0)(void);
+	u32 (*read_cntv_tval_el0)(void);
+	u64 (*read_cntvct_el0)(void);
+};
+
+extern const struct arch_timer_erratum_workaround *timer_unstable_counter_workaround;
 
 #define arch_timer_reg_read_stable(reg) 		\
 ({							\
 	u64 _val;					\
-	if (needs_fsl_a008585_workaround())		\
-		_val = __fsl_a008585_read_##reg();	\
+	if (needs_unstable_timer_counter_workaround())		\
+		_val = timer_unstable_counter_workaround->read_##reg();\
 	else						\
 		_val = read_sysreg(reg);		\
 	_val;						\
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 4002d6d..1945af2 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -342,10 +342,14 @@ config ARM_ARCH_TIMER_EVTSTREAM
 	  This must be disabled for hardware validation purposes to detect any
 	  hardware anomalies of missing events.
 
+config ARM_ARCH_TIMER_OOL_WORKAROUND
+	bool
+
 config FSL_ERRATUM_A008585
 	bool "Workaround for Freescale/NXP Erratum A-008585"
 	default y
 	depends on ARM_ARCH_TIMER && ARM64
+	select ARM_ARCH_TIMER_OOL_WORKAROUND
 	help
 	  This option enables a workaround for Freescale/NXP Erratum
 	  A-008585 ("ARM generic timer may contain an erroneous
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 6a9d031..2af0739 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -96,27 +96,58 @@ early_param("clocksource.arm_arch_timer.evtstrm", early_evtstrm_cfg);
  */
 
 #ifdef CONFIG_FSL_ERRATUM_A008585
-DEFINE_STATIC_KEY_FALSE(arch_timer_read_ool_enabled);
-EXPORT_SYMBOL_GPL(arch_timer_read_ool_enabled);
-
-static int fsl_a008585_enable = -1;
-
-u32 __fsl_a008585_read_cntp_tval_el0(void)
+/*
+ * The number of retries is an arbitrary value well beyond the highest number
+ * of iterations the loop has been observed to take.
+ */
+#define __fsl_a008585_read_reg(reg) ({			\
+	u64 _old, _new;					\
+	int _retries = 200;				\
+							\
+	do {						\
+		_old = read_sysreg(reg);		\
+		_new = read_sysreg(reg);		\
+		_retries--;				\
+	} while (unlikely(_old != _new) && _retries);	\
+							\
+	WARN_ON_ONCE(!_retries);			\
+	_new;						\
+})
+
+static u32 notrace fsl_a008585_read_cntp_tval_el0(void)
 {
 	return __fsl_a008585_read_reg(cntp_tval_el0);
 }
 
-u32 __fsl_a008585_read_cntv_tval_el0(void)
+static u32 notrace fsl_a008585_read_cntv_tval_el0(void)
 {
 	return __fsl_a008585_read_reg(cntv_tval_el0);
 }
 
-u64 __fsl_a008585_read_cntvct_el0(void)
+static u64 notrace fsl_a008585_read_cntvct_el0(void)
 {
 	return __fsl_a008585_read_reg(cntvct_el0);
 }
-EXPORT_SYMBOL(__fsl_a008585_read_cntvct_el0);
-#endif /* CONFIG_FSL_ERRATUM_A008585 */
+#endif
+
+#ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
+const struct arch_timer_erratum_workaround *timer_unstable_counter_workaround = NULL;
+EXPORT_SYMBOL_GPL(timer_unstable_counter_workaround);
+
+DEFINE_STATIC_KEY_FALSE(arch_timer_read_ool_enabled);
+EXPORT_SYMBOL_GPL(arch_timer_read_ool_enabled);
+
+static const struct arch_timer_erratum_workaround ool_workarounds[] = {
+#ifdef CONFIG_FSL_ERRATUM_A008585
+	{
+		.id = "fsl,erratum-a008585",
+		.read_cntp_tval_el0 = fsl_a008585_read_cntp_tval_el0,
+		.read_cntv_tval_el0 = fsl_a008585_read_cntv_tval_el0,
+		.read_cntvct_el0 = fsl_a008585_read_cntvct_el0,
+	},
+#endif
+};
+#endif /* CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND */
 
 static __always_inline
 void arch_timer_reg_write(int access, enum arch_timer_reg reg, u32 val,
@@ -267,8 +298,8 @@ static __always_inline void set_next_event(const int access, unsigned long evt,
 	arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
 }
 
-#ifdef CONFIG_FSL_ERRATUM_A008585
-static __always_inline void fsl_a008585_set_next_event(const int access,
+#ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
+static __always_inline void erratum_set_next_event_generic(const int access,
 		unsigned long evt, struct clock_event_device *clk)
 {
 	unsigned long ctrl;
@@ -286,20 +317,20 @@ static __always_inline void fsl_a008585_set_next_event(const int access,
 	arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
 }
 
-static int fsl_a008585_set_next_event_virt(unsigned long evt,
+static int erratum_set_next_event_virt(unsigned long evt,
 					   struct clock_event_device *clk)
 {
-	fsl_a008585_set_next_event(ARCH_TIMER_VIRT_ACCESS, evt, clk);
+	erratum_set_next_event_generic(ARCH_TIMER_VIRT_ACCESS, evt, clk);
 	return 0;
 }
 
-static int fsl_a008585_set_next_event_phys(unsigned long evt,
+static int erratum_set_next_event_phys(unsigned long evt,
 					   struct clock_event_device *clk)
 {
-	fsl_a008585_set_next_event(ARCH_TIMER_PHYS_ACCESS, evt, clk);
+	erratum_set_next_event_generic(ARCH_TIMER_PHYS_ACCESS, evt, clk);
 	return 0;
 }
-#endif /* CONFIG_FSL_ERRATUM_A008585 */
+#endif /* CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND */
 
 static int arch_timer_set_next_event_virt(unsigned long evt,
 					  struct clock_event_device *clk)
@@ -329,16 +360,16 @@ static int arch_timer_set_next_event_phys_mem(unsigned long evt,
 	return 0;
 }
 
-static void fsl_a008585_set_sne(struct clock_event_device *clk)
+static void erratum_workaround_set_sne(struct clock_event_device *clk)
 {
-#ifdef CONFIG_FSL_ERRATUM_A008585
+#ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
 	if (!static_branch_unlikely(&arch_timer_read_ool_enabled))
 		return;
 
 	if (arch_timer_uses_ppi == VIRT_PPI)
-		clk->set_next_event = fsl_a008585_set_next_event_virt;
+		clk->set_next_event = erratum_set_next_event_virt;
 	else
-		clk->set_next_event = fsl_a008585_set_next_event_phys;
+		clk->set_next_event = erratum_set_next_event_phys;
 #endif
 }
 
@@ -371,7 +402,7 @@ static void __arch_timer_setup(unsigned type,
 			BUG();
 		}
 
-		fsl_a008585_set_sne(clk);
+		erratum_workaround_set_sne(clk);
 	} else {
 		clk->features |= CLOCK_EVT_FEAT_DYNIRQ;
 		clk->name = "arch_mem_timer";
@@ -591,7 +622,7 @@ static void __init arch_counter_register(unsigned type)
 
 		clocksource_counter.archdata.vdso_direct = true;
 
-#ifdef CONFIG_FSL_ERRATUM_A008585
+#ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
 		/*
 		 * Don't use the vdso fastpath if errata require using
 		 * the out-of-line counter accessor.
@@ -879,12 +910,15 @@ static int __init arch_timer_of_init(struct device_node *np)
 
 	arch_timer_c3stop = !of_property_read_bool(np, "always-on");
 
-#ifdef CONFIG_FSL_ERRATUM_A008585
-	if (fsl_a008585_enable < 0)
-		fsl_a008585_enable = of_property_read_bool(np, "fsl,erratum-a008585");
-	if (fsl_a008585_enable) {
-		static_branch_enable(&arch_timer_read_ool_enabled);
-		pr_info("Enabling workaround for FSL erratum A-008585\n");
+#ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
+	for (i = 0; i < ARRAY_SIZE(ool_workarounds); i++) {
+		if (of_property_read_bool(np, ool_workarounds[i].id)) {
+			timer_unstable_counter_workaround = &ool_workarounds[i];
+			static_branch_enable(&arch_timer_read_ool_enabled);
+			pr_info("arch_timer: Enabling workaround for %s\n",
+				timer_unstable_counter_workaround->id);
+			break;
+		}
 	}
 #endif
 
-- 
2.7.4

[PATCH 10/10] clocksource/drivers/arm_arch_timer: Work around Hisilicon erratum 161010101

[Daniel Lezcano]

From: Ding Tianhong <dingtianhong@huawei.com>

Erratum Hisilicon-161010101 says that the ARM generic timer counter "has
the potential to contain an erroneous value when the timer value
changes". Accesses to TVAL (both read and write) are also affected due
to the implicit counter read. Accesses to CVAL are not affected.

The workaround is to reread the system count registers until the value
of the second read is larger than the first one by less than 32, the
system counter can be guaranteed not to return wrong value twice by
back-to-back read and the error value is always larger than the correct
one by 32. Writes to TVAL are replaced with an equivalent write to CVAL.

Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
[Mark: split patch, fix Kconfig, reword commit message]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 drivers/clocksource/Kconfig          | 10 ++++++++
 drivers/clocksource/arm_arch_timer.c | 49 ++++++++++++++++++++++++++++++++++++
 2 files changed, 59 insertions(+)

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 1945af2..3356ab8 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -356,6 +356,16 @@ config FSL_ERRATUM_A008585
 	  value").  The workaround will only be active if the
 	  fsl,erratum-a008585 property is found in the timer node.
 
+config HISILICON_ERRATUM_161010101
+	bool "Workaround for Hisilicon Erratum 161010101"
+	default y
+	select ARM_ARCH_TIMER_OOL_WORKAROUND
+	depends on ARM_ARCH_TIMER && ARM64
+	help
+	  This option enables a workaround for Hisilicon Erratum
+	  161010101. The workaround will be active if the hisilicon,erratum-161010101
+	  property is found in the timer node.
+
 config ARM_GLOBAL_TIMER
 	bool "Support for the ARM global timer" if COMPILE_TEST
 	select CLKSRC_OF if OF
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 2af0739..7b06aef 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -130,6 +130,47 @@ static u64 notrace fsl_a008585_read_cntvct_el0(void)
 }
 #endif
 
+#ifdef CONFIG_HISILICON_ERRATUM_161010101
+/*
+ * Verify whether the value of the second read is larger than the first by
+ * less than 32 is the only way to confirm the value is correct, so clear the
+ * lower 5 bits to check whether the difference is greater than 32 or not.
+ * Theoretically the erratum should not occur more than twice in succession
+ * when reading the system counter, but it is possible that some interrupts
+ * may lead to more than twice read errors, triggering the warning, so setting
+ * the number of retries far beyond the number of iterations the loop has been
+ * observed to take.
+ */
+#define __hisi_161010101_read_reg(reg) ({				\
+	u64 _old, _new;						\
+	int _retries = 50;					\
+								\
+	do {							\
+		_old = read_sysreg(reg);			\
+		_new = read_sysreg(reg);			\
+		_retries--;					\
+	} while (unlikely((_new - _old) >> 5) && _retries);	\
+								\
+	WARN_ON_ONCE(!_retries);				\
+	_new;							\
+})
+
+static u32 notrace hisi_161010101_read_cntp_tval_el0(void)
+{
+	return __hisi_161010101_read_reg(cntp_tval_el0);
+}
+
+static u32 notrace hisi_161010101_read_cntv_tval_el0(void)
+{
+	return __hisi_161010101_read_reg(cntv_tval_el0);
+}
+
+static u64 notrace hisi_161010101_read_cntvct_el0(void)
+{
+	return __hisi_161010101_read_reg(cntvct_el0);
+}
+#endif
+
 #ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
 const struct arch_timer_erratum_workaround *timer_unstable_counter_workaround = NULL;
 EXPORT_SYMBOL_GPL(timer_unstable_counter_workaround);
@@ -146,6 +187,14 @@ static const struct arch_timer_erratum_workaround ool_workarounds[] = {
 		.read_cntvct_el0 = fsl_a008585_read_cntvct_el0,
 	},
 #endif
+#ifdef CONFIG_HISILICON_ERRATUM_161010101
+	{
+		.id = "hisilicon,erratum-161010101",
+		.read_cntp_tval_el0 = hisi_161010101_read_cntp_tval_el0,
+		.read_cntv_tval_el0 = hisi_161010101_read_cntv_tval_el0,
+		.read_cntvct_el0 = hisi_161010101_read_cntvct_el0,
+	},
+#endif
 };
 #endif /* CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND */
 
-- 
2.7.4

[PATCH 10/10] clocksource/drivers/arm_arch_timer: Work around Hisilicon erratum 161010101

[Daniel Lezcano]

From: Ding Tianhong <dingtianhong@huawei.com>

Erratum Hisilicon-161010101 says that the ARM generic timer counter "has
the potential to contain an erroneous value when the timer value
changes". Accesses to TVAL (both read and write) are also affected due
to the implicit counter read. Accesses to CVAL are not affected.

The workaround is to reread the system count registers until the value
of the second read is larger than the first one by less than 32, the
system counter can be guaranteed not to return wrong value twice by
back-to-back read and the error value is always larger than the correct
one by 32. Writes to TVAL are replaced with an equivalent write to CVAL.

Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
[Mark: split patch, fix Kconfig, reword commit message]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 drivers/clocksource/Kconfig          | 10 ++++++++
 drivers/clocksource/arm_arch_timer.c | 49 ++++++++++++++++++++++++++++++++++++
 2 files changed, 59 insertions(+)

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 1945af2..3356ab8 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -356,6 +356,16 @@ config FSL_ERRATUM_A008585
 	  value").  The workaround will only be active if the
 	  fsl,erratum-a008585 property is found in the timer node.
 
+config HISILICON_ERRATUM_161010101
+	bool "Workaround for Hisilicon Erratum 161010101"
+	default y
+	select ARM_ARCH_TIMER_OOL_WORKAROUND
+	depends on ARM_ARCH_TIMER && ARM64
+	help
+	  This option enables a workaround for Hisilicon Erratum
+	  161010101. The workaround will be active if the hisilicon,erratum-161010101
+	  property is found in the timer node.
+
 config ARM_GLOBAL_TIMER
 	bool "Support for the ARM global timer" if COMPILE_TEST
 	select CLKSRC_OF if OF
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 2af0739..7b06aef 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -130,6 +130,47 @@ static u64 notrace fsl_a008585_read_cntvct_el0(void)
 }
 #endif
 
+#ifdef CONFIG_HISILICON_ERRATUM_161010101
+/*
+ * Verify whether the value of the second read is larger than the first by
+ * less than 32 is the only way to confirm the value is correct, so clear the
+ * lower 5 bits to check whether the difference is greater than 32 or not.
+ * Theoretically the erratum should not occur more than twice in succession
+ * when reading the system counter, but it is possible that some interrupts
+ * may lead to more than twice read errors, triggering the warning, so setting
+ * the number of retries far beyond the number of iterations the loop has been
+ * observed to take.
+ */
+#define __hisi_161010101_read_reg(reg) ({				\
+	u64 _old, _new;						\
+	int _retries = 50;					\
+								\
+	do {							\
+		_old = read_sysreg(reg);			\
+		_new = read_sysreg(reg);			\
+		_retries--;					\
+	} while (unlikely((_new - _old) >> 5) && _retries);	\
+								\
+	WARN_ON_ONCE(!_retries);				\
+	_new;							\
+})
+
+static u32 notrace hisi_161010101_read_cntp_tval_el0(void)
+{
+	return __hisi_161010101_read_reg(cntp_tval_el0);
+}
+
+static u32 notrace hisi_161010101_read_cntv_tval_el0(void)
+{
+	return __hisi_161010101_read_reg(cntv_tval_el0);
+}
+
+static u64 notrace hisi_161010101_read_cntvct_el0(void)
+{
+	return __hisi_161010101_read_reg(cntvct_el0);
+}
+#endif
+
 #ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
 const struct arch_timer_erratum_workaround *timer_unstable_counter_workaround = NULL;
 EXPORT_SYMBOL_GPL(timer_unstable_counter_workaround);
@@ -146,6 +187,14 @@ static const struct arch_timer_erratum_workaround ool_workarounds[] = {
 		.read_cntvct_el0 = fsl_a008585_read_cntvct_el0,
 	},
 #endif
+#ifdef CONFIG_HISILICON_ERRATUM_161010101
+	{
+		.id = "hisilicon,erratum-161010101",
+		.read_cntp_tval_el0 = hisi_161010101_read_cntp_tval_el0,
+		.read_cntv_tval_el0 = hisi_161010101_read_cntv_tval_el0,
+		.read_cntvct_el0 = hisi_161010101_read_cntvct_el0,
+	},
+#endif
 };
 #endif /* CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND */
 
-- 
2.7.4