[PATCH V8 0/6] Add X-Gene platform reboot mechanism

[PATCH V8 0/6] Add X-Gene platform reboot mechanism

[Feng Kan]

Enable reboot driver for the X-Gene platform. Add generic syscon reboot
driver.

V8 Change:
	- change Kconfig to depend on ARM || ARM64 || COMPILE_TEST

V7 Change:
	- Seem V3 on, the patches were not making in to the mailinglist.
	- Fix build error produced by other ARCH while including this
	  driver. Set to depend on arm64 ARCH for now.

V6 Change:
	- Add documentation for scu node.

V5 Change:
	- Documentation update, endian and access size.

V4 Change:
	- Remove old X-Gene reboot driver
	- Add generic syscon reboot driver
	- Add DTS and Kconfig for X-Gene reboot using syscon method

V3 Change:
	- Remove the reboot driver's use of acpi resource patch.
	- Change the reboot driver to use syscon to parse out 
	  system clock register. Remove the old method of getting
	  register from the reboot driver directly.
	- Remove documentation since its now simple.

V2 Change:
	- Add support for using ACPI resource.


Feng Kan (6):
  power: reset: Add generic SYSCON register mapped reset
  Documentation: power: reset: Add documentation for generic SYSCON
    reboot driver
  Documentation: arm64: add SCU dts binding documentation to linux
    kernel
  arm64: dts: Add X-Gene reboot driver dts node
  arm64: Select reboot driver for X-Gene platform
  power: reset: Remove X-Gene reboot driver

 Documentation/devicetree/bindings/arm/apm/scu.txt  |  17 ++++
 .../bindings/power/reset/syscon-reboot.txt         |  23 +++++
 arch/arm64/Kconfig                                 |   2 +
 arch/arm64/boot/dts/apm-storm.dtsi                 |  12 +++
 drivers/power/reset/Kconfig                        |  13 ++-
 drivers/power/reset/Makefile                       |   2 +-
 drivers/power/reset/syscon-reboot.c                |  91 ++++++++++++++++++
 drivers/power/reset/xgene-reboot.c                 | 103 ---------------------
 8 files changed, 152 insertions(+), 111 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/arm/apm/scu.txt
 create mode 100644 Documentation/devicetree/bindings/power/reset/syscon-reboot.txt
 create mode 100644 drivers/power/reset/syscon-reboot.c
 delete mode 100644 drivers/power/reset/xgene-reboot.c

-- 
1.9.1

[PATCH V8 1/6] power: reset: Add generic SYSCON register mapped reset

[Feng Kan]

Add a generic SYSCON register mapped reset mechanism.

Signed-off-by: Feng Kan <fkan@apm.com>
---
 drivers/power/reset/Kconfig         |  6 +++
 drivers/power/reset/Makefile        |  1 +
 drivers/power/reset/syscon-reboot.c | 91 +++++++++++++++++++++++++++++++++++++
 3 files changed, 98 insertions(+)
 create mode 100644 drivers/power/reset/syscon-reboot.c

diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
index bdcf517..5877b38 100644
--- a/drivers/power/reset/Kconfig
+++ b/drivers/power/reset/Kconfig
@@ -80,3 +80,9 @@ config POWER_RESET_KEYSTONE
 	help
 	  Reboot support for the KEYSTONE SoCs.
 
+config POWER_RESET_SYSCON
+	bool "Generic SYSCON regmap reset driver"
+	depends on ARM || ARM64 || COMPILE_TEST
+	depends on POWER_RESET && MFD_SYSCON && OF
+	help
+	  Reboot support for generic SYSCON mapped register reset.
diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
index dde2e8b..b1b5ab3 100644
--- a/drivers/power/reset/Makefile
+++ b/drivers/power/reset/Makefile
@@ -8,3 +8,4 @@ obj-$(CONFIG_POWER_RESET_SUN6I) += sun6i-reboot.o
 obj-$(CONFIG_POWER_RESET_VEXPRESS) += vexpress-poweroff.o
 obj-$(CONFIG_POWER_RESET_XGENE) += xgene-reboot.o
 obj-$(CONFIG_POWER_RESET_KEYSTONE) += keystone-reset.o
+obj-$(CONFIG_POWER_RESET_SYSCON) += syscon-reboot.o
diff --git a/drivers/power/reset/syscon-reboot.c b/drivers/power/reset/syscon-reboot.c
new file mode 100644
index 0000000..9c15ba5
--- /dev/null
+++ b/drivers/power/reset/syscon-reboot.c
@@ -0,0 +1,91 @@
+/*
+ * Generic Syscon Reboot Driver
+ *
+ * Copyright (c) 2013, Applied Micro Circuits Corporation
+ * Author: Feng Kan <fkan@apm.com>
+ *
+ * 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, or (at your option) any later version.
+ *
+ * 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/io.h>
+#include <linux/of_device.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/stat.h>
+#include <linux/slab.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
+#include <linux/reboot.h>
+#include <asm/system_misc.h>
+
+struct syscon_reboot_context {
+	struct regmap *map;
+	u32 offset;
+	u32 mask;
+};
+
+static struct syscon_reboot_context *syscon_reboot_ctx;
+
+static void syscon_restart(enum reboot_mode reboot_mode, const char *cmd)
+{
+	struct syscon_reboot_context *ctx = syscon_reboot_ctx;
+	unsigned long timeout;
+
+	/* Issue the reboot */
+	if (ctx->map)
+		regmap_write(ctx->map, ctx->offset, ctx->mask);
+
+	timeout = jiffies + HZ;
+	while (time_before(jiffies, timeout))
+		cpu_relax();
+
+	pr_emerg("Unable to restart system\n");
+}
+
+static int syscon_reboot_probe(struct platform_device *pdev)
+{
+	struct syscon_reboot_context *ctx;
+	struct device *dev = &pdev->dev;
+
+	ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
+	if (!ctx) {
+		dev_err(&pdev->dev, "out of memory for context\n");
+		return -ENOMEM;
+	}
+
+	ctx->map = syscon_regmap_lookup_by_phandle(dev->of_node, "regmap");
+	if (IS_ERR(ctx->map))
+		return PTR_ERR(ctx->map);
+
+	if (of_property_read_u32(pdev->dev.of_node, "offset", &ctx->offset))
+		return -EINVAL;
+
+	if (of_property_read_u32(pdev->dev.of_node, "mask", &ctx->mask))
+		return -EINVAL;
+
+	arm_pm_restart = syscon_restart;
+	syscon_reboot_ctx = ctx;
+
+	return 0;
+}
+
+static struct of_device_id syscon_reboot_of_match[] = {
+	{ .compatible = "syscon-reboot" },
+	{}
+};
+
+static struct platform_driver syscon_reboot_driver = {
+	.probe = syscon_reboot_probe,
+	.driver = {
+		.name = "syscon-reboot",
+		.of_match_table = syscon_reboot_of_match,
+	},
+};
+module_platform_driver(syscon_reboot_driver);
-- 
1.9.1

[PATCH V8 2/6] Documentation: power: reset: Add documentation for generic SYSCON reboot driver

[Feng Kan]

Add documentation for generic SYSCON reboot driver.

Signed-off-by: Feng Kan <fkan@apm.com>
---
 .../bindings/power/reset/syscon-reboot.txt         | 23 ++++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/power/reset/syscon-reboot.txt

diff --git a/Documentation/devicetree/bindings/power/reset/syscon-reboot.txt b/Documentation/devicetree/bindings/power/reset/syscon-reboot.txt
new file mode 100644
index 0000000..1190631
--- /dev/null
+++ b/Documentation/devicetree/bindings/power/reset/syscon-reboot.txt
@@ -0,0 +1,23 @@
+Generic SYSCON mapped register reset driver
+
+This is a generic reset driver using syscon to map the reset register.
+The reset is generally performed with a write to the reset register
+defined by the register map pointed by syscon reference plus the offset
+with the mask defined in the reboot node.
+
+Required properties:
+- compatible: should contain "syscon-reboot"
+- regmap: this is phandle to the register map node
+- offset: offset in the register map for the reboot register (in bytes)
+- mask: the reset value written to the reboot register (32 bit access)
+
+Default will be little endian mode, 32 bit access only.
+
+Examples:
+
+	reboot {
+	   compatible = "syscon-reboot";
+	   regmap = <&regmapnode>;
+	   offset = <0x0>;
+	   mask = <0x1>;
+	};
-- 
1.9.1

[PATCH V8 3/6] Documentation: arm64: add SCU dts binding documentation to linux kernel

[Feng Kan]

This add documentation for the SCU system clock unit device tree binding
to the kernel.

Signed-off-by: Feng Kan <fkan@apm.com>
---
 Documentation/devicetree/bindings/arm/apm/scu.txt | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/arm/apm/scu.txt

diff --git a/Documentation/devicetree/bindings/arm/apm/scu.txt b/Documentation/devicetree/bindings/arm/apm/scu.txt
new file mode 100644
index 0000000..b45be06
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/apm/scu.txt
@@ -0,0 +1,17 @@
+APM X-GENE SoC series SCU Registers
+
+This system clock unit contain various register that control block resets,
+clock enable/disables, clock divisors and other deepsleep registers.
+
+Properties:
+ - compatible : should contain two values. First value must be:
+		   - "apm,xgene-scu"
+		second value must be always "syscon".
+
+ - reg : offset and length of the register set.
+
+Example :
+	scu: system-clk-controller at 17000000 {
+		compatible = "apm,xgene-scu","syscon";
+		reg = <0x0 0x17000000 0x0 0x400>;
+	};
-- 
1.9.1

[PATCH V8 4/6] arm64: dts: Add X-Gene reboot driver dts node

[Feng Kan]

Add X-Gene platform reboot driver dts node.

Signed-off-by: Feng Kan <fkan@apm.com>
---
 arch/arm64/boot/dts/apm-storm.dtsi | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/arm64/boot/dts/apm-storm.dtsi b/arch/arm64/boot/dts/apm-storm.dtsi
index 40aa96c..876952c 100644
--- a/arch/arm64/boot/dts/apm-storm.dtsi
+++ b/arch/arm64/boot/dts/apm-storm.dtsi
@@ -103,6 +103,11 @@
 		#size-cells = <2>;
 		ranges;
 
+		scu: system-clk-controller at 17000000 {
+			compatible = "apm,xgene-scu","syscon";
+			reg = <0x0 0x17000000 0x0 0x400>;
+		};
+
 		clocks {
 			#address-cells = <2>;
 			#size-cells = <2>;
@@ -397,5 +402,12 @@
 			#clock-cells = <1>;
 			clocks = <&rtcclk 0>;
 		};
+
+		reboot: reboot at 17000014 {
+			compatible = "syscon-reboot";
+			regmap = <&scu>;
+			offset = <0x14>;
+			mask = <0x1>;
+		};
 	};
 };
-- 
1.9.1

[PATCH V8 5/6] arm64: Select reboot driver for X-Gene platform

[Feng Kan]

Select reboot driver for X-Gene platform.

Signed-off-by: Feng Kan <fkan@apm.com>
---
 arch/arm64/Kconfig | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index a474de34..91a2e25 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -140,6 +140,8 @@ config ARCH_VEXPRESS
 
 config ARCH_XGENE
 	bool "AppliedMicro X-Gene SOC Family"
+	select MFD_SYSCON
+	select POWER_RESET_SYSCON
 	help
 	  This enables support for AppliedMicro X-Gene SOC Family
 
-- 
1.9.1

[PATCH V8 6/6] power: reset: Remove X-Gene reboot driver

[Feng Kan]

Remove X-Gene reboot driver.

Signed-off-by: Feng Kan <fkan@apm.com>
---
 drivers/power/reset/Kconfig        |   7 ---
 drivers/power/reset/Makefile       |   1 -
 drivers/power/reset/xgene-reboot.c | 103 -------------------------------------
 3 files changed, 111 deletions(-)
 delete mode 100644 drivers/power/reset/xgene-reboot.c

diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
index 5877b38..f548f72 100644
--- a/drivers/power/reset/Kconfig
+++ b/drivers/power/reset/Kconfig
@@ -66,13 +66,6 @@ config POWER_RESET_VEXPRESS
 	  Power off and reset support for the ARM Ltd. Versatile
 	  Express boards.
 
-config POWER_RESET_XGENE
-	bool "APM SoC X-Gene reset driver"
-	depends on ARM64
-	depends on POWER_RESET
-	help
-	  Reboot support for the APM SoC X-Gene Eval boards.
-
 config POWER_RESET_KEYSTONE
 	bool "Keystone reset driver"
 	depends on ARCH_KEYSTONE
diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
index b1b5ab3..62088d8 100644
--- a/drivers/power/reset/Makefile
+++ b/drivers/power/reset/Makefile
@@ -6,6 +6,5 @@ obj-$(CONFIG_POWER_RESET_QNAP) += qnap-poweroff.o
 obj-$(CONFIG_POWER_RESET_RESTART) += restart-poweroff.o
 obj-$(CONFIG_POWER_RESET_SUN6I) += sun6i-reboot.o
 obj-$(CONFIG_POWER_RESET_VEXPRESS) += vexpress-poweroff.o
-obj-$(CONFIG_POWER_RESET_XGENE) += xgene-reboot.o
 obj-$(CONFIG_POWER_RESET_KEYSTONE) += keystone-reset.o
 obj-$(CONFIG_POWER_RESET_SYSCON) += syscon-reboot.o
diff --git a/drivers/power/reset/xgene-reboot.c b/drivers/power/reset/xgene-reboot.c
deleted file mode 100644
index ecd55f8..0000000
--- a/drivers/power/reset/xgene-reboot.c
+++ /dev/null
@@ -1,103 +0,0 @@
-/*
- * AppliedMicro X-Gene SoC Reboot Driver
- *
- * Copyright (c) 2013, Applied Micro Circuits Corporation
- * Author: Feng Kan <fkan@apm.com>
- * Author: Loc Ho <lho@apm.com>
- *
- * 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, or (at your option) any later version.
- *
- * 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.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
- * MA 02111-1307 USA
- *
- * This driver provides system reboot functionality for APM X-Gene SoC.
- * For system shutdown, this is board specify. If a board designer
- * implements GPIO shutdown, use the gpio-poweroff.c driver.
- */
-#include <linux/io.h>
-#include <linux/of_device.h>
-#include <linux/of_address.h>
-#include <linux/platform_device.h>
-#include <linux/stat.h>
-#include <linux/slab.h>
-#include <asm/system_misc.h>
-
-struct xgene_reboot_context {
-	struct platform_device *pdev;
-	void *csr;
-	u32 mask;
-};
-
-static struct xgene_reboot_context *xgene_restart_ctx;
-
-static void xgene_restart(char str, const char *cmd)
-{
-	struct xgene_reboot_context *ctx = xgene_restart_ctx;
-	unsigned long timeout;
-
-	/* Issue the reboot */
-	if (ctx)
-		writel(ctx->mask, ctx->csr);
-
-	timeout = jiffies + HZ;
-	while (time_before(jiffies, timeout))
-		cpu_relax();
-
-	dev_emerg(&ctx->pdev->dev, "Unable to restart system\n");
-}
-
-static int xgene_reboot_probe(struct platform_device *pdev)
-{
-	struct xgene_reboot_context *ctx;
-
-	ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
-	if (!ctx) {
-		dev_err(&pdev->dev, "out of memory for context\n");
-		return -ENODEV;
-	}
-
-	ctx->csr = of_iomap(pdev->dev.of_node, 0);
-	if (!ctx->csr) {
-		devm_kfree(&pdev->dev, ctx);
-		dev_err(&pdev->dev, "can not map resource\n");
-		return -ENODEV;
-	}
-
-	if (of_property_read_u32(pdev->dev.of_node, "mask", &ctx->mask))
-		ctx->mask = 0xFFFFFFFF;
-
-	ctx->pdev = pdev;
-	arm_pm_restart = xgene_restart;
-	xgene_restart_ctx = ctx;
-
-	return 0;
-}
-
-static struct of_device_id xgene_reboot_of_match[] = {
-	{ .compatible = "apm,xgene-reboot" },
-	{}
-};
-
-static struct platform_driver xgene_reboot_driver = {
-	.probe = xgene_reboot_probe,
-	.driver = {
-		.name = "xgene-reboot",
-		.of_match_table = xgene_reboot_of_match,
-	},
-};
-
-static int __init xgene_reboot_init(void)
-{
-	return platform_driver_register(&xgene_reboot_driver);
-}
-device_initcall(xgene_reboot_init);
-- 
1.9.1

[PATCH V8 1/6] power: reset: Add generic SYSCON register mapped reset

[Guenter Roeck]

On 07/08/2014 07:15 PM, Feng Kan wrote:
> Add a generic SYSCON register mapped reset mechanism.
>
> Signed-off-by: Feng Kan <fkan@apm.com>
> ---
>   drivers/power/reset/Kconfig         |  6 +++
>   drivers/power/reset/Makefile        |  1 +
>   drivers/power/reset/syscon-reboot.c | 91 +++++++++++++++++++++++++++++++++++++
>   3 files changed, 98 insertions(+)
>   create mode 100644 drivers/power/reset/syscon-reboot.c
>
> diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
> index bdcf517..5877b38 100644
> --- a/drivers/power/reset/Kconfig
> +++ b/drivers/power/reset/Kconfig
> @@ -80,3 +80,9 @@ config POWER_RESET_KEYSTONE
>   	help
>   	  Reboot support for the KEYSTONE SoCs.
>
> +config POWER_RESET_SYSCON
> +	bool "Generic SYSCON regmap reset driver"
> +	depends on ARM || ARM64 || COMPILE_TEST

As written, this driver is really not generic but very arm specific.
I don't think COMPILE_TEST is a good idea either, since arm_pm_restart
is only defined for the arm architecture. Did you try compiling allmodconfig
or allyesconfig for, say, x86_64 with this patch applied ?

I think this might benefit from using [1], which would make it really
generic.

Guenter

[1] http://www.spinics.net/lists/kernel/msg1780939.html

[PATCH V8 1/6] power: reset: Add generic SYSCON register mapped reset

[Feng Kan]

On Tue, Jul 8, 2014 at 8:54 PM, Guenter Roeck <linux@roeck-us.net> wrote:
> On 07/08/2014 07:15 PM, Feng Kan wrote:
>>
>> Add a generic SYSCON register mapped reset mechanism.
>>
>> Signed-off-by: Feng Kan <fkan@apm.com>
>> ---
>>   drivers/power/reset/Kconfig         |  6 +++
>>   drivers/power/reset/Makefile        |  1 +
>>   drivers/power/reset/syscon-reboot.c | 91
>> +++++++++++++++++++++++++++++++++++++
>>   3 files changed, 98 insertions(+)
>>   create mode 100644 drivers/power/reset/syscon-reboot.c
>>
>> diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
>> index bdcf517..5877b38 100644
>> --- a/drivers/power/reset/Kconfig
>> +++ b/drivers/power/reset/Kconfig
>> @@ -80,3 +80,9 @@ config POWER_RESET_KEYSTONE
>>         help
>>           Reboot support for the KEYSTONE SoCs.
>>
>> +config POWER_RESET_SYSCON
>> +       bool "Generic SYSCON regmap reset driver"
>> +       depends on ARM || ARM64 || COMPILE_TEST
>
>
> As written, this driver is really not generic but very arm specific.
> I don't think COMPILE_TEST is a good idea either, since arm_pm_restart
> is only defined for the arm architecture. Did you try compiling allmodconfig
> or allyesconfig for, say, x86_64 with this patch applied ?
>
> I think this might benefit from using [1], which would make it really
> generic.
>
> Guenter
>
> [1] http://www.spinics.net/lists/kernel/msg1780939.html
This is great, I will base off this list. Did it make it to a branch anywhere?

>

[PATCH V8 1/6] power: reset: Add generic SYSCON register mapped reset

[Guenter Roeck]

On Wed, Jul 09, 2014 at 02:15:44PM -0700, Feng Kan wrote:
> On Tue, Jul 8, 2014 at 8:54 PM, Guenter Roeck <linux@roeck-us.net> wrote:
> > On 07/08/2014 07:15 PM, Feng Kan wrote:
> >>
> >> Add a generic SYSCON register mapped reset mechanism.
> >>
> >> Signed-off-by: Feng Kan <fkan@apm.com>
> >> ---
> >>   drivers/power/reset/Kconfig         |  6 +++
> >>   drivers/power/reset/Makefile        |  1 +
> >>   drivers/power/reset/syscon-reboot.c | 91
> >> +++++++++++++++++++++++++++++++++++++
> >>   3 files changed, 98 insertions(+)
> >>   create mode 100644 drivers/power/reset/syscon-reboot.c
> >>
> >> diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
> >> index bdcf517..5877b38 100644
> >> --- a/drivers/power/reset/Kconfig
> >> +++ b/drivers/power/reset/Kconfig
> >> @@ -80,3 +80,9 @@ config POWER_RESET_KEYSTONE
> >>         help
> >>           Reboot support for the KEYSTONE SoCs.
> >>
> >> +config POWER_RESET_SYSCON
> >> +       bool "Generic SYSCON regmap reset driver"
> >> +       depends on ARM || ARM64 || COMPILE_TEST
> >
> >
> > As written, this driver is really not generic but very arm specific.
> > I don't think COMPILE_TEST is a good idea either, since arm_pm_restart
> > is only defined for the arm architecture. Did you try compiling allmodconfig
> > or allyesconfig for, say, x86_64 with this patch applied ?
> >
> > I think this might benefit from using [1], which would make it really
> > generic.
> >
> > Guenter
> >
> > [1] http://www.spinics.net/lists/kernel/msg1780939.html
> This is great, I will base off this list. Did it make it to a branch anywhere?
> 
Still in review. I hope it will make it into 3.17.
Of course it might be useful if you (and others)
help making the case for it.

Thanks,
Guenter