[PATCH v2 0/2] Add cpuidle driver for Sunplus SP7021

[PATCH v2 0/2] Add cpuidle driver for Sunplus SP7021

[Edwin Chiu]

This is a patch series for cpuidle driver for Sunplus SP7021 SoC.

Sunplus SP7021 is an ARM Cortex A7 (4 cores) based SoC. It integrates
many peripherals (ex: UART, I2C, SPI, SDIO, eMMC, USB, SD card and 
etc.) into a single chip. It is designed for industrial control.

Refer to:
https://sunplus-tibbo.atlassian.net/wiki/spaces/doc/overview
https://tibbo.com/store/plus1.html

Edwin Chiu (2):
  dt-bingings:arm:sunplus:add sp7021 compatible string to
    sunplus,idle-state.yaml
  cpuidle:sunplus:create cpuidle driver for sunplus sp7021

 .../bindings/arm/sunplus/sunplus,idle-state.yaml   |  55 +++++++
 MAINTAINERS                                        |   9 ++
 drivers/cpuidle/Kconfig.arm                        |   7 +
 drivers/cpuidle/Makefile                           |   1 +
 drivers/cpuidle/cpuidle-sunplus.c                  | 180 +++++++++++++++++++++
 include/linux/platform_data/cpuidle-sunplus.h      |  13 ++
 6 files changed, 265 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/arm/sunplus/sunplus,idle-state.yaml
 create mode 100644 drivers/cpuidle/cpuidle-sunplus.c
 create mode 100644 include/linux/platform_data/cpuidle-sunplus.h

-- 
2.7.4

[PATCH v2 1/2] dt-bingings:arm:sunplus:add sp7021 compatible string to sunplus,idle-state.yaml

[Edwin Chiu]

Add the compatible string for cpuidle state on sp7021

Signed-off-by: Edwin Chiu <edwinchiu0505tw@gmail.com>
---
Changes in v2
 - Align email address of sob and sender

 .../bindings/arm/sunplus/sunplus,idle-state.yaml   | 55 ++++++++++++++++++++++
 MAINTAINERS                                        |  5 ++
 2 files changed, 60 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/arm/sunplus/sunplus,idle-state.yaml

diff --git a/Documentation/devicetree/bindings/arm/sunplus/sunplus,idle-state.yaml b/Documentation/devicetree/bindings/arm/sunplus/sunplus,idle-state.yaml
new file mode 100644
index 0000000..649e953
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/sunplus/sunplus,idle-state.yaml
@@ -0,0 +1,55 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright (C) Sunplus Co., Ltd. 2021
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/arm/sunplus/sunplus,idle-state.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Sunplus cpuidle state
+
+maintainers:
+  - edwin.chiu <edwin.chiu@sunplus.com>
+
+description: |
+  Sunplus SOC cpuidle state
+
+properties:
+  compatible:
+    const: arm,idle-state
+
+  entry-latency-us:
+    description:
+      Worst case latency in microseconds required to enter the idle state.
+
+  exit-latency-us:
+    description:
+      Worst case latency in microseconds required to exit the idle state.
+      The exit-latency-us duration may be guaranteed only after
+      entry-latency-us has passed.
+
+  min-residency-us:
+    description:
+      Minimum residency duration in microseconds, inclusive of preparation
+      and entry, for this idle state to be considered worthwhile energy wise
+      (refer to section 2 of this document for a complete description).
+
+required:
+  - compatible
+  - entry-latency-us
+  - exit-latency-us
+  - min-residency-us
+
+additionalProperties: true
+
+examples:
+  - |
+    idle-states {
+      CLUSTER_SLEEP_BIG: cluster-sleep-big {
+        compatible = "arm,idle-state";
+        entry-latency-us = <8000>;
+        exit-latency-us = <700>;
+        min-residency-us = <9000>;
+      };
+    };
+
+...
diff --git a/MAINTAINERS b/MAINTAINERS
index 3b79fd4..41957c7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17945,6 +17945,11 @@ L:	netdev@vger.kernel.org
 S:	Maintained
 F:	drivers/net/ethernet/dlink/sundance.c
 
+SUNPLUS CPUIDLE DRIVER
+M:	Edwin Chiu <edwinchiu0505tw@gmail.com>
+S:	Maintained
+F:	Documentation/devicetree/bindings/arm/sunplus/sunplus,idle-state.yaml
+
 SUPERH
 M:	Yoshinori Sato <ysato@users.sourceforge.jp>
 M:	Rich Felker <dalias@libc.org>
-- 
2.7.4

[PATCH v2 2/2] cpuidle:sunplus:create cpuidle driver for sunplus sp7021

[Edwin Chiu]

Create cpuidle driver for sunplus sp7021 chip

Signed-off-by: Edwin Chiu <edwinchiu0505tw@gmail.com>
---
Changes in v2
 - Rearrangement #include sequence
 - Change // to /*~*/
 - Align author email address to same as sob

 MAINTAINERS                                   |   4 +
 drivers/cpuidle/Kconfig.arm                   |   7 +
 drivers/cpuidle/Makefile                      |   1 +
 drivers/cpuidle/cpuidle-sunplus.c             | 180 ++++++++++++++++++++++++++
 include/linux/platform_data/cpuidle-sunplus.h |  13 ++
 5 files changed, 205 insertions(+)
 create mode 100644 drivers/cpuidle/cpuidle-sunplus.c
 create mode 100644 include/linux/platform_data/cpuidle-sunplus.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 41957c7..c5eab79 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17949,6 +17949,10 @@ SUNPLUS CPUIDLE DRIVER
 M:	Edwin Chiu <edwinchiu0505tw@gmail.com>
 S:	Maintained
 F:	Documentation/devicetree/bindings/arm/sunplus/sunplus,idle-state.yaml
+F:	drivers/cpuidle/Kconfig.arm
+F:	drivers/cpuidle/Makefile
+F:	drivers/cpuidle/cpuidle-sunplus.c
+F:	include/linux/platform_data/cpuidle-sunplus.h
 
 SUPERH
 M:	Yoshinori Sato <ysato@users.sourceforge.jp>
diff --git a/drivers/cpuidle/Kconfig.arm b/drivers/cpuidle/Kconfig.arm
index 334f83e..ad9956c 100644
--- a/drivers/cpuidle/Kconfig.arm
+++ b/drivers/cpuidle/Kconfig.arm
@@ -117,3 +117,10 @@ config ARM_QCOM_SPM_CPUIDLE
 	  The Subsystem Power Manager (SPM) controls low power modes for the
 	  CPU and L2 cores. It interface with various system drivers to put
 	  the cores in low power modes.
+
+config ARM_SUNPLUS_CPUIDLE
+	bool "CPU Idle Driver For SUNPLUS SoCs"
+	depends on !ARM64
+	select DT_IDLE_STATES
+	help
+	  Select this to enable cpuidle on SP7021 processors.
diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile
index 26bbc5e..0a020d1 100644
--- a/drivers/cpuidle/Makefile
+++ b/drivers/cpuidle/Makefile
@@ -25,6 +25,7 @@ obj-$(CONFIG_ARM_PSCI_CPUIDLE)		+= cpuidle-psci.o
 obj-$(CONFIG_ARM_PSCI_CPUIDLE_DOMAIN)	+= cpuidle-psci-domain.o
 obj-$(CONFIG_ARM_TEGRA_CPUIDLE)		+= cpuidle-tegra.o
 obj-$(CONFIG_ARM_QCOM_SPM_CPUIDLE)	+= cpuidle-qcom-spm.o
+obj-$(CONFIG_ARM_SUNPLUS_CPUIDLE)		+= cpuidle-sunplus.o
 
 ###############################################################################
 # MIPS drivers
diff --git a/drivers/cpuidle/cpuidle-sunplus.c b/drivers/cpuidle/cpuidle-sunplus.c
new file mode 100644
index 0000000..88671e6
--- /dev/null
+++ b/drivers/cpuidle/cpuidle-sunplus.c
@@ -0,0 +1,180 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ARM/ARM64 generic CPU idle driver.
+ *
+ */
+#define pr_fmt(fmt) "CPUidle arm: " fmt
+
+#include <asm/suspend.h>
+#include <linux/cpu_cooling.h>
+#include <linux/cpuidle.h>
+#include <linux/cpumask.h>
+#include <linux/cpu_pm.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+#include <linux/platform_data/cpuidle-sunplus.h>
+
+#include "dt_idle_states.h"
+
+static int sp7021_wfi_finisher(unsigned long flags)
+{
+	cpu_v7_do_idle();   /* idle to WFI */
+
+	return -1;
+}
+
+static int sp7021_enter_idle_state(struct cpuidle_device *dev,
+				struct cpuidle_driver *drv, int idx)
+{
+	int ret;
+
+  /* if idx=0, call cpu_do_idle() */
+	if (!idx) {
+		cpu_v7_do_idle();
+		return idx;
+	}
+
+	/* if idx>0, call cpu_suspend() */
+	ret = cpu_pm_enter();
+	if (!ret) {
+	/*
+	 * Pass idle state index to cpuidle_suspend which in turn
+	 * will call the CPU ops suspend protocol with idle index as a
+	 * parameter.
+	 */
+		ret = cpu_suspend(idx, sp7021_wfi_finisher);
+	}
+	cpu_pm_exit();
+
+	return ret ? -1:idx;
+}
+
+static struct cpuidle_driver sp7021_idle_driver __initdata = {
+	.name = "sp7021_idle",
+	.owner = THIS_MODULE,
+	/*
+	 * State at index 0 is standby wfi and considered standard
+	 * on all ARM platforms. If in some platforms simple wfi
+	 * can't be used as "state 0", DT bindings must be implemented
+	 * to work around this issue and allow installing a special
+	 * handler for idle state index 0.
+	 */
+	.states[0] = {
+		.enter                  = sp7021_enter_idle_state,
+		.exit_latency           = 1,
+		.target_residency       = 1,
+		.power_usage		= UINT_MAX,
+		.name                   = "WFI",
+		.desc                   = "ARM WFI",
+	}
+};
+
+static const struct of_device_id sp7021_idle_state_match[] __initconst = {
+	{ .compatible = "arm,idle-state",
+		.data = sp7021_enter_idle_state },
+	{ },
+};
+
+/*
+ * arm_idle_init - Initializes arm cpuidle driver
+ *
+ * Initializes arm cpuidle driver for all CPUs, if any CPU fails
+ * to register cpuidle driver then rollback to cancel all CPUs
+ * registration.
+ */
+static int __init sp7021_idle_init(void)
+{
+	int cpu, ret;
+	struct cpuidle_driver *drv;
+	struct cpuidle_device *dev;
+
+	drv = kmemdup(&sp7021_idle_driver, sizeof(*drv), GFP_KERNEL);
+	if (!drv)
+		return -ENOMEM;
+
+	drv->cpumask = (struct cpumask *)cpumask_of(cpu);
+	/*
+	 * Initialize idle states data, starting at index 1.  This
+	 * driver is DT only, if no DT idle states are detected (ret
+	 * == 0) let the driver initialization fail accordingly since
+	 * there is no reason to initialize the idle driver if only
+	 * wfi is supported.
+	 */
+	ret = dt_init_idle_driver(drv, sp7021_idle_state_match, 1);
+	if (ret <= 0)
+		return ret ? : -ENODEV;
+
+	ret = cpuidle_register_driver(drv);
+	if (ret) {
+		pr_err("Failed to register cpuidle driver\n");
+		return ret;
+	}
+
+	/*
+	 * Call arch CPU operations in order to initialize
+	 * idle states suspend back-end specific data
+	 */
+	for_each_possible_cpu(cpu) {
+		/*
+		 * Skip the cpuidle device initialization if the reported
+		 * failure is a HW misconfiguration/breakage (-ENXIO)
+		 */
+		if (ret == -ENXIO)
+			continue;
+
+		if (ret) {
+			pr_err("CPU %d failed to init idle CPU ops\n", cpu);
+			goto out_fail;
+		}
+		dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+		if (!dev) {
+			ret = -ENOMEM;
+			goto out_fail;
+		}
+		dev->cpu = cpu;
+
+		ret = cpuidle_register_device(dev);
+		if (ret) {
+			pr_err("Failed to register cpuidle device for CPU %d\n", cpu);
+			kfree(dev);
+			goto out_fail;
+		}
+	}
+
+	return 0;
+
+out_fail:
+	while (--cpu >= 0) {
+		dev = per_cpu(cpuidle_devices, cpu);
+		cpuidle_unregister_device(dev);
+		kfree(dev);
+	}
+	cpuidle_unregister_driver(drv);
+
+	return ret;
+}
+
+static int __init idle_init(void)
+{
+	int ret;
+
+	if (of_machine_is_compatible("sunplus,sp7021-achip")) {
+		sp7021_idle_init();
+		ret = 0;
+	}	else
+		ret = -1;
+
+	if (ret) {
+		pr_err("failed to cpuidle init\n");
+		return ret;
+	}
+
+	return ret;
+}
+device_initcall(idle_init);
+
+MODULE_AUTHOR("Edwin Chiu <edwinchiu0505tw@gmail.com>");
+MODULE_DESCRIPTION("Sunplus sp7021 cpuidle driver");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/platform_data/cpuidle-sunplus.h b/include/linux/platform_data/cpuidle-sunplus.h
new file mode 100644
index 0000000..d63efad
--- /dev/null
+++ b/include/linux/platform_data/cpuidle-sunplus.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __CPUIDLE_SP7021_H
+#define __CPUIDLE_SP7021_H
+
+extern int cpu_v7_do_idle(void);
+
+#endif
-- 
2.7.4

Re: [PATCH v2 0/2] Add cpuidle driver for Sunplus SP7021

[Daniel Lezcano]

Hi Edwin,

sorry but I don't get the series. The bindings and the generic cpuidle
should already take into account the idle path.

Did I miss something ?


On 20/12/2021 06:37, Edwin Chiu wrote:
> This is a patch series for cpuidle driver for Sunplus SP7021 SoC.
> 
> Sunplus SP7021 is an ARM Cortex A7 (4 cores) based SoC. It integrates
> many peripherals (ex: UART, I2C, SPI, SDIO, eMMC, USB, SD card and 
> etc.) into a single chip. It is designed for industrial control.
> 
> Refer to:
> https://sunplus-tibbo.atlassian.net/wiki/spaces/doc/overview
> https://tibbo.com/store/plus1.html
> 
> Edwin Chiu (2):
>   dt-bingings:arm:sunplus:add sp7021 compatible string to
>     sunplus,idle-state.yaml
>   cpuidle:sunplus:create cpuidle driver for sunplus sp7021
> 
>  .../bindings/arm/sunplus/sunplus,idle-state.yaml   |  55 +++++++
>  MAINTAINERS                                        |   9 ++
>  drivers/cpuidle/Kconfig.arm                        |   7 +
>  drivers/cpuidle/Makefile                           |   1 +
>  drivers/cpuidle/cpuidle-sunplus.c                  | 180 +++++++++++++++++++++
>  include/linux/platform_data/cpuidle-sunplus.h      |  13 ++
>  6 files changed, 265 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/arm/sunplus/sunplus,idle-state.yaml
>  create mode 100644 drivers/cpuidle/cpuidle-sunplus.c
>  create mode 100644 include/linux/platform_data/cpuidle-sunplus.h
> 


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Re: [PATCH v2 2/2] cpuidle:sunplus:create cpuidle driver for sunplus sp7021

[Sudeep Holla]

On Mon, Dec 20, 2021 at 01:37:32PM +0800, Edwin Chiu wrote:
> Create cpuidle driver for sunplus sp7021 chip
> 

Based on the driver here, I couldn't understand why you can't make use of
existing cpuidle-arm.c driver

-- 
Regards,
Sudeep

RE: [PATCH v2 2/2] cpuidle:sunplus:create cpuidle driver for sunplus sp7021

[Edwin Chiu 邱垂峰]

Hi Sudeep and Daniel:

Thanks your response.
My CPU is arm CA7 that is 32bits cpu.
If I directly used cpuidle-arm.c function with enable "Generic ARM/ARM64 CPU idle Driver",
the cpuidle driver mount fail with "unsupported enable-method property".

This is due to linux kernel no invoke CPUIDLE_METHOD_OF_DECLARE for arm 32bits cpu.
There have no define cpuidle_ops.init and cpuidle_ops.suspend function for arm 32bits cpu too.

So I create cpuidle-sunplus.c to execute my cpuidle function.
Please correct me if I got mistake.


邱垂峰 EdwinChiu
智能運算專案
T: +886-3-5786005 ext.2590
edwin.chiu@sunplus.com
300 新竹科學園區創新一路19號

> -----Original Message-----
> From: Sudeep Holla <sudeep.holla@arm.com>
> Sent: Monday, December 20, 2021 8:11 PM
> To: Edwin Chiu <edwinchiu0505tw@gmail.com>
> Cc: robh+dt@kernel.org; Edwin Chiu 邱垂峰 <edwin.chiu@sunplus.com>; devicetree@vger.kernel.org;
> linux-kernel@vger.kernel.org; rafael@kernel.org; Sudeep Holla <sudeep.holla@arm.com>;
> daniel.lezcano@linaro.org; linux-pm@vger.kernel.org
> Subject: Re: [PATCH v2 2/2] cpuidle:sunplus:create cpuidle driver for sunplus sp7021
> 
> On Mon, Dec 20, 2021 at 01:37:32PM +0800, Edwin Chiu wrote:
> > Create cpuidle driver for sunplus sp7021 chip
> >
> 
> Based on the driver here, I couldn't understand why you can't make use of existing cpuidle-arm.c driver
> 
> --
> Regards,
> Sudeep