Add cpuidle driver interface to allow cpus to go into C-States.
Signed-off-by: Lina Iyer <lina.i...@linaro.org>
---
.../devicetree/bindings/arm/msm/qcom,cpuidle.txt | 73 +++++++++++
drivers/cpuidle/Makefile | 1 +
drivers/cpuidle/cpuidle-qcom.c | 140 +++++++++++++++++++++
3 files changed, 214 insertions(+)
create mode 100644 Documentation/devicetree/bindings/arm/msm/qcom,cpuidle.txt
create mode 100644 drivers/cpuidle/cpuidle-qcom.c
diff --git a/Documentation/devicetree/bindings/arm/msm/qcom,cpuidle.txt
b/Documentation/devicetree/bindings/arm/msm/qcom,cpuidle.txt
new file mode 100644
index 0000000..b094baf
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/msm/qcom,cpuidle.txt
@@ -0,0 +1,73 @@
+Qualcomm CPUIdle driver
+
+The Qualcomm cpuidle driver enables the processor to enter low power modes
+when idle. The processors support 4 low power modes.
+ wfi - also known as clock gating
+ retention - processor clock gated and processor power is reduced.
+ standalone-pc - processor is powered down and when reset, the core
+ boots into secure mode and trampolines back to the kernel.
+ Every core can individually enter this low power mode without
+ affecting the state of the other cores.
+ pc - essentially standalone power collapse, but indicates that the
+ latency to put SoC into a low power state is tolerable.
+
+The cpuidle node is comprised of nodes, each of which represent a C-State the
+processor can achieve. Each node provides the latency and residency which
+helps the cpuidle governor to choose the appropriate low power mode based on
+the time available. Not all SoCs may support all the above low power modes.
+
+PROPERTIES
+
+- compatible:
+ Usage: required
+ Value type: <string>
+ Definition: Should be "qcom,cpuidle"
+
+- qcom,cpu-level:
+ Usage: required
+ Value type: { Node }
+ Definition: Describes a C-State of the processor
+
+ PROPERTIES of qcom,cpu-level
+
+ - reg:
+ Usage: required
+ Value type: <integer>
+ Definition: Index of the C-State
+
+ - qcom,state-name:
+ Usage: required
+ Value type: <string>
+ Definition: C-State moniker
+
+ - qcom,spm-cpu-mode:
+ Usage: required
+ Value type: <string>
+ Definition: The description of the h/w mode that will be
+ achieved in this C-State.
+
+ - qcom,latency-us:
+ Usage: required
+ Value type: <integer>
+ Defintion: Time taken to exit from the C-State
+
+ - qcom,residency-us:
+ Usage: required
+ Value type: <integer>
+ Defintion: Time to be spent in this C-State for the power
+ saving to be beneficial.
+
+Example:
+
+ qcom,cpuidle {
+ compatible = "qcom,cpuidle";
+ #address-cells = <1>;
+ #size-cells = <0>;
+ qcom,cpu-level@0 {
+ reg = <0x0>;
+ qcom,state-name = "C1";
+ qcom,spm-cpu-mode = "wfi";
+ qcom,latency-us = <1>;
+ qcom,residency-us = <1>;
+ };
+ };
diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile
index 11edb31..4a2c446 100644
--- a/drivers/cpuidle/Makefile
+++ b/drivers/cpuidle/Makefile
@@ -16,6 +16,7 @@ obj-$(CONFIG_ARM_ZYNQ_CPUIDLE) +=
cpuidle-zynq.o
obj-$(CONFIG_ARM_U8500_CPUIDLE) += cpuidle-ux500.o
obj-$(CONFIG_ARM_AT91_CPUIDLE) += cpuidle-at91.o
obj-$(CONFIG_ARM_EXYNOS_CPUIDLE) += cpuidle-exynos.o
+obj-$(CONFIG_ARM_QCOM_CPUIDLE) += cpuidle-qcom.o
###############################################################################
# MIPS drivers
diff --git a/drivers/cpuidle/cpuidle-qcom.c b/drivers/cpuidle/cpuidle-qcom.c
new file mode 100644
index 0000000..8e70a88
--- /dev/null
+++ b/drivers/cpuidle/cpuidle-qcom.c
@@ -0,0 +1,140 @@
+/* Copyright (c) 2014, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2014 Linaro.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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/module.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+#include <linux/cpuidle.h>
+
+#include <soc/qcom/pm.h>
+
+struct lookup {
+ enum msm_pm_sleep_mode mode;
+ char *name;
+};
+
+static enum msm_pm_sleep_mode spm_sleep_modes[MSM_PM_SLEEP_MODE_NR];
+
+static int qcom_lpm_enter(struct cpuidle_device *dev,
+ struct cpuidle_driver *drv,
+ int index)
+{
+ return msm_cpu_pm_enter_sleep(spm_sleep_modes[index], true);
+}
+
+static struct cpuidle_driver qcom_cpuidle_driver = {
+ .name = "qcom_cpuidle",
+ .owner = THIS_MODULE,
+};
+
+static int qcom_cpuidle_probe(struct platform_device *pdev)
+{
+ int ret;
+ struct device_node *top = pdev->dev.of_node;
+ struct device_node *n;
+ char *key;
+ const char *val;
+ int index = 0;
+ int i;
+ struct cpuidle_state *state;
+ static const struct lookup pm_sm_lookup[] = {
+ {MSM_PM_SLEEP_MODE_WAIT_FOR_INTERRUPT,
+ "wfi"},
+ {MSM_PM_SLEEP_MODE_POWER_COLLAPSE_STANDALONE,
+ "standalone_pc"},
+ {MSM_PM_SLEEP_MODE_POWER_COLLAPSE,
+ "pc"},
+ {MSM_PM_SLEEP_MODE_RETENTION,
+ "retention"},
+ };
+
+ if (!top)
+ return -ENODEV;
+
+ for_each_child_of_node(top, n) {
+ key = "qcom,cpu-level";
+ if (of_node_cmp(n->name, key))
+ continue;
+
+ state = &qcom_cpuidle_driver.states[index];
+
+ key = "qcom,spm-cpu-mode";
+ ret = of_property_read_string(n, key, &val);
+ if (ret)
+ goto failed;
+ for (i = 0; i < ARRAY_SIZE(pm_sm_lookup); i++) {
+ if (!strcmp(val, pm_sm_lookup[i].name)) {
+ spm_sleep_modes[index] = pm_sm_lookup[i].mode;
+ break;
+ }
+ }
+ if (i == ARRAY_SIZE(pm_sm_lookup)) {
+ ret = -EFAULT;
+ goto failed;
+ }
+
+ strncpy(state->desc, val, CPUIDLE_DESC_LEN);
+
+ key = "qcom,state-name";
+ ret = of_property_read_string(n, key, &val);
+ if (ret)
+ goto failed;
+ strncpy(state->name, val, CPUIDLE_NAME_LEN);
+
+ key = "qcom,latency-us";
+ ret = of_property_read_u32(n, key, &state->exit_latency);
+ if (ret)
+ goto failed;
+
+ key = "qcom,residency-us";
+ ret = of_property_read_u32(n, key, &state->target_residency);
+ if (ret)
+ goto failed;
+
+ state->flags = CPUIDLE_FLAG_TIME_VALID;
+ state->enter = qcom_lpm_enter;
+ index++;
+ }
+
+ qcom_cpuidle_driver.state_count = index;
+ qcom_cpuidle_driver.safe_state_index = 0;
+
+ ret = cpuidle_register(&qcom_cpuidle_driver, NULL);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to register cpuidle driver\n");
+ return ret;
+ }
+
+ return 0;
+
+failed:
+ dev_err(&pdev->dev, "error parsing key: %s\n", key);
+ return ret;
+}
+
+static struct of_device_id qcom_cpuidle_match_tbl[] = {
+ {.compatible = "qcom,cpuidle"},
+ {},
+};
+
+static struct platform_driver qcom_cpuidle_platform_driver = {
+ .probe = qcom_cpuidle_probe,
+ .driver = {
+ .name = "qcom,cpuidle",
+ .owner = THIS_MODULE,
+ .of_match_table = qcom_cpuidle_match_tbl,
+ },
+};
+
+module_platform_driver(qcom_cpuidle_platform_driver);
--
1.9.1
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