[RFC,07/13] qcom: sleep-status: Add ability to recognize cpu power down state

diff --git a/Documentation/devicetree/bindings/arm/msm/qcom,cpu-sleep-status.txt b/Documentation/devicetree/bindings/arm/msm/qcom,cpu-sleep-status.txt
new file mode 100644
index 0000000..3d2974e
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/msm/qcom,cpu-sleep-status.txt
@@ -0,0 +1,41 @@ 
+* MSM Sleep Status
+
+MSM Sleep status device is used to check the power collapsed status of a
+offlined core. The core that initiates the hotplug would wait on the
+sleep status device before CPU_DEAD notifications are sent out. Some hardware
+devices require that the offlined core is power collapsed before turning off
+the resources that are used by the offlined core.
+
+
+PROPERTIES
+
+- compatible:
+	Usage: required
+	Value type: <string>
+	Definition: Should be "qcom,cpu-sleep-status"
+
+- reg:
+	Usage: required
+	Value type: <register address>
+	Definition: The physical address of the sleep status register for
+	core0, the second element is the size of the register.
+
+- qcom,cpu-alias-addr:
+	Usage: required
+	Value type: <integer>
+	Definition: On MSM chipset, the each cores registers are at a
+	fixed offset each other.
+
+- qcom,cpu-sleep-status-mask:
+	Usage: required
+	Value type: <integer>
+	Definition: The bit mask within the status register that
+	indicates the Core's sleep state.
+
+Example:
+	qcom,cpu-sleep-status@f9088008 {
+		compatible = "qcom,cpu-sleep-status";
+		reg = <0xf9088008 0x4>;
+		qcom,cpu-alias-addr = <0x10000>;
+		qcom,sleep-status-mask = <0x80000>;
+	};
diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index 87c3b9704..d2cc9c0 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -1,5 +1,5 @@ 
 obj-$(CONFIG_QCOM_GSBI)	+=	qcom_gsbi.o
-obj-$(CONFIG_QCOM_PM) +=	spm_devices.o spm.o msm-pm.o
+obj-$(CONFIG_QCOM_PM) +=	spm_devices.o spm.o msm-pm.o sleep-status.o
 
 CFLAGS_scm.o :=$(call as-instr,.arch_extension sec,-DREQUIRES_SEC=1)
 obj-$(CONFIG_QCOM_SCM) += scm.o scm-boot.o
diff --git a/drivers/soc/qcom/sleep-status.c b/drivers/soc/qcom/sleep-status.c
new file mode 100644
index 0000000..aa6340c
--- /dev/null
+++ b/drivers/soc/qcom/sleep-status.c
@@ -0,0 +1,178 @@ 
+/* Copyright (c) 2010-2014, The Linux Foundation. All rights reserved.
+ *
+ * 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/kernel.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/of_platform.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+
+#include <soc/qcom/spm.h>
+#include <soc/qcom/pm.h>
+
+struct msm_pm_sleep_status_data {
+	void *base_addr;
+	uint32_t cpu_offset;
+	uint32_t mask;
+};
+
+static struct msm_pm_sleep_status_data *msm_pm_slp_sts;
+
+/**
+ * msm_pm_wait_cpu_shutdown() - Wait for a core to be power collapsed during
+ *				hotplug
+ *
+ * @ cpu - cpu to wait on.
+ *
+ * Blocking function call that waits on the core to be power collapsed. This
+ * function is called from platform_cpu_die to ensure that a core is power
+ * collapsed before sending the CPU_DEAD notification so the drivers could
+ * remove the resource votes for this CPU(regulator and clock)
+ */
+int msm_pm_wait_cpu_shutdown(unsigned int cpu)
+{
+	int timeout = 0;
+
+	if (!msm_pm_slp_sts)
+		return 0;
+
+	if (!msm_pm_slp_sts[cpu].base_addr)
+		return 0;
+
+	while (1) {
+		/*
+		 * Check for the SPM of the core being hotplugged to set
+		 * its sleep state.The SPM sleep state indicates that the
+		 * core has been power collapsed.
+		 */
+		int acc_sts = __raw_readl(msm_pm_slp_sts[cpu].base_addr);
+
+		if (acc_sts & msm_pm_slp_sts[cpu].mask)
+			return 0;
+
+		udelay(100);
+		/*
+		 * Dump spm registers for debugging
+		 */
+		if (++timeout == 20) {
+			msm_spm_dump_regs(cpu);
+			__WARN_printf(
+			"CPU%u didn't collapse in 2ms, sleep status: 0x%x\n",
+					cpu, acc_sts);
+		}
+	}
+
+	return -EBUSY;
+}
+
+static int msm_cpu_status_probe(struct platform_device *pdev)
+{
+	struct msm_pm_sleep_status_data *pdata;
+	char *key;
+	u32 cpu;
+
+	if (!pdev)
+		return -EFAULT;
+
+	msm_pm_slp_sts = devm_kcalloc(&pdev->dev, num_possible_cpus(),
+					sizeof(*msm_pm_slp_sts), GFP_KERNEL);
+
+	if (!msm_pm_slp_sts)
+		return -ENOMEM;
+
+	if (pdev->dev.of_node) {
+		struct resource *res;
+		u32 offset;
+		int rc;
+		u32 mask;
+		bool offset_available = true;
+
+		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+		if (!res)
+			return -ENODEV;
+
+		key = "qcom,cpu-alias-addr";
+		rc = of_property_read_u32(pdev->dev.of_node, key, &offset);
+
+		if (rc)
+			offset_available = false;
+
+		key = "qcom,sleep-status-mask";
+		rc = of_property_read_u32(pdev->dev.of_node, key, &mask);
+
+		if (rc)
+			return -ENODEV;
+
+		for_each_possible_cpu(cpu) {
+			phys_addr_t base_c;
+
+			if (offset_available)
+				base_c = res->start + cpu * offset;
+			else {
+				res = platform_get_resource(pdev,
+							IORESOURCE_MEM, cpu);
+				if (!res)
+					return -ENODEV;
+				base_c = res->start;
+			}
+
+			msm_pm_slp_sts[cpu].base_addr =
+				devm_ioremap(&pdev->dev, base_c,
+						resource_size(res));
+			msm_pm_slp_sts[cpu].mask = mask;
+
+			if (!msm_pm_slp_sts[cpu].base_addr)
+				return -ENOMEM;
+		}
+	} else {
+		pdata = pdev->dev.platform_data;
+		if (!pdev->dev.platform_data)
+			return -EINVAL;
+
+		for_each_possible_cpu(cpu) {
+			msm_pm_slp_sts[cpu].base_addr =
+				pdata->base_addr + cpu * pdata->cpu_offset;
+			msm_pm_slp_sts[cpu].mask = pdata->mask;
+		}
+	}
+
+	return 0;
+};
+
+static struct of_device_id msm_slp_sts_match_tbl[] = {
+	{.compatible = "qcom,cpu-sleep-status"},
+	{},
+};
+
+static struct platform_driver msm_cpu_status_driver = {
+	.probe = msm_cpu_status_probe,
+	.driver = {
+		.name = "qcom,cpu-sleep-status",
+		.owner = THIS_MODULE,
+		.of_match_table = msm_slp_sts_match_tbl,
+	},
+};
+
+int __init msm_pm_sleep_status_init(void)
+{
+	static bool registered;
+
+	if (registered)
+		return 0;
+	registered = true;
+
+	return platform_driver_register(&msm_cpu_status_driver);
+}
+arch_initcall(msm_pm_sleep_status_init);
diff --git a/include/soc/qcom/pm.h b/include/soc/qcom/pm.h
index ed6124a..3de04b8 100644
--- a/include/soc/qcom/pm.h
+++ b/include/soc/qcom/pm.h
@@ -32,12 +32,14 @@  enum msm_pm_l2_scm_flag {
 bool msm_cpu_pm_enter_sleep(enum msm_pm_sleep_mode mode, bool from_idle);
 int msm_pm_cpu_hotplug_enter(unsigned int cpu);
 int msm_pm_secondary_startup(unsigned int cpu);
+int msm_pm_wait_cpu_shutdown(unsigned int cpu);
 #else
 static inline bool msm_cpu_pm_enter_sleep(enum msm_pm_sleep_mode mode,
 						bool from_idle)
 { return true; }
 static inline int msm_pm_cpu_hotplug_enter(unsigned int cpu) { return 0; }
 static inline int msm_pm_secondary_startup(unsigned int cpu) { return 0; }
+static inline int msm_pm_wait_cpu_shutdown(unsigned int cpu) { return 0; }
 #endif
 
 #endif  /* __QCOM_PM_H */