soc: qcom: Add support for Cx iPeak limit driver

Implement common driver to limit Cx ipeak based on
voting from various clients in multimedia.

Change-Id: Ie0a57e49f7a8ba8a4fa3aa7f50dd0947f8e9d11b
Signed-off-by: Rajesh Kemisetti <rajeshk@codeaurora.org>
Signed-off-by: samit vats <svats@codeaurora.org>

Documentation/devicetree/bindings/soc/qcom/qcom,cx_ipeak.txt

@@ -0,0 +1,22 @@
+* Cx iPeak driver to handle requests from various multimedia clients.
+
+Cx ipeak HW module is used to limit the current drawn by various subsystem
+blocks on Cx power rail. Each client needs to set their
+bit in tcsr register if it is going to cross its own threshold. If all
+clients are going to cross their thresholds then Cx ipeak hw module will raise
+an interrupt to cDSP block to throttle cDSP's fmax.
+
+Required properties:
+
+- compatible : name of the component used for driver matching, should be
+	       "qcom,cx-ipeak-sdm660"
+
+- reg : physical base address and length of the register set(s), SRAM and XPU
+	of the component.
+
+Example:
+
+	cx_ipeak_lm: cx_ipeak@1fe5040 {
+		compatible = "qcom,cx-ipeak-sdm660";
+		reg = <0x01fe5040 0x28>;
+	};

drivers/soc/qcom/Kconfig

@@ -787,4 +787,13 @@ config QCOM_CDSP_RM
 	  improving CDSP performance. Using this driver, CDSP can set appropriate
 	  CPU L3 clock for improving IO-Coherent throughput and opt for QoS mode
 	  to improve RPC latency.
+
+config QCOM_CX_IPEAK
+	bool "Common driver to handle Cx iPeak limitation"
+	help
+	  Cx ipeak HW module is used to limit the current drawn by various subsystem
+	  blocks on Cx power rail. Each client needs to set their
+	  bit in tcsr register if it is going to cross its own threshold. If all
+	  clients are going to cross their thresholds then Cx ipeak hw module will raise
+	  an interrupt to cDSP block to throttle cDSP fmax.
 endmenu

drivers/soc/qcom/Makefile

@@ -92,3 +92,4 @@ endif
 obj-$(CONFIG_QCOM_SMP2P_SLEEPSTATE) += smp2p_sleepstate.o
 obj-$(CONFIG_QCOM_MEM_OFFLINE) += mem-offline.o
 obj-$(CONFIG_QCOM_CDSP_RM) += cdsprm.o
+obj-$(CONFIG_QCOM_CX_IPEAK) += cx_ipeak.o

drivers/soc/qcom/cx_ipeak.c

@@ -0,0 +1,202 @@
+/* Copyright (c) 2018, 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/io.h>
+#include <linux/iopoll.h>
+#include <linux/printk.h>
+#include <linux/spinlock.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+
+#include <soc/qcom/cx_ipeak.h>
+
+#define TCSR_CXIP_LM_VOTE_BYPASS_OFFSET                 0x4
+#define TCSR_CXIP_LM_VOTE_CLEAR_OFFSET                  0x8
+#define TCSR_CXIP_LM_VOTE_SET_OFFSET                    0xC
+#define TCSR_CXIP_LM_VOTE_FEATURE_ENABLE_OFFSET         0x10
+#define TCSR_CXIP_LM_TRS_OFFSET                         0x24
+
+#define CXIP_POLL_TIMEOUT_US (50 * 1000)
+
+static struct cx_ipeak_device {
+	spinlock_t vote_lock;
+	void __iomem *tcsr_vptr;
+} device_ipeak;
+
+struct cx_ipeak_client {
+	int vote_count;
+	unsigned int vote_mask;
+	struct cx_ipeak_device *dev;
+};
+
+/**
+ * cx_ipeak_register() - allocate client structure and fill device private and
+ *			bit details.
+ * @dev_node: device node of the client
+ * @client_name: property name of the client
+ *
+ * Allocate client memory and fill the structure with device private and bit
+ *
+ */
+struct cx_ipeak_client *cx_ipeak_register(struct device_node *dev_node,
+		const char *client_name)
+{
+	struct of_phandle_args cx_spec;
+	struct cx_ipeak_client *client;
+	unsigned int reg_enable, reg_bypass;
+	int ret;
+
+	ret = of_parse_phandle_with_fixed_args(dev_node, client_name,
+			1, 0, &cx_spec);
+	if (ret)
+		return ERR_PTR(-EINVAL);
+
+	if (!of_device_is_available(cx_spec.np))
+		return NULL;
+
+	if (device_ipeak.tcsr_vptr == NULL)
+		return ERR_PTR(-EPROBE_DEFER);
+
+	if (cx_spec.args[0] > 31)
+		return ERR_PTR(-EINVAL);
+
+	reg_enable = readl_relaxed(device_ipeak.tcsr_vptr +
+			TCSR_CXIP_LM_VOTE_FEATURE_ENABLE_OFFSET);
+	reg_bypass = readl_relaxed(device_ipeak.tcsr_vptr +
+			TCSR_CXIP_LM_VOTE_BYPASS_OFFSET) &
+			BIT(cx_spec.args[0]);
+
+	if (!reg_enable || reg_bypass)
+		return NULL;
+
+	client = kzalloc(sizeof(struct cx_ipeak_client), GFP_KERNEL);
+	if (!client)
+		return ERR_PTR(-ENOMEM);
+
+	client->vote_mask = BIT(cx_spec.args[0]);
+	client->dev = &device_ipeak;
+
+	return client;
+}
+EXPORT_SYMBOL(cx_ipeak_register);
+
+/**
+ * cx_ipeak_unregister() - unregister client
+ * @client: client address to free
+ *
+ * Free the client memory
+ */
+void cx_ipeak_unregister(struct cx_ipeak_client *client)
+{
+	kfree(client);
+}
+EXPORT_SYMBOL(cx_ipeak_unregister);
+
+/*
+ * cx_ipeak_update() - Set/Clear client vote for Cx iPeak limit
+ * manager to throttle cDSP.
+ * @client: client handle.
+ * @vote: True to set the vote and False for reset.
+ *
+ * Receives vote from each client and decides whether to throttle cDSP or not.
+ * This function is NOP for the targets which does not support TCSR Cx iPeak.
+ */
+int cx_ipeak_update(struct cx_ipeak_client *client, bool vote)
+{
+	unsigned int reg_val;
+	int ret = 0;
+
+	/* Check for client and device availability and proceed */
+	if (client == NULL || client->dev->tcsr_vptr == NULL)
+		return ret;
+
+	spin_lock(&client->dev->vote_lock);
+
+	if (vote) {
+		if (client->vote_count == 0) {
+			writel_relaxed(client->vote_mask,
+				client->dev->tcsr_vptr +
+				TCSR_CXIP_LM_VOTE_SET_OFFSET);
+
+			/*
+			 * Do a dummy read to give enough time for TRS register
+			 * to become 1 when the last client votes.
+			 */
+			readl_relaxed(client->dev->tcsr_vptr +
+				TCSR_CXIP_LM_TRS_OFFSET);
+
+			ret = readl_poll_timeout(client->dev->tcsr_vptr +
+				TCSR_CXIP_LM_TRS_OFFSET, reg_val, !reg_val,
+				0, CXIP_POLL_TIMEOUT_US);
+			if (ret) {
+				writel_relaxed(client->vote_mask,
+					client->dev->tcsr_vptr +
+					TCSR_CXIP_LM_VOTE_CLEAR_OFFSET);
+				goto done;
+			}
+		}
+		client->vote_count++;
+	} else {
+		if (client->vote_count > 0) {
+			client->vote_count--;
+			if (client->vote_count == 0) {
+				writel_relaxed(client->vote_mask,
+					client->dev->tcsr_vptr +
+					TCSR_CXIP_LM_VOTE_CLEAR_OFFSET);
+			}
+		} else
+			ret = -EINVAL;
+	}
+
+done:
+	spin_unlock(&client->dev->vote_lock);
+	return ret;
+}
+EXPORT_SYMBOL(cx_ipeak_update);
+
+static int cx_ipeak_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	device_ipeak.tcsr_vptr = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(device_ipeak.tcsr_vptr))
+		return PTR_ERR(device_ipeak.tcsr_vptr);
+
+	spin_lock_init(&device_ipeak.vote_lock);
+	return 0;
+}
+
+static const struct of_device_id cx_ipeak_match_table[] = {
+	{ .compatible = "qcom,cx-ipeak-sdm660"},
+	{}
+};
+
+static struct platform_driver cx_ipeak_platform_driver = {
+	.probe = cx_ipeak_probe,
+	.driver = {
+		.name  = "cx_ipeak",
+		.of_match_table = cx_ipeak_match_table,
+		.suppress_bind_attrs = true,
+	}
+};
+
+static int __init cx_ipeak_init(void)
+{
+	return platform_driver_register(&cx_ipeak_platform_driver);
+}
+
+arch_initcall(cx_ipeak_init);

include/soc/qcom/cx_ipeak.h

@@ -0,0 +1,46 @@
+/* Copyright (c) 2018, 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.
+ */
+
+#ifndef __SOC_COM_CX_IPEAK_H
+#define __SOC_COM_CX_IPEAK_H
+
+struct device_node;
+struct cx_ipeak_client;
+
+#ifndef CONFIG_QCOM_CX_IPEAK
+
+static inline struct cx_ipeak_client *cx_ipeak_register(
+		struct device_node *dev_node,
+		const char *client_name)
+{
+	return NULL;
+}
+
+static inline void cx_ipeak_unregister(struct cx_ipeak_client *client)
+{
+}
+
+static inline int cx_ipeak_update(struct cx_ipeak_client *ipeak_client,
+			bool vote)
+{
+	return 0;
+}
+#else
+
+struct cx_ipeak_client *cx_ipeak_register(struct device_node *dev_node,
+		const char *client_name);
+void cx_ipeak_unregister(struct cx_ipeak_client *client);
+int cx_ipeak_update(struct cx_ipeak_client *ipeak_client, bool vote);
+
+#endif
+
+#endif /*__SOC_COM_CX_IPEAK_H*/