drivers: qcom: rpmh: add RPMH helper functions

Sending RPMH requests and waiting for response from the controller
through a callback is common functionality across all platform drivers.
To simplify drivers, add a library functions to create RPMH client and
send resource state requests.

rpmh_write() is a synchronous blocking call that can be used to send
active state requests.

Signed-off-by: Lina Iyer <[e-mail]>
Signed-off-by: Raju P.L.S.S.S.N <[e-mail]>
Signed-off-by: Andy Gross <[e-mail]>

drivers/soc/qcom/Makefile

···
 obj-$(CONFIG_QCOM_QMI_HELPERS)	+= qmi_helpers.o
 qmi_helpers-y	+= qmi_encdec.o qmi_interface.o
 obj-$(CONFIG_QCOM_RMTFS_MEM)	+= rmtfs_mem.o
-obj-$(CONFIG_QCOM_RPMH)	+=	rpmh-rsc.o
+obj-$(CONFIG_QCOM_RPMH)		+= qcom_rpmh.o
+qcom_rpmh-y			+= rpmh-rsc.o
+qcom_rpmh-y			+= rpmh.o
 obj-$(CONFIG_QCOM_SMD_RPM)	+= smd-rpm.o
 obj-$(CONFIG_QCOM_SMEM) +=	smem.o
 obj-$(CONFIG_QCOM_SMEM_STATE) += smem_state.o

drivers/soc/qcom/rpmh-internal.h

···
 };
 
 /**
+ * struct rpmh_request: the message to be sent to rpmh-rsc
+ *
+ * @msg: the request
+ * @cmd: the payload that will be part of the @msg
+ * @completion: triggered when request is done
+ * @dev: the device making the request
+ * @err: err return from the controller
+ */
+struct rpmh_request {
+	struct tcs_request msg;
+	struct tcs_cmd cmd[MAX_RPMH_PAYLOAD];
+	struct completion *completion;
+	const struct device *dev;
+	int err;
+};
+
+/**
+ * struct rpmh_ctrlr: our representation of the controller
+ *
+ * @drv: the controller instance
+ */
+struct rpmh_ctrlr {
+	struct rsc_drv *drv;
+};
+
+/**
  * struct rsc_drv: the Direct Resource Voter (DRV) of the
  * Resource State Coordinator controller (RSC)
  *
···
  * @tcs:        TCS groups
  * @tcs_in_use: s/w state of the TCS
  * @lock:       synchronize state of the controller
+ * @client:     handle to the DRV's client.
  */
 struct rsc_drv {
 	const char *name;
···
 	struct tcs_group tcs[TCS_TYPE_NR];
 	DECLARE_BITMAP(tcs_in_use, MAX_TCS_NR);
 	spinlock_t lock;
+	struct rpmh_ctrlr client;
 };
 
-
 int rpmh_rsc_send_data(struct rsc_drv *drv, const struct tcs_request *msg);
+
+void rpmh_tx_done(const struct tcs_request *msg, int r);
 
 #endif /* __RPM_INTERNAL_H__ */

drivers/soc/qcom/rpmh-rsc.c

···
 static irqreturn_t tcs_tx_done(int irq, void *p)
 {
 	struct rsc_drv *drv = p;
-	int i, j, err;
+	int i, j, err = 0;
 	unsigned long irq_status;
 	const struct tcs_request *req;
 	struct tcs_cmd *cmd;
···
 		spin_lock(&drv->lock);
 		clear_bit(i, drv->tcs_in_use);
 		spin_unlock(&drv->lock);
+		if (req)
+			rpmh_tx_done(req, err);
 	}
 
 	return IRQ_HANDLED;
···
 
 	/* Enable the active TCS to send requests immediately */
 	write_tcs_reg(drv, RSC_DRV_IRQ_ENABLE, 0, drv->tcs[ACTIVE_TCS].mask);
+
+	dev_set_drvdata(&pdev->dev, drv);
 
 	return devm_of_platform_populate(&pdev->dev);
 }

drivers/soc/qcom/rpmh.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2016-2018, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/atomic.h>
+#include <linux/bug.h>
+#include <linux/interrupt.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+
+#include <soc/qcom/rpmh.h>
+
+#include "rpmh-internal.h"
+
+#define RPMH_TIMEOUT_MS			msecs_to_jiffies(10000)
+
+#define DEFINE_RPMH_MSG_ONSTACK(dev, s, q, name)	\
+	struct rpmh_request name = {			\
+		.msg = {				\
+			.state = s,			\
+			.cmds = name.cmd,		\
+			.num_cmds = 0,			\
+			.wait_for_compl = true,		\
+		},					\
+		.cmd = { { 0 } },			\
+		.completion = q,			\
+		.dev = dev,				\
+	}
+
+#define ctrlr_to_drv(ctrlr) container_of(ctrlr, struct rsc_drv, client)
+
+static struct rpmh_ctrlr *get_rpmh_ctrlr(const struct device *dev)
+{
+	struct rsc_drv *drv = dev_get_drvdata(dev->parent);
+
+	return &drv->client;
+}
+
+void rpmh_tx_done(const struct tcs_request *msg, int r)
+{
+	struct rpmh_request *rpm_msg = container_of(msg, struct rpmh_request,
+						    msg);
+	struct completion *compl = rpm_msg->completion;
+
+	rpm_msg->err = r;
+
+	if (r)
+		dev_err(rpm_msg->dev, "RPMH TX fail in msg addr=%#x, err=%d\n",
+			rpm_msg->msg.cmds[0].addr, r);
+
+	/* Signal the blocking thread we are done */
+	if (compl)
+		complete(compl);
+}
+
+/**
+ * __rpmh_write: send the RPMH request
+ *
+ * @dev: The device making the request
+ * @state: Active/Sleep request type
+ * @rpm_msg: The data that needs to be sent (cmds).
+ */
+static int __rpmh_write(const struct device *dev, enum rpmh_state state,
+			struct rpmh_request *rpm_msg)
+{
+	struct rpmh_ctrlr *ctrlr = get_rpmh_ctrlr(dev);
+
+	rpm_msg->msg.state = state;
+
+	if (state != RPMH_ACTIVE_ONLY_STATE)
+		return -EINVAL;
+
+	WARN_ON(irqs_disabled());
+
+	return rpmh_rsc_send_data(ctrlr_to_drv(ctrlr), &rpm_msg->msg);
+}
+
+/**
+ * rpmh_write: Write a set of RPMH commands and block until response
+ *
+ * @rc: The RPMH handle got from rpmh_get_client
+ * @state: Active/sleep set
+ * @cmd: The payload data
+ * @n: The number of elements in @cmd
+ *
+ * May sleep. Do not call from atomic contexts.
+ */
+int rpmh_write(const struct device *dev, enum rpmh_state state,
+	       const struct tcs_cmd *cmd, u32 n)
+{
+	DECLARE_COMPLETION_ONSTACK(compl);
+	DEFINE_RPMH_MSG_ONSTACK(dev, state, &compl, rpm_msg);
+	int ret;
+
+	if (!cmd || !n || n > MAX_RPMH_PAYLOAD)
+		return -EINVAL;
+
+	memcpy(rpm_msg.cmd, cmd, n * sizeof(*cmd));
+	rpm_msg.msg.num_cmds = n;
+
+	ret = __rpmh_write(dev, state, &rpm_msg);
+	if (ret)
+		return ret;
+
+	ret = wait_for_completion_timeout(&compl, RPMH_TIMEOUT_MS);
+	WARN_ON(!ret);
+	return (ret > 0) ? 0 : -ETIMEDOUT;
+}
+EXPORT_SYMBOL(rpmh_write);

include/soc/qcom/rpmh.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2016-2018, The Linux Foundation. All rights reserved.
+ */
+
+#ifndef __SOC_QCOM_RPMH_H__
+#define __SOC_QCOM_RPMH_H__
+
+#include <soc/qcom/tcs.h>
+#include <linux/platform_device.h>
+
+
+#if IS_ENABLED(CONFIG_QCOM_RPMH)
+int rpmh_write(const struct device *dev, enum rpmh_state state,
+	       const struct tcs_cmd *cmd, u32 n);
+
+#else
+
+static inline int rpmh_write(const struct device *dev, enum rpmh_state state,
+			     const struct tcs_cmd *cmd, u32 n)
+{ return -ENODEV; }
+
+#endif /* CONFIG_QCOM_RPMH */
+
+#endif /* __SOC_QCOM_RPMH_H__ */