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 <il...@codeaurora.org>
---
 drivers/soc/qcom/Makefile        |   4 +-
 drivers/soc/qcom/rpmh-internal.h |   2 +
 drivers/soc/qcom/rpmh-rsc.c      |   7 ++
 drivers/soc/qcom/rpmh.c          | 257 +++++++++++++++++++++++++++++++++++++++
 include/soc/qcom/rpmh.h          |  34 ++++++
 5 files changed, 303 insertions(+), 1 deletion(-)
 create mode 100644 drivers/soc/qcom/rpmh.c
 create mode 100644 include/soc/qcom/rpmh.h

diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index bb013d56b5a1..5c9c6c442ea9 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -13,4 +13,6 @@ obj-$(CONFIG_QCOM_SMEM_STATE) += smem_state.o
 obj-$(CONFIG_QCOM_SMP2P)       += smp2p.o
 obj-$(CONFIG_QCOM_SMSM)        += smsm.o
 obj-$(CONFIG_QCOM_WCNSS_CTRL) += wcnss_ctrl.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
diff --git a/drivers/soc/qcom/rpmh-internal.h b/drivers/soc/qcom/rpmh-internal.h
index 12faec77c4f3..1442a64ac4c5 100644
--- a/drivers/soc/qcom/rpmh-internal.h
+++ b/drivers/soc/qcom/rpmh-internal.h
@@ -84,4 +84,6 @@ struct rsc_drv {
 
 int rpmh_rsc_send_data(struct rsc_drv *drv, struct tcs_request *msg);
 
+void rpmh_tx_done(struct tcs_request *msg, int r);
+
 #endif /* __RPM_INTERNAL_H__ */
diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
index 4322e23a2ba6..b5b39b86f904 100644
--- a/drivers/soc/qcom/rpmh-rsc.c
+++ b/drivers/soc/qcom/rpmh-rsc.c
@@ -263,6 +263,8 @@ static void tcs_notify_tx_done(unsigned long data)
        struct rsc_drv *drv = (struct rsc_drv *)data;
        struct tcs_response *resp;
        unsigned long flags;
+       struct tcs_request *msg;
+       int err;
 
        for (;;) {
                spin_lock_irqsave(&drv->drv_lock, flags);
@@ -275,7 +277,10 @@ static void tcs_notify_tx_done(unsigned long data)
                list_del(&resp->list);
                spin_unlock_irqrestore(&drv->drv_lock, flags);
                trace_rpmh_notify_tx_done(drv, resp);
+               msg = resp->msg;
+               err = resp->err;
                free_response(resp);
+               rpmh_tx_done(msg, err);
        }
 }
 
@@ -575,6 +580,8 @@ static int rpmh_rsc_probe(struct platform_device *pdev)
        write_tcs_reg(drv, RSC_DRV_IRQ_ENABLE, 0, 0,
                     drv->tcs[ACTIVE_TCS].tcs_mask);
 
+       dev_set_drvdata(&pdev->dev, drv);
+
        return of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
 }
 
diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c
new file mode 100644
index 000000000000..d95ea3fa8b67
--- /dev/null
+++ b/drivers/soc/qcom/rpmh.c
@@ -0,0 +1,257 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2016-2018, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/atomic.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/mailbox_client.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_MAX_MBOXES                        2
+#define RPMH_TIMEOUT                   (10 * HZ)
+
+#define DEFINE_RPMH_MSG_ONSTACK(rc, s, q, c, name)     \
+       struct rpmh_request name = {                    \
+               .msg = {                                \
+                       .state = s,                     \
+                       .payload = name.cmd,            \
+                       .num_payload = 0,               \
+                       .is_complete = true,            \
+               },                                      \
+               .cmd = { { 0 } },                       \
+               .completion = q,                        \
+               .wait_count = c,                        \
+               .rc = rc,                               \
+       }
+
+/**
+ * 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
+ * @wait_count: count of waiters for this completion
+ * @err: err return from the controller
+ */
+struct rpmh_request {
+       struct tcs_request msg;
+       struct tcs_cmd cmd[MAX_RPMH_PAYLOAD];
+       struct completion *completion;
+       atomic_t *wait_count;
+       struct rpmh_client *rc;
+       int err;
+};
+
+/**
+ * rpmh_ctrlr: our representation of the controller
+ *
+ * @drv: the controller instance
+ */
+struct rpmh_ctrlr {
+       struct rsc_drv *drv;
+};
+
+/**
+ * rpmh_client: the client object
+ *
+ * @dev: the platform device that is the owner
+ * @ctrlr: the controller associated with this client.
+ */
+struct rpmh_client {
+       struct device *dev;
+       struct rpmh_ctrlr *ctrlr;
+};
+
+static struct rpmh_ctrlr rpmh_rsc[RPMH_MAX_MBOXES];
+static DEFINE_MUTEX(rpmh_ctrlr_mutex);
+
+void rpmh_tx_done(struct tcs_request *msg, int r)
+{
+       struct rpmh_request *rpm_msg = container_of(msg,
+                                                  struct rpmh_request, msg);
+       atomic_t *wc = rpm_msg->wait_count;
+       struct completion *compl = rpm_msg->completion;
+
+       rpm_msg->err = r;
+
+       if (r)
+               dev_err(rpm_msg->rc->dev,
+                      "RPMH TX fail in msg addr 0x%x, err=%d\n",
+                      rpm_msg->msg.payload[0].addr, r);
+
+       /* Signal the blocking thread we are done */
+       if (wc && atomic_dec_and_test(wc) && compl)
+               complete(compl);
+}
+EXPORT_SYMBOL(rpmh_tx_done);
+
+/**
+ * wait_for_tx_done: Wait until the response is received.
+ *
+ * @rc: The RPMH client
+ * @compl: The completion object
+ * @addr: An addr that we sent in that request
+ * @data: The data for the address in that request
+ *
+ */
+static int wait_for_tx_done(struct rpmh_client *rc,
+                          struct completion *compl, u32 addr, u32 data)
+{
+       int ret;
+
+       ret = wait_for_completion_timeout(compl, RPMH_TIMEOUT);
+       if (ret)
+               dev_dbg(rc->dev,
+                      "RPMH response received addr=0x%x data=0x%x\n",
+                      addr, data);
+       else
+               dev_err(rc->dev,
+                       "RPMH response timeout addr=0x%x data=0x%x\n",
+                       addr, data);
+
+       return (ret > 0) ? 0 : -ETIMEDOUT;
+}
+
+/**
+ * __rpmh_write: send the RPMH request
+ *
+ * @rc: The RPMH client
+ * @state: Active/Sleep request type
+ * @rpm_msg: The data that needs to be sent (payload).
+ */
+static int __rpmh_write(struct rpmh_client *rc, enum rpmh_state state,
+                      struct rpmh_request *rpm_msg)
+{
+       int ret = -EFAULT;
+
+       rpm_msg->msg.state = state;
+
+       if (state == RPMH_ACTIVE_ONLY_STATE) {
+               WARN_ON(irqs_disabled());
+               ret = rpmh_rsc_send_data(rc->ctrlr->drv, &rpm_msg->msg);
+               if (!ret)
+                       dev_dbg(rc->dev,
+                              "RPMH request sent addr=0x%x, data=0x%x\n",
+                              rpm_msg->msg.payload[0].addr,
+                              rpm_msg->msg.payload[0].data);
+               else
+                       dev_warn(rc->dev,
+                               "Error in RPMH request addr=0x%x, data=0x%x\n",
+                               rpm_msg->msg.payload[0].addr,
+                               rpm_msg->msg.payload[0].data);
+       }
+
+       return ret;
+}
+
+/**
+ * rpmh_write: Write a set of RPMH commands and block until response
+ *
+ * @rc: The RPMh handle got from rpmh_get_dev_channel
+ * @state: Active/sleep set
+ * @cmd: The payload data
+ * @n: The number of elements in payload
+ *
+ * May sleep. Do not call from atomic contexts.
+ */
+int rpmh_write(struct rpmh_client *rc, enum rpmh_state state,
+             struct tcs_cmd *cmd, int n)
+{
+       DECLARE_COMPLETION_ONSTACK(compl);
+       atomic_t wait_count = ATOMIC_INIT(1);
+       DEFINE_RPMH_MSG_ONSTACK(rc, state, &compl, &wait_count, rpm_msg);
+       int ret;
+
+       if (IS_ERR_OR_NULL(rc) || !cmd || n <= 0 || n > MAX_RPMH_PAYLOAD)
+               return -EINVAL;
+
+       might_sleep();
+
+       memcpy(rpm_msg.cmd, cmd, n * sizeof(*cmd));
+       rpm_msg.msg.num_payload = n;
+
+       ret = __rpmh_write(rc, state, &rpm_msg);
+       if (ret)
+               return ret;
+
+       return wait_for_tx_done(rc, &compl, cmd[0].addr, cmd[0].data);
+}
+EXPORT_SYMBOL(rpmh_write);
+
+static struct rpmh_ctrlr *get_rpmh_ctrlr(struct platform_device *pdev)
+{
+       int i;
+       struct rsc_drv *drv = dev_get_drvdata(pdev->dev.parent);
+       struct rpmh_ctrlr *ctrlr = ERR_PTR(-EFAULT);
+
+       if (!drv)
+               return ctrlr;
+
+       mutex_lock(&rpmh_ctrlr_mutex);
+       for (i = 0; i < RPMH_MAX_MBOXES; i++) {
+               if (rpmh_rsc[i].drv == drv) {
+                       ctrlr = &rpmh_rsc[i];
+                       goto unlock;
+               }
+       }
+
+       for (i = 0; i < RPMH_MAX_MBOXES; i++) {
+               if (rpmh_rsc[i].drv == NULL) {
+                       ctrlr = &rpmh_rsc[i];
+                       ctrlr->drv = drv;
+                       break;
+               }
+       }
+       WARN_ON(i == RPMH_MAX_MBOXES);
+unlock:
+       mutex_unlock(&rpmh_ctrlr_mutex);
+       return ctrlr;
+}
+
+/**
+ * rpmh_get_client: Get the RPMh handle
+ *
+ * @pdev: the platform device which needs to communicate with RPM
+ * accelerators
+ * May sleep.
+ */
+struct rpmh_client *rpmh_get_client(struct platform_device *pdev)
+{
+       struct rpmh_client *rc;
+
+       rc = kzalloc(sizeof(*rc), GFP_KERNEL);
+       if (!rc)
+               return ERR_PTR(-ENOMEM);
+
+       rc->dev = &pdev->dev;
+       rc->ctrlr = get_rpmh_ctrlr(pdev);
+       if (IS_ERR(rc->ctrlr)) {
+               kfree(rc);
+               return ERR_PTR(-EFAULT);
+       }
+
+       return rc;
+}
+EXPORT_SYMBOL(rpmh_get_client);
+
+/**
+ * rpmh_release: Release the RPMH client
+ *
+ * @rc: The RPMh handle to be freed.
+ */
+void rpmh_release(struct rpmh_client *rc)
+{
+       kfree(rc);
+}
+EXPORT_SYMBOL(rpmh_release);
diff --git a/include/soc/qcom/rpmh.h b/include/soc/qcom/rpmh.h
new file mode 100644
index 000000000000..53cc145990c2
--- /dev/null
+++ b/include/soc/qcom/rpmh.h
@@ -0,0 +1,34 @@
+/* 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>
+
+struct rpmh_client;
+
+#if IS_ENABLED(CONFIG_QCOM_RPMH)
+int rpmh_write(struct rpmh_client *rc, enum rpmh_state state,
+             struct tcs_cmd *cmd, int n);
+
+struct rpmh_client *rpmh_get_client(struct platform_device *pdev);
+
+void rpmh_release(struct rpmh_client *rc);
+
+#else
+
+static inline int rpmh_write(struct rpmh_client *rc, enum rpmh_state state,
+                           struct tcs_cmd *cmd, int n)
+{ return -ENODEV; }
+
+static inline struct rpmh_client *rpmh_get_client(struct platform_device *pdev)
+{ return ERR_PTR(-ENODEV); }
+
+static inline void rpmh_release(struct rpmh_client *rc) { }
+#endif /* CONFIG_QCOM_RPMH */
+
+#endif /* __SOC_QCOM_RPMH_H__ */
-- 
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