soc: qcom: Driver for the Qualcomm RPM over SMD

Driver for the Resource Power Manager (RPM) found in Qualcomm 8974 based
devices.
The driver exposes resources that child drivers can operate on; to
implementing regulator, clock and bus frequency drivers.

Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Signed-off-by: Andy Gross <agross@codeaurora.org>

4 files changed, 294 insertions, 0 deletions

diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index 188295e2c9ba..ba47b70f4d85 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -27,6 +27,20 @@ config QCOM_SMD
           providing communication channels to remote processors in Qualcomm
           platforms.
 
+config QCOM_SMD_RPM
+        tristate "Qualcomm Resource Power Manager (RPM) over SMD"
+        depends on QCOM_SMD && OF
+        help
+          If you say yes to this option, support will be included for the
+          Resource Power Manager system found in the Qualcomm 8974 based
+          devices.
+
+          This is required to access many regulators, clocks and bus
+          frequencies controlled by the RPM on these devices.
+
+          Say M here if you want to include support for the Qualcomm RPM as a
+          module. This will build a module called "qcom-smd-rpm".
+
 config QCOM_SMEM
         tristate "Qualcomm Shared Memory Manager (SMEM)"
         depends on ARCH_QCOM
diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index f961a8796ed2..10a93d168e0e 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -1,4 +1,5 @@
 obj-$(CONFIG_QCOM_GSBI) +=      qcom_gsbi.o
 obj-$(CONFIG_QCOM_PM)   +=      spm.o
 obj-$(CONFIG_QCOM_SMD) +=       smd.o
+obj-$(CONFIG_QCOM_SMD_RPM)      += smd-rpm.o
 obj-$(CONFIG_QCOM_SMEM) +=      smem.o
diff --git a/drivers/soc/qcom/smd-rpm.c b/drivers/soc/qcom/smd-rpm.c
new file mode 100644
index 000000000000..1392ccf14a20
--- /dev/null
+++ b/drivers/soc/qcom/smd-rpm.c
@@ -0,0 +1,244 @@
+/*
+ * Copyright (c) 2015, Sony Mobile Communications AB.
+ * Copyright (c) 2012-2013, 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/platform_device.h>
+#include <linux/of_platform.h>
+#include <linux/io.h>
+#include <linux/interrupt.h>
+
+#include <linux/soc/qcom/smd.h>
+#include <linux/soc/qcom/smd-rpm.h>
+
+#define RPM_REQUEST_TIMEOUT     (5 * HZ)
+
+/**
+ * struct qcom_smd_rpm - state of the rpm device driver
+ * @rpm_channel:        reference to the smd channel
+ * @ack:                completion for acks
+ * @lock:               mutual exclusion around the send/complete pair
+ * @ack_status:         result of the rpm request
+ */
+struct qcom_smd_rpm {
+        struct qcom_smd_channel *rpm_channel;
+
+        struct completion ack;
+        struct mutex lock;
+        int ack_status;
+};
+
+/**
+ * struct qcom_rpm_header - header for all rpm requests and responses
+ * @service_type:       identifier of the service
+ * @length:             length of the payload
+ */
+struct qcom_rpm_header {
+        u32 service_type;
+        u32 length;
+};
+
+/**
+ * struct qcom_rpm_request - request message to the rpm
+ * @msg_id:     identifier of the outgoing message
+ * @flags:      active/sleep state flags
+ * @type:       resource type
+ * @id:         resource id
+ * @data_len:   length of the payload following this header
+ */
+struct qcom_rpm_request {
+        u32 msg_id;
+        u32 flags;
+        u32 type;
+        u32 id;
+        u32 data_len;
+};
+
+/**
+ * struct qcom_rpm_message - response message from the rpm
+ * @msg_type:   indicator of the type of message
+ * @length:     the size of this message, including the message header
+ * @msg_id:     message id
+ * @message:    textual message from the rpm
+ *
+ * Multiple of these messages can be stacked in an rpm message.
+ */
+struct qcom_rpm_message {
+        u32 msg_type;
+        u32 length;
+        union {
+                u32 msg_id;
+                u8 message[0];
+        };
+};
+
+#define RPM_SERVICE_TYPE_REQUEST        0x00716572 /* "req\0" */
+
+#define RPM_MSG_TYPE_ERR                0x00727265 /* "err\0" */
+#define RPM_MSG_TYPE_MSG_ID             0x2367736d /* "msg#" */
+
+/**
+ * qcom_rpm_smd_write - write @buf to @type:@id
+ * @rpm:        rpm handle
+ * @type:       resource type
+ * @id:         resource identifier
+ * @buf:        the data to be written
+ * @count:      number of bytes in @buf
+ */
+int qcom_rpm_smd_write(struct qcom_smd_rpm *rpm,
+                       int state,
+                       u32 type, u32 id,
+                       void *buf,
+                       size_t count)
+{
+        static unsigned msg_id = 1;
+        int left;
+        int ret;
+
+        struct {
+                struct qcom_rpm_header hdr;
+                struct qcom_rpm_request req;
+                u8 payload[count];
+        } pkt;
+
+        /* SMD packets to the RPM may not exceed 256 bytes */
+        if (WARN_ON(sizeof(pkt) >= 256))
+                return -EINVAL;
+
+        mutex_lock(&rpm->lock);
+
+        pkt.hdr.service_type = RPM_SERVICE_TYPE_REQUEST;
+        pkt.hdr.length = sizeof(struct qcom_rpm_request) + count;
+
+        pkt.req.msg_id = msg_id++;
+        pkt.req.flags = BIT(state);
+        pkt.req.type = type;
+        pkt.req.id = id;
+        pkt.req.data_len = count;
+        memcpy(pkt.payload, buf, count);
+
+        ret = qcom_smd_send(rpm->rpm_channel, &pkt, sizeof(pkt));
+        if (ret)
+                goto out;
+
+        left = wait_for_completion_timeout(&rpm->ack, RPM_REQUEST_TIMEOUT);
+        if (!left)
+                ret = -ETIMEDOUT;
+        else
+                ret = rpm->ack_status;
+
+out:
+        mutex_unlock(&rpm->lock);
+        return ret;
+}
+EXPORT_SYMBOL(qcom_rpm_smd_write);
+
+static int qcom_smd_rpm_callback(struct qcom_smd_device *qsdev,
+                                 const void *data,
+                                 size_t count)
+{
+        const struct qcom_rpm_header *hdr = data;
+        const struct qcom_rpm_message *msg;
+        struct qcom_smd_rpm *rpm = dev_get_drvdata(&qsdev->dev);
+        const u8 *buf = data + sizeof(struct qcom_rpm_header);
+        const u8 *end = buf + hdr->length;
+        char msgbuf[32];
+        int status = 0;
+        u32 len;
+
+        if (hdr->service_type != RPM_SERVICE_TYPE_REQUEST ||
+            hdr->length < sizeof(struct qcom_rpm_message)) {
+                dev_err(&qsdev->dev, "invalid request\n");
+                return 0;
+        }
+
+        while (buf < end) {
+                msg = (struct qcom_rpm_message *)buf;
+                switch (msg->msg_type) {
+                case RPM_MSG_TYPE_MSG_ID:
+                        break;
+                case RPM_MSG_TYPE_ERR:
+                        len = min_t(u32, ALIGN(msg->length, 4), sizeof(msgbuf));
+                        memcpy_fromio(msgbuf, msg->message, len);
+                        msgbuf[len - 1] = 0;
+
+                        if (!strcmp(msgbuf, "resource does not exist"))
+                                status = -ENXIO;
+                        else
+                                status = -EINVAL;
+                        break;
+                }
+
+                buf = PTR_ALIGN(buf + 2 * sizeof(u32) + msg->length, 4);
+        }
+
+        rpm->ack_status = status;
+        complete(&rpm->ack);
+        return 0;
+}
+
+static int qcom_smd_rpm_probe(struct qcom_smd_device *sdev)
+{
+        struct qcom_smd_rpm *rpm;
+
+        rpm = devm_kzalloc(&sdev->dev, sizeof(*rpm), GFP_KERNEL);
+        if (!rpm)
+                return -ENOMEM;
+
+        mutex_init(&rpm->lock);
+        init_completion(&rpm->ack);
+
+        rpm->rpm_channel = sdev->channel;
+
+        dev_set_drvdata(&sdev->dev, rpm);
+
+        return of_platform_populate(sdev->dev.of_node, NULL, NULL, &sdev->dev);
+}
+
+static void qcom_smd_rpm_remove(struct qcom_smd_device *sdev)
+{
+        of_platform_depopulate(&sdev->dev);
+}
+
+static const struct of_device_id qcom_smd_rpm_of_match[] = {
+        { .compatible = "qcom,rpm-msm8974" },
+        {}
+};
+MODULE_DEVICE_TABLE(of, qcom_smd_rpm_of_match);
+
+static struct qcom_smd_driver qcom_smd_rpm_driver = {
+        .probe = qcom_smd_rpm_probe,
+        .remove = qcom_smd_rpm_remove,
+        .callback = qcom_smd_rpm_callback,
+        .driver  = {
+                .name  = "qcom_smd_rpm",
+                .owner = THIS_MODULE,
+                .of_match_table = qcom_smd_rpm_of_match,
+        },
+};
+
+static int __init qcom_smd_rpm_init(void)
+{
+        return qcom_smd_driver_register(&qcom_smd_rpm_driver);
+}
+arch_initcall(qcom_smd_rpm_init);
+
+static void __exit qcom_smd_rpm_exit(void)
+{
+        qcom_smd_driver_unregister(&qcom_smd_rpm_driver);
+}
+module_exit(qcom_smd_rpm_exit);
+
+MODULE_AUTHOR("Bjorn Andersson <bjorn.andersson@sonymobile.com>");
+MODULE_DESCRIPTION("Qualcomm SMD backed RPM driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/soc/qcom/smd-rpm.h b/include/linux/soc/qcom/smd-rpm.h
new file mode 100644
index 000000000000..2a53dcaeeeed
--- /dev/null
+++ b/include/linux/soc/qcom/smd-rpm.h
@@ -0,0 +1,35 @@
+#ifndef __QCOM_SMD_RPM_H__
+#define __QCOM_SMD_RPM_H__
+
+struct qcom_smd_rpm;
+
+#define QCOM_SMD_RPM_ACTIVE_STATE        0
+#define QCOM_SMD_RPM_SLEEP_STATE         1
+
+/*
+ * Constants used for addressing resources in the RPM.
+ */
+#define QCOM_SMD_RPM_BOOST      0x61747362
+#define QCOM_SMD_RPM_BUS_CLK    0x316b6c63
+#define QCOM_SMD_RPM_BUS_MASTER 0x73616d62
+#define QCOM_SMD_RPM_BUS_SLAVE  0x766c7362
+#define QCOM_SMD_RPM_CLK_BUF_A  0x616B6C63
+#define QCOM_SMD_RPM_LDOA       0x616f646c
+#define QCOM_SMD_RPM_LDOB       0x626F646C
+#define QCOM_SMD_RPM_MEM_CLK    0x326b6c63
+#define QCOM_SMD_RPM_MISC_CLK   0x306b6c63
+#define QCOM_SMD_RPM_NCPA       0x6170636E
+#define QCOM_SMD_RPM_NCPB       0x6270636E
+#define QCOM_SMD_RPM_OCMEM_PWR  0x706d636f
+#define QCOM_SMD_RPM_QPIC_CLK   0x63697071
+#define QCOM_SMD_RPM_SMPA       0x61706d73
+#define QCOM_SMD_RPM_SMPB       0x62706d73
+#define QCOM_SMD_RPM_SPDM       0x63707362
+#define QCOM_SMD_RPM_VSA        0x00617376
+
+int qcom_rpm_smd_write(struct qcom_smd_rpm *rpm,
+                       int state,
+                       u32 resource_type, u32 resource_id,
+                       void *buf, size_t count);
+
+#endif