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 <[e-mail]>
Signed-off-by: Andy Gross <[e-mail]>

drivers/soc/qcom/Kconfig

···
 	  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

drivers/soc/qcom/Makefile

···
 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

drivers/soc/qcom/smd-rpm.c

···
+/*
+ * 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 <[e-mail]>");
+MODULE_DESCRIPTION("Qualcomm SMD backed RPM driver");
+MODULE_LICENSE("GPL v2");

include/linux/soc/qcom/smd-rpm.h

···
+#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