Re: [PATCH v2 06/11] mfd: qcom-smd-rpm: Driver for the Qualcomm RPM over SMD

[Lee Jones <lee.jones@linaro.org>]

On Fri, 26 Jun 2015, bjorn@kryo.se wrote:

> From: Bjorn Andersson <bjorn.andersson@sonymobile.com>
> 
> 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>
> ---
>  drivers/mfd/Kconfig              |  14 +++
>  drivers/mfd/Makefile             |   1 +
>  drivers/mfd/qcom-smd-rpm.c       | 236 +++++++++++++++++++++++++++++++++++++++
>  include/linux/mfd/qcom-smd-rpm.h |  35 ++++++
>  4 files changed, 286 insertions(+)
>  create mode 100644 drivers/mfd/qcom-smd-rpm.c
>  create mode 100644 include/linux/mfd/qcom-smd-rpm.h
> 
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index 6538159..666c812 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -656,6 +656,20 @@ config MFD_QCOM_RPM
>  	  Say M here if you want to include support for the Qualcomm RPM as a
>  	  module. This will build a module called "qcom_rpm".
>  
> +config MFD_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".

I'm not exactly sure what makes this an MFD device.

>  config MFD_SPMI_PMIC
>  	tristate "Qualcomm SPMI PMICs"
>  	depends on ARCH_QCOM || COMPILE_TEST
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index ea40e07..289bd24 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -156,6 +156,7 @@ obj-$(CONFIG_MFD_CS5535)	+= cs5535-mfd.o
>  obj-$(CONFIG_MFD_OMAP_USB_HOST)	+= omap-usb-host.o omap-usb-tll.o
>  obj-$(CONFIG_MFD_PM8921_CORE) 	+= pm8921-core.o ssbi.o
>  obj-$(CONFIG_MFD_QCOM_RPM)	+= qcom_rpm.o
> +obj-$(CONFIG_MFD_QCOM_SMD_RPM)	+= qcom-smd-rpm.o
>  obj-$(CONFIG_MFD_SPMI_PMIC)	+= qcom-spmi-pmic.o
>  obj-$(CONFIG_TPS65911_COMPARATOR)	+= tps65911-comparator.o
>  obj-$(CONFIG_MFD_TPS65090)	+= tps65090.o
> diff --git a/drivers/mfd/qcom-smd-rpm.c b/drivers/mfd/qcom-smd-rpm.c
> new file mode 100644
> index 0000000..d6faf85
> --- /dev/null
> +++ b/drivers/mfd/qcom-smd-rpm.c
> @@ -0,0 +1,236 @@
> +/*
> + * 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/mfd/qcom-smd-rpm.h>
> +
> +#include <dt-bindings/mfd/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);
> +
> +#define RPM_ERR_INVALID_RESOURCE "resource does not exist"

I don't like this at all.

> +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;
> +	const size_t inv_res_len = sizeof(RPM_ERR_INVALID_RESOURCE) - 1;
> +	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;
> +	int status = 0;
> +
> +	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:
> +			if (msg->length == inv_res_len &&
> +			    !memcmp(msg->message,
> +				    RPM_ERR_INVALID_RESOURCE,
> +				    inv_res_len))

strncpy(msg->message, "resource does not exist", 23);

> +				status = -ENXIO;
> +			else
> +				status = -EIO;
> +			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,

Remove this line.

> +		.of_match_table = qcom_smd_rpm_of_match,
> +	},
> +};
> +
> +module_qcom_smd_driver(qcom_smd_rpm_driver);
> +
> +MODULE_AUTHOR("Bjorn Andersson <bjorn.andersson@sonymobile.com>");
> +MODULE_DESCRIPTION("Qualcomm SMD backed RPM driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/mfd/qcom-smd-rpm.h b/include/linux/mfd/qcom-smd-rpm.h
> new file mode 100644
> index 0000000..2a53dca
> --- /dev/null
> +++ b/include/linux/mfd/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

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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