Date:   Tue, 25 Apr 2017 18:51:34 +0530
From:   Sricharan R <sricharan@...eaurora.org>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>,
        Andy Gross <andy.gross@...aro.org>,
        David Brown <david.brown@...aro.org>,
        Frank Rowand <frowand.list@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>
Cc:     linux-arm-msm@...r.kernel.org, linux-soc@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC 3/3] soc: qcom: rfsa driver

Hi Bjorn,

On 4/22/2017 11:05 PM, Bjorn Andersson wrote:
> The rfsa driver is used for allocating and exposing regions of shared
> memory with remote processors for the purpose of exchanging sector-data
> between the remote filesystem service and its clients.
> 
> It provides accessors for the properties needed by the user space remote
> filesystem implementation through sysfs and a character device that can be used
> to read and write the requested chunks of data.
> 

couple of minor nits.

> Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
> ---
>  drivers/soc/qcom/Kconfig  |   8 ++
>  drivers/soc/qcom/Makefile |   1 +
>  drivers/soc/qcom/rfsa.c   | 261 ++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 270 insertions(+)
>  create mode 100644 drivers/soc/qcom/rfsa.c
> 
> diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
> index 9fca977ef18d..788a63cd430e 100644
> --- a/drivers/soc/qcom/Kconfig
> +++ b/drivers/soc/qcom/Kconfig
> @@ -24,6 +24,14 @@ config QCOM_PM
>  	  modes. It interface with various system drivers to put the cores in
>  	  low power modes.
>  
> +config QCOM_RFSA
> +	tristate "Qualcomm Remote Filesystem Access driver"

 depends on ARCH_QCOM ?

> +	help
> +	  The Qualcomm remote filesystem access driver is used for allocating
> +	  and exposing regions of shared memory with remote processors for the
> +	  purpose of exchanging sector-data between the remote filesystem
> +	  service and its clients.
> +
>  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 414f0de274fa..d1bbc791ddc0 100644
> --- a/drivers/soc/qcom/Makefile
> +++ b/drivers/soc/qcom/Makefile
> @@ -1,6 +1,7 @@
>  obj-$(CONFIG_QCOM_GSBI)	+=	qcom_gsbi.o
>  obj-$(CONFIG_QCOM_MDT_LOADER)	+= mdt_loader.o
>  obj-$(CONFIG_QCOM_PM)	+=	spm.o
> +obj-$(CONFIG_QCOM_RFSA)	+=	rfsa.o
>  obj-$(CONFIG_QCOM_SMD_RPM)	+= smd-rpm.o
>  obj-$(CONFIG_QCOM_SMEM) +=	smem.o
>  obj-$(CONFIG_QCOM_SMEM_STATE) += smem_state.o
> diff --git a/drivers/soc/qcom/rfsa.c b/drivers/soc/qcom/rfsa.c
> new file mode 100644
> index 000000000000..1b79976dad9d
> --- /dev/null
> +++ b/drivers/soc/qcom/rfsa.c
> @@ -0,0 +1,261 @@
> +/*
> + * Copyright (c) 2017 Linaro Ltd.
> + *
> + * 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/kernel.h>
> +#include <linux/cdev.h>
> +#include <linux/err.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/of.h>
> +#include <linux/of_reserved_mem.h>
> +#include <linux/of_fdt.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/slab.h>
> +#include <linux/uaccess.h>
> +#include <linux/io.h>
> +
> +#define QCOM_RFSA_DEV_MAX	(MINORMASK + 1)
> +
> +static dev_t qcom_rfsa_major;
> +
> +struct qcom_rfsa {
> +	struct device dev;
> +	struct cdev cdev;
> +
> +	void *base;
> +	phys_addr_t addr;
> +	phys_addr_t size;
> +
> +	unsigned int client_id;
> +};
> +
> +static ssize_t qcom_rfsa_show(struct device *dev,
> +			      struct device_attribute *attr,
> +			      char *buf);
> +
> +static DEVICE_ATTR(phys_addr, 0400, qcom_rfsa_show, NULL);
> +static DEVICE_ATTR(size, 0400, qcom_rfsa_show, NULL);
> +static DEVICE_ATTR(client_id, 0400, qcom_rfsa_show, NULL);
> +
> +static ssize_t qcom_rfsa_show(struct device *dev,
> +			      struct device_attribute *attr,
> +			      char *buf)
> +{
> +	struct qcom_rfsa *rfsa = container_of(dev, struct qcom_rfsa, dev);
> +
> +	if (attr == &dev_attr_phys_addr)
> +		return sprintf(buf, "%pa\n", &rfsa->addr);
> +	if (attr == &dev_attr_size)
> +		return sprintf(buf, "%pa\n", &rfsa->size);
> +	if (attr == &dev_attr_client_id)
> +		return sprintf(buf, "%d\n", rfsa->client_id);
> +
> +	return -EINVAL;
> +}
> +
> +static struct attribute *qcom_rfsa_attrs[] = {
> +	&dev_attr_phys_addr.attr,
> +	&dev_attr_size.attr,
> +	&dev_attr_client_id.attr,
> +	NULL
> +};
> +ATTRIBUTE_GROUPS(qcom_rfsa);
> +
> +static int qcom_rfsa_open(struct inode *inode, struct file *filp)
> +{
> +	struct qcom_rfsa *rfsa = container_of(inode->i_cdev, struct qcom_rfsa, cdev);
> +
> +	get_device(&rfsa->dev);
> +	filp->private_data = rfsa;
> +
> +	return 0;
> +}
> +static ssize_t qcom_rfsa_read(struct file *filp,
> +			      char __user *buf, size_t count, loff_t *f_pos)
> +{
> +	struct qcom_rfsa *rfsa = filp->private_data;
> +
> +	if (*f_pos >= rfsa->size)
> +		return 0;
> +
> +	if (*f_pos + count >= rfsa->size)
> +		count = rfsa->size - *f_pos;
> +
> +	if (copy_to_user(buf, rfsa->base + *f_pos, count))
> +		return -EFAULT;
> +
> +	*f_pos += count;
> +	return count;
> +}
> +
> +static ssize_t qcom_rfsa_write(struct file *filp,
> +			       const char __user *buf, size_t count,
> +			       loff_t *f_pos)
> +{
> +	struct qcom_rfsa *rfsa = filp->private_data;
> +
> +	if (*f_pos >= rfsa->size)
> +		return 0;
> +
> +	if (*f_pos + count >= rfsa->size)
> +		count = rfsa->size - *f_pos;
> +
> +	if (copy_from_user(rfsa->base + *f_pos, buf, count))
> +		return -EFAULT;
> +
> +	*f_pos += count;
> +	return count;
> +}
> +
> +static int qcom_rfsa_release(struct inode *inode, struct file *filp)
> +{
> +	struct qcom_rfsa *rfsa = filp->private_data;
> +
> +	put_device(&rfsa->dev);
> +
> +	return 0;
> +}
> +
> +static const struct file_operations qcom_rfsa_fops = {
> +	.owner = THIS_MODULE,
> +	.open = qcom_rfsa_open,
> +	.read = qcom_rfsa_read,
> +	.write = qcom_rfsa_write,
> +	.release = qcom_rfsa_release,
> +	.llseek = default_llseek,
> +};
> +
> +static void qcom_rfsa_release_device(struct device *dev)
> +{
> +	struct qcom_rfsa *rfsa = container_of(dev, struct qcom_rfsa, dev);
> +
> +	kfree(rfsa);
> +}
> +
> +static int qcom_rfsa_probe(struct platform_device *pdev)
> +{
> +	struct device_node *node = pdev->dev.of_node;
> +	struct reserved_mem *rmem;
> +	struct qcom_rfsa *rfsa;
> +	u32 client_id;
> +	int ret;
> +
> +	rmem = of_get_reserved_mem_by_idx(node, 0);
> +	if (!rmem) {
> +		dev_err(&pdev->dev, "failed to acquire memory region\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = of_property_read_u32(node, "qcom,client-id", &client_id);
> +	if (ret) {
> +		dev_err(&pdev->dev, "failed to parse \"qcom,client-id\"\n");
> +		return ret;
> +
> +	}
> +
> +	rfsa = kzalloc(sizeof(*rfsa), GFP_KERNEL);
> +	if (!rfsa)
> +		return -ENOMEM;
> +
> +	rfsa->addr = rmem->base;
> +	rfsa->client_id = client_id;
> +	rfsa->size = rmem->size;
> +
> +	device_initialize(&rfsa->dev);
> +	rfsa->dev.parent = &pdev->dev;
> +	rfsa->dev.groups = qcom_rfsa_groups;
> +
> +	cdev_init(&rfsa->cdev, &qcom_rfsa_fops);
> +	rfsa->cdev.owner = THIS_MODULE;
> +
> +	dev_set_name(&rfsa->dev, "qcom_rfsa%d", client_id);
> +	rfsa->dev.id = client_id;
> +	rfsa->dev.devt = MKDEV(MAJOR(qcom_rfsa_major), client_id);
> +
> +	ret = cdev_device_add(&rfsa->cdev, &rfsa->dev);
> +	if (ret) {
> +		dev_err(&pdev->dev, "failed to add cdev: %d\n", ret);
> +		put_device(&rfsa->dev);
> +		return ret;
> +	}
> +
> +	rfsa->dev.release = qcom_rfsa_release_device;
> +
> +	rfsa->base = devm_memremap(&rfsa->dev, rfsa->addr, rfsa->size, MEMREMAP_WC);
> +	if (IS_ERR(rfsa->base)) {
> +		dev_err(&pdev->dev, "failed to remap rfsa region\n");
> +
> +		device_del(&rfsa->dev);
> +		put_device(&rfsa->dev);
> +
> +		return PTR_ERR(rfsa->base);
> +	}
> +
> +	dev_set_drvdata(&pdev->dev, rfsa);
> +
> +	return 0;
> +}
> +
> +static int qcom_rfsa_remove(struct platform_device *pdev)
> +{
> +	struct qcom_rfsa *rfsa = dev_get_drvdata(&pdev->dev);
> +
> +	cdev_del(&rfsa->cdev);
> +	device_del(&rfsa->dev);

cdev_device_del instead of the above two ?

Regards,
 Sricharan


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