Re: [PATCH v7 5/6] usb:cdns3 Add Cadence USB3 DRD Driver

[Heikki Krogerus]

On Wed, Jun 05, 2019 at 11:03:49AM +0100, Pawel Laszczak wrote:
> diff --git a/drivers/usb/cdns3/debugfs.c b/drivers/usb/cdns3/debugfs.c
> new file mode 100644
> index 000000000000..dfcbeb5e14f8
> --- /dev/null
> +++ b/drivers/usb/cdns3/debugfs.c
> @@ -0,0 +1,173 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Cadence USBSS DRD Controller DebugFS filer.
> + *
> + * Copyright (C) 2018-2019 Cadence.
> + *
> + * Author: Pawel Laszczak <pawell@xxxxxxxxxxx>
> + */
> +
> +#include <linux/types.h>
> +#include <linux/debugfs.h>
> +#include <linux/seq_file.h>
> +#include <linux/uaccess.h>
> +
> +#include "core.h"
> +#include "gadget.h"
> +#include "drd.h"

static const char *const cdns3_mode[] = {
        [USB_DR_MODE_UNKNOWN]           = "unknown",
        [USB_DR_MODE_OTG]               = "otg",
        [USB_DR_MODE_HOST]              = "host",
        [USB_DR_MODE_PERIPHERAL]        = "device",
};

> +static int cdns3_mode_show(struct seq_file *s, void *unused)
> +{
> +	struct cdns3 *cdns = s->private;
> +
> +	switch (cdns->current_dr_mode) {
> +	case USB_DR_MODE_HOST:
> +		seq_puts(s, "host\n");
> +		break;
> +	case USB_DR_MODE_PERIPHERAL:
> +		seq_puts(s, "device\n");
> +		break;
> +	case USB_DR_MODE_OTG:
> +		seq_puts(s, "otg\n");
> +		break;
> +	default:
> +		seq_puts(s, "UNKNOWN mode\n");
> +	}

All you should need here is:

        seq_puts(s, cdns3_mode[cdns->current_dr_mode]);

> +	return 0;
> +}
> +
> +static int cdns3_mode_open(struct inode *inode, struct file *file)
> +{
> +	return single_open(file, cdns3_mode_show, inode->i_private);
> +}
> +
> +static ssize_t cdns3_mode_write(struct file *file,
> +				const char __user *ubuf,
> +				size_t count, loff_t *ppos)
> +{
> +	struct seq_file	 *s = file->private_data;
> +	struct cdns3 *cdns = s->private;
> +	u32 mode = USB_DR_MODE_UNKNOWN;
> +	char buf[32];
> +	int ret = 0;

        int ret;

> +	if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
> +		return -EFAULT;

                return -EINVAL;

> +
> +	if (cdns->debug_disable) {
> +		dev_err(cdns->dev,
> +			"Mode can't be changed when disable is set\n");
> +		return -EFAULT;

                return -EPERM;

> +	}
> +
> +	if (!strncmp(buf, "host", 4)) {
> +		if (cdns->dr_mode == USB_DR_MODE_HOST ||
> +		    cdns->dr_mode == USB_DR_MODE_OTG) {
> +			mode = USB_DR_MODE_HOST;
> +		}
> +	}
> +
> +	if (!strncmp(buf, "device", 6))
> +		if (cdns->dr_mode == USB_DR_MODE_PERIPHERAL ||
> +		    cdns->dr_mode == USB_DR_MODE_OTG)
> +			mode = USB_DR_MODE_PERIPHERAL;
> +
> +	if (!strncmp(buf, "otg", 3) && cdns->dr_mode == USB_DR_MODE_OTG)
> +		mode = USB_DR_MODE_OTG;
> +
> +	if (mode == USB_DR_MODE_UNKNOWN) {
> +		dev_err(cdns->dev, "Failed: incorrect mode setting\n");
> +		return -EFAULT;
> +	}

To cover all those, you just need to:

        ret = match_string(cdns3_mode, ARRAY_SIZE(cdns3_mode), buf));
        if (ret < 0 || ret == USB_DR_MODE_UNKNOWN)
                return -EINVAL;

> +	if (cdns->current_dr_mode != mode) {
> +		cdns->desired_dr_mode = mode;

        if (cdns->current_dr_mode != ret)
		cdns->desired_dr_mode = ret;

> +		cdns3_role_stop(cdns);
> +		ret = cdns3_drd_update_mode(cdns);
> +		if (ret)
> +			return ret;
> +
> +		queue_work(system_freezable_wq, &cdns->role_switch_wq);
> +	}
> +
> +	return count;
> +}
> +
> +static const struct file_operations cdns3_mode_fops = {
> +	.open			= cdns3_mode_open,
> +	.write			= cdns3_mode_write,
> +	.read			= seq_read,
> +	.llseek			= seq_lseek,
> +	.release		= single_release,
> +};
> +
> +static int cdns3_disable_show(struct seq_file *s, void *unused)
> +{
> +	struct cdns3 *cdns = s->private;
> +
> +	if (!cdns->debug_disable)
> +		seq_puts(s, "0\n");
> +	else
> +		seq_puts(s, "1\n");
> +
> +	return 0;
> +}
> +
> +static ssize_t cdns3_disable_write(struct file *file,
> +				   const char __user *ubuf,
> +				   size_t count, loff_t *ppos)
> +{
> +	struct seq_file	 *s = file->private_data;
> +	struct cdns3 *cdns = s->private;
> +	bool disable;
> +	char buf[16];
> +
> +	if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
> +		return -EFAULT;
> +
> +	if (kstrtobool(buf, &disable)) {
> +		dev_err(cdns->dev, "wrong setting\n");
> +		return -EINVAL;
> +	}
> +
> +	if (disable != cdns->debug_disable) {
> +		cdns->debug_disable = disable;
> +		queue_work(system_freezable_wq, &cdns->role_switch_wq);
> +	}
> +
> +	return count;
> +}
> +
> +static int cdns3_disable_open(struct inode *inode, struct file *file)
> +{
> +	return single_open(file, cdns3_disable_show, inode->i_private);
> +}
> +
> +static const struct file_operations cdns3_disable_fops = {
> +	.open			= cdns3_disable_open,
> +	.write			= cdns3_disable_write,
> +	.read			= seq_read,
> +	.llseek			= seq_lseek,
> +	.release		= single_release,
> +};
> +
> +void cdns3_debugfs_init(struct cdns3 *cdns)
> +{
> +	struct dentry *root;
> +
> +	root = debugfs_create_dir(dev_name(cdns->dev), NULL);
> +	cdns->root = root;
> +	if (IS_ENABLED(CONFIG_USB_CDNS3_GADGET) &&
> +	    IS_ENABLED(CONFIG_USB_CDNS3_HOST))
> +		debugfs_create_file("mode", 0644, root, cdns,
> +				    &cdns3_mode_fops);
> +
> +	debugfs_create_file("disable", 0644, root, cdns,
> +			    &cdns3_disable_fops);
> +}
> +
> +void cdns3_debugfs_exit(struct cdns3 *cdns)
> +{
> +	debugfs_remove_recursive(cdns->root);
> +}

thanks,

-- 
heikki