[mirror_ubuntu-kernels.git] / drivers / platform / chrome / cros_ec_vbc.c

// SPDX-License-Identifier: GPL-2.0+
// Expose the vboot context nvram to userspace
//
// Copyright (C) 2012 Google, Inc.
// Copyright (C) 2015 Collabora Ltd.

#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/mfd/cros_ec.h>
#include <linux/mfd/cros_ec_commands.h>
#include <linux/module.h>
#include <linux/slab.h>

#define DRV_NAME "cros-ec-vbc"

static ssize_t vboot_context_read(struct file *filp, struct kobject *kobj,
				  struct bin_attribute *att, char *buf,
				  loff_t pos, size_t count)
{
	struct device *dev = container_of(kobj, struct device, kobj);
	struct cros_ec_dev *ec = to_cros_ec_dev(dev);
	struct cros_ec_device *ecdev = ec->ec_dev;
	struct ec_params_vbnvcontext *params;
	struct cros_ec_command *msg;
	int err;
	const size_t para_sz = sizeof(params->op);
	const size_t resp_sz = sizeof(struct ec_response_vbnvcontext);
	const size_t payload = max(para_sz, resp_sz);

	msg = kmalloc(sizeof(*msg) + payload, GFP_KERNEL);
	if (!msg)
		return -ENOMEM;

	/* NB: we only kmalloc()ated enough space for the op field */
	params = (struct ec_params_vbnvcontext *)msg->data;
	params->op = EC_VBNV_CONTEXT_OP_READ;

	msg->version = EC_VER_VBNV_CONTEXT;
	msg->command = EC_CMD_VBNV_CONTEXT;
	msg->outsize = para_sz;
	msg->insize = resp_sz;

	err = cros_ec_cmd_xfer(ecdev, msg);
	if (err < 0) {
		dev_err(dev, "Error sending read request: %d\n", err);
		kfree(msg);
		return err;
	}

	memcpy(buf, msg->data, resp_sz);

	kfree(msg);
	return resp_sz;
}

static ssize_t vboot_context_write(struct file *filp, struct kobject *kobj,
				   struct bin_attribute *attr, char *buf,
				   loff_t pos, size_t count)
{
	struct device *dev = container_of(kobj, struct device, kobj);
	struct cros_ec_dev *ec = to_cros_ec_dev(dev);
	struct cros_ec_device *ecdev = ec->ec_dev;
	struct ec_params_vbnvcontext *params;
	struct cros_ec_command *msg;
	int err;
	const size_t para_sz = sizeof(*params);
	const size_t data_sz = sizeof(params->block);

	/* Only write full values */
	if (count != data_sz)
		return -EINVAL;

	msg = kmalloc(sizeof(*msg) + para_sz, GFP_KERNEL);
	if (!msg)
		return -ENOMEM;

	params = (struct ec_params_vbnvcontext *)msg->data;
	params->op = EC_VBNV_CONTEXT_OP_WRITE;
	memcpy(params->block, buf, data_sz);

	msg->version = EC_VER_VBNV_CONTEXT;
	msg->command = EC_CMD_VBNV_CONTEXT;
	msg->outsize = para_sz;
	msg->insize = 0;

	err = cros_ec_cmd_xfer(ecdev, msg);
	if (err < 0) {
		dev_err(dev, "Error sending write request: %d\n", err);
		kfree(msg);
		return err;
	}

	kfree(msg);
	return data_sz;
}

static BIN_ATTR_RW(vboot_context, 16);

static struct bin_attribute *cros_ec_vbc_bin_attrs[] = {
	&bin_attr_vboot_context,
	NULL
};

struct attribute_group cros_ec_vbc_attr_group = {
	.name = "vbc",
	.bin_attrs = cros_ec_vbc_bin_attrs,
};

static int cros_ec_vbc_probe(struct platform_device *pd)
{
	struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
	struct device *dev = &pd->dev;
	int ret;

	ret = sysfs_create_group(&ec_dev->class_dev.kobj,
				 &cros_ec_vbc_attr_group);
	if (ret < 0)
		dev_err(dev, "failed to create %s attributes. err=%d\n",
			cros_ec_vbc_attr_group.name, ret);

	return ret;
}

static int cros_ec_vbc_remove(struct platform_device *pd)
{
	struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);

	sysfs_remove_group(&ec_dev->class_dev.kobj,
			   &cros_ec_vbc_attr_group);

	return 0;
}

static struct platform_driver cros_ec_vbc_driver = {
	.driver = {
		.name = DRV_NAME,
	},
	.probe = cros_ec_vbc_probe,
	.remove = cros_ec_vbc_remove,
};

module_platform_driver(cros_ec_vbc_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Expose the vboot context nvram to userspace");
MODULE_ALIAS("platform:" DRV_NAME);
Commit	Line	Data
27755cf7 EBS	1	// SPDX-License-Identifier: GPL-2.0+
	2	// Expose the vboot context nvram to userspace
	3	//
	4	// Copyright (C) 2012 Google, Inc.
	5	// Copyright (C) 2015 Collabora Ltd.
18800fc7 EL	6
	7	#include <linux/of.h>
	8	#include <linux/platform_device.h>
	9	#include <linux/mfd/cros_ec.h>
	10	#include <linux/mfd/cros_ec_commands.h>
acb9900f	11	#include <linux/module.h>
18800fc7 EL	12	#include <linux/slab.h>
18800fc7 EL	13
acb9900f EBS	14	#define DRV_NAME "cros-ec-vbc"
acb9900f EBS	15
18800fc7 EL	16	static ssize_t vboot_context_read(struct file filp, struct kobject kobj,
	17	struct bin_attribute att, char buf,
	18	loff_t pos, size_t count)
	19	{
	20	struct device *dev = container_of(kobj, struct device, kobj);
79a3d603	21	struct cros_ec_dev *ec = to_cros_ec_dev(dev);
18800fc7 EL	22	struct cros_ec_device *ecdev = ec->ec_dev;
	23	struct ec_params_vbnvcontext *params;
	24	struct cros_ec_command *msg;
	25	int err;
	26	const size_t para_sz = sizeof(params->op);
	27	const size_t resp_sz = sizeof(struct ec_response_vbnvcontext);
	28	const size_t payload = max(para_sz, resp_sz);
	29
	30	msg = kmalloc(sizeof(*msg) + payload, GFP_KERNEL);
	31	if (!msg)
	32	return -ENOMEM;
	33
	34	/* NB: we only kmalloc()ated enough space for the op field */
	35	params = (struct ec_params_vbnvcontext *)msg->data;
	36	params->op = EC_VBNV_CONTEXT_OP_READ;
	37
	38	msg->version = EC_VER_VBNV_CONTEXT;
	39	msg->command = EC_CMD_VBNV_CONTEXT;
	40	msg->outsize = para_sz;
	41	msg->insize = resp_sz;
	42
	43	err = cros_ec_cmd_xfer(ecdev, msg);
	44	if (err < 0) {
	45	dev_err(dev, "Error sending read request: %d\n", err);
	46	kfree(msg);
	47	return err;
	48	}
	49
	50	memcpy(buf, msg->data, resp_sz);
	51
	52	kfree(msg);
	53	return resp_sz;
	54	}
	55
	56	static ssize_t vboot_context_write(struct file filp, struct kobject kobj,
	57	struct bin_attribute attr, char buf,
	58	loff_t pos, size_t count)
	59	{
	60	struct device *dev = container_of(kobj, struct device, kobj);
79a3d603	61	struct cros_ec_dev *ec = to_cros_ec_dev(dev);
18800fc7 EL	62	struct cros_ec_device *ecdev = ec->ec_dev;
	63	struct ec_params_vbnvcontext *params;
	64	struct cros_ec_command *msg;
	65	int err;
	66	const size_t para_sz = sizeof(*params);
	67	const size_t data_sz = sizeof(params->block);
	68
	69	/* Only write full values */
	70	if (count != data_sz)
	71	return -EINVAL;
	72
	73	msg = kmalloc(sizeof(*msg) + para_sz, GFP_KERNEL);
	74	if (!msg)
	75	return -ENOMEM;
	76
	77	params = (struct ec_params_vbnvcontext *)msg->data;
	78	params->op = EC_VBNV_CONTEXT_OP_WRITE;
	79	memcpy(params->block, buf, data_sz);
	80
	81	msg->version = EC_VER_VBNV_CONTEXT;
	82	msg->command = EC_CMD_VBNV_CONTEXT;
	83	msg->outsize = para_sz;
	84	msg->insize = 0;
	85
	86	err = cros_ec_cmd_xfer(ecdev, msg);
	87	if (err < 0) {
	88	dev_err(dev, "Error sending write request: %d\n", err);
	89	kfree(msg);
	90	return err;
	91	}
	92
	93	kfree(msg);
	94	return data_sz;
	95	}
	96
18800fc7 EL	97	static BIN_ATTR_RW(vboot_context, 16);
	98
	99	static struct bin_attribute *cros_ec_vbc_bin_attrs[] = {
	100	&bin_attr_vboot_context,
	101	NULL
	102	};
	103
	104	struct attribute_group cros_ec_vbc_attr_group = {
	105	.name = "vbc",
	106	.bin_attrs = cros_ec_vbc_bin_attrs,
18800fc7	107	};
acb9900f EBS	108
	109	static int cros_ec_vbc_probe(struct platform_device *pd)
	110	{
	111	struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
	112	struct device *dev = &pd->dev;
	113	int ret;
	114
	115	ret = sysfs_create_group(&ec_dev->class_dev.kobj,
	116	&cros_ec_vbc_attr_group);
	117	if (ret < 0)
	118	dev_err(dev, "failed to create %s attributes. err=%d\n",
	119	cros_ec_vbc_attr_group.name, ret);
	120
	121	return ret;
	122	}
	123
	124	static int cros_ec_vbc_remove(struct platform_device *pd)
	125	{
	126	struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
	127
	128	sysfs_remove_group(&ec_dev->class_dev.kobj,
	129	&cros_ec_vbc_attr_group);
	130
	131	return 0;
	132	}
	133
	134	static struct platform_driver cros_ec_vbc_driver = {
	135	.driver = {
	136	.name = DRV_NAME,
	137	},
	138	.probe = cros_ec_vbc_probe,
	139	.remove = cros_ec_vbc_remove,
	140	};
	141
	142	module_platform_driver(cros_ec_vbc_driver);
	143
	144	MODULE_LICENSE("GPL");
	145	MODULE_DESCRIPTION("Expose the vboot context nvram to userspace");
	146	MODULE_ALIAS("platform:" DRV_NAME);