diff options
Diffstat (limited to 'drivers/platform/chrome/cros_ec_vbc.c')
| -rw-r--r-- | drivers/platform/chrome/cros_ec_vbc.c | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/drivers/platform/chrome/cros_ec_vbc.c b/drivers/platform/chrome/cros_ec_vbc.c new file mode 100644 index 000000000000..5ee8adaa6564 --- /dev/null +++ b/drivers/platform/chrome/cros_ec_vbc.c @@ -0,0 +1,155 @@ +// 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/mod_devicetable.h> +#include <linux/module.h> +#include <linux/platform_data/cros_ec_commands.h> +#include <linux/platform_data/cros_ec_proto.h> +#include <linux/slab.h> + +#define DRV_NAME "cros-ec-vbc" + +static ssize_t vboot_context_read(struct file *filp, struct kobject *kobj, + const struct bin_attribute *att, char *buf, + loff_t pos, size_t count) +{ + struct device *dev = kobj_to_dev(kobj); + struct cros_ec_dev *ec = to_cros_ec_dev(dev); + struct cros_ec_device *ecdev = ec->ec_dev; + struct cros_ec_command *msg; + /* + * This should be a pointer to the same type as op field in + * struct ec_params_vbnvcontext. + */ + uint32_t *params_op; + 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_op = (uint32_t *)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_status(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, + const struct bin_attribute *attr, char *buf, + loff_t pos, size_t count) +{ + struct device *dev = kobj_to_dev(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_status(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 const BIN_ATTR_RW(vboot_context, 16); + +static const struct bin_attribute *const cros_ec_vbc_bin_attrs[] = { + &bin_attr_vboot_context, + NULL +}; + +static const 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 void 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); +} + +static const struct platform_device_id cros_ec_vbc_id[] = { + { DRV_NAME, 0 }, + {} +}; +MODULE_DEVICE_TABLE(platform, cros_ec_vbc_id); + +static struct platform_driver cros_ec_vbc_driver = { + .driver = { + .name = DRV_NAME, + }, + .probe = cros_ec_vbc_probe, + .remove = cros_ec_vbc_remove, + .id_table = cros_ec_vbc_id, +}; + +module_platform_driver(cros_ec_vbc_driver); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Expose the vboot context nvram to userspace"); |