--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Miscellaneous character driver for ChromeOS Embedded Controller
+ *
+ * Copyright 2014 Google, Inc.
+ * Copyright 2019 Google LLC
+ *
+ * This file is a rework and part of the code is ported from
+ * drivers/mfd/cros_ec_dev.c that was originally written by
+ * Bill Richardson.
+ */
+
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/mfd/cros_ec.h>
+#include <linux/mfd/cros_ec_commands.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/platform_data/cros_ec_chardev.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+
+#define DRV_NAME "cros-ec-chardev"
+
+struct chardev_data {
+ struct cros_ec_dev *ec_dev;
+ struct miscdevice misc;
+};
+
+static int ec_get_version(struct cros_ec_dev *ec, char *str, int maxlen)
+{
+ static const char * const current_image_name[] = {
+ "unknown", "read-only", "read-write", "invalid",
+ };
+ struct ec_response_get_version *resp;
+ struct cros_ec_command *msg;
+ int ret;
+
+ msg = kzalloc(sizeof(*msg) + sizeof(*resp), GFP_KERNEL);
+ if (!msg)
+ return -ENOMEM;
+
+ msg->command = EC_CMD_GET_VERSION + ec->cmd_offset;
+ msg->insize = sizeof(*resp);
+
+ ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
+ if (ret < 0) {
+ snprintf(str, maxlen,
+ "Unknown EC version, returned error: %d\n",
+ msg->result);
+ goto exit;
+ }
+
+ resp = (struct ec_response_get_version *)msg->data;
+ if (resp->current_image >= ARRAY_SIZE(current_image_name))
+ resp->current_image = 3; /* invalid */
+
+ snprintf(str, maxlen, "%s\n%s\n%s\n%s\n", CROS_EC_DEV_VERSION,
+ resp->version_string_ro, resp->version_string_rw,
+ current_image_name[resp->current_image]);
+
+ ret = 0;
+exit:
+ kfree(msg);
+ return ret;
+}
+
+/*
+ * Device file ops
+ */
+static int cros_ec_chardev_open(struct inode *inode, struct file *filp)
+{
+ struct miscdevice *mdev = filp->private_data;
+ struct cros_ec_dev *ec_dev = dev_get_drvdata(mdev->parent);
+
+ filp->private_data = ec_dev;
+ nonseekable_open(inode, filp);
+
+ return 0;
+}
+
+static ssize_t cros_ec_chardev_read(struct file *filp, char __user *buffer,
+ size_t length, loff_t *offset)
+{
+ char msg[sizeof(struct ec_response_get_version) +
+ sizeof(CROS_EC_DEV_VERSION)];
+ struct cros_ec_dev *ec = filp->private_data;
+ size_t count;
+ int ret;
+
+ if (*offset != 0)
+ return 0;
+
+ ret = ec_get_version(ec, msg, sizeof(msg));
+ if (ret)
+ return ret;
+
+ count = min(length, strlen(msg));
+
+ if (copy_to_user(buffer, msg, count))
+ return -EFAULT;
+
+ *offset = count;
+ return count;
+}
+
+/*
+ * Ioctls
+ */
+static long cros_ec_chardev_ioctl_xcmd(struct cros_ec_dev *ec, void __user *arg)
+{
+ struct cros_ec_command *s_cmd;
+ struct cros_ec_command u_cmd;
+ long ret;
+
+ if (copy_from_user(&u_cmd, arg, sizeof(u_cmd)))
+ return -EFAULT;
+
+ if (u_cmd.outsize > EC_MAX_MSG_BYTES ||
+ u_cmd.insize > EC_MAX_MSG_BYTES)
+ return -EINVAL;
+
+ s_cmd = kmalloc(sizeof(*s_cmd) + max(u_cmd.outsize, u_cmd.insize),
+ GFP_KERNEL);
+ if (!s_cmd)
+ return -ENOMEM;
+
+ if (copy_from_user(s_cmd, arg, sizeof(*s_cmd) + u_cmd.outsize)) {
+ ret = -EFAULT;
+ goto exit;
+ }
+
+ if (u_cmd.outsize != s_cmd->outsize ||
+ u_cmd.insize != s_cmd->insize) {
+ ret = -EINVAL;
+ goto exit;
+ }
+
+ s_cmd->command += ec->cmd_offset;
+ ret = cros_ec_cmd_xfer(ec->ec_dev, s_cmd);
+ /* Only copy data to userland if data was received. */
+ if (ret < 0)
+ goto exit;
+
+ if (copy_to_user(arg, s_cmd, sizeof(*s_cmd) + s_cmd->insize))
+ ret = -EFAULT;
+exit:
+ kfree(s_cmd);
+ return ret;
+}
+
+static long cros_ec_chardev_ioctl_readmem(struct cros_ec_dev *ec,
+ void __user *arg)
+{
+ struct cros_ec_device *ec_dev = ec->ec_dev;
+ struct cros_ec_readmem s_mem = { };
+ long num;
+
+ /* Not every platform supports direct reads */
+ if (!ec_dev->cmd_readmem)
+ return -ENOTTY;
+
+ if (copy_from_user(&s_mem, arg, sizeof(s_mem)))
+ return -EFAULT;
+
+ num = ec_dev->cmd_readmem(ec_dev, s_mem.offset, s_mem.bytes,
+ s_mem.buffer);
+ if (num <= 0)
+ return num;
+
+ if (copy_to_user((void __user *)arg, &s_mem, sizeof(s_mem)))
+ return -EFAULT;
+
+ return num;
+}
+
+static long cros_ec_chardev_ioctl(struct file *filp, unsigned int cmd,
+ unsigned long arg)
+{
+ struct cros_ec_dev *ec = filp->private_data;
+
+ if (_IOC_TYPE(cmd) != CROS_EC_DEV_IOC)
+ return -ENOTTY;
+
+ switch (cmd) {
+ case CROS_EC_DEV_IOCXCMD:
+ return cros_ec_chardev_ioctl_xcmd(ec, (void __user *)arg);
+ case CROS_EC_DEV_IOCRDMEM:
+ return cros_ec_chardev_ioctl_readmem(ec, (void __user *)arg);
+ }
+
+ return -ENOTTY;
+}
+
+static const struct file_operations chardev_fops = {
+ .open = cros_ec_chardev_open,
+ .read = cros_ec_chardev_read,
+ .unlocked_ioctl = cros_ec_chardev_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = cros_ec_chardev_ioctl,
+#endif
+};
+
+static int cros_ec_chardev_probe(struct platform_device *pdev)
+{
+ struct cros_ec_dev *ec_dev = dev_get_drvdata(pdev->dev.parent);
+ struct cros_ec_platform *ec_platform = dev_get_platdata(ec_dev->dev);
+ struct chardev_data *data;
+
+ /* Create a char device: we want to create it anew */
+ data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ data->ec_dev = ec_dev;
+ data->misc.minor = MISC_DYNAMIC_MINOR;
+ data->misc.fops = &chardev_fops;
+ data->misc.name = ec_platform->ec_name;
+ data->misc.parent = pdev->dev.parent;
+
+ dev_set_drvdata(&pdev->dev, data);
+
+ return misc_register(&data->misc);
+}
+
+static int cros_ec_chardev_remove(struct platform_device *pdev)
+{
+ struct chardev_data *data = dev_get_drvdata(&pdev->dev);
+
+ misc_deregister(&data->misc);
+
+ return 0;
+}
+
+static struct platform_driver cros_ec_chardev_driver = {
+ .driver = {
+ .name = DRV_NAME,
+ },
+ .probe = cros_ec_chardev_probe,
+ .remove = cros_ec_chardev_remove,
+};
+
+module_platform_driver(cros_ec_chardev_driver);
+
+MODULE_ALIAS("platform:" DRV_NAME);
+MODULE_AUTHOR("Enric Balletbo i Serra <enric.balletbo@collabora.com>");
+MODULE_DESCRIPTION("ChromeOS EC Miscellaneous Character Driver");
+MODULE_LICENSE("GPL");
projects / platform / kernel / linux-starfive.git / commitdiff