1*18800fc7SEmilio López /* 2*18800fc7SEmilio López * cros_ec_vbc - Expose the vboot context nvram to userspace 3*18800fc7SEmilio López * 4*18800fc7SEmilio López * Copyright (C) 2015 Collabora Ltd. 5*18800fc7SEmilio López * 6*18800fc7SEmilio López * based on vendor driver, 7*18800fc7SEmilio López * 8*18800fc7SEmilio López * Copyright (C) 2012 The Chromium OS Authors 9*18800fc7SEmilio López * 10*18800fc7SEmilio López * This program is free software; you can redistribute it and/or modify 11*18800fc7SEmilio López * it under the terms of the GNU General Public License as published by 12*18800fc7SEmilio López * the Free Software Foundation; either version 2 of the License, or 13*18800fc7SEmilio López * (at your option) any later version. 14*18800fc7SEmilio López * 15*18800fc7SEmilio López * This program is distributed in the hope that it will be useful, 16*18800fc7SEmilio López * but WITHOUT ANY WARRANTY; without even the implied warranty of 17*18800fc7SEmilio López * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18*18800fc7SEmilio López * GNU General Public License for more details. 19*18800fc7SEmilio López */ 20*18800fc7SEmilio López 21*18800fc7SEmilio López #include <linux/of.h> 22*18800fc7SEmilio López #include <linux/platform_device.h> 23*18800fc7SEmilio López #include <linux/mfd/cros_ec.h> 24*18800fc7SEmilio López #include <linux/mfd/cros_ec_commands.h> 25*18800fc7SEmilio López #include <linux/slab.h> 26*18800fc7SEmilio López 27*18800fc7SEmilio López static ssize_t vboot_context_read(struct file *filp, struct kobject *kobj, 28*18800fc7SEmilio López struct bin_attribute *att, char *buf, 29*18800fc7SEmilio López loff_t pos, size_t count) 30*18800fc7SEmilio López { 31*18800fc7SEmilio López struct device *dev = container_of(kobj, struct device, kobj); 32*18800fc7SEmilio López struct cros_ec_dev *ec = container_of(dev, struct cros_ec_dev, 33*18800fc7SEmilio López class_dev); 34*18800fc7SEmilio López struct cros_ec_device *ecdev = ec->ec_dev; 35*18800fc7SEmilio López struct ec_params_vbnvcontext *params; 36*18800fc7SEmilio López struct cros_ec_command *msg; 37*18800fc7SEmilio López int err; 38*18800fc7SEmilio López const size_t para_sz = sizeof(params->op); 39*18800fc7SEmilio López const size_t resp_sz = sizeof(struct ec_response_vbnvcontext); 40*18800fc7SEmilio López const size_t payload = max(para_sz, resp_sz); 41*18800fc7SEmilio López 42*18800fc7SEmilio López msg = kmalloc(sizeof(*msg) + payload, GFP_KERNEL); 43*18800fc7SEmilio López if (!msg) 44*18800fc7SEmilio López return -ENOMEM; 45*18800fc7SEmilio López 46*18800fc7SEmilio López /* NB: we only kmalloc()ated enough space for the op field */ 47*18800fc7SEmilio López params = (struct ec_params_vbnvcontext *)msg->data; 48*18800fc7SEmilio López params->op = EC_VBNV_CONTEXT_OP_READ; 49*18800fc7SEmilio López 50*18800fc7SEmilio López msg->version = EC_VER_VBNV_CONTEXT; 51*18800fc7SEmilio López msg->command = EC_CMD_VBNV_CONTEXT; 52*18800fc7SEmilio López msg->outsize = para_sz; 53*18800fc7SEmilio López msg->insize = resp_sz; 54*18800fc7SEmilio López 55*18800fc7SEmilio López err = cros_ec_cmd_xfer(ecdev, msg); 56*18800fc7SEmilio López if (err < 0) { 57*18800fc7SEmilio López dev_err(dev, "Error sending read request: %d\n", err); 58*18800fc7SEmilio López kfree(msg); 59*18800fc7SEmilio López return err; 60*18800fc7SEmilio López } 61*18800fc7SEmilio López 62*18800fc7SEmilio López memcpy(buf, msg->data, resp_sz); 63*18800fc7SEmilio López 64*18800fc7SEmilio López kfree(msg); 65*18800fc7SEmilio López return resp_sz; 66*18800fc7SEmilio López } 67*18800fc7SEmilio López 68*18800fc7SEmilio López static ssize_t vboot_context_write(struct file *filp, struct kobject *kobj, 69*18800fc7SEmilio López struct bin_attribute *attr, char *buf, 70*18800fc7SEmilio López loff_t pos, size_t count) 71*18800fc7SEmilio López { 72*18800fc7SEmilio López struct device *dev = container_of(kobj, struct device, kobj); 73*18800fc7SEmilio López struct cros_ec_dev *ec = container_of(dev, struct cros_ec_dev, 74*18800fc7SEmilio López class_dev); 75*18800fc7SEmilio López struct cros_ec_device *ecdev = ec->ec_dev; 76*18800fc7SEmilio López struct ec_params_vbnvcontext *params; 77*18800fc7SEmilio López struct cros_ec_command *msg; 78*18800fc7SEmilio López int err; 79*18800fc7SEmilio López const size_t para_sz = sizeof(*params); 80*18800fc7SEmilio López const size_t data_sz = sizeof(params->block); 81*18800fc7SEmilio López 82*18800fc7SEmilio López /* Only write full values */ 83*18800fc7SEmilio López if (count != data_sz) 84*18800fc7SEmilio López return -EINVAL; 85*18800fc7SEmilio López 86*18800fc7SEmilio López msg = kmalloc(sizeof(*msg) + para_sz, GFP_KERNEL); 87*18800fc7SEmilio López if (!msg) 88*18800fc7SEmilio López return -ENOMEM; 89*18800fc7SEmilio López 90*18800fc7SEmilio López params = (struct ec_params_vbnvcontext *)msg->data; 91*18800fc7SEmilio López params->op = EC_VBNV_CONTEXT_OP_WRITE; 92*18800fc7SEmilio López memcpy(params->block, buf, data_sz); 93*18800fc7SEmilio López 94*18800fc7SEmilio López msg->version = EC_VER_VBNV_CONTEXT; 95*18800fc7SEmilio López msg->command = EC_CMD_VBNV_CONTEXT; 96*18800fc7SEmilio López msg->outsize = para_sz; 97*18800fc7SEmilio López msg->insize = 0; 98*18800fc7SEmilio López 99*18800fc7SEmilio López err = cros_ec_cmd_xfer(ecdev, msg); 100*18800fc7SEmilio López if (err < 0) { 101*18800fc7SEmilio López dev_err(dev, "Error sending write request: %d\n", err); 102*18800fc7SEmilio López kfree(msg); 103*18800fc7SEmilio López return err; 104*18800fc7SEmilio López } 105*18800fc7SEmilio López 106*18800fc7SEmilio López kfree(msg); 107*18800fc7SEmilio López return data_sz; 108*18800fc7SEmilio López } 109*18800fc7SEmilio López 110*18800fc7SEmilio López static umode_t cros_ec_vbc_is_visible(struct kobject *kobj, 111*18800fc7SEmilio López struct bin_attribute *a, int n) 112*18800fc7SEmilio López { 113*18800fc7SEmilio López struct device *dev = container_of(kobj, struct device, kobj); 114*18800fc7SEmilio López struct cros_ec_dev *ec = container_of(dev, struct cros_ec_dev, 115*18800fc7SEmilio López class_dev); 116*18800fc7SEmilio López struct device_node *np = ec->ec_dev->dev->of_node; 117*18800fc7SEmilio López 118*18800fc7SEmilio López if (IS_ENABLED(CONFIG_OF) && np) { 119*18800fc7SEmilio López if (of_property_read_bool(np, "google,has-vbc-nvram")) 120*18800fc7SEmilio López return a->attr.mode; 121*18800fc7SEmilio López } 122*18800fc7SEmilio López 123*18800fc7SEmilio López return 0; 124*18800fc7SEmilio López } 125*18800fc7SEmilio López 126*18800fc7SEmilio López static BIN_ATTR_RW(vboot_context, 16); 127*18800fc7SEmilio López 128*18800fc7SEmilio López static struct bin_attribute *cros_ec_vbc_bin_attrs[] = { 129*18800fc7SEmilio López &bin_attr_vboot_context, 130*18800fc7SEmilio López NULL 131*18800fc7SEmilio López }; 132*18800fc7SEmilio López 133*18800fc7SEmilio López struct attribute_group cros_ec_vbc_attr_group = { 134*18800fc7SEmilio López .name = "vbc", 135*18800fc7SEmilio López .bin_attrs = cros_ec_vbc_bin_attrs, 136*18800fc7SEmilio López .is_bin_visible = cros_ec_vbc_is_visible, 137*18800fc7SEmilio López }; 138