From 7f5028cf6190407b7a632b0f30b83187577824cc Mon Sep 17 00:00:00 2001 From: Emilio López Date: Mon, 21 Sep 2015 10:38:20 -0300 Subject: sysfs: Support is_visible() on binary attributes MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit According to the sysfs header file: "The returned value will replace static permissions defined in struct attribute or struct bin_attribute." but this isn't the case, as is_visible is only called on struct attribute only. This patch introduces a new is_bin_visible() function to implement the same functionality for binary attributes, and updates documentation accordingly. Note that to keep functionality and code similar to that of normal attributes, the mode is now checked as well to ensure it contains only read/write permissions or SYSFS_PREALLOC. Reviewed-by: Guenter Roeck Signed-off-by: Emilio López Acked-by: Greg Kroah-Hartman Signed-off-by: Olof Johansson --- include/linux/sysfs.h | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) (limited to 'include') diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h index 9f65758311a4..2f66050d073b 100644 --- a/include/linux/sysfs.h +++ b/include/linux/sysfs.h @@ -64,10 +64,18 @@ do { \ * a new subdirectory with this name. * @is_visible: Optional: Function to return permissions associated with an * attribute of the group. Will be called repeatedly for each - * attribute in the group. Only read/write permissions as well as - * SYSFS_PREALLOC are accepted. Must return 0 if an attribute is - * not visible. The returned value will replace static permissions - * defined in struct attribute or struct bin_attribute. + * non-binary attribute in the group. Only read/write + * permissions as well as SYSFS_PREALLOC are accepted. Must + * return 0 if an attribute is not visible. The returned value + * will replace static permissions defined in struct attribute. + * @is_bin_visible: + * Optional: Function to return permissions associated with a + * binary attribute of the group. Will be called repeatedly + * for each binary attribute in the group. Only read/write + * permissions as well as SYSFS_PREALLOC are accepted. Must + * return 0 if a binary attribute is not visible. The returned + * value will replace static permissions defined in + * struct bin_attribute. * @attrs: Pointer to NULL terminated list of attributes. * @bin_attrs: Pointer to NULL terminated list of binary attributes. * Either attrs or bin_attrs or both must be provided. @@ -76,6 +84,8 @@ struct attribute_group { const char *name; umode_t (*is_visible)(struct kobject *, struct attribute *, int); + umode_t (*is_bin_visible)(struct kobject *, + struct bin_attribute *, int); struct attribute **attrs; struct bin_attribute **bin_attrs; }; -- cgit v1.2.3-59-g8ed1b From 18800fc7a04e7df8a345e7ef4fc3064368276f83 Mon Sep 17 00:00:00 2001 From: Emilio López Date: Mon, 21 Sep 2015 10:38:22 -0300 Subject: platform/chrome: Support reading/writing the vboot context MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Some EC implementations include a small nvram space used to store verified boot context data. This patch offers a way to expose this data to userspace. Reviewed-by: Javier Martinez Canillas Signed-off-by: Emilio López Signed-off-by: Olof Johansson --- drivers/platform/chrome/Makefile | 3 +- drivers/platform/chrome/cros_ec_dev.c | 1 + drivers/platform/chrome/cros_ec_vbc.c | 137 ++++++++++++++++++++++++++++++++++ include/linux/mfd/cros_ec.h | 1 + 4 files changed, 141 insertions(+), 1 deletion(-) create mode 100644 drivers/platform/chrome/cros_ec_vbc.c (limited to 'include') diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile index 4a11b010f5d8..bc498bda8211 100644 --- a/drivers/platform/chrome/Makefile +++ b/drivers/platform/chrome/Makefile @@ -1,7 +1,8 @@ obj-$(CONFIG_CHROMEOS_LAPTOP) += chromeos_laptop.o obj-$(CONFIG_CHROMEOS_PSTORE) += chromeos_pstore.o -cros_ec_devs-objs := cros_ec_dev.o cros_ec_sysfs.o cros_ec_lightbar.o +cros_ec_devs-objs := cros_ec_dev.o cros_ec_sysfs.o \ + cros_ec_lightbar.o cros_ec_vbc.o obj-$(CONFIG_CROS_EC_CHARDEV) += cros_ec_devs.o obj-$(CONFIG_CROS_EC_LPC) += cros_ec_lpc.o obj-$(CONFIG_CROS_EC_PROTO) += cros_ec_proto.o diff --git a/drivers/platform/chrome/cros_ec_dev.c b/drivers/platform/chrome/cros_ec_dev.c index 2f4099820480..d45cd254ed1c 100644 --- a/drivers/platform/chrome/cros_ec_dev.c +++ b/drivers/platform/chrome/cros_ec_dev.c @@ -32,6 +32,7 @@ static int ec_major; static const struct attribute_group *cros_ec_groups[] = { &cros_ec_attr_group, &cros_ec_lightbar_attr_group, + &cros_ec_vbc_attr_group, NULL, }; diff --git a/drivers/platform/chrome/cros_ec_vbc.c b/drivers/platform/chrome/cros_ec_vbc.c new file mode 100644 index 000000000000..564a0d08c8bf --- /dev/null +++ b/drivers/platform/chrome/cros_ec_vbc.c @@ -0,0 +1,137 @@ +/* + * cros_ec_vbc - Expose the vboot context nvram to userspace + * + * Copyright (C) 2015 Collabora Ltd. + * + * based on vendor driver, + * + * Copyright (C) 2012 The Chromium OS Authors + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include +#include +#include +#include +#include + +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 = container_of(dev, struct cros_ec_dev, + class_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 = container_of(dev, struct cros_ec_dev, + class_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 umode_t cros_ec_vbc_is_visible(struct kobject *kobj, + struct bin_attribute *a, int n) +{ + struct device *dev = container_of(kobj, struct device, kobj); + struct cros_ec_dev *ec = container_of(dev, struct cros_ec_dev, + class_dev); + struct device_node *np = ec->ec_dev->dev->of_node; + + if (IS_ENABLED(CONFIG_OF) && np) { + if (of_property_read_bool(np, "google,has-vbc-nvram")) + return a->attr.mode; + } + + return 0; +} + +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, + .is_bin_visible = cros_ec_vbc_is_visible, +}; diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h index da72671a42fa..494682ce4bf3 100644 --- a/include/linux/mfd/cros_ec.h +++ b/include/linux/mfd/cros_ec.h @@ -255,5 +255,6 @@ int cros_ec_query_all(struct cros_ec_device *ec_dev); /* sysfs stuff */ extern struct attribute_group cros_ec_attr_group; extern struct attribute_group cros_ec_lightbar_attr_group; +extern struct attribute_group cros_ec_vbc_attr_group; #endif /* __LINUX_MFD_CROS_EC_H */ -- cgit v1.2.3-59-g8ed1b