From 0c0b7ea23aed0b55ef2f9803f13ddaae1943713d Mon Sep 17 00:00:00 2001 From: Nick Crews Date: Wed, 24 Apr 2019 10:56:50 -0600 Subject: platform/chrome: wilco_ec: Add property helper library A Property is typically a data item that is stored to NVRAM by the EC. Each of these data items has an index associated with it, known as the Property ID (PID). Properties may have variable lengths, up to a max of WILCO_EC_PROPERTY_MAX_SIZE bytes. Properties can be simple integers, or they may be more complex binary data. This patch adds support for getting and setting properties. This will be useful for setting the charge algorithm and charge schedules, which all use properties. Signed-off-by: Nick Crews Signed-off-by: Enric Balletbo i Serra --- include/linux/platform_data/wilco-ec.h | 71 ++++++++++++++++++++++++++++++++++ 1 file changed, 71 insertions(+) (limited to 'include/linux/platform_data') diff --git a/include/linux/platform_data/wilco-ec.h b/include/linux/platform_data/wilco-ec.h index 1ff224793c99..50a21bd5fd44 100644 --- a/include/linux/platform_data/wilco-ec.h +++ b/include/linux/platform_data/wilco-ec.h @@ -123,4 +123,75 @@ struct wilco_ec_message { */ int wilco_ec_mailbox(struct wilco_ec_device *ec, struct wilco_ec_message *msg); +/* + * A Property is typically a data item that is stored to NVRAM + * by the EC. Each of these data items has an index associated + * with it, known as the Property ID (PID). Properties may have + * variable lengths, up to a max of WILCO_EC_PROPERTY_MAX_SIZE + * bytes. Properties can be simple integers, or they may be more + * complex binary data. + */ + +#define WILCO_EC_PROPERTY_MAX_SIZE 4 + +/** + * struct ec_property_set_msg - Message to get or set a property. + * @property_id: Which property to get or set. + * @length: Number of bytes of |data| that are used. + * @data: Actual property data. + */ +struct wilco_ec_property_msg { + u32 property_id; + int length; + u8 data[WILCO_EC_PROPERTY_MAX_SIZE]; +}; + +/** + * wilco_ec_get_property() - Retrieve a property from the EC. + * @ec: Embedded Controller device. + * @prop_msg: Message for request and response. + * + * The property_id field of |prop_msg| should be filled before calling this + * function. The result will be stored in the data and length fields. + * + * Return: 0 on success, negative error code on failure. + */ +int wilco_ec_get_property(struct wilco_ec_device *ec, + struct wilco_ec_property_msg *prop_msg); + +/** + * wilco_ec_set_property() - Store a property on the EC. + * @ec: Embedded Controller device. + * @prop_msg: Message for request and response. + * + * The property_id, length, and data fields of |prop_msg| should be + * filled before calling this function. + * + * Return: 0 on success, negative error code on failure. + */ +int wilco_ec_set_property(struct wilco_ec_device *ec, + struct wilco_ec_property_msg *prop_msg); + +/** + * wilco_ec_get_byte_property() - Retrieve a byte-size property from the EC. + * @ec: Embedded Controller device. + * @property_id: Which property to retrieve. + * @val: The result value, will be filled by this function. + * + * Return: 0 on success, negative error code on failure. + */ +int wilco_ec_get_byte_property(struct wilco_ec_device *ec, u32 property_id, + u8 *val); + +/** + * wilco_ec_get_byte_property() - Store a byte-size property on the EC. + * @ec: Embedded Controller device. + * @property_id: Which property to store. + * @val: Value to store. + * + * Return: 0 on success, negative error code on failure. + */ +int wilco_ec_set_byte_property(struct wilco_ec_device *ec, u32 property_id, + u8 val); + #endif /* WILCO_EC_H */ -- cgit v1.2.3-59-g8ed1b From 4c1ca625c622b7a9f04c2949fd1ffdc6effa86de Mon Sep 17 00:00:00 2001 From: Nick Crews Date: Tue, 16 Apr 2019 19:20:47 -0600 Subject: platform/chrome: wilco_ec: Add Boot on AC support Boot on AC is a policy which makes the device boot from S5 when AC power is connected. This is useful for users who want to run their device headless or with a dock. Signed-off-by: Nick Crews Signed-off-by: Enric Balletbo i Serra --- Documentation/ABI/testing/sysfs-platform-wilco-ec | 9 +++ drivers/platform/chrome/wilco_ec/Makefile | 2 +- drivers/platform/chrome/wilco_ec/core.c | 9 +++ drivers/platform/chrome/wilco_ec/sysfs.c | 77 +++++++++++++++++++++++ include/linux/platform_data/wilco-ec.h | 12 ++++ 5 files changed, 108 insertions(+), 1 deletion(-) create mode 100644 Documentation/ABI/testing/sysfs-platform-wilco-ec create mode 100644 drivers/platform/chrome/wilco_ec/sysfs.c (limited to 'include/linux/platform_data') diff --git a/Documentation/ABI/testing/sysfs-platform-wilco-ec b/Documentation/ABI/testing/sysfs-platform-wilco-ec new file mode 100644 index 000000000000..8e5d6eee44db --- /dev/null +++ b/Documentation/ABI/testing/sysfs-platform-wilco-ec @@ -0,0 +1,9 @@ +What: /sys/bus/platform/devices/GOOG000C\:00/boot_on_ac +Date: April 2019 +KernelVersion: 5.3 +Description: + Boot on AC is a policy which makes the device boot from S5 + when AC power is connected. This is useful for users who + want to run their device headless or with a dock. + + Input should be parseable by kstrtou8() to 0 or 1. diff --git a/drivers/platform/chrome/wilco_ec/Makefile b/drivers/platform/chrome/wilco_ec/Makefile index 29b734137786..72df9b5e1983 100644 --- a/drivers/platform/chrome/wilco_ec/Makefile +++ b/drivers/platform/chrome/wilco_ec/Makefile @@ -1,6 +1,6 @@ # SPDX-License-Identifier: GPL-2.0 -wilco_ec-objs := core.o mailbox.o properties.o +wilco_ec-objs := core.o mailbox.o properties.o sysfs.o obj-$(CONFIG_WILCO_EC) += wilco_ec.o wilco_ec_debugfs-objs := debugfs.o obj-$(CONFIG_WILCO_EC_DEBUGFS) += wilco_ec_debugfs.o diff --git a/drivers/platform/chrome/wilco_ec/core.c b/drivers/platform/chrome/wilco_ec/core.c index 05e1e2be1c91..abd15d04e57b 100644 --- a/drivers/platform/chrome/wilco_ec/core.c +++ b/drivers/platform/chrome/wilco_ec/core.c @@ -89,8 +89,16 @@ static int wilco_ec_probe(struct platform_device *pdev) goto unregister_debugfs; } + ret = wilco_ec_add_sysfs(ec); + if (ret < 0) { + dev_err(dev, "Failed to create sysfs entries: %d", ret); + goto unregister_rtc; + } + return 0; +unregister_rtc: + platform_device_unregister(ec->rtc_pdev); unregister_debugfs: if (ec->debugfs_pdev) platform_device_unregister(ec->debugfs_pdev); @@ -102,6 +110,7 @@ static int wilco_ec_remove(struct platform_device *pdev) { struct wilco_ec_device *ec = platform_get_drvdata(pdev); + wilco_ec_remove_sysfs(ec); platform_device_unregister(ec->rtc_pdev); if (ec->debugfs_pdev) platform_device_unregister(ec->debugfs_pdev); diff --git a/drivers/platform/chrome/wilco_ec/sysfs.c b/drivers/platform/chrome/wilco_ec/sysfs.c new file mode 100644 index 000000000000..f84f0480460a --- /dev/null +++ b/drivers/platform/chrome/wilco_ec/sysfs.c @@ -0,0 +1,77 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright 2019 Google LLC + * + * Sysfs properties to view and modify EC-controlled features on Wilco devices. + * The entries will appear under /sys/bus/platform/devices/GOOG000C:00/ + * + * See Documentation/ABI/testing/sysfs-platform-wilco-ec for more information. + */ + +#include +#include + +#define CMD_KB_CMOS 0x7C +#define SUB_CMD_KB_CMOS_AUTO_ON 0x03 + +struct boot_on_ac_request { + u8 cmd; /* Always CMD_KB_CMOS */ + u8 reserved1; + u8 sub_cmd; /* Always SUB_CMD_KB_CMOS_AUTO_ON */ + u8 reserved3to5[3]; + u8 val; /* Either 0 or 1 */ + u8 reserved7; +} __packed; + +static ssize_t boot_on_ac_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct wilco_ec_device *ec = dev_get_drvdata(dev); + struct boot_on_ac_request rq; + struct wilco_ec_message msg; + int ret; + u8 val; + + ret = kstrtou8(buf, 10, &val); + if (ret < 0) + return ret; + if (val > 1) + return -EINVAL; + + memset(&rq, 0, sizeof(rq)); + rq.cmd = CMD_KB_CMOS; + rq.sub_cmd = SUB_CMD_KB_CMOS_AUTO_ON; + rq.val = val; + + memset(&msg, 0, sizeof(msg)); + msg.type = WILCO_EC_MSG_LEGACY; + msg.request_data = &rq; + msg.request_size = sizeof(rq); + ret = wilco_ec_mailbox(ec, &msg); + if (ret < 0) + return ret; + + return count; +} + +static DEVICE_ATTR_WO(boot_on_ac); + +static struct attribute *wilco_dev_attrs[] = { + &dev_attr_boot_on_ac.attr, + NULL, +}; + +static struct attribute_group wilco_dev_attr_group = { + .attrs = wilco_dev_attrs, +}; + +int wilco_ec_add_sysfs(struct wilco_ec_device *ec) +{ + return sysfs_create_group(&ec->dev->kobj, &wilco_dev_attr_group); +} + +void wilco_ec_remove_sysfs(struct wilco_ec_device *ec) +{ + sysfs_remove_group(&ec->dev->kobj, &wilco_dev_attr_group); +} diff --git a/include/linux/platform_data/wilco-ec.h b/include/linux/platform_data/wilco-ec.h index 50a21bd5fd44..af68fc0563cc 100644 --- a/include/linux/platform_data/wilco-ec.h +++ b/include/linux/platform_data/wilco-ec.h @@ -194,4 +194,16 @@ int wilco_ec_get_byte_property(struct wilco_ec_device *ec, u32 property_id, int wilco_ec_set_byte_property(struct wilco_ec_device *ec, u32 property_id, u8 val); +/** + * wilco_ec_add_sysfs() - Create sysfs entries + * @ec: Wilco EC device + * + * wilco_ec_remove_sysfs() needs to be called afterwards + * to perform the necessary cleanup. + * + * Return: 0 on success or negative error code on failure. + */ +int wilco_ec_add_sysfs(struct wilco_ec_device *ec); +void wilco_ec_remove_sysfs(struct wilco_ec_device *ec); + #endif /* WILCO_EC_H */ -- cgit v1.2.3-59-g8ed1b From 2ad1f7a91449de48d4bd5d1ec361ba7bb9026505 Mon Sep 17 00:00:00 2001 From: Nick Crews Date: Wed, 8 May 2019 15:38:09 -0600 Subject: platform/chrome: wilco_ec: Remove 256 byte transfers The 0xF6 command, intended to send and receive 256 byte payloads to and from the EC, is not needed. The 0xF5 command for 32 byte payloads is sufficient. This patch removes support for the 0xF6 command and 256 byte payloads. Signed-off-by: Nick Crews Signed-off-by: Enric Balletbo i Serra --- Documentation/ABI/testing/debugfs-wilco-ec | 16 +++++++--------- drivers/platform/chrome/wilco_ec/core.c | 4 +--- drivers/platform/chrome/wilco_ec/debugfs.c | 10 ++-------- drivers/platform/chrome/wilco_ec/mailbox.c | 21 +++++---------------- include/linux/platform_data/wilco-ec.h | 9 ++------- 5 files changed, 17 insertions(+), 43 deletions(-) (limited to 'include/linux/platform_data') diff --git a/Documentation/ABI/testing/debugfs-wilco-ec b/Documentation/ABI/testing/debugfs-wilco-ec index 73a5a66ddca6..9d8d9d2def5b 100644 --- a/Documentation/ABI/testing/debugfs-wilco-ec +++ b/Documentation/ABI/testing/debugfs-wilco-ec @@ -23,11 +23,9 @@ Description: For writing, bytes 0-1 indicate the message type, one of enum wilco_ec_msg_type. Byte 2+ consist of the data passed in the - request, starting at MBOX[0] - - At least three bytes are required for writing, two for the type - and at least a single byte of data. Only the first - EC_MAILBOX_DATA_SIZE bytes of MBOX will be used. + request, starting at MBOX[0]. At least three bytes are required + for writing, two for the type and at least a single byte of + data. Example: // Request EC info type 3 (EC firmware build date) @@ -40,7 +38,7 @@ Description: $ cat /sys/kernel/debug/wilco_ec/raw 00 00 31 32 2f 32 31 2f 31 38 00 38 00 01 00 2f 00 ..12/21/18.8... - Note that the first 32 bytes of the received MBOX[] will be - printed, even if some of the data is junk. It is up to you to - know how many of the first bytes of data are the actual - response. + Note that the first 16 bytes of the received MBOX[] will be + printed, even if some of the data is junk, and skipping bytes + 17 to 32. It is up to you to know how many of the first bytes of + data are the actual response. diff --git a/drivers/platform/chrome/wilco_ec/core.c b/drivers/platform/chrome/wilco_ec/core.c index abd15d04e57b..45cf3a5ed062 100644 --- a/drivers/platform/chrome/wilco_ec/core.c +++ b/drivers/platform/chrome/wilco_ec/core.c @@ -52,9 +52,7 @@ static int wilco_ec_probe(struct platform_device *pdev) ec->dev = dev; mutex_init(&ec->mailbox_lock); - /* Largest data buffer size requirement is extended data response */ - ec->data_size = sizeof(struct wilco_ec_response) + - EC_MAILBOX_DATA_SIZE_EXTENDED; + ec->data_size = sizeof(struct wilco_ec_response) + EC_MAILBOX_DATA_SIZE; ec->data_buffer = devm_kzalloc(dev, ec->data_size, GFP_KERNEL); if (!ec->data_buffer) return -ENOMEM; diff --git a/drivers/platform/chrome/wilco_ec/debugfs.c b/drivers/platform/chrome/wilco_ec/debugfs.c index f163476d080d..281ec595e8e0 100644 --- a/drivers/platform/chrome/wilco_ec/debugfs.c +++ b/drivers/platform/chrome/wilco_ec/debugfs.c @@ -17,13 +17,13 @@ #define DRV_NAME "wilco-ec-debugfs" /* The 256 raw bytes will take up more space when represented as a hex string */ -#define FORMATTED_BUFFER_SIZE (EC_MAILBOX_DATA_SIZE_EXTENDED * 4) +#define FORMATTED_BUFFER_SIZE (EC_MAILBOX_DATA_SIZE * 4) struct wilco_ec_debugfs { struct wilco_ec_device *ec; struct dentry *dir; size_t response_size; - u8 raw_data[EC_MAILBOX_DATA_SIZE_EXTENDED]; + u8 raw_data[EC_MAILBOX_DATA_SIZE]; u8 formatted_data[FORMATTED_BUFFER_SIZE]; }; static struct wilco_ec_debugfs *debug_info; @@ -124,12 +124,6 @@ static ssize_t raw_write(struct file *file, const char __user *user_buf, msg.response_data = debug_info->raw_data; msg.response_size = EC_MAILBOX_DATA_SIZE; - /* Telemetry commands use extended response data */ - if (msg.type == WILCO_EC_MSG_TELEMETRY_LONG) { - msg.flags |= WILCO_EC_FLAG_EXTENDED_DATA; - msg.response_size = EC_MAILBOX_DATA_SIZE_EXTENDED; - } - ret = wilco_ec_mailbox(debug_info->ec, &msg); if (ret < 0) return ret; diff --git a/drivers/platform/chrome/wilco_ec/mailbox.c b/drivers/platform/chrome/wilco_ec/mailbox.c index 7fb58b487963..ced1f9f3dcee 100644 --- a/drivers/platform/chrome/wilco_ec/mailbox.c +++ b/drivers/platform/chrome/wilco_ec/mailbox.c @@ -119,7 +119,6 @@ static int wilco_ec_transfer(struct wilco_ec_device *ec, struct wilco_ec_response *rs; u8 checksum; u8 flag; - size_t size; /* Write request header, then data */ cros_ec_lpc_io_bytes_mec(MEC_IO_WRITE, 0, sizeof(*rq), (u8 *)rq); @@ -148,21 +147,11 @@ static int wilco_ec_transfer(struct wilco_ec_device *ec, return -EIO; } - /* - * The EC always returns either EC_MAILBOX_DATA_SIZE or - * EC_MAILBOX_DATA_SIZE_EXTENDED bytes of data, so we need to - * calculate the checksum on **all** of this data, even if we - * won't use all of it. - */ - if (msg->flags & WILCO_EC_FLAG_EXTENDED_DATA) - size = EC_MAILBOX_DATA_SIZE_EXTENDED; - else - size = EC_MAILBOX_DATA_SIZE; - /* Read back response */ rs = ec->data_buffer; checksum = cros_ec_lpc_io_bytes_mec(MEC_IO_READ, 0, - sizeof(*rs) + size, (u8 *)rs); + sizeof(*rs) + EC_MAILBOX_DATA_SIZE, + (u8 *)rs); if (checksum) { dev_dbg(ec->dev, "bad packet checksum 0x%02x\n", rs->checksum); return -EBADMSG; @@ -173,9 +162,9 @@ static int wilco_ec_transfer(struct wilco_ec_device *ec, return -EBADMSG; } - if (rs->data_size != size) { - dev_dbg(ec->dev, "unexpected packet size (%u != %zu)", - rs->data_size, size); + if (rs->data_size != EC_MAILBOX_DATA_SIZE) { + dev_dbg(ec->dev, "unexpected packet size (%u != %u)", + rs->data_size, EC_MAILBOX_DATA_SIZE); return -EMSGSIZE; } diff --git a/include/linux/platform_data/wilco-ec.h b/include/linux/platform_data/wilco-ec.h index af68fc0563cc..e3ce9ce49b11 100644 --- a/include/linux/platform_data/wilco-ec.h +++ b/include/linux/platform_data/wilco-ec.h @@ -13,12 +13,9 @@ /* Message flags for using the mailbox() interface */ #define WILCO_EC_FLAG_NO_RESPONSE BIT(0) /* EC does not respond */ -#define WILCO_EC_FLAG_EXTENDED_DATA BIT(1) /* EC returns 256 data bytes */ /* Normal commands have a maximum 32 bytes of data */ #define EC_MAILBOX_DATA_SIZE 32 -/* Extended commands have 256 bytes of response data */ -#define EC_MAILBOX_DATA_SIZE_EXTENDED 256 /** * struct wilco_ec_device - Wilco Embedded Controller handle. @@ -85,14 +82,12 @@ struct wilco_ec_response { * enum wilco_ec_msg_type - Message type to select a set of command codes. * @WILCO_EC_MSG_LEGACY: Legacy EC messages for standard EC behavior. * @WILCO_EC_MSG_PROPERTY: Get/Set/Sync EC controlled NVRAM property. - * @WILCO_EC_MSG_TELEMETRY_SHORT: 32 bytes of telemetry data provided by the EC. - * @WILCO_EC_MSG_TELEMETRY_LONG: 256 bytes of telemetry data provided by the EC. + * @WILCO_EC_MSG_TELEMETRY: Request telemetry data from the EC. */ enum wilco_ec_msg_type { WILCO_EC_MSG_LEGACY = 0x00f0, WILCO_EC_MSG_PROPERTY = 0x00f2, - WILCO_EC_MSG_TELEMETRY_SHORT = 0x00f5, - WILCO_EC_MSG_TELEMETRY_LONG = 0x00f6, + WILCO_EC_MSG_TELEMETRY = 0x00f5, }; /** -- cgit v1.2.3-59-g8ed1b From 1210d1e6bad1e7ccccb19627b880a50d7c15dd51 Mon Sep 17 00:00:00 2001 From: Nick Crews Date: Tue, 21 May 2019 13:20:45 -0600 Subject: platform/chrome: wilco_ec: Add telemetry char device interface The Wilco Embedded Controller is able to send telemetry data which is useful for enterprise applications. A daemon running on the OS sends a command to the EC via a write() to a char device, and can read the response with a read(). The write() request is verified by the driver to ensure that it is performing only one of the whitelisted commands, and that no extraneous data is being transmitted to the EC. The response is passed directly back to the reader with no modification. The character device will appear as /dev/wilco_telemN, where N is some small non-negative integer, starting with 0. Only one process may have the file descriptor open at a time. The calling userspace program needs to keep the device file descriptor open between the calls to write() and read() in order to preserve the response. Up to 32 bytes will be available for reading. For testing purposes, try requesting the EC's firmware build date, by sending the WILCO_EC_TELEM_GET_VERSION command with argument index=3. i.e. write [0x38, 0x00, 0x03] to the device node. An ASCII string of the build date is returned. Signed-off-by: Nick Crews Signed-off-by: Enric Balletbo i Serra --- drivers/platform/chrome/wilco_ec/Kconfig | 7 + drivers/platform/chrome/wilco_ec/Makefile | 2 + drivers/platform/chrome/wilco_ec/core.c | 13 + drivers/platform/chrome/wilco_ec/debugfs.c | 2 +- drivers/platform/chrome/wilco_ec/telemetry.c | 450 +++++++++++++++++++++++++++ include/linux/platform_data/wilco-ec.h | 2 + 6 files changed, 475 insertions(+), 1 deletion(-) create mode 100644 drivers/platform/chrome/wilco_ec/telemetry.c (limited to 'include/linux/platform_data') diff --git a/drivers/platform/chrome/wilco_ec/Kconfig b/drivers/platform/chrome/wilco_ec/Kconfig index 2c8f6f15f28f..90336874af59 100644 --- a/drivers/platform/chrome/wilco_ec/Kconfig +++ b/drivers/platform/chrome/wilco_ec/Kconfig @@ -27,3 +27,10 @@ config WILCO_EC_EVENTS (such as power state changes) to userspace. The EC sends the events over ACPI, and a driver queues up the events to be read by a userspace daemon from /dev/wilco_event using read() and poll(). + +config WILCO_EC_TELEMETRY + tristate "Enable querying telemetry data from EC" + depends on WILCO_EC + help + If you say Y here, you get support to query EC telemetry data from + /dev/wilco_telem0 using write() and then read(). diff --git a/drivers/platform/chrome/wilco_ec/Makefile b/drivers/platform/chrome/wilco_ec/Makefile index 4d8a5f068f8b..bc817164596e 100644 --- a/drivers/platform/chrome/wilco_ec/Makefile +++ b/drivers/platform/chrome/wilco_ec/Makefile @@ -6,3 +6,5 @@ wilco_ec_debugfs-objs := debugfs.o obj-$(CONFIG_WILCO_EC_DEBUGFS) += wilco_ec_debugfs.o wilco_ec_events-objs := event.o obj-$(CONFIG_WILCO_EC_EVENTS) += wilco_ec_events.o +wilco_ec_telem-objs := telemetry.o +obj-$(CONFIG_WILCO_EC_TELEMETRY) += wilco_ec_telem.o diff --git a/drivers/platform/chrome/wilco_ec/core.c b/drivers/platform/chrome/wilco_ec/core.c index 45cf3a5ed062..3724bf4b77c6 100644 --- a/drivers/platform/chrome/wilco_ec/core.c +++ b/drivers/platform/chrome/wilco_ec/core.c @@ -93,8 +93,20 @@ static int wilco_ec_probe(struct platform_device *pdev) goto unregister_rtc; } + /* Register child device that will be found by the telemetry driver. */ + ec->telem_pdev = platform_device_register_data(dev, "wilco_telem", + PLATFORM_DEVID_AUTO, + ec, sizeof(*ec)); + if (IS_ERR(ec->telem_pdev)) { + dev_err(dev, "Failed to create telemetry platform device\n"); + ret = PTR_ERR(ec->telem_pdev); + goto remove_sysfs; + } + return 0; +remove_sysfs: + wilco_ec_remove_sysfs(ec); unregister_rtc: platform_device_unregister(ec->rtc_pdev); unregister_debugfs: @@ -109,6 +121,7 @@ static int wilco_ec_remove(struct platform_device *pdev) struct wilco_ec_device *ec = platform_get_drvdata(pdev); wilco_ec_remove_sysfs(ec); + platform_device_unregister(ec->telem_pdev); platform_device_unregister(ec->rtc_pdev); if (ec->debugfs_pdev) platform_device_unregister(ec->debugfs_pdev); diff --git a/drivers/platform/chrome/wilco_ec/debugfs.c b/drivers/platform/chrome/wilco_ec/debugfs.c index 281ec595e8e0..8d65a1e2f1a3 100644 --- a/drivers/platform/chrome/wilco_ec/debugfs.c +++ b/drivers/platform/chrome/wilco_ec/debugfs.c @@ -16,7 +16,7 @@ #define DRV_NAME "wilco-ec-debugfs" -/* The 256 raw bytes will take up more space when represented as a hex string */ +/* The raw bytes will take up more space when represented as a hex string */ #define FORMATTED_BUFFER_SIZE (EC_MAILBOX_DATA_SIZE * 4) struct wilco_ec_debugfs { diff --git a/drivers/platform/chrome/wilco_ec/telemetry.c b/drivers/platform/chrome/wilco_ec/telemetry.c new file mode 100644 index 000000000000..94cdc166c840 --- /dev/null +++ b/drivers/platform/chrome/wilco_ec/telemetry.c @@ -0,0 +1,450 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Telemetry communication for Wilco EC + * + * Copyright 2019 Google LLC + * + * The Wilco Embedded Controller is able to send telemetry data + * which is useful for enterprise applications. A daemon running on + * the OS sends a command to the EC via a write() to a char device, + * and can read the response with a read(). The write() request is + * verified by the driver to ensure that it is performing only one + * of the whitelisted commands, and that no extraneous data is + * being transmitted to the EC. The response is passed directly + * back to the reader with no modification. + * + * The character device will appear as /dev/wilco_telemN, where N + * is some small non-negative integer, starting with 0. Only one + * process may have the file descriptor open at a time. The calling + * userspace program needs to keep the device file descriptor open + * between the calls to write() and read() in order to preserve the + * response. Up to 32 bytes will be available for reading. + * + * For testing purposes, try requesting the EC's firmware build + * date, by sending the WILCO_EC_TELEM_GET_VERSION command with + * argument index=3. i.e. write [0x38, 0x00, 0x03] + * to the device node. An ASCII string of the build date is + * returned. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define TELEM_DEV_NAME "wilco_telem" +#define TELEM_CLASS_NAME TELEM_DEV_NAME +#define DRV_NAME TELEM_DEV_NAME +#define TELEM_DEV_NAME_FMT (TELEM_DEV_NAME "%d") +static struct class telem_class = { + .owner = THIS_MODULE, + .name = TELEM_CLASS_NAME, +}; + +/* Keep track of all the device numbers used. */ +#define TELEM_MAX_DEV 128 +static int telem_major; +static DEFINE_IDA(telem_ida); + +/* EC telemetry command codes */ +#define WILCO_EC_TELEM_GET_LOG 0x99 +#define WILCO_EC_TELEM_GET_VERSION 0x38 +#define WILCO_EC_TELEM_GET_FAN_INFO 0x2E +#define WILCO_EC_TELEM_GET_DIAG_INFO 0xFA +#define WILCO_EC_TELEM_GET_TEMP_INFO 0x95 +#define WILCO_EC_TELEM_GET_TEMP_READ 0x2C +#define WILCO_EC_TELEM_GET_BATT_EXT_INFO 0x07 + +#define TELEM_ARGS_SIZE_MAX 30 + +/** + * struct wilco_ec_telem_request - Telemetry command and arguments sent to EC. + * @command: One of WILCO_EC_TELEM_GET_* command codes. + * @reserved: Must be 0. + * @args: The first N bytes are one of telem_args_get_* structs, the rest is 0. + */ +struct wilco_ec_telem_request { + u8 command; + u8 reserved; + u8 args[TELEM_ARGS_SIZE_MAX]; +} __packed; + +/* + * The following telem_args_get_* structs are embedded within the |args| field + * of wilco_ec_telem_request. + */ + +struct telem_args_get_log { + u8 log_type; + u8 log_index; +} __packed; + +/* + * Get a piece of info about the EC firmware version: + * 0 = label + * 1 = svn_rev + * 2 = model_no + * 3 = build_date + * 4 = frio_version + */ +struct telem_args_get_version { + u8 index; +} __packed; + +struct telem_args_get_fan_info { + u8 command; + u8 fan_number; + u8 arg; +} __packed; + +struct telem_args_get_diag_info { + u8 type; + u8 sub_type; +} __packed; + +struct telem_args_get_temp_info { + u8 command; + u8 index; + u8 field; + u8 zone; +} __packed; + +struct telem_args_get_temp_read { + u8 sensor_index; +} __packed; + +struct telem_args_get_batt_ext_info { + u8 var_args[5]; +} __packed; + +/** + * check_telem_request() - Ensure that a request from userspace is valid. + * @rq: Request buffer copied from userspace. + * @size: Number of bytes copied from userspace. + * + * Return: 0 if valid, -EINVAL if bad command or reserved byte is non-zero, + * -EMSGSIZE if the request is too long. + * + * We do not want to allow userspace to send arbitrary telemetry commands to + * the EC. Therefore we check to ensure that + * 1. The request follows the format of struct wilco_ec_telem_request. + * 2. The supplied command code is one of the whitelisted commands. + * 3. The request only contains the necessary data for the header and arguments. + */ +static int check_telem_request(struct wilco_ec_telem_request *rq, + size_t size) +{ + size_t max_size = offsetof(struct wilco_ec_telem_request, args); + + if (rq->reserved) + return -EINVAL; + + switch (rq->command) { + case WILCO_EC_TELEM_GET_LOG: + max_size += sizeof(struct telem_args_get_log); + break; + case WILCO_EC_TELEM_GET_VERSION: + max_size += sizeof(struct telem_args_get_version); + break; + case WILCO_EC_TELEM_GET_FAN_INFO: + max_size += sizeof(struct telem_args_get_fan_info); + break; + case WILCO_EC_TELEM_GET_DIAG_INFO: + max_size += sizeof(struct telem_args_get_diag_info); + break; + case WILCO_EC_TELEM_GET_TEMP_INFO: + max_size += sizeof(struct telem_args_get_temp_info); + break; + case WILCO_EC_TELEM_GET_TEMP_READ: + max_size += sizeof(struct telem_args_get_temp_read); + break; + case WILCO_EC_TELEM_GET_BATT_EXT_INFO: + max_size += sizeof(struct telem_args_get_batt_ext_info); + break; + default: + return -EINVAL; + } + + return (size <= max_size) ? 0 : -EMSGSIZE; +} + +/** + * struct telem_device_data - Data for a Wilco EC device that queries telemetry. + * @cdev: Char dev that userspace reads and polls from. + * @dev: Device associated with the %cdev. + * @ec: Wilco EC that we will be communicating with using the mailbox interface. + * @available: Boolean of if the device can be opened. + */ +struct telem_device_data { + struct device dev; + struct cdev cdev; + struct wilco_ec_device *ec; + atomic_t available; +}; + +#define TELEM_RESPONSE_SIZE EC_MAILBOX_DATA_SIZE + +/** + * struct telem_session_data - Data that exists between open() and release(). + * @dev_data: Pointer to get back to the device data and EC. + * @request: Command and arguments sent to EC. + * @response: Response buffer of data from EC. + * @has_msg: Is there data available to read from a previous write? + */ +struct telem_session_data { + struct telem_device_data *dev_data; + struct wilco_ec_telem_request request; + u8 response[TELEM_RESPONSE_SIZE]; + bool has_msg; +}; + +/** + * telem_open() - Callback for when the device node is opened. + * @inode: inode for this char device node. + * @filp: file for this char device node. + * + * We need to ensure that after writing a command to the device, + * the same userspace process reads the corresponding result. + * Therefore, we increment a refcount on opening the device, so that + * only one process can communicate with the EC at a time. + * + * Return: 0 on success, or negative error code on failure. + */ +static int telem_open(struct inode *inode, struct file *filp) +{ + struct telem_device_data *dev_data; + struct telem_session_data *sess_data; + + /* Ensure device isn't already open */ + dev_data = container_of(inode->i_cdev, struct telem_device_data, cdev); + if (atomic_cmpxchg(&dev_data->available, 1, 0) == 0) + return -EBUSY; + + get_device(&dev_data->dev); + + sess_data = kzalloc(sizeof(*sess_data), GFP_KERNEL); + if (!sess_data) { + atomic_set(&dev_data->available, 1); + return -ENOMEM; + } + sess_data->dev_data = dev_data; + sess_data->has_msg = false; + + nonseekable_open(inode, filp); + filp->private_data = sess_data; + + return 0; +} + +static ssize_t telem_write(struct file *filp, const char __user *buf, + size_t count, loff_t *pos) +{ + struct telem_session_data *sess_data = filp->private_data; + struct wilco_ec_message msg = {}; + int ret; + + if (count > sizeof(sess_data->request)) + return -EMSGSIZE; + if (copy_from_user(&sess_data->request, buf, count)) + return -EFAULT; + ret = check_telem_request(&sess_data->request, count); + if (ret < 0) + return ret; + + memset(sess_data->response, 0, sizeof(sess_data->response)); + msg.type = WILCO_EC_MSG_TELEMETRY; + msg.request_data = &sess_data->request; + msg.request_size = sizeof(sess_data->request); + msg.response_data = sess_data->response; + msg.response_size = sizeof(sess_data->response); + + ret = wilco_ec_mailbox(sess_data->dev_data->ec, &msg); + if (ret < 0) + return ret; + if (ret != sizeof(sess_data->response)) + return -EMSGSIZE; + + sess_data->has_msg = true; + + return count; +} + +static ssize_t telem_read(struct file *filp, char __user *buf, size_t count, + loff_t *pos) +{ + struct telem_session_data *sess_data = filp->private_data; + + if (!sess_data->has_msg) + return -ENODATA; + if (count > sizeof(sess_data->response)) + return -EINVAL; + + if (copy_to_user(buf, sess_data->response, count)) + return -EFAULT; + + sess_data->has_msg = false; + + return count; +} + +static int telem_release(struct inode *inode, struct file *filp) +{ + struct telem_session_data *sess_data = filp->private_data; + + atomic_set(&sess_data->dev_data->available, 1); + put_device(&sess_data->dev_data->dev); + kfree(sess_data); + + return 0; +} + +static const struct file_operations telem_fops = { + .open = telem_open, + .write = telem_write, + .read = telem_read, + .release = telem_release, + .llseek = no_llseek, + .owner = THIS_MODULE, +}; + +/** + * telem_device_free() - Callback to free the telem_device_data structure. + * @d: The device embedded in our device data, which we have been ref counting. + * + * Once all open file descriptors are closed and the device has been removed, + * the refcount of the device will fall to 0 and this will be called. + */ +static void telem_device_free(struct device *d) +{ + struct telem_device_data *dev_data; + + dev_data = container_of(d, struct telem_device_data, dev); + kfree(dev_data); +} + +/** + * telem_device_probe() - Callback when creating a new device. + * @pdev: platform device that we will be receiving telems from. + * + * This finds a free minor number for the device, allocates and initializes + * some device data, and creates a new device and char dev node. + * + * Return: 0 on success, negative error code on failure. + */ +static int telem_device_probe(struct platform_device *pdev) +{ + struct telem_device_data *dev_data; + int error, minor; + + /* Get the next available device number */ + minor = ida_alloc_max(&telem_ida, TELEM_MAX_DEV-1, GFP_KERNEL); + if (minor < 0) { + error = minor; + dev_err(&pdev->dev, "Failed to find minor number: %d", error); + return error; + } + + dev_data = kzalloc(sizeof(*dev_data), GFP_KERNEL); + if (!dev_data) { + ida_simple_remove(&telem_ida, minor); + return -ENOMEM; + } + + /* Initialize the device data */ + dev_data->ec = dev_get_platdata(&pdev->dev); + atomic_set(&dev_data->available, 1); + platform_set_drvdata(pdev, dev_data); + + /* Initialize the device */ + dev_data->dev.devt = MKDEV(telem_major, minor); + dev_data->dev.class = &telem_class; + dev_data->dev.release = telem_device_free; + dev_set_name(&dev_data->dev, TELEM_DEV_NAME_FMT, minor); + device_initialize(&dev_data->dev); + + /* Initialize the character device and add it to userspace */; + cdev_init(&dev_data->cdev, &telem_fops); + error = cdev_device_add(&dev_data->cdev, &dev_data->dev); + if (error) { + put_device(&dev_data->dev); + ida_simple_remove(&telem_ida, minor); + return error; + } + + return 0; +} + +static int telem_device_remove(struct platform_device *pdev) +{ + struct telem_device_data *dev_data = platform_get_drvdata(pdev); + + cdev_device_del(&dev_data->cdev, &dev_data->dev); + put_device(&dev_data->dev); + ida_simple_remove(&telem_ida, MINOR(dev_data->dev.devt)); + + return 0; +} + +static struct platform_driver telem_driver = { + .probe = telem_device_probe, + .remove = telem_device_remove, + .driver = { + .name = DRV_NAME, + }, +}; + +static int __init telem_module_init(void) +{ + dev_t dev_num = 0; + int ret; + + ret = class_register(&telem_class); + if (ret) { + pr_err(DRV_NAME ": Failed registering class: %d", ret); + return ret; + } + + /* Request the kernel for device numbers, starting with minor=0 */ + ret = alloc_chrdev_region(&dev_num, 0, TELEM_MAX_DEV, TELEM_DEV_NAME); + if (ret) { + pr_err(DRV_NAME ": Failed allocating dev numbers: %d", ret); + goto destroy_class; + } + telem_major = MAJOR(dev_num); + + ret = platform_driver_register(&telem_driver); + if (ret < 0) { + pr_err(DRV_NAME ": Failed registering driver: %d\n", ret); + goto unregister_region; + } + + return 0; + +unregister_region: + unregister_chrdev_region(MKDEV(telem_major, 0), TELEM_MAX_DEV); +destroy_class: + class_unregister(&telem_class); + ida_destroy(&telem_ida); + return ret; +} + +static void __exit telem_module_exit(void) +{ + platform_driver_unregister(&telem_driver); + unregister_chrdev_region(MKDEV(telem_major, 0), TELEM_MAX_DEV); + class_unregister(&telem_class); + ida_destroy(&telem_ida); +} + +module_init(telem_module_init); +module_exit(telem_module_exit); + +MODULE_AUTHOR("Nick Crews "); +MODULE_DESCRIPTION("Wilco EC telemetry driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:" DRV_NAME); diff --git a/include/linux/platform_data/wilco-ec.h b/include/linux/platform_data/wilco-ec.h index e3ce9ce49b11..ad03b586a095 100644 --- a/include/linux/platform_data/wilco-ec.h +++ b/include/linux/platform_data/wilco-ec.h @@ -29,6 +29,7 @@ * @data_size: Size of the data buffer used for EC communication. * @debugfs_pdev: The child platform_device used by the debugfs sub-driver. * @rtc_pdev: The child platform_device used by the RTC sub-driver. + * @telem_pdev: The child platform_device used by the telemetry sub-driver. */ struct wilco_ec_device { struct device *dev; @@ -40,6 +41,7 @@ struct wilco_ec_device { size_t data_size; struct platform_device *debugfs_pdev; struct platform_device *rtc_pdev; + struct platform_device *telem_pdev; }; /** -- cgit v1.2.3-59-g8ed1b