diff options
Diffstat (limited to 'drivers/platform/chrome/wilco_ec')
| -rw-r--r-- | drivers/platform/chrome/wilco_ec/Kconfig | 38 | ||||
| -rw-r--r-- | drivers/platform/chrome/wilco_ec/Makefile | 11 | ||||
| -rw-r--r-- | drivers/platform/chrome/wilco_ec/core.c | 174 | ||||
| -rw-r--r-- | drivers/platform/chrome/wilco_ec/debugfs.c | 285 | ||||
| -rw-r--r-- | drivers/platform/chrome/wilco_ec/event.c | 581 | ||||
| -rw-r--r-- | drivers/platform/chrome/wilco_ec/keyboard_leds.c | 203 | ||||
| -rw-r--r-- | drivers/platform/chrome/wilco_ec/mailbox.c | 215 | ||||
| -rw-r--r-- | drivers/platform/chrome/wilco_ec/properties.c | 135 | ||||
| -rw-r--r-- | drivers/platform/chrome/wilco_ec/sysfs.c | 251 | ||||
| -rw-r--r-- | drivers/platform/chrome/wilco_ec/telemetry.c | 472 |
10 files changed, 2365 insertions, 0 deletions
diff --git a/drivers/platform/chrome/wilco_ec/Kconfig b/drivers/platform/chrome/wilco_ec/Kconfig new file mode 100644 index 000000000..49e8530ca --- /dev/null +++ b/drivers/platform/chrome/wilco_ec/Kconfig @@ -0,0 +1,38 @@ +# SPDX-License-Identifier: GPL-2.0-only +config WILCO_EC + tristate "ChromeOS Wilco Embedded Controller" + depends on X86 || COMPILE_TEST + depends on ACPI && CROS_EC_LPC && LEDS_CLASS + help + If you say Y here, you get support for talking to the ChromeOS + Wilco EC over an eSPI bus. This uses a simple byte-level protocol + with a checksum. + + To compile this driver as a module, choose M here: the + module will be called wilco_ec. + +config WILCO_EC_DEBUGFS + tristate "Enable raw access to EC via debugfs" + depends on WILCO_EC + help + If you say Y here, you get support for sending raw commands to + the Wilco EC via debugfs. These commands do not do any byte + manipulation and allow for testing arbitrary commands. This + interface is intended for debug only and will not be present + on production devices. + +config WILCO_EC_EVENTS + tristate "Enable event forwarding from EC to userspace" + depends on WILCO_EC + help + If you say Y here, you get support for the EC to send 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 new file mode 100644 index 000000000..ecb3145ca --- /dev/null +++ b/drivers/platform/chrome/wilco_ec/Makefile @@ -0,0 +1,11 @@ +# SPDX-License-Identifier: GPL-2.0 + +wilco_ec-objs := core.o keyboard_leds.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 +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 new file mode 100644 index 000000000..5b42992bf --- /dev/null +++ b/drivers/platform/chrome/wilco_ec/core.c @@ -0,0 +1,174 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Core driver for Wilco Embedded Controller + * + * Copyright 2018 Google LLC + * + * This is the entry point for the drivers that control the Wilco EC. + */ + +#include <linux/acpi.h> +#include <linux/device.h> +#include <linux/ioport.h> +#include <linux/module.h> +#include <linux/platform_data/wilco-ec.h> +#include <linux/platform_device.h> + +#include "../cros_ec_lpc_mec.h" + +#define DRV_NAME "wilco-ec" + +static struct resource *wilco_get_resource(struct platform_device *pdev, + int index) +{ + struct device *dev = &pdev->dev; + struct resource *res; + + res = platform_get_resource(pdev, IORESOURCE_IO, index); + if (!res) { + dev_dbg(dev, "Couldn't find IO resource %d\n", index); + return res; + } + + return devm_request_region(dev, res->start, resource_size(res), + dev_name(dev)); +} + +static int wilco_ec_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct wilco_ec_device *ec; + int ret; + + ec = devm_kzalloc(dev, sizeof(*ec), GFP_KERNEL); + if (!ec) + return -ENOMEM; + + platform_set_drvdata(pdev, ec); + ec->dev = dev; + mutex_init(&ec->mailbox_lock); + + 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; + + /* Prepare access to IO regions provided by ACPI */ + ec->io_data = wilco_get_resource(pdev, 0); /* Host Data */ + ec->io_command = wilco_get_resource(pdev, 1); /* Host Command */ + ec->io_packet = wilco_get_resource(pdev, 2); /* MEC EMI */ + if (!ec->io_data || !ec->io_command || !ec->io_packet) + return -ENODEV; + + /* Initialize cros_ec register interface for communication */ + cros_ec_lpc_mec_init(ec->io_packet->start, + ec->io_packet->start + EC_MAILBOX_DATA_SIZE); + + /* + * Register a child device that will be found by the debugfs driver. + * Ignore failure. + */ + ec->debugfs_pdev = platform_device_register_data(dev, + "wilco-ec-debugfs", + PLATFORM_DEVID_AUTO, + NULL, 0); + + /* Register a child device that will be found by the RTC driver. */ + ec->rtc_pdev = platform_device_register_data(dev, "rtc-wilco-ec", + PLATFORM_DEVID_AUTO, + NULL, 0); + if (IS_ERR(ec->rtc_pdev)) { + dev_err(dev, "Failed to create RTC platform device\n"); + ret = PTR_ERR(ec->rtc_pdev); + goto unregister_debugfs; + } + + /* Set up the keyboard backlight LEDs. */ + ret = wilco_keyboard_leds_init(ec); + if (ret < 0) { + dev_err(dev, + "Failed to initialize keyboard LEDs: %d\n", + ret); + goto unregister_rtc; + } + + ret = wilco_ec_add_sysfs(ec); + if (ret < 0) { + dev_err(dev, "Failed to create sysfs entries: %d\n", ret); + goto unregister_rtc; + } + + /* Register child device to be found by charger config driver. */ + ec->charger_pdev = platform_device_register_data(dev, "wilco-charger", + PLATFORM_DEVID_AUTO, + NULL, 0); + if (IS_ERR(ec->charger_pdev)) { + dev_err(dev, "Failed to create charger platform device\n"); + ret = PTR_ERR(ec->charger_pdev); + goto remove_sysfs; + } + + /* 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 unregister_charge_config; + } + + return 0; + +unregister_charge_config: + platform_device_unregister(ec->charger_pdev); +remove_sysfs: + wilco_ec_remove_sysfs(ec); +unregister_rtc: + platform_device_unregister(ec->rtc_pdev); +unregister_debugfs: + if (ec->debugfs_pdev) + platform_device_unregister(ec->debugfs_pdev); + cros_ec_lpc_mec_destroy(); + return ret; +} + +static int wilco_ec_remove(struct platform_device *pdev) +{ + struct wilco_ec_device *ec = platform_get_drvdata(pdev); + + platform_device_unregister(ec->telem_pdev); + platform_device_unregister(ec->charger_pdev); + wilco_ec_remove_sysfs(ec); + platform_device_unregister(ec->rtc_pdev); + if (ec->debugfs_pdev) + platform_device_unregister(ec->debugfs_pdev); + + /* Teardown cros_ec interface */ + cros_ec_lpc_mec_destroy(); + + return 0; +} + +static const struct acpi_device_id wilco_ec_acpi_device_ids[] = { + { "GOOG000C", 0 }, + { } +}; +MODULE_DEVICE_TABLE(acpi, wilco_ec_acpi_device_ids); + +static struct platform_driver wilco_ec_driver = { + .driver = { + .name = DRV_NAME, + .acpi_match_table = wilco_ec_acpi_device_ids, + }, + .probe = wilco_ec_probe, + .remove = wilco_ec_remove, +}; + +module_platform_driver(wilco_ec_driver); + +MODULE_AUTHOR("Nick Crews <ncrews@chromium.org>"); +MODULE_AUTHOR("Duncan Laurie <dlaurie@chromium.org>"); +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("ChromeOS Wilco Embedded Controller driver"); +MODULE_ALIAS("platform:" DRV_NAME); diff --git a/drivers/platform/chrome/wilco_ec/debugfs.c b/drivers/platform/chrome/wilco_ec/debugfs.c new file mode 100644 index 000000000..a812788a0 --- /dev/null +++ b/drivers/platform/chrome/wilco_ec/debugfs.c @@ -0,0 +1,285 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * debugfs attributes for Wilco EC + * + * Copyright 2019 Google LLC + * + * See Documentation/ABI/testing/debugfs-wilco-ec for usage. + */ + +#include <linux/ctype.h> +#include <linux/debugfs.h> +#include <linux/fs.h> +#include <linux/module.h> +#include <linux/platform_data/wilco-ec.h> +#include <linux/platform_device.h> + +#define DRV_NAME "wilco-ec-debugfs" + +/* 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 { + struct wilco_ec_device *ec; + struct dentry *dir; + size_t response_size; + u8 raw_data[EC_MAILBOX_DATA_SIZE]; + u8 formatted_data[FORMATTED_BUFFER_SIZE]; +}; +static struct wilco_ec_debugfs *debug_info; + +/** + * parse_hex_sentence() - Convert a ascii hex representation into byte array. + * @in: Input buffer of ascii. + * @isize: Length of input buffer. + * @out: Output buffer. + * @osize: Length of output buffer, e.g. max number of bytes to parse. + * + * An valid input is a series of ascii hexadecimal numbers, separated by spaces. + * An example valid input is + * " 00 f2 0 000076 6 0 ff" + * + * If an individual "word" within the hex sentence is longer than MAX_WORD_SIZE, + * then the sentence is illegal, and parsing will fail. + * + * Return: Number of bytes parsed, or negative error code on failure. + */ +static int parse_hex_sentence(const char *in, int isize, u8 *out, int osize) +{ + int n_parsed = 0; + int word_start = 0; + int word_end; + int word_len; + /* Temp buffer for holding a "word" of chars that represents one byte */ + #define MAX_WORD_SIZE 16 + char tmp[MAX_WORD_SIZE + 1]; + u8 byte; + + while (word_start < isize && n_parsed < osize) { + /* Find the start of the next word */ + while (word_start < isize && isspace(in[word_start])) + word_start++; + /* reached the end of the input before next word? */ + if (word_start >= isize) + break; + + /* Find the end of this word */ + word_end = word_start; + while (word_end < isize && !isspace(in[word_end])) + word_end++; + + /* Copy to a tmp NULL terminated string */ + word_len = word_end - word_start; + if (word_len > MAX_WORD_SIZE) + return -EINVAL; + memcpy(tmp, in + word_start, word_len); + tmp[word_len] = '\0'; + + /* + * Convert from hex string, place in output. If fails to parse, + * just return -EINVAL because specific error code is only + * relevant for this one word, returning it would be confusing. + */ + if (kstrtou8(tmp, 16, &byte)) + return -EINVAL; + out[n_parsed++] = byte; + + word_start = word_end; + } + return n_parsed; +} + +/* The message type takes up two bytes*/ +#define TYPE_AND_DATA_SIZE ((EC_MAILBOX_DATA_SIZE) + 2) + +static ssize_t raw_write(struct file *file, const char __user *user_buf, + size_t count, loff_t *ppos) +{ + char *buf = debug_info->formatted_data; + struct wilco_ec_message msg; + u8 request_data[TYPE_AND_DATA_SIZE]; + ssize_t kcount; + int ret; + + if (count > FORMATTED_BUFFER_SIZE) + return -EINVAL; + + kcount = simple_write_to_buffer(buf, FORMATTED_BUFFER_SIZE, ppos, + user_buf, count); + if (kcount < 0) + return kcount; + + ret = parse_hex_sentence(buf, kcount, request_data, TYPE_AND_DATA_SIZE); + if (ret < 0) + return ret; + /* Need at least two bytes for message type and one byte of data */ + if (ret < 3) + return -EINVAL; + + msg.type = request_data[0] << 8 | request_data[1]; + msg.flags = 0; + msg.request_data = request_data + 2; + msg.request_size = ret - 2; + memset(debug_info->raw_data, 0, sizeof(debug_info->raw_data)); + msg.response_data = debug_info->raw_data; + msg.response_size = EC_MAILBOX_DATA_SIZE; + + ret = wilco_ec_mailbox(debug_info->ec, &msg); + if (ret < 0) + return ret; + debug_info->response_size = ret; + + return count; +} + +static ssize_t raw_read(struct file *file, char __user *user_buf, size_t count, + loff_t *ppos) +{ + int fmt_len = 0; + + if (debug_info->response_size) { + fmt_len = hex_dump_to_buffer(debug_info->raw_data, + debug_info->response_size, + 16, 1, debug_info->formatted_data, + sizeof(debug_info->formatted_data), + true); + /* Only return response the first time it is read */ + debug_info->response_size = 0; + } + + return simple_read_from_buffer(user_buf, count, ppos, + debug_info->formatted_data, fmt_len); +} + +static const struct file_operations fops_raw = { + .owner = THIS_MODULE, + .read = raw_read, + .write = raw_write, + .llseek = no_llseek, +}; + +#define CMD_KB_CHROME 0x88 +#define SUB_CMD_H1_GPIO 0x0A +#define SUB_CMD_TEST_EVENT 0x0B + +struct ec_request { + u8 cmd; /* Always CMD_KB_CHROME */ + u8 reserved; + u8 sub_cmd; +} __packed; + +struct ec_response { + u8 status; /* 0 if allowed */ + u8 val; +} __packed; + +static int send_ec_cmd(struct wilco_ec_device *ec, u8 sub_cmd, u8 *out_val) +{ + struct ec_request rq; + struct ec_response rs; + struct wilco_ec_message msg; + int ret; + + memset(&rq, 0, sizeof(rq)); + rq.cmd = CMD_KB_CHROME; + rq.sub_cmd = sub_cmd; + + memset(&msg, 0, sizeof(msg)); + msg.type = WILCO_EC_MSG_LEGACY; + msg.request_data = &rq; + msg.request_size = sizeof(rq); + msg.response_data = &rs; + msg.response_size = sizeof(rs); + ret = wilco_ec_mailbox(ec, &msg); + if (ret < 0) + return ret; + if (rs.status) + return -EIO; + + *out_val = rs.val; + + return 0; +} + +/** + * h1_gpio_get() - Gets h1 gpio status. + * @arg: The wilco EC device. + * @val: BIT(0)=ENTRY_TO_FACT_MODE, BIT(1)=SPI_CHROME_SEL + */ +static int h1_gpio_get(void *arg, u64 *val) +{ + int ret; + + ret = send_ec_cmd(arg, SUB_CMD_H1_GPIO, (u8 *)val); + if (ret == 0) + *val &= 0xFF; + return ret; +} + +DEFINE_DEBUGFS_ATTRIBUTE(fops_h1_gpio, h1_gpio_get, NULL, "0x%02llx\n"); + +/** + * test_event_set() - Sends command to EC to cause an EC test event. + * @arg: The wilco EC device. + * @val: unused. + */ +static int test_event_set(void *arg, u64 val) +{ + u8 ret; + + return send_ec_cmd(arg, SUB_CMD_TEST_EVENT, &ret); +} + +/* Format is unused since it is only required for get method which is NULL */ +DEFINE_DEBUGFS_ATTRIBUTE(fops_test_event, NULL, test_event_set, "%llu\n"); + +/** + * wilco_ec_debugfs_probe() - Create the debugfs node + * @pdev: The platform device, probably created in core.c + * + * Try to create a debugfs node. If it fails, then we don't want to change + * behavior at all, this is for debugging after all. Just fail silently. + * + * Return: 0 always. + */ +static int wilco_ec_debugfs_probe(struct platform_device *pdev) +{ + struct wilco_ec_device *ec = dev_get_drvdata(pdev->dev.parent); + + debug_info = devm_kzalloc(&pdev->dev, sizeof(*debug_info), GFP_KERNEL); + if (!debug_info) + return 0; + debug_info->ec = ec; + debug_info->dir = debugfs_create_dir("wilco_ec", NULL); + if (!debug_info->dir) + return 0; + debugfs_create_file("raw", 0644, debug_info->dir, NULL, &fops_raw); + debugfs_create_file("h1_gpio", 0444, debug_info->dir, ec, + &fops_h1_gpio); + debugfs_create_file("test_event", 0200, debug_info->dir, ec, + &fops_test_event); + + return 0; +} + +static int wilco_ec_debugfs_remove(struct platform_device *pdev) +{ + debugfs_remove_recursive(debug_info->dir); + + return 0; +} + +static struct platform_driver wilco_ec_debugfs_driver = { + .driver = { + .name = DRV_NAME, + }, + .probe = wilco_ec_debugfs_probe, + .remove = wilco_ec_debugfs_remove, +}; + +module_platform_driver(wilco_ec_debugfs_driver); + +MODULE_ALIAS("platform:" DRV_NAME); +MODULE_AUTHOR("Nick Crews <ncrews@chromium.org>"); +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("Wilco EC debugfs driver"); diff --git a/drivers/platform/chrome/wilco_ec/event.c b/drivers/platform/chrome/wilco_ec/event.c new file mode 100644 index 000000000..32e400590 --- /dev/null +++ b/drivers/platform/chrome/wilco_ec/event.c @@ -0,0 +1,581 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * ACPI event handling for Wilco Embedded Controller + * + * Copyright 2019 Google LLC + * + * The Wilco Embedded Controller can create custom events that + * are not handled as standard ACPI objects. These events can + * contain information about changes in EC controlled features, + * such as errors and events in the dock or display. For example, + * an event is triggered if the dock is plugged into a display + * incorrectly. These events are needed for telemetry and + * diagnostics reasons, and for possibly alerting the user. + + * These events are triggered by the EC with an ACPI Notify(0x90), + * and then the BIOS reads the event buffer from EC RAM via an + * ACPI method. When the OS receives these events via ACPI, + * it passes them along to this driver. The events are put into + * a queue which can be read by a userspace daemon via a char device + * that implements read() and poll(). The event queue acts as a + * circular buffer of size 64, so if there are no userspace consumers + * the kernel will not run out of memory. The char device will appear at + * /dev/wilco_event{n}, where n is some small non-negative integer, + * starting from 0. Standard ACPI events such as the battery getting + * plugged/unplugged can also come through this path, but they are + * dealt with via other paths, and are ignored here. + + * To test, you can tail the binary data with + * $ cat /dev/wilco_event0 | hexdump -ve '1/1 "%x\n"' + * and then create an event by plugging/unplugging the battery. + */ + +#include <linux/acpi.h> +#include <linux/cdev.h> +#include <linux/device.h> +#include <linux/fs.h> +#include <linux/idr.h> +#include <linux/io.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/poll.h> +#include <linux/spinlock.h> +#include <linux/uaccess.h> +#include <linux/wait.h> + +/* ACPI Notify event code indicating event data is available. */ +#define EC_ACPI_NOTIFY_EVENT 0x90 +/* ACPI Method to execute to retrieve event data buffer from the EC. */ +#define EC_ACPI_GET_EVENT "QSET" +/* Maximum number of words in event data returned by the EC. */ +#define EC_ACPI_MAX_EVENT_WORDS 6 +#define EC_ACPI_MAX_EVENT_SIZE \ + (sizeof(struct ec_event) + (EC_ACPI_MAX_EVENT_WORDS) * sizeof(u16)) + +/* Node will appear in /dev/EVENT_DEV_NAME */ +#define EVENT_DEV_NAME "wilco_event" +#define EVENT_CLASS_NAME EVENT_DEV_NAME +#define DRV_NAME EVENT_DEV_NAME +#define EVENT_DEV_NAME_FMT (EVENT_DEV_NAME "%d") +static struct class event_class = { + .owner = THIS_MODULE, + .name = EVENT_CLASS_NAME, +}; + +/* Keep track of all the device numbers used. */ +#define EVENT_MAX_DEV 128 +static int event_major; +static DEFINE_IDA(event_ida); + +/* Size of circular queue of events. */ +#define MAX_NUM_EVENTS 64 + +/** + * struct ec_event - Extended event returned by the EC. + * @size: Number of 16bit words in structure after the size word. + * @type: Extended event type, meaningless for us. + * @event: Event data words. Max count is %EC_ACPI_MAX_EVENT_WORDS. + */ +struct ec_event { + u16 size; + u16 type; + u16 event[]; +} __packed; + +#define ec_event_num_words(ev) (ev->size - 1) +#define ec_event_size(ev) (sizeof(*ev) + (ec_event_num_words(ev) * sizeof(u16))) + +/** + * struct ec_event_queue - Circular queue for events. + * @capacity: Number of elements the queue can hold. + * @head: Next index to write to. + * @tail: Next index to read from. + * @entries: Array of events. + */ +struct ec_event_queue { + int capacity; + int head; + int tail; + struct ec_event *entries[]; +}; + +/* Maximum number of events to store in ec_event_queue */ +static int queue_size = 64; +module_param(queue_size, int, 0644); + +static struct ec_event_queue *event_queue_new(int capacity) +{ + struct ec_event_queue *q; + + q = kzalloc(struct_size(q, entries, capacity), GFP_KERNEL); + if (!q) + return NULL; + + q->capacity = capacity; + + return q; +} + +static inline bool event_queue_empty(struct ec_event_queue *q) +{ + /* head==tail when both full and empty, but head==NULL when empty */ + return q->head == q->tail && !q->entries[q->head]; +} + +static inline bool event_queue_full(struct ec_event_queue *q) +{ + /* head==tail when both full and empty, but head!=NULL when full */ + return q->head == q->tail && q->entries[q->head]; +} + +static struct ec_event *event_queue_pop(struct ec_event_queue *q) +{ + struct ec_event *ev; + + if (event_queue_empty(q)) + return NULL; + + ev = q->entries[q->tail]; + q->entries[q->tail] = NULL; + q->tail = (q->tail + 1) % q->capacity; + + return ev; +} + +/* + * If full, overwrite the oldest event and return it so the caller + * can kfree it. If not full, return NULL. + */ +static struct ec_event *event_queue_push(struct ec_event_queue *q, + struct ec_event *ev) +{ + struct ec_event *popped = NULL; + + if (event_queue_full(q)) + popped = event_queue_pop(q); + q->entries[q->head] = ev; + q->head = (q->head + 1) % q->capacity; + + return popped; +} + +static void event_queue_free(struct ec_event_queue *q) +{ + struct ec_event *event; + + while ((event = event_queue_pop(q)) != NULL) + kfree(event); + + kfree(q); +} + +/** + * struct event_device_data - Data for a Wilco EC device that responds to ACPI. + * @events: Circular queue of EC events to be provided to userspace. + * @queue_lock: Protect the queue from simultaneous read/writes. + * @wq: Wait queue to notify processes when events are available or the + * device has been removed. + * @cdev: Char dev that userspace reads() and polls() from. + * @dev: Device associated with the %cdev. + * @exist: Has the device been not been removed? Once a device has been removed, + * writes, reads, and new opens will fail. + * @available: Guarantee only one client can open() file and read from queue. + * + * There will be one of these structs for each ACPI device registered. This data + * is the queue of events received from ACPI that still need to be read from + * userspace, the device and char device that userspace is using, a wait queue + * used to notify different threads when something has changed, plus a flag + * on whether the ACPI device has been removed. + */ +struct event_device_data { + struct ec_event_queue *events; + spinlock_t queue_lock; + wait_queue_head_t wq; + struct device dev; + struct cdev cdev; + bool exist; + atomic_t available; +}; + +/** + * enqueue_events() - Place EC events in queue to be read by userspace. + * @adev: Device the events came from. + * @buf: Buffer of event data. + * @length: Length of event data buffer. + * + * %buf contains a number of ec_event's, packed one after the other. + * Each ec_event is of variable length. Start with the first event, copy it + * into a persistent ec_event, store that entry in the queue, move on + * to the next ec_event in buf, and repeat. + * + * Return: 0 on success or negative error code on failure. + */ +static int enqueue_events(struct acpi_device *adev, const u8 *buf, u32 length) +{ + struct event_device_data *dev_data = adev->driver_data; + struct ec_event *event, *queue_event, *old_event; + size_t num_words, event_size; + u32 offset = 0; + + while (offset < length) { + event = (struct ec_event *)(buf + offset); + + num_words = ec_event_num_words(event); + event_size = ec_event_size(event); + if (num_words > EC_ACPI_MAX_EVENT_WORDS) { + dev_err(&adev->dev, "Too many event words: %zu > %d\n", + num_words, EC_ACPI_MAX_EVENT_WORDS); + return -EOVERFLOW; + } + + /* Ensure event does not overflow the available buffer */ + if ((offset + event_size) > length) { + dev_err(&adev->dev, "Event exceeds buffer: %zu > %d\n", + offset + event_size, length); + return -EOVERFLOW; + } + + /* Point to the next event in the buffer */ + offset += event_size; + + /* Copy event into the queue */ + queue_event = kmemdup(event, event_size, GFP_KERNEL); + if (!queue_event) + return -ENOMEM; + spin_lock(&dev_data->queue_lock); + old_event = event_queue_push(dev_data->events, queue_event); + spin_unlock(&dev_data->queue_lock); + kfree(old_event); + wake_up_interruptible(&dev_data->wq); + } + + return 0; +} + +/** + * event_device_notify() - Callback when EC generates an event over ACPI. + * @adev: The device that the event is coming from. + * @value: Value passed to Notify() in ACPI. + * + * This function will read the events from the device and enqueue them. + */ +static void event_device_notify(struct acpi_device *adev, u32 value) +{ + struct acpi_buffer event_buffer = { ACPI_ALLOCATE_BUFFER, NULL }; + union acpi_object *obj; + acpi_status status; + + if (value != EC_ACPI_NOTIFY_EVENT) { + dev_err(&adev->dev, "Invalid event: 0x%08x\n", value); + return; + } + + /* Execute ACPI method to get event data buffer. */ + status = acpi_evaluate_object(adev->handle, EC_ACPI_GET_EVENT, + NULL, &event_buffer); + if (ACPI_FAILURE(status)) { + dev_err(&adev->dev, "Error executing ACPI method %s()\n", + EC_ACPI_GET_EVENT); + return; + } + + obj = (union acpi_object *)event_buffer.pointer; + if (!obj) { + dev_err(&adev->dev, "Nothing returned from %s()\n", + EC_ACPI_GET_EVENT); + return; + } + if (obj->type != ACPI_TYPE_BUFFER) { + dev_err(&adev->dev, "Invalid object returned from %s()\n", + EC_ACPI_GET_EVENT); + kfree(obj); + return; + } + if (obj->buffer.length < sizeof(struct ec_event)) { + dev_err(&adev->dev, "Invalid buffer length %d from %s()\n", + obj->buffer.length, EC_ACPI_GET_EVENT); + kfree(obj); + return; + } + + enqueue_events(adev, obj->buffer.pointer, obj->buffer.length); + kfree(obj); +} + +static int event_open(struct inode *inode, struct file *filp) +{ + struct event_device_data *dev_data; + + dev_data = container_of(inode->i_cdev, struct event_device_data, cdev); + if (!dev_data->exist) + return -ENODEV; + + if (atomic_cmpxchg(&dev_data->available, 1, 0) == 0) + return -EBUSY; + + /* Increase refcount on device so dev_data is not freed */ + get_device(&dev_data->dev); + stream_open(inode, filp); + filp->private_data = dev_data; + + return 0; +} + +static __poll_t event_poll(struct file *filp, poll_table *wait) +{ + struct event_device_data *dev_data = filp->private_data; + __poll_t mask = 0; + + poll_wait(filp, &dev_data->wq, wait); + if (!dev_data->exist) + return EPOLLHUP; + if (!event_queue_empty(dev_data->events)) + mask |= EPOLLIN | EPOLLRDNORM | EPOLLPRI; + return mask; +} + +/** + * event_read() - Callback for passing event data to userspace via read(). + * @filp: The file we are reading from. + * @buf: Pointer to userspace buffer to fill with one event. + * @count: Number of bytes requested. Must be at least EC_ACPI_MAX_EVENT_SIZE. + * @pos: File position pointer, irrelevant since we don't support seeking. + * + * Removes the first event from the queue, places it in the passed buffer. + * + * If there are no events in the queue, then one of two things happens, + * depending on if the file was opened in nonblocking mode: If in nonblocking + * mode, then return -EAGAIN to say there's no data. If in blocking mode, then + * block until an event is available. + * + * Return: Number of bytes placed in buffer, negative error code on failure. + */ +static ssize_t event_read(struct file *filp, char __user *buf, size_t count, + loff_t *pos) +{ + struct event_device_data *dev_data = filp->private_data; + struct ec_event *event; + ssize_t n_bytes_written = 0; + int err; + + /* We only will give them the entire event at once */ + if (count != 0 && count < EC_ACPI_MAX_EVENT_SIZE) + return -EINVAL; + + spin_lock(&dev_data->queue_lock); + while (event_queue_empty(dev_data->events)) { + spin_unlock(&dev_data->queue_lock); + if (filp->f_flags & O_NONBLOCK) + return -EAGAIN; + + err = wait_event_interruptible(dev_data->wq, + !event_queue_empty(dev_data->events) || + !dev_data->exist); + if (err) + return err; + + /* Device was removed as we waited? */ + if (!dev_data->exist) + return -ENODEV; + spin_lock(&dev_data->queue_lock); + } + event = event_queue_pop(dev_data->events); + spin_unlock(&dev_data->queue_lock); + n_bytes_written = ec_event_size(event); + if (copy_to_user(buf, event, n_bytes_written)) + n_bytes_written = -EFAULT; + kfree(event); + + return n_bytes_written; +} + +static int event_release(struct inode *inode, struct file *filp) +{ + struct event_device_data *dev_data = filp->private_data; + + atomic_set(&dev_data->available, 1); + put_device(&dev_data->dev); + + return 0; +} + +static const struct file_operations event_fops = { + .open = event_open, + .poll = event_poll, + .read = event_read, + .release = event_release, + .llseek = no_llseek, + .owner = THIS_MODULE, +}; + +/** + * free_device_data() - Callback to free the event_device_data structure. + * @d: The device embedded in our device data, which we have been ref counting. + * + * This is called only after event_device_remove() has been called and all + * userspace programs have called event_release() on all the open file + * descriptors. + */ +static void free_device_data(struct device *d) +{ + struct event_device_data *dev_data; + + dev_data = container_of(d, struct event_device_data, dev); + event_queue_free(dev_data->events); + kfree(dev_data); +} + +static void hangup_device(struct event_device_data *dev_data) +{ + dev_data->exist = false; + /* Wake up the waiting processes so they can close. */ + wake_up_interruptible(&dev_data->wq); + put_device(&dev_data->dev); +} + +/** + * event_device_add() - Callback when creating a new device. + * @adev: ACPI device that we will be receiving events 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. + * + * The device data is freed in free_device_data(), which is called when + * %dev_data->dev is release()ed. This happens after all references to + * %dev_data->dev are dropped, which happens once both event_device_remove() + * has been called and every open()ed file descriptor has been release()ed. + * + * Return: 0 on success, negative error code on failure. + */ +static int event_device_add(struct acpi_device *adev) +{ + struct event_device_data *dev_data; + int error, minor; + + minor = ida_alloc_max(&event_ida, EVENT_MAX_DEV-1, GFP_KERNEL); + if (minor < 0) { + error = minor; + dev_err(&adev->dev, "Failed to find minor number: %d\n", error); + return error; + } + + dev_data = kzalloc(sizeof(*dev_data), GFP_KERNEL); + if (!dev_data) { + error = -ENOMEM; + goto free_minor; + } + + /* Initialize the device data. */ + adev->driver_data = dev_data; + dev_data->events = event_queue_new(queue_size); + if (!dev_data->events) { + kfree(dev_data); + error = -ENOMEM; + goto free_minor; + } + spin_lock_init(&dev_data->queue_lock); + init_waitqueue_head(&dev_data->wq); + dev_data->exist = true; + atomic_set(&dev_data->available, 1); + + /* Initialize the device. */ + dev_data->dev.devt = MKDEV(event_major, minor); + dev_data->dev.class = &event_class; + dev_data->dev.release = free_device_data; + dev_set_name(&dev_data->dev, EVENT_DEV_NAME_FMT, minor); + device_initialize(&dev_data->dev); + + /* Initialize the character device, and add it to userspace. */ + cdev_init(&dev_data->cdev, &event_fops); + error = cdev_device_add(&dev_data->cdev, &dev_data->dev); + if (error) + goto free_dev_data; + + return 0; + +free_dev_data: + hangup_device(dev_data); +free_minor: + ida_simple_remove(&event_ida, minor); + return error; +} + +static int event_device_remove(struct acpi_device *adev) +{ + struct event_device_data *dev_data = adev->driver_data; + + cdev_device_del(&dev_data->cdev, &dev_data->dev); + ida_simple_remove(&event_ida, MINOR(dev_data->dev.devt)); + hangup_device(dev_data); + + return 0; +} + +static const struct acpi_device_id event_acpi_ids[] = { + { "GOOG000D", 0 }, + { } +}; +MODULE_DEVICE_TABLE(acpi, event_acpi_ids); + +static struct acpi_driver event_driver = { + .name = DRV_NAME, + .class = DRV_NAME, + .ids = event_acpi_ids, + .ops = { + .add = event_device_add, + .notify = event_device_notify, + .remove = event_device_remove, + }, + .owner = THIS_MODULE, +}; + +static int __init event_module_init(void) +{ + dev_t dev_num = 0; + int ret; + + ret = class_register(&event_class); + if (ret) { + pr_err(DRV_NAME ": Failed registering class: %d\n", ret); + return ret; + } + + /* Request device numbers, starting with minor=0. Save the major num. */ + ret = alloc_chrdev_region(&dev_num, 0, EVENT_MAX_DEV, EVENT_DEV_NAME); + if (ret) { + pr_err(DRV_NAME ": Failed allocating dev numbers: %d\n", ret); + goto destroy_class; + } + event_major = MAJOR(dev_num); + + ret = acpi_bus_register_driver(&event_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(event_major, 0), EVENT_MAX_DEV); +destroy_class: + class_unregister(&event_class); + ida_destroy(&event_ida); + return ret; +} + +static void __exit event_module_exit(void) +{ + acpi_bus_unregister_driver(&event_driver); + unregister_chrdev_region(MKDEV(event_major, 0), EVENT_MAX_DEV); + class_unregister(&event_class); + ida_destroy(&event_ida); +} + +module_init(event_module_init); +module_exit(event_module_exit); + +MODULE_AUTHOR("Nick Crews <ncrews@chromium.org>"); +MODULE_DESCRIPTION("Wilco EC ACPI event driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:" DRV_NAME); diff --git a/drivers/platform/chrome/wilco_ec/keyboard_leds.c b/drivers/platform/chrome/wilco_ec/keyboard_leds.c new file mode 100644 index 000000000..6ce9c6782 --- /dev/null +++ b/drivers/platform/chrome/wilco_ec/keyboard_leds.c @@ -0,0 +1,203 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Keyboard backlight LED driver for the Wilco Embedded Controller + * + * Copyright 2019 Google LLC + * + * Since the EC will never change the backlight level of its own accord, + * we don't need to implement a brightness_get() method. + */ + +#include <linux/device.h> +#include <linux/kernel.h> +#include <linux/leds.h> +#include <linux/platform_data/wilco-ec.h> +#include <linux/slab.h> + +#define WILCO_EC_COMMAND_KBBL 0x75 +#define WILCO_KBBL_MODE_FLAG_PWM BIT(1) /* Set brightness by percent. */ +#define WILCO_KBBL_DEFAULT_BRIGHTNESS 0 + +struct wilco_keyboard_leds { + struct wilco_ec_device *ec; + struct led_classdev keyboard; +}; + +enum wilco_kbbl_subcommand { + WILCO_KBBL_SUBCMD_GET_FEATURES = 0x00, + WILCO_KBBL_SUBCMD_GET_STATE = 0x01, + WILCO_KBBL_SUBCMD_SET_STATE = 0x02, +}; + +/** + * struct wilco_keyboard_leds_msg - Message to/from EC for keyboard LED control. + * @command: Always WILCO_EC_COMMAND_KBBL. + * @status: Set by EC to 0 on success, 0xFF on failure. + * @subcmd: One of enum wilco_kbbl_subcommand. + * @reserved3: Should be 0. + * @mode: Bit flags for used mode, we want to use WILCO_KBBL_MODE_FLAG_PWM. + * @reserved5to8: Should be 0. + * @percent: Brightness in 0-100. Only meaningful in PWM mode. + * @reserved10to15: Should be 0. + */ +struct wilco_keyboard_leds_msg { + u8 command; + u8 status; + u8 subcmd; + u8 reserved3; + u8 mode; + u8 reserved5to8[4]; + u8 percent; + u8 reserved10to15[6]; +} __packed; + +/* Send a request, get a response, and check that the response is good. */ +static int send_kbbl_msg(struct wilco_ec_device *ec, + struct wilco_keyboard_leds_msg *request, + struct wilco_keyboard_leds_msg *response) +{ + struct wilco_ec_message msg; + int ret; + + memset(&msg, 0, sizeof(msg)); + msg.type = WILCO_EC_MSG_LEGACY; + msg.request_data = request; + msg.request_size = sizeof(*request); + msg.response_data = response; + msg.response_size = sizeof(*response); + + ret = wilco_ec_mailbox(ec, &msg); + if (ret < 0) { + dev_err(ec->dev, + "Failed sending keyboard LEDs command: %d\n", ret); + return ret; + } + + return 0; +} + +static int set_kbbl(struct wilco_ec_device *ec, enum led_brightness brightness) +{ + struct wilco_keyboard_leds_msg request; + struct wilco_keyboard_leds_msg response; + int ret; + + memset(&request, 0, sizeof(request)); + request.command = WILCO_EC_COMMAND_KBBL; + request.subcmd = WILCO_KBBL_SUBCMD_SET_STATE; + request.mode = WILCO_KBBL_MODE_FLAG_PWM; + request.percent = brightness; + + ret = send_kbbl_msg(ec, &request, &response); + if (ret < 0) + return ret; + + if (response.status) { + dev_err(ec->dev, + "EC reported failure sending keyboard LEDs command: %d\n", + response.status); + return -EIO; + } + + return 0; +} + +static int kbbl_exist(struct wilco_ec_device *ec, bool *exists) +{ + struct wilco_keyboard_leds_msg request; + struct wilco_keyboard_leds_msg response; + int ret; + + memset(&request, 0, sizeof(request)); + request.command = WILCO_EC_COMMAND_KBBL; + request.subcmd = WILCO_KBBL_SUBCMD_GET_FEATURES; + + ret = send_kbbl_msg(ec, &request, &response); + if (ret < 0) + return ret; + + *exists = response.status != 0xFF; + + return 0; +} + +/** + * kbbl_init() - Initialize the state of the keyboard backlight. + * @ec: EC device to talk to. + * + * Gets the current brightness, ensuring that the BIOS already initialized the + * backlight to PWM mode. If not in PWM mode, then the current brightness is + * meaningless, so set the brightness to WILCO_KBBL_DEFAULT_BRIGHTNESS. + * + * Return: Final brightness of the keyboard, or negative error code on failure. + */ +static int kbbl_init(struct wilco_ec_device *ec) +{ + struct wilco_keyboard_leds_msg request; + struct wilco_keyboard_leds_msg response; + int ret; + + memset(&request, 0, sizeof(request)); + request.command = WILCO_EC_COMMAND_KBBL; + request.subcmd = WILCO_KBBL_SUBCMD_GET_STATE; + + ret = send_kbbl_msg(ec, &request, &response); + if (ret < 0) + return ret; + + if (response.status) { + dev_err(ec->dev, + "EC reported failure sending keyboard LEDs command: %d\n", + response.status); + return -EIO; + } + + if (response.mode & WILCO_KBBL_MODE_FLAG_PWM) + return response.percent; + + ret = set_kbbl(ec, WILCO_KBBL_DEFAULT_BRIGHTNESS); + if (ret < 0) + return ret; + + return WILCO_KBBL_DEFAULT_BRIGHTNESS; +} + +static int wilco_keyboard_leds_set(struct led_classdev *cdev, + enum led_brightness brightness) +{ + struct wilco_keyboard_leds *wkl = + container_of(cdev, struct wilco_keyboard_leds, keyboard); + return set_kbbl(wkl->ec, brightness); +} + +int wilco_keyboard_leds_init(struct wilco_ec_device *ec) +{ + struct wilco_keyboard_leds *wkl; + bool leds_exist; + int ret; + + ret = kbbl_exist(ec, &leds_exist); + if (ret < 0) { + dev_err(ec->dev, + "Failed checking keyboard LEDs support: %d\n", ret); + return ret; + } + if (!leds_exist) + return 0; + + wkl = devm_kzalloc(ec->dev, sizeof(*wkl), GFP_KERNEL); + if (!wkl) + return -ENOMEM; + + wkl->ec = ec; + wkl->keyboard.name = "platform::kbd_backlight"; + wkl->keyboard.max_brightness = 100; + wkl->keyboard.flags = LED_CORE_SUSPENDRESUME; + wkl->keyboard.brightness_set_blocking = wilco_keyboard_leds_set; + ret = kbbl_init(ec); + if (ret < 0) + return ret; + wkl->keyboard.brightness = ret; + + return devm_led_classdev_register(ec->dev, &wkl->keyboard); +} diff --git a/drivers/platform/chrome/wilco_ec/mailbox.c b/drivers/platform/chrome/wilco_ec/mailbox.c new file mode 100644 index 000000000..0f98358ea --- /dev/null +++ b/drivers/platform/chrome/wilco_ec/mailbox.c @@ -0,0 +1,215 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Mailbox interface for Wilco Embedded Controller + * + * Copyright 2018 Google LLC + * + * The Wilco EC is similar to a typical ChromeOS embedded controller. + * It uses the same MEC based low-level communication and a similar + * protocol, but with some important differences. The EC firmware does + * not support the same mailbox commands so it is not registered as a + * cros_ec device type. + * + * Most messages follow a standard format, but there are some exceptions + * and an interface is provided to do direct/raw transactions that do not + * make assumptions about byte placement. + */ + +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/io.h> +#include <linux/platform_data/wilco-ec.h> +#include <linux/platform_device.h> + +#include "../cros_ec_lpc_mec.h" + +/* Version of mailbox interface */ +#define EC_MAILBOX_VERSION 0 + +/* Command to start mailbox transaction */ +#define EC_MAILBOX_START_COMMAND 0xda + +/* Version of EC protocol */ +#define EC_MAILBOX_PROTO_VERSION 3 + +/* Number of header bytes to be counted as data bytes */ +#define EC_MAILBOX_DATA_EXTRA 2 + +/* Maximum timeout */ +#define EC_MAILBOX_TIMEOUT HZ + +/* EC response flags */ +#define EC_CMDR_DATA BIT(0) /* Data ready for host to read */ +#define EC_CMDR_PENDING BIT(1) /* Write pending to EC */ +#define EC_CMDR_BUSY BIT(2) /* EC is busy processing a command */ +#define EC_CMDR_CMD BIT(3) /* Last host write was a command */ + +/** + * wilco_ec_response_timed_out() - Wait for EC response. + * @ec: EC device. + * + * Return: true if EC timed out, false if EC did not time out. + */ +static bool wilco_ec_response_timed_out(struct wilco_ec_device *ec) +{ + unsigned long timeout = jiffies + EC_MAILBOX_TIMEOUT; + + do { + if (!(inb(ec->io_command->start) & + (EC_CMDR_PENDING | EC_CMDR_BUSY))) + return false; + usleep_range(100, 200); + } while (time_before(jiffies, timeout)); + + return true; +} + +/** + * wilco_ec_checksum() - Compute 8-bit checksum over data range. + * @data: Data to checksum. + * @size: Number of bytes to checksum. + * + * Return: 8-bit checksum of provided data. + */ +static u8 wilco_ec_checksum(const void *data, size_t size) +{ + u8 *data_bytes = (u8 *)data; + u8 checksum = 0; + size_t i; + + for (i = 0; i < size; i++) + checksum += data_bytes[i]; + + return checksum; +} + +/** + * wilco_ec_prepare() - Prepare the request structure for the EC. + * @msg: EC message with request information. + * @rq: EC request structure to fill. + */ +static void wilco_ec_prepare(struct wilco_ec_message *msg, + struct wilco_ec_request *rq) +{ + memset(rq, 0, sizeof(*rq)); + rq->struct_version = EC_MAILBOX_PROTO_VERSION; + rq->mailbox_id = msg->type; + rq->mailbox_version = EC_MAILBOX_VERSION; + rq->data_size = msg->request_size; + + /* Checksum header and data */ + rq->checksum = wilco_ec_checksum(rq, sizeof(*rq)); + rq->checksum += wilco_ec_checksum(msg->request_data, msg->request_size); + rq->checksum = -rq->checksum; +} + +/** + * wilco_ec_transfer() - Perform actual data transfer. + * @ec: EC device. + * @msg: EC message data for request and response. + * @rq: Filled in request structure + * + * Context: ec->mailbox_lock should be held while using this function. + * Return: number of bytes received or negative error code on failure. + */ +static int wilco_ec_transfer(struct wilco_ec_device *ec, + struct wilco_ec_message *msg, + struct wilco_ec_request *rq) +{ + struct wilco_ec_response *rs; + u8 checksum; + u8 flag; + + /* Write request header, then data */ + cros_ec_lpc_io_bytes_mec(MEC_IO_WRITE, 0, sizeof(*rq), (u8 *)rq); + cros_ec_lpc_io_bytes_mec(MEC_IO_WRITE, sizeof(*rq), msg->request_size, + msg->request_data); + + /* Start the command */ + outb(EC_MAILBOX_START_COMMAND, ec->io_command->start); + + /* For some commands (eg shutdown) the EC will not respond, that's OK */ + if (msg->flags & WILCO_EC_FLAG_NO_RESPONSE) { + dev_dbg(ec->dev, "EC does not respond to this command\n"); + return 0; + } + + /* Wait for it to complete */ + if (wilco_ec_response_timed_out(ec)) { + dev_dbg(ec->dev, "response timed out\n"); + return -ETIMEDOUT; + } + + /* Check result */ + flag = inb(ec->io_data->start); + if (flag) { + dev_dbg(ec->dev, "bad response: 0x%02x\n", flag); + return -EIO; + } + + /* Read back response */ + rs = ec->data_buffer; + checksum = cros_ec_lpc_io_bytes_mec(MEC_IO_READ, 0, + sizeof(*rs) + EC_MAILBOX_DATA_SIZE, + (u8 *)rs); + if (checksum) { + dev_dbg(ec->dev, "bad packet checksum 0x%02x\n", rs->checksum); + return -EBADMSG; + } + + if (rs->result) { + dev_dbg(ec->dev, "EC reported failure: 0x%02x\n", rs->result); + return -EBADMSG; + } + + if (rs->data_size != EC_MAILBOX_DATA_SIZE) { + dev_dbg(ec->dev, "unexpected packet size (%u != %u)\n", + rs->data_size, EC_MAILBOX_DATA_SIZE); + return -EMSGSIZE; + } + + if (rs->data_size < msg->response_size) { + dev_dbg(ec->dev, "EC didn't return enough data (%u < %zu)\n", + rs->data_size, msg->response_size); + return -EMSGSIZE; + } + + memcpy(msg->response_data, rs->data, msg->response_size); + + return rs->data_size; +} + +/** + * wilco_ec_mailbox() - Send EC request and receive EC response. + * @ec: EC device. + * @msg: EC message data for request and response. + * + * On entry msg->type, msg->request_size, and msg->request_data should all be + * filled in. If desired, msg->flags can be set. + * + * If a response is expected, msg->response_size should be set, and + * msg->response_data should point to a buffer with enough space. On exit + * msg->response_data will be filled. + * + * Return: number of bytes received or negative error code on failure. + */ +int wilco_ec_mailbox(struct wilco_ec_device *ec, struct wilco_ec_message *msg) +{ + struct wilco_ec_request *rq; + int ret; + + dev_dbg(ec->dev, "type=%04x flags=%02x rslen=%zu rqlen=%zu\n", + msg->type, msg->flags, msg->response_size, msg->request_size); + + mutex_lock(&ec->mailbox_lock); + /* Prepare request packet */ + rq = ec->data_buffer; + wilco_ec_prepare(msg, rq); + + ret = wilco_ec_transfer(ec, msg, rq); + mutex_unlock(&ec->mailbox_lock); + + return ret; + +} +EXPORT_SYMBOL_GPL(wilco_ec_mailbox); diff --git a/drivers/platform/chrome/wilco_ec/properties.c b/drivers/platform/chrome/wilco_ec/properties.c new file mode 100644 index 000000000..c2bf4c95c --- /dev/null +++ b/drivers/platform/chrome/wilco_ec/properties.c @@ -0,0 +1,135 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright 2019 Google LLC + */ + +#include <linux/errno.h> +#include <linux/export.h> +#include <linux/platform_data/wilco-ec.h> +#include <linux/string.h> +#include <linux/types.h> +#include <asm/unaligned.h> + +/* Operation code; what the EC should do with the property */ +enum ec_property_op { + EC_OP_GET = 0, + EC_OP_SET = 1, +}; + +struct ec_property_request { + u8 op; /* One of enum ec_property_op */ + u8 property_id[4]; /* The 32 bit PID is stored Little Endian */ + u8 length; + u8 data[WILCO_EC_PROPERTY_MAX_SIZE]; +} __packed; + +struct ec_property_response { + u8 reserved[2]; + u8 op; /* One of enum ec_property_op */ + u8 property_id[4]; /* The 32 bit PID is stored Little Endian */ + u8 length; + u8 data[WILCO_EC_PROPERTY_MAX_SIZE]; +} __packed; + +static int send_property_msg(struct wilco_ec_device *ec, + struct ec_property_request *rq, + struct ec_property_response *rs) +{ + struct wilco_ec_message ec_msg; + int ret; + + memset(&ec_msg, 0, sizeof(ec_msg)); + ec_msg.type = WILCO_EC_MSG_PROPERTY; + ec_msg.request_data = rq; + ec_msg.request_size = sizeof(*rq); + ec_msg.response_data = rs; + ec_msg.response_size = sizeof(*rs); + + ret = wilco_ec_mailbox(ec, &ec_msg); + if (ret < 0) + return ret; + if (rs->op != rq->op) + return -EBADMSG; + if (memcmp(rq->property_id, rs->property_id, sizeof(rs->property_id))) + return -EBADMSG; + + return 0; +} + +int wilco_ec_get_property(struct wilco_ec_device *ec, + struct wilco_ec_property_msg *prop_msg) +{ + struct ec_property_request rq; + struct ec_property_response rs; + int ret; + + memset(&rq, 0, sizeof(rq)); + rq.op = EC_OP_GET; + put_unaligned_le32(prop_msg->property_id, rq.property_id); + + ret = send_property_msg(ec, &rq, &rs); + if (ret < 0) + return ret; + + prop_msg->length = rs.length; + memcpy(prop_msg->data, rs.data, rs.length); + + return 0; +} +EXPORT_SYMBOL_GPL(wilco_ec_get_property); + +int wilco_ec_set_property(struct wilco_ec_device *ec, + struct wilco_ec_property_msg *prop_msg) +{ + struct ec_property_request rq; + struct ec_property_response rs; + int ret; + + memset(&rq, 0, sizeof(rq)); + rq.op = EC_OP_SET; + put_unaligned_le32(prop_msg->property_id, rq.property_id); + rq.length = prop_msg->length; + memcpy(rq.data, prop_msg->data, prop_msg->length); + + ret = send_property_msg(ec, &rq, &rs); + if (ret < 0) + return ret; + if (rs.length != prop_msg->length) + return -EBADMSG; + + return 0; +} +EXPORT_SYMBOL_GPL(wilco_ec_set_property); + +int wilco_ec_get_byte_property(struct wilco_ec_device *ec, u32 property_id, + u8 *val) +{ + struct wilco_ec_property_msg msg; + int ret; + + msg.property_id = property_id; + + ret = wilco_ec_get_property(ec, &msg); + if (ret < 0) + return ret; + if (msg.length != 1) + return -EBADMSG; + + *val = msg.data[0]; + + return 0; +} +EXPORT_SYMBOL_GPL(wilco_ec_get_byte_property); + +int wilco_ec_set_byte_property(struct wilco_ec_device *ec, u32 property_id, + u8 val) +{ + struct wilco_ec_property_msg msg; + + msg.property_id = property_id; + msg.data[0] = val; + msg.length = 1; + + return wilco_ec_set_property(ec, &msg); +} +EXPORT_SYMBOL_GPL(wilco_ec_set_byte_property); diff --git a/drivers/platform/chrome/wilco_ec/sysfs.c b/drivers/platform/chrome/wilco_ec/sysfs.c new file mode 100644 index 000000000..79a5e8fa6 --- /dev/null +++ b/drivers/platform/chrome/wilco_ec/sysfs.c @@ -0,0 +1,251 @@ +// 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 <linux/device.h> +#include <linux/kernel.h> +#include <linux/platform_data/wilco-ec.h> +#include <linux/string.h> +#include <linux/sysfs.h> +#include <linux/types.h> + +#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; + +#define CMD_USB_CHARGE 0x39 + +enum usb_charge_op { + USB_CHARGE_GET = 0, + USB_CHARGE_SET = 1, +}; + +struct usb_charge_request { + u8 cmd; /* Always CMD_USB_CHARGE */ + u8 reserved; + u8 op; /* One of enum usb_charge_op */ + u8 val; /* When setting, either 0 or 1 */ +} __packed; + +struct usb_charge_response { + u8 reserved; + u8 status; /* Set by EC to 0 on success, other value on failure */ + u8 val; /* When getting, set by EC to either 0 or 1 */ +} __packed; + +#define CMD_EC_INFO 0x38 +enum get_ec_info_op { + CMD_GET_EC_LABEL = 0, + CMD_GET_EC_REV = 1, + CMD_GET_EC_MODEL = 2, + CMD_GET_EC_BUILD_DATE = 3, +}; + +struct get_ec_info_req { + u8 cmd; /* Always CMD_EC_INFO */ + u8 reserved; + u8 op; /* One of enum get_ec_info_op */ +} __packed; + +struct get_ec_info_resp { + u8 reserved[2]; + char value[9]; /* __nonstring: might not be null terminated */ +} __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 ssize_t get_info(struct device *dev, char *buf, enum get_ec_info_op op) +{ + struct wilco_ec_device *ec = dev_get_drvdata(dev); + struct get_ec_info_req req = { .cmd = CMD_EC_INFO, .op = op }; + struct get_ec_info_resp resp; + int ret; + + struct wilco_ec_message msg = { + .type = WILCO_EC_MSG_LEGACY, + .request_data = &req, + .request_size = sizeof(req), + .response_data = &resp, + .response_size = sizeof(resp), + }; + + ret = wilco_ec_mailbox(ec, &msg); + if (ret < 0) + return ret; + + return scnprintf(buf, PAGE_SIZE, "%.*s\n", (int)sizeof(resp.value), + (char *)&resp.value); +} + +static ssize_t version_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + return get_info(dev, buf, CMD_GET_EC_LABEL); +} + +static DEVICE_ATTR_RO(version); + +static ssize_t build_revision_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return get_info(dev, buf, CMD_GET_EC_REV); +} + +static DEVICE_ATTR_RO(build_revision); + +static ssize_t build_date_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return get_info(dev, buf, CMD_GET_EC_BUILD_DATE); +} + +static DEVICE_ATTR_RO(build_date); + +static ssize_t model_number_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return get_info(dev, buf, CMD_GET_EC_MODEL); +} + +static DEVICE_ATTR_RO(model_number); + +static int send_usb_charge(struct wilco_ec_device *ec, + struct usb_charge_request *rq, + struct usb_charge_response *rs) +{ + struct wilco_ec_message msg; + int ret; + + memset(&msg, 0, sizeof(msg)); + msg.type = WILCO_EC_MSG_LEGACY; + msg.request_data = rq; + msg.request_size = sizeof(*rq); + msg.response_data = rs; + msg.response_size = sizeof(*rs); + ret = wilco_ec_mailbox(ec, &msg); + if (ret < 0) + return ret; + if (rs->status) + return -EIO; + + return 0; +} + +static ssize_t usb_charge_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct wilco_ec_device *ec = dev_get_drvdata(dev); + struct usb_charge_request rq; + struct usb_charge_response rs; + int ret; + + memset(&rq, 0, sizeof(rq)); + rq.cmd = CMD_USB_CHARGE; + rq.op = USB_CHARGE_GET; + + ret = send_usb_charge(ec, &rq, &rs); + if (ret < 0) + return ret; + + return sprintf(buf, "%d\n", rs.val); +} + +static ssize_t usb_charge_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct wilco_ec_device *ec = dev_get_drvdata(dev); + struct usb_charge_request rq; + struct usb_charge_response rs; + 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_USB_CHARGE; + rq.op = USB_CHARGE_SET; + rq.val = val; + + ret = send_usb_charge(ec, &rq, &rs); + if (ret < 0) + return ret; + + return count; +} + +static DEVICE_ATTR_RW(usb_charge); + +static struct attribute *wilco_dev_attrs[] = { + &dev_attr_boot_on_ac.attr, + &dev_attr_build_date.attr, + &dev_attr_build_revision.attr, + &dev_attr_model_number.attr, + &dev_attr_usb_charge.attr, + &dev_attr_version.attr, + NULL, +}; + +static const 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/drivers/platform/chrome/wilco_ec/telemetry.c b/drivers/platform/chrome/wilco_ec/telemetry.c new file mode 100644 index 000000000..60da7a29f --- /dev/null +++ b/drivers/platform/chrome/wilco_ec/telemetry.c @@ -0,0 +1,472 @@ +// 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 allowlisted 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 <linux/cdev.h> +#include <linux/device.h> +#include <linux/fs.h> +#include <linux/module.h> +#include <linux/platform_data/wilco-ec.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/types.h> +#include <linux/uaccess.h> + +#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 WILCO_EC_TELEM_GET_BATT_PPID_INFO 0x8A + +#define TELEM_ARGS_SIZE_MAX 30 + +/* + * 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; + +struct telem_args_get_batt_ppid_info { + u8 always1; /* Should always be 1 */ +} __packed; + +/** + * 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; + union { + u8 buf[TELEM_ARGS_SIZE_MAX]; + struct telem_args_get_log get_log; + struct telem_args_get_version get_version; + struct telem_args_get_fan_info get_fan_info; + struct telem_args_get_diag_info get_diag_info; + struct telem_args_get_temp_info get_temp_info; + struct telem_args_get_temp_read get_temp_read; + struct telem_args_get_batt_ext_info get_batt_ext_info; + struct telem_args_get_batt_ppid_info get_batt_ppid_info; + } args; +} __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 allowlisted 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(rq->args.get_log); + break; + case WILCO_EC_TELEM_GET_VERSION: + max_size += sizeof(rq->args.get_version); + break; + case WILCO_EC_TELEM_GET_FAN_INFO: + max_size += sizeof(rq->args.get_fan_info); + break; + case WILCO_EC_TELEM_GET_DIAG_INFO: + max_size += sizeof(rq->args.get_diag_info); + break; + case WILCO_EC_TELEM_GET_TEMP_INFO: + max_size += sizeof(rq->args.get_temp_info); + break; + case WILCO_EC_TELEM_GET_TEMP_READ: + max_size += sizeof(rq->args.get_temp_read); + break; + case WILCO_EC_TELEM_GET_BATT_EXT_INFO: + max_size += sizeof(rq->args.get_batt_ext_info); + break; + case WILCO_EC_TELEM_GET_BATT_PPID_INFO: + if (rq->args.get_batt_ppid_info.always1 != 1) + return -EINVAL; + + max_size += sizeof(rq->args.get_batt_ppid_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; + + stream_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; + memset(&sess_data->request, 0, sizeof(sess_data->request)); + 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\n", 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); + ida_simple_remove(&telem_ida, MINOR(dev_data->dev.devt)); + put_device(&dev_data->dev); + + 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\n", 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\n", 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 <ncrews@chromium.org>"); +MODULE_DESCRIPTION("Wilco EC telemetry driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:" DRV_NAME); |