diff options
Diffstat (limited to 'drivers/input/serio/hyperv-keyboard.c')
| -rw-r--r-- | drivers/input/serio/hyperv-keyboard.c | 442 |
1 files changed, 442 insertions, 0 deletions
diff --git a/drivers/input/serio/hyperv-keyboard.c b/drivers/input/serio/hyperv-keyboard.c new file mode 100644 index 000000000..1a7b72a90 --- /dev/null +++ b/drivers/input/serio/hyperv-keyboard.c @@ -0,0 +1,442 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2013, Microsoft Corporation. + */ + +#include <linux/init.h> +#include <linux/module.h> +#include <linux/device.h> +#include <linux/completion.h> +#include <linux/hyperv.h> +#include <linux/serio.h> +#include <linux/slab.h> + +/* + * Current version 1.0 + * + */ +#define SYNTH_KBD_VERSION_MAJOR 1 +#define SYNTH_KBD_VERSION_MINOR 0 +#define SYNTH_KBD_VERSION (SYNTH_KBD_VERSION_MINOR | \ + (SYNTH_KBD_VERSION_MAJOR << 16)) + + +/* + * Message types in the synthetic input protocol + */ +enum synth_kbd_msg_type { + SYNTH_KBD_PROTOCOL_REQUEST = 1, + SYNTH_KBD_PROTOCOL_RESPONSE = 2, + SYNTH_KBD_EVENT = 3, + SYNTH_KBD_LED_INDICATORS = 4, +}; + +/* + * Basic message structures. + */ +struct synth_kbd_msg_hdr { + __le32 type; +}; + +struct synth_kbd_msg { + struct synth_kbd_msg_hdr header; + char data[]; /* Enclosed message */ +}; + +union synth_kbd_version { + __le32 version; +}; + +/* + * Protocol messages + */ +struct synth_kbd_protocol_request { + struct synth_kbd_msg_hdr header; + union synth_kbd_version version_requested; +}; + +#define PROTOCOL_ACCEPTED BIT(0) +struct synth_kbd_protocol_response { + struct synth_kbd_msg_hdr header; + __le32 proto_status; +}; + +#define IS_UNICODE BIT(0) +#define IS_BREAK BIT(1) +#define IS_E0 BIT(2) +#define IS_E1 BIT(3) +struct synth_kbd_keystroke { + struct synth_kbd_msg_hdr header; + __le16 make_code; + __le16 reserved0; + __le32 info; /* Additional information */ +}; + + +#define HK_MAXIMUM_MESSAGE_SIZE 256 + +#define KBD_VSC_SEND_RING_BUFFER_SIZE VMBUS_RING_SIZE(36 * 1024) +#define KBD_VSC_RECV_RING_BUFFER_SIZE VMBUS_RING_SIZE(36 * 1024) + +#define XTKBD_EMUL0 0xe0 +#define XTKBD_EMUL1 0xe1 +#define XTKBD_RELEASE 0x80 + + +/* + * Represents a keyboard device + */ +struct hv_kbd_dev { + struct hv_device *hv_dev; + struct serio *hv_serio; + struct synth_kbd_protocol_request protocol_req; + struct synth_kbd_protocol_response protocol_resp; + /* Synchronize the request/response if needed */ + struct completion wait_event; + spinlock_t lock; /* protects 'started' field */ + bool started; +}; + +static void hv_kbd_on_receive(struct hv_device *hv_dev, + struct synth_kbd_msg *msg, u32 msg_length) +{ + struct hv_kbd_dev *kbd_dev = hv_get_drvdata(hv_dev); + struct synth_kbd_keystroke *ks_msg; + unsigned long flags; + u32 msg_type = __le32_to_cpu(msg->header.type); + u32 info; + u16 scan_code; + + switch (msg_type) { + case SYNTH_KBD_PROTOCOL_RESPONSE: + /* + * Validate the information provided by the host. + * If the host is giving us a bogus packet, + * drop the packet (hoping the problem + * goes away). + */ + if (msg_length < sizeof(struct synth_kbd_protocol_response)) { + dev_err(&hv_dev->device, + "Illegal protocol response packet (len: %d)\n", + msg_length); + break; + } + + memcpy(&kbd_dev->protocol_resp, msg, + sizeof(struct synth_kbd_protocol_response)); + complete(&kbd_dev->wait_event); + break; + + case SYNTH_KBD_EVENT: + /* + * Validate the information provided by the host. + * If the host is giving us a bogus packet, + * drop the packet (hoping the problem + * goes away). + */ + if (msg_length < sizeof(struct synth_kbd_keystroke)) { + dev_err(&hv_dev->device, + "Illegal keyboard event packet (len: %d)\n", + msg_length); + break; + } + + ks_msg = (struct synth_kbd_keystroke *)msg; + info = __le32_to_cpu(ks_msg->info); + + /* + * Inject the information through the serio interrupt. + */ + spin_lock_irqsave(&kbd_dev->lock, flags); + if (kbd_dev->started) { + if (info & IS_E0) + serio_interrupt(kbd_dev->hv_serio, + XTKBD_EMUL0, 0); + if (info & IS_E1) + serio_interrupt(kbd_dev->hv_serio, + XTKBD_EMUL1, 0); + scan_code = __le16_to_cpu(ks_msg->make_code); + if (info & IS_BREAK) + scan_code |= XTKBD_RELEASE; + + serio_interrupt(kbd_dev->hv_serio, scan_code, 0); + } + spin_unlock_irqrestore(&kbd_dev->lock, flags); + + /* + * Only trigger a wakeup on key down, otherwise + * "echo freeze > /sys/power/state" can't really enter the + * state because the Enter-UP can trigger a wakeup at once. + */ + if (!(info & IS_BREAK)) + pm_wakeup_hard_event(&hv_dev->device); + + break; + + default: + dev_err(&hv_dev->device, + "unhandled message type %d\n", msg_type); + } +} + +static void hv_kbd_handle_received_packet(struct hv_device *hv_dev, + struct vmpacket_descriptor *desc, + u32 bytes_recvd, + u64 req_id) +{ + struct synth_kbd_msg *msg; + u32 msg_sz; + + switch (desc->type) { + case VM_PKT_COMP: + break; + + case VM_PKT_DATA_INBAND: + /* + * We have a packet that has "inband" data. The API used + * for retrieving the packet guarantees that the complete + * packet is read. So, minimally, we should be able to + * parse the payload header safely (assuming that the host + * can be trusted. Trusting the host seems to be a + * reasonable assumption because in a virtualized + * environment there is not whole lot you can do if you + * don't trust the host. + * + * Nonetheless, let us validate if the host can be trusted + * (in a trivial way). The interesting aspect of this + * validation is how do you recover if we discover that the + * host is not to be trusted? Simply dropping the packet, I + * don't think is an appropriate recovery. In the interest + * of failing fast, it may be better to crash the guest. + * For now, I will just drop the packet! + */ + + msg_sz = bytes_recvd - (desc->offset8 << 3); + if (msg_sz <= sizeof(struct synth_kbd_msg_hdr)) { + /* + * Drop the packet and hope + * the problem magically goes away. + */ + dev_err(&hv_dev->device, + "Illegal packet (type: %d, tid: %llx, size: %d)\n", + desc->type, req_id, msg_sz); + break; + } + + msg = (void *)desc + (desc->offset8 << 3); + hv_kbd_on_receive(hv_dev, msg, msg_sz); + break; + + default: + dev_err(&hv_dev->device, + "unhandled packet type %d, tid %llx len %d\n", + desc->type, req_id, bytes_recvd); + break; + } +} + +static void hv_kbd_on_channel_callback(void *context) +{ + struct vmpacket_descriptor *desc; + struct hv_device *hv_dev = context; + u32 bytes_recvd; + u64 req_id; + + foreach_vmbus_pkt(desc, hv_dev->channel) { + bytes_recvd = desc->len8 * 8; + req_id = desc->trans_id; + + hv_kbd_handle_received_packet(hv_dev, desc, bytes_recvd, + req_id); + } +} + +static int hv_kbd_connect_to_vsp(struct hv_device *hv_dev) +{ + struct hv_kbd_dev *kbd_dev = hv_get_drvdata(hv_dev); + struct synth_kbd_protocol_request *request; + struct synth_kbd_protocol_response *response; + u32 proto_status; + int error; + + reinit_completion(&kbd_dev->wait_event); + + request = &kbd_dev->protocol_req; + memset(request, 0, sizeof(struct synth_kbd_protocol_request)); + request->header.type = __cpu_to_le32(SYNTH_KBD_PROTOCOL_REQUEST); + request->version_requested.version = __cpu_to_le32(SYNTH_KBD_VERSION); + + error = vmbus_sendpacket(hv_dev->channel, request, + sizeof(struct synth_kbd_protocol_request), + (unsigned long)request, + VM_PKT_DATA_INBAND, + VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED); + if (error) + return error; + + if (!wait_for_completion_timeout(&kbd_dev->wait_event, 10 * HZ)) + return -ETIMEDOUT; + + response = &kbd_dev->protocol_resp; + proto_status = __le32_to_cpu(response->proto_status); + if (!(proto_status & PROTOCOL_ACCEPTED)) { + dev_err(&hv_dev->device, + "synth_kbd protocol request failed (version %d)\n", + SYNTH_KBD_VERSION); + return -ENODEV; + } + + return 0; +} + +static int hv_kbd_start(struct serio *serio) +{ + struct hv_kbd_dev *kbd_dev = serio->port_data; + unsigned long flags; + + spin_lock_irqsave(&kbd_dev->lock, flags); + kbd_dev->started = true; + spin_unlock_irqrestore(&kbd_dev->lock, flags); + + return 0; +} + +static void hv_kbd_stop(struct serio *serio) +{ + struct hv_kbd_dev *kbd_dev = serio->port_data; + unsigned long flags; + + spin_lock_irqsave(&kbd_dev->lock, flags); + kbd_dev->started = false; + spin_unlock_irqrestore(&kbd_dev->lock, flags); +} + +static int hv_kbd_probe(struct hv_device *hv_dev, + const struct hv_vmbus_device_id *dev_id) +{ + struct hv_kbd_dev *kbd_dev; + struct serio *hv_serio; + int error; + + kbd_dev = kzalloc(sizeof(struct hv_kbd_dev), GFP_KERNEL); + hv_serio = kzalloc(sizeof(struct serio), GFP_KERNEL); + if (!kbd_dev || !hv_serio) { + error = -ENOMEM; + goto err_free_mem; + } + + kbd_dev->hv_dev = hv_dev; + kbd_dev->hv_serio = hv_serio; + spin_lock_init(&kbd_dev->lock); + init_completion(&kbd_dev->wait_event); + hv_set_drvdata(hv_dev, kbd_dev); + + hv_serio->dev.parent = &hv_dev->device; + hv_serio->id.type = SERIO_8042_XL; + hv_serio->port_data = kbd_dev; + strlcpy(hv_serio->name, dev_name(&hv_dev->device), + sizeof(hv_serio->name)); + strlcpy(hv_serio->phys, dev_name(&hv_dev->device), + sizeof(hv_serio->phys)); + + hv_serio->start = hv_kbd_start; + hv_serio->stop = hv_kbd_stop; + + error = vmbus_open(hv_dev->channel, + KBD_VSC_SEND_RING_BUFFER_SIZE, + KBD_VSC_RECV_RING_BUFFER_SIZE, + NULL, 0, + hv_kbd_on_channel_callback, + hv_dev); + if (error) + goto err_free_mem; + + error = hv_kbd_connect_to_vsp(hv_dev); + if (error) + goto err_close_vmbus; + + serio_register_port(kbd_dev->hv_serio); + + device_init_wakeup(&hv_dev->device, true); + + return 0; + +err_close_vmbus: + vmbus_close(hv_dev->channel); +err_free_mem: + kfree(hv_serio); + kfree(kbd_dev); + return error; +} + +static int hv_kbd_remove(struct hv_device *hv_dev) +{ + struct hv_kbd_dev *kbd_dev = hv_get_drvdata(hv_dev); + + serio_unregister_port(kbd_dev->hv_serio); + vmbus_close(hv_dev->channel); + kfree(kbd_dev); + + hv_set_drvdata(hv_dev, NULL); + + return 0; +} + +static int hv_kbd_suspend(struct hv_device *hv_dev) +{ + vmbus_close(hv_dev->channel); + + return 0; +} + +static int hv_kbd_resume(struct hv_device *hv_dev) +{ + int ret; + + ret = vmbus_open(hv_dev->channel, + KBD_VSC_SEND_RING_BUFFER_SIZE, + KBD_VSC_RECV_RING_BUFFER_SIZE, + NULL, 0, + hv_kbd_on_channel_callback, + hv_dev); + if (ret == 0) + ret = hv_kbd_connect_to_vsp(hv_dev); + + return ret; +} + +static const struct hv_vmbus_device_id id_table[] = { + /* Keyboard guid */ + { HV_KBD_GUID, }, + { }, +}; + +MODULE_DEVICE_TABLE(vmbus, id_table); + +static struct hv_driver hv_kbd_drv = { + .name = KBUILD_MODNAME, + .id_table = id_table, + .probe = hv_kbd_probe, + .remove = hv_kbd_remove, + .suspend = hv_kbd_suspend, + .resume = hv_kbd_resume, + .driver = { + .probe_type = PROBE_PREFER_ASYNCHRONOUS, + }, +}; + +static int __init hv_kbd_init(void) +{ + return vmbus_driver_register(&hv_kbd_drv); +} + +static void __exit hv_kbd_exit(void) +{ + vmbus_driver_unregister(&hv_kbd_drv); +} + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Microsoft Hyper-V Synthetic Keyboard Driver"); + +module_init(hv_kbd_init); +module_exit(hv_kbd_exit); |