Input: add a driver to support Hyper-V synthetic keyboard
authorK. Y. Srinivasan <kys@microsoft.com>
Wed, 18 Sep 2013 19:50:42 +0000 (12:50 -0700)
committerDmitry Torokhov <dmitry.torokhov@gmail.com>
Thu, 19 Sep 2013 15:58:02 +0000 (08:58 -0700)
Add a new driver to support synthetic keyboard. On the next generation
Hyper-V guest firmware, many legacy devices will not be emulated and this
driver will be required.

I would like to thank Vojtech Pavlik <vojtech@suse.cz> for helping me with the
details of the AT keyboard driver. I would also like to thank
Dan Carpenter <dan.carpenter@oracle.com> and
Dmitry Torokhov <dmitry.torokhov@gmail.com> for their detailed review of this
driver.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
drivers/input/serio/Kconfig
drivers/input/serio/Makefile
drivers/input/serio/hyperv-keyboard.c [new file with mode: 0644]

index 1e691a3..a5f342e 100644 (file)
@@ -267,4 +267,14 @@ config SERIO_OLPC_APSP
          To compile this driver as a module, choose M here: the module will
          be called olpc_apsp.
 
+config HYPERV_KEYBOARD
+       tristate "Microsoft Synthetic Keyboard driver"
+       depends on HYPERV
+       default HYPERV
+       help
+         Select this option to enable the Hyper-V Keyboard driver.
+
+         To compile this driver as a module, choose M here: the module will
+         be called hyperv_keyboard.
+
 endif
index 12298b1..815d874 100644 (file)
@@ -28,3 +28,4 @@ obj-$(CONFIG_SERIO_ALTERA_PS2)        += altera_ps2.o
 obj-$(CONFIG_SERIO_ARC_PS2)    += arc_ps2.o
 obj-$(CONFIG_SERIO_APBPS2)     += apbps2.o
 obj-$(CONFIG_SERIO_OLPC_APSP)  += olpc_apsp.o
+obj-$(CONFIG_HYPERV_KEYBOARD)  += hyperv-keyboard.o
diff --git a/drivers/input/serio/hyperv-keyboard.c b/drivers/input/serio/hyperv-keyboard.c
new file mode 100644 (file)
index 0000000..3a83c3c
--- /dev/null
@@ -0,0 +1,437 @@
+/*
+ *  Copyright (c) 2013, Microsoft Corporation.
+ *
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under the terms and conditions of the GNU General Public License,
+ *  version 2, as published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ *  more details.
+ */
+
+#include <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          (10 * PAGE_SIZE)
+#define KBD_VSC_RECV_RING_BUFFER_SIZE          (10 * PAGE_SIZE)
+
+#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);
+
+                       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);
+               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 hv_device *hv_dev = context;
+       void *buffer;
+       int bufferlen = 0x100; /* Start with sensible size */
+       u32 bytes_recvd;
+       u64 req_id;
+       int error;
+
+       buffer = kmalloc(bufferlen, GFP_ATOMIC);
+       if (!buffer)
+               return;
+
+       while (1) {
+               error = vmbus_recvpacket_raw(hv_dev->channel, buffer, bufferlen,
+                                            &bytes_recvd, &req_id);
+               switch (error) {
+               case 0:
+                       if (bytes_recvd == 0) {
+                               kfree(buffer);
+                               return;
+                       }
+
+                       hv_kbd_handle_received_packet(hv_dev, buffer,
+                                                     bytes_recvd, req_id);
+                       break;
+
+               case -ENOBUFS:
+                       kfree(buffer);
+                       /* Handle large packet */
+                       bufferlen = bytes_recvd;
+                       buffer = kmalloc(bytes_recvd, GFP_ATOMIC);
+                       if (!buffer)
+                               return;
+                       break;
+               }
+       }
+}
+
+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;
+
+       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);
+       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;
+}
+
+/*
+ * Keyboard GUID
+ * {f912ad6d-2b17-48ea-bd65-f927a61c7684}
+ */
+#define HV_KBD_GUID \
+       .guid = { \
+                       0x6d, 0xad, 0x12, 0xf9, 0x17, 0x2b, 0xea, 0x48, \
+                       0xbd, 0x65, 0xf9, 0x27, 0xa6, 0x1c, 0x76, 0x84 \
+       }
+
+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,
+};
+
+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_init(hv_kbd_init);
+module_exit(hv_kbd_exit);