From a9298824599e570c8f95f8617b84fea72da74d47 Mon Sep 17 00:00:00 2001 From: Drew Fisher Date: Sun, 23 Oct 2011 19:23:24 -0700 Subject: [PATCH 1/1] Initial commit of a proof-of-concept TouchMouse driver built on libusb. I'll want to give this an actual API, rework it atop libhid instead of libusb for other platforms (libusb on OSX can't unbind the HID driver), and do lots of cleanup, but first let's get this in git. Signed-off-by: Drew Fisher --- Makefile | 7 + touchmouse.c | 368 +++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 375 insertions(+) create mode 100644 Makefile create mode 100644 touchmouse.c diff --git a/Makefile b/Makefile new file mode 100644 index 0000000..6c085ac --- /dev/null +++ b/Makefile @@ -0,0 +1,7 @@ +CC=gcc +CFLAGS=-lusb-1.0 + +touchmouse: touchmouse.c + +clean: + rm -f report diff --git a/touchmouse.c b/touchmouse.c new file mode 100644 index 0000000..405c236 --- /dev/null +++ b/touchmouse.c @@ -0,0 +1,368 @@ +/* Copyright 2011 Drew Fisher (drew.m.fisher@gmail.com). All rights reserved. + * + * Redistribution and use in source and binary forms, with or without modification, are + * permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, this list of + * conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright notice, this list + * of conditions and the following disclaimer in the documentation and/or other materials + * provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER ''AS IS'' AND ANY EXPRESS OR IMPLIED + * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND + * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR + * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON + * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF + * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * The views and conclusions contained in the software and documentation are those of the + * authors and should not be interpreted as representing official policies, either expressed + * or implied, of the copyright holder. +*/ +#include +#include +#include +#include +#include + +int quit = 0; + +// A signal handler so we can ^C cleanly +void handler(int signum) { + printf("Caught signal, quitting\n"); + quit = 1; +} + +#pragma pack(1) +// The USB HID reports that contain our data are always 32 bytes, with the +// following structure: +typedef struct { + uint8_t report_id; // HID report ID. In this case, we only care about the + // ones that have report_id 0x27. + uint8_t length; // Length of the useful data in this transfer, including + // both timestamp and data[] buffer. + uint32_t magic; // Four magic bytes. These are always the same: + // 0x14 0x01 0x00 0x51 + uint8_t timestamp; // Measured in milliseconds since the last series of + // touch events began, but wraps at 256. If two or + // more consecutive transfers have the same timestamp, + // it is likely that their data should be taken + // together + uint8_t data[25]; // Compressed touchmouse image data. Only length-1 + // bytes of this buffer are useful. +} report; +#pragma pack() + +// The image that we get is 181 bytes that are part of a 13x15 (195 pixel) +// grid laid out like this: +// +// 1 2 3 4 5 6 7 8 9 a b c d e f +// -----------------------------+ +// 0 0 0 0 0 0 0 0 0 | 1 +// 0 0 0 0 0 0 0 0 0 0 0 | 2 +// 0 0 0 0 0 0 0 0 0 0 0 0 0 | 3 +// 0 0 0 0 0 0 0 0 0 0 0 0 0 | 4 +// 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0| 5 +// 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0| 6 +// 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0| 7 +// 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0| 8 +// 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0| 9 +// 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0| 10 +// 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0| 11 +// 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0| 12 +// 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0| 13 +// +// Each "pixel" in the image may have one of 15 values - 0 through 0xE. We +// receive a stream of nybbles that encodes these 181 bytes, but should present +// the unpacked version to the client. +// +// The data we receive is ordered as is English - left to right, top to bottom. +// +// When processing nybbles, it turns out we should process the less-significant +// nybble first and the more-significant nybble second. +// +// The compression scheme is simple - pixels are expressed with their raw value +// (0 - E) unless there is a run of at least three 0's, in which case two nybbles +// F, X encode a run of X+3 zeroes. Since zeroes are the most common value, this +// results in a decent amount of compression. +// +// Note that the usable touch area on the mouse may be even smaller than this 181 +// pixel arrangement - some of even these pixels may always give a value of 0. + +typedef void (*touchmouse_callback)(void* dev, uint8_t* image, uint8_t timestamp); + +// Tracks internal state of the decoder +typedef struct { + int buf_index; + int next_is_run_encoded; + uint8_t partial_image[181]; + uint8_t image[195]; + touchmouse_callback cb; +} decoder; + +void print_table(void* placeholder, uint8_t* image, uint8_t timestamp) { + // Sample callback - simply print out the table. + int row; + printf("Current touch state:\n"); + for(row = 0; row < 13 ; row++) { + int col; + for(col = 0; col < 15; col++) { + printf("%02X ", image[row * 15 + col]); + } + printf("\n"); + } +} + +void reset_decoder(decoder* state) { + // Don't set the callback to NULL. + state->buf_index = 0; + state->next_is_run_encoded = 0; + memset(state->partial_image, 0, 181); + memset(state->image, 0, 195); +} + +// There are 15 possible values that each pixel can take on, but we'd like to +// scale them up to the full range of a uint8_t for convenience. +uint8_t decoder_table[15] = {0, 18, 36, 55, 73, 91, 109, 128, 146, 164, 182, 200, 219, 237, 255 }; + +enum { + DECODER_BEGIN, + DECODER_IN_PROGRESS, + DECODER_COMPLETE, + DECODER_ERROR, +} decoder_state; + +int process_nybble(decoder* state, uint8_t nybble) { + //printf("process_nybble: buf_index = %d\t%01x\n", state->buf_index, nybble); + if (nybble >= 16) { + printf("process_nybble: got nybble >= 16, wtf: %d\n", nybble); + return DECODER_ERROR; + } + if (state->next_is_run_encoded) { + // Previous nybble was 0xF, so this one is (the number of bytes to skip - 3) + if (state->buf_index + nybble + 3 > 181) { + // Completing this decode would overrun the buffer. We've been + // given invalid data. Abort. + return DECODER_ERROR; + } + int i; + for(i = 0 ; i < nybble + 3; i++) { + state->partial_image[state->buf_index] = 0; + state->buf_index++; + } + state->next_is_run_encoded = 0; + } else { + if (nybble == 0xf) { + state->next_is_run_encoded = 1; + } else { + state->partial_image[state->buf_index] = nybble; + state->buf_index++; + } + } + // If we're done collecting the data, unpack it into image as described above + // This could probably be reworked to unpack the image in-place reusing the + // image buffer, but right now I'm being lazy. + if (state->buf_index == 181) { + memset(state->image, 0, 195); + int row; + int i = 0; + int startcol; + int endcol; + for(row = 0; row < 13 ; row++) { + switch(row) { + // Note: inclusive bounds + case 0: startcol = 0x3; + endcol = 0xb; + break; + case 1: startcol = 0x2; + endcol = 0xc; + break; + case 2: + case 3: startcol = 0x1; + endcol = 0xd; + break; + default: + startcol = 0x0; + endcol = 0xe; + break; + } + int col; + for(col = startcol ; col <= endcol ; col++) { + state->image[row * 15 + col] = decoder_table[state->partial_image[i++]]; + } + } + return DECODER_COMPLETE; + } + return DECODER_IN_PROGRESS; +} + +int enable_mouse_image_mode(libusb_device_handle* dev) { + // We need to set two bits in a particular Feature report. We first fetch + // the current state of the feature report, set the interesting bits, and + // write that feature report back to the device. + printf("Reading current config flags\n"); + unsigned char data[256] = {0}; + int transferred = 0; + transferred = libusb_control_transfer(dev, + 0xa1, // bmRequestType = IN, Class + 0x01, // GET_REPORT + 0x322, // wValue = 0x0322 -> Feature, id 0x22 = 34 + 0x02, // wIndex = 2: endpoint 3 + data, // buffer for data + 0x1B, // expect 27 bytes reply + 0 // infinite timeout + ); + + printf("%d bytes received:\n", transferred); + int i; + for(i = 0; i < transferred; i++) { + printf("%02X ", data[i]); + } + printf("\n"); + if (transferred != 0x1B) { + printf("Failed to read Feature 0x22 correctly; expected 27 bytes, got %d\n", transferred); + return -1; + } + + // This particular byte/setting appears to control the + // "send all the raw input" flag. + data[4] = 0x06; + + printf("Trying to enable full touch updates...\n"); + transferred = libusb_control_transfer(dev, + 0x21, // bmRequestType = OUT, Class + 0x09, // SET_REPORT + 0x322, // wValue = 0x0322 -> Feature, id 0x22 = 34 + 0x02, // wIndex = 2: endpoint 3 + data, // buffer for data + 0x1B, // nBytes + 0 // infinite timeout + ); + printf("Wrote %d bytes\n", transferred); + if (transferred == 0x1B) { + printf("Successfully enabled full touch updates.\n"); + return 0; + } + printf("Failed to enable full touch updates.\n"); + return -1; +} + +int main(void) { + signal(SIGINT, handler); + + libusb_context *ctx; + libusb_device_handle *dev; + int res = 0; + + libusb_init(&ctx); + + dev = libusb_open_device_with_vid_pid(ctx, 0x045e, 0x0773); + if (!dev) { + printf("Failed to open device, aborting\n"); + return -1; + } + + res = libusb_kernel_driver_active(dev, 2); + if (res == 1) { + printf("Kernel driver active, will try to detach\n"); + res = libusb_detach_kernel_driver(dev, 2); + if (res < 0) { + printf("Failed to detach kernel driver, aborting: %d\n", res); + return -1; + } + } else if (res < 0) { + printf("Something unlikely happened in libusb_kernel_driver_active(): %d\n", res); + return -1; + } + + res = libusb_claim_interface(dev, 2); + if (res < 0) { + printf("Failed to claim interface 2 on device (error %d), aborting\n", res); + return -1; + } + + res = enable_mouse_image_mode(dev); + if (res != 0) { + printf("Failed to enable full touch updates, aborting\n"); + return -1; + } + + // Initialize decoder + decoder* state = (decoder*)malloc(sizeof(decoder)); + memset(state, 0, sizeof(*state)); + state->cb = print_table; + + uint8_t last_timestamp = 0; + + unsigned char data[256] = {}; + int transferred = 0; + printf("polling for interrupts...\n"); + while(!quit) { + res = libusb_interrupt_transfer(dev, + 0x83, // Endpoint 0x83 + data, // pointer to data + 0x20, // Expected transfer length (32 bytes) + &transferred, // pointer to number of bytes actually transferred + 1000); // 1 second timeout so we can respond to ^C + if (res < 0 && res != LIBUSB_ERROR_TIMEOUT) { + printf("Interrupt transfer failed: %d\n", res); + } else if (res == 0) { + // Dump contents of transfer + printf("Got reply: %d bytes:", transferred); + int j; + for(j = 0; j < transferred; j++) { + printf(" %02X", data[j]); + } + printf("\n"); + // Interpret contents. + report* r = (report*)data; + // We only care about report ID 39 (0x27), which should be 32 bytes long + if (transferred == 32 && r->report_id == 0x27) { + printf("Timestamp: %02X\t%02X bytes:", r->timestamp, r->length - 1); + int t; + for(t = 0; t < r->length - 1; t++) { + printf(" %02X", r->data[t]); + } + printf("\n"); + if (r->timestamp != last_timestamp) { + reset_decoder(state); // Reset decoder for next transfer + last_timestamp = r->timestamp; + } + for(t = 0; t < r->length - 1; t++) { // Note that we subtract one byte because the length includes the timestamp byte. + int res; + // Yes, we process the low nybble first. Embedded systems are funny like that. + res = process_nybble(state, r->data[t] & 0xf); + if (res == DECODER_COMPLETE) { + state->cb(state, state->image, r->timestamp); + reset_decoder(state); // Reset decoder for next transfer + break; + } + if (res == DECODER_ERROR) { + printf("Caught error in decoder, aborting!\n"); + goto cleanup; + } + res = process_nybble(state, (r->data[t] & 0xf0) >> 4); + if (res == DECODER_COMPLETE) { + state->cb(state, state->image, r->timestamp); + reset_decoder(state); // Reset decoder for next transfer + break; + } + if (res == DECODER_ERROR) { + printf("Caught error in decoder, aborting!\n"); + goto cleanup; + } + } + } + } + } +cleanup: + libusb_close(dev); + dev = NULL; + libusb_exit(ctx); + ctx = NULL; +} -- 2.39.5