[PATCH] USB: input/touchkitusb: handle multiple packets

Some versions of the controller seem to put multiple report packet into a
single urb. also it can happen that a packet is split across multiple urbs.
unpatched you get a jumpy cursor on some screens.
the patch does:
- handle multiple packets per urb
- handle packets split across multiple urb
- check packet type
- cleanups

Signed-off-by: Daniel Ritz <daniel.ritz@gmx.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 126 insertions, 22 deletions

diff --git a/drivers/usb/input/touchkitusb.c b/drivers/usb/input/touchkitusb.c
index 75e7c12e7189..3b3c7b4120a2 100644
--- a/drivers/usb/input/touchkitusb.c
+++ b/drivers/usb/input/touchkitusb.c
@@ -1,7 +1,7 @@
 /******************************************************************************
  * touchkitusb.c  --  Driver for eGalax TouchKit USB Touchscreens
  *
- * Copyright (C) 2004 by Daniel Ritz
+ * Copyright (C) 2004-2005 by Daniel Ritz <daniel.ritz@gmx.ch>
  * Copyright (C) by Todd E. Johnson (mtouchusb.c)
  *
  * This program is free software; you can redistribute it and/or
@@ -41,15 +41,13 @@
 #define TOUCHKIT_MAX_YC                 0x07ff
 #define TOUCHKIT_YC_FUZZ                0x0
 #define TOUCHKIT_YC_FLAT                0x0
-#define TOUCHKIT_REPORT_DATA_SIZE       8
+#define TOUCHKIT_REPORT_DATA_SIZE       16
 
 #define TOUCHKIT_DOWN                   0x01
-#define TOUCHKIT_POINT_TOUCH            0x81
-#define TOUCHKIT_POINT_NOTOUCH          0x80
 
-#define TOUCHKIT_GET_TOUCHED(dat)       ((((dat)[0]) & TOUCHKIT_DOWN) ? 1 : 0)
-#define TOUCHKIT_GET_X(dat)             (((dat)[3] << 7) | (dat)[4])
-#define TOUCHKIT_GET_Y(dat)             (((dat)[1] << 7) | (dat)[2])
+#define TOUCHKIT_PKT_TYPE_MASK          0xFE
+#define TOUCHKIT_PKT_TYPE_REPT          0x80
+#define TOUCHKIT_PKT_TYPE_DIAG          0x0A
 
 #define DRIVER_VERSION                  "v0.1"
 #define DRIVER_AUTHOR                   "Daniel Ritz <daniel.ritz@gmx.ch>"
@@ -62,6 +60,8 @@ MODULE_PARM_DESC(swap_xy, "If set X and Y axes are swapped.");
 struct touchkit_usb {
         unsigned char *data;
         dma_addr_t data_dma;
+        char buffer[TOUCHKIT_REPORT_DATA_SIZE];
+        int buf_len;
         struct urb *irq;
         struct usb_device *udev;
         struct input_dev *input;
@@ -77,11 +77,128 @@ static struct usb_device_id touchkit_devices[] = {
         {}
 };
 
+/* helpers to read the data */
+static inline int touchkit_get_touched(char *data)
+{
+        return (data[0] & TOUCHKIT_DOWN) ? 1 : 0;
+}
+
+static inline int touchkit_get_x(char *data)
+{
+        return ((data[3] & 0x0F) << 7) | (data[4] & 0x7F);
+}
+
+static inline int touchkit_get_y(char *data)
+{
+        return ((data[1] & 0x0F) << 7) | (data[2] & 0x7F);
+}
+
+
+/* processes one input packet. */
+static void touchkit_process_pkt(struct touchkit_usb *touchkit,
+                                 struct pt_regs *regs, char *pkt)
+{
+        int x, y;
+
+        /* only process report packets */
+        if ((pkt[0] & TOUCHKIT_PKT_TYPE_MASK) != TOUCHKIT_PKT_TYPE_REPT)
+                return;
+
+        if (swap_xy) {
+                y = touchkit_get_x(pkt);
+                x = touchkit_get_y(pkt);
+        } else {
+                x = touchkit_get_x(pkt);
+                y = touchkit_get_y(pkt);
+        }
+
+        input_regs(touchkit->input, regs);
+        input_report_key(touchkit->input, BTN_TOUCH, touchkit_get_touched(pkt));
+        input_report_abs(touchkit->input, ABS_X, x);
+        input_report_abs(touchkit->input, ABS_Y, y);
+        input_sync(touchkit->input);
+}
+
+
+static int touchkit_get_pkt_len(char *buf)
+{
+        switch (buf[0] & TOUCHKIT_PKT_TYPE_MASK) {
+        case TOUCHKIT_PKT_TYPE_REPT:
+                return 5;
+
+        case TOUCHKIT_PKT_TYPE_DIAG:
+                return buf[1] + 2;
+        }
+
+        return 0;
+}
+
+static void touchkit_process(struct touchkit_usb *touchkit, int len,
+                             struct pt_regs *regs)
+{
+        char *buffer;
+        int pkt_len, buf_len, pos;
+
+        /* if the buffer contains data, append */
+        if (unlikely(touchkit->buf_len)) {
+                int tmp;
+
+                /* if only 1 byte in buffer, add another one to get length */
+                if (touchkit->buf_len == 1)
+                        touchkit->buffer[1] = touchkit->data[0];
+
+                pkt_len = touchkit_get_pkt_len(touchkit->buffer);
+
+                /* unknown packet: drop everything */
+                if (!pkt_len)
+                        return;
+
+                /* append, process */
+                tmp = pkt_len - touchkit->buf_len;
+                memcpy(touchkit->buffer + touchkit->buf_len, touchkit->data, tmp);
+                touchkit_process_pkt(touchkit, regs, touchkit->buffer);
+
+                buffer = touchkit->data + tmp;
+                buf_len = len - tmp;
+        } else {
+                buffer = touchkit->data;
+                buf_len = len;
+        }
+
+        /* only one byte left in buffer */
+        if (unlikely(buf_len == 1)) {
+                touchkit->buffer[0] = buffer[0];
+                touchkit->buf_len = 1;
+                return;
+        }
+
+        /* loop over the buffer */
+        pos = 0;
+        while (pos < buf_len) {
+                /* get packet len */
+                pkt_len = touchkit_get_pkt_len(buffer + pos);
+
+                /* unknown packet: drop everything */
+                if (unlikely(!pkt_len))
+                        return;
+
+                /* full packet: process */
+                if (likely(pkt_len <= buf_len)) {
+                        touchkit_process_pkt(touchkit, regs, buffer + pos);
+                } else {
+                        /* incomplete packet: save in buffer */
+                        memcpy(touchkit->buffer, buffer + pos, buf_len - pos);
+                        touchkit->buf_len = buf_len - pos;
+                }
+                pos += pkt_len;
+        }
+}
+
+
 static void touchkit_irq(struct urb *urb, struct pt_regs *regs)
 {
         struct touchkit_usb *touchkit = urb->context;
         int retval;
-        int x, y;
 
         switch (urb->status) {
         case 0:
@@ -105,20 +222,7 @@ static void touchkit_irq(struct urb *urb, struct pt_regs *regs)
                 goto exit;
         }
 
-        if (swap_xy) {
-                y = TOUCHKIT_GET_X(touchkit->data);
-                x = TOUCHKIT_GET_Y(touchkit->data);
-        } else {
-                x = TOUCHKIT_GET_X(touchkit->data);
-                y = TOUCHKIT_GET_Y(touchkit->data);
-        }
-
-        input_regs(touchkit->input, regs);
-        input_report_key(touchkit->input, BTN_TOUCH,
-                         TOUCHKIT_GET_TOUCHED(touchkit->data));
-        input_report_abs(touchkit->input, ABS_X, x);
-        input_report_abs(touchkit->input, ABS_Y, y);
-        input_sync(touchkit->input);
+        touchkit_process(touchkit, urb->actual_length, regs);
 
 exit:
         retval = usb_submit_urb(urb, GFP_ATOMIC);