media: rc: imon_raw: use fls rather than loop per bit

[sfrench/cifs-2.6.git] / drivers / media / rc / imon_raw.c

diff --git a/drivers/media/rc/imon_raw.c b/drivers/media/rc/imon_raw.c
index 7796098d9c307a54ed811db1e6c987fadfd2535f..25e56c5b13c02fd6690595e5dfd7cc7e1cb70966 100644 (file)
--- a/drivers/media/rc/imon_raw.c
+++ b/drivers/media/rc/imon_raw.c
@@ -14,51 +14,50 @@ struct imon {
        struct device *dev;
        struct urb *ir_urb;
        struct rc_dev *rcdev;
-       u8 ir_buf[8];
+       u8 ir_buf[8] __aligned(__alignof__(u64));
        char phys[64];
 };
 
 /*
- * ffs/find_next_bit() searches in the wrong direction, so open-code our own.
+ * The first 5 bytes of data represent IR pulse or space. Each bit, starting
+ * from highest bit in the first byte, represents 250µs of data. It is 1
+ * for space and 0 for pulse.
+ *
+ * The station sends 10 packets, and the 7th byte will be number 1 to 10, so
+ * when we receive 10 we assume all the data has arrived.
  */
-static inline int is_bit_set(const u8 *buf, int bit)
-{
-       return buf[bit / 8] & (0x80 >> (bit & 7));
-}
-
 static void imon_ir_data(struct imon *imon)
 {
        struct ir_raw_event rawir = {};
-       int offset = 0, size = 5 * 8;
+       u64 d = be64_to_cpup((__be64 *)imon->ir_buf) >> 24;
+       int offset = 40;
        int bit;
 
        dev_dbg(imon->dev, "data: %*ph", 8, imon->ir_buf);
 
-       while (offset < size) {
-               bit = offset;
-               while (!is_bit_set(imon->ir_buf, bit) && bit < size)
-                       bit++;
-               dev_dbg(imon->dev, "pulse: %d bits", bit - offset);
-               if (bit > offset) {
+       do {
+               bit = fls64(d & (BIT_ULL(offset) - 1));
+               if (bit < offset) {
+                       dev_dbg(imon->dev, "pulse: %d bits", offset - bit);
                        rawir.pulse = true;
-                       rawir.duration = (bit - offset) * BIT_DURATION;
+                       rawir.duration = (offset - bit) * BIT_DURATION;
                        ir_raw_event_store_with_filter(imon->rcdev, &rawir);
-               }
 
-               if (bit >= size)
-                       break;
+                       if (bit == 0)
+                               break;
 
-               offset = bit;
-               while (is_bit_set(imon->ir_buf, bit) && bit < size)
-                       bit++;
-               dev_dbg(imon->dev, "space: %d bits", bit - offset);
+                       offset = bit;
+               }
+
+               bit = fls64(~d & (BIT_ULL(offset) - 1));
+               dev_dbg(imon->dev, "space: %d bits", offset - bit);
 
                rawir.pulse = false;
-               rawir.duration = (bit - offset) * BIT_DURATION;
+               rawir.duration = (offset - bit) * BIT_DURATION;
                ir_raw_event_store_with_filter(imon->rcdev, &rawir);
 
                offset = bit;
-       }
+       } while (offset > 0);
 
        if (imon->ir_buf[7] == 0x0a) {
                ir_raw_event_set_idle(imon->rcdev, true);