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Posted to commits@mynewt.apache.org by an...@apache.org on 2017/04/11 22:45:31 UTC
[02/14] incubator-mynewt-core git commit: nimble/controller: Add
Channel Selection Algorithm #2 implementation
nimble/controller: Add Channel Selection Algorithm #2 implementation
This adds implementation of Channel Selection Algorithm #2 as specified
in Core Specification 5.0 Vol 6 Part B 4.6.14.
Project: http://git-wip-us.apache.org/repos/asf/incubator-mynewt-core/repo
Commit: http://git-wip-us.apache.org/repos/asf/incubator-mynewt-core/commit/51d1ea26
Tree: http://git-wip-us.apache.org/repos/asf/incubator-mynewt-core/tree/51d1ea26
Diff: http://git-wip-us.apache.org/repos/asf/incubator-mynewt-core/diff/51d1ea26
Branch: refs/heads/bluetooth5
Commit: 51d1ea26a6436be6c9fde415e0b973bc81381ce1
Parents: 646b35d
Author: Szymon Janc <sz...@codecoup.pl>
Authored: Mon Apr 3 17:03:13 2017 +0200
Committer: Szymon Janc <sz...@codecoup.pl>
Committed: Fri Apr 7 11:06:20 2017 +0200
----------------------------------------------------------------------
net/nimble/controller/src/ble_ll_conn.c | 105 +++++++++++++++++++++++++++
1 file changed, 105 insertions(+)
----------------------------------------------------------------------
http://git-wip-us.apache.org/repos/asf/incubator-mynewt-core/blob/51d1ea26/net/nimble/controller/src/ble_ll_conn.c
----------------------------------------------------------------------
diff --git a/net/nimble/controller/src/ble_ll_conn.c b/net/nimble/controller/src/ble_ll_conn.c
index 2d4c099..d85bb5a 100644
--- a/net/nimble/controller/src/ble_ll_conn.c
+++ b/net/nimble/controller/src/ble_ll_conn.c
@@ -563,6 +563,111 @@ ble_ll_conn_calc_access_addr(void)
return aa;
}
+static uint16_t
+ble_ll_conn_csa2_perm(uint16_t in)
+{
+ uint16_t out = 0;
+ int i;
+
+ for (i = 0; i < 8; i++) {
+ out |= ((in >> i) & 0x00000001) << (7 - i);
+ }
+
+ for (i = 8; i < 16; i++) {
+ out |= ((in >> i) & 0x00000001) << (15 + 8 - i);
+ }
+
+ return out;
+}
+
+static uint16_t
+ble_ll_conn_csa2_prng(uint16_t counter, uint16_t ch_id)
+{
+ uint16_t prn_e;
+
+ prn_e = counter ^ ch_id;
+
+ prn_e = ble_ll_conn_csa2_perm(prn_e);
+ prn_e = (prn_e * 17) + ch_id;
+
+ prn_e = ble_ll_conn_csa2_perm(prn_e);
+ prn_e = (prn_e * 17) + ch_id;
+
+ prn_e = ble_ll_conn_csa2_perm(prn_e);
+ prn_e = (prn_e * 17) + ch_id;
+
+ prn_e = prn_e ^ ch_id;
+
+ return prn_e;
+}
+
+static uint8_t
+ble_ll_conn_csa2_remapped_channel(uint8_t remap_index, const uint8_t *chanmap)
+{
+ uint8_t cntr;
+ uint8_t mask;
+ uint8_t usable_chans;
+ uint8_t chan;
+ int i, j;
+
+ /* NOTE: possible to build a map but this would use memory. For now,
+ we just calculate */
+ /* Iterate through channel map to find this channel */
+ chan = 0;
+ cntr = 0;
+ for (i = 0; i < BLE_LL_CONN_CHMAP_LEN; i++) {
+ usable_chans = chanmap[i];
+ if (usable_chans != 0) {
+ mask = 0x01;
+ for (j = 0; j < 8; j++) {
+ if (usable_chans & mask) {
+ if (cntr == remap_index) {
+ return (chan + j);
+ }
+ ++cntr;
+ }
+ mask <<= 1;
+ }
+ }
+ chan += 8;
+ }
+
+ /* we should never reach here */
+ assert(0);
+ return 0;
+}
+
+uint8_t
+ble_ll_conn_calc_dci_csa2(struct ble_ll_conn_sm *conn)
+{
+ uint16_t channel_unmapped;
+ uint16_t channel_id;
+ uint8_t remap_index;
+
+ uint16_t prn_e;
+ uint8_t bitpos;
+
+ channel_id = ((conn->access_addr & 0xffff0000) >> 16) ^
+ (conn->access_addr & 0x0000ffff);
+
+ prn_e = ble_ll_conn_csa2_prng(conn->event_cntr, channel_id);
+
+ channel_unmapped = prn_e % 37;
+
+ /*
+ * If unmapped channel is the channel index of a used channel it is used
+ * as channel index.
+ */
+ bitpos = 1 << (channel_unmapped & 0x07);
+ if (conn->chanmap[channel_unmapped >> 3] & bitpos) {
+ return channel_unmapped;
+ }
+
+ remap_index = (conn->num_used_chans * prn_e) / 0x10000;
+
+ return ble_ll_conn_csa2_remapped_channel(remap_index, conn->chanmap);
+}
+
/**
* Determine data channel index to be used for the upcoming/current
* connection event