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path: root/drivers/net/ethernet/intel/ice/ice_ptp.h
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Diffstat (limited to 'drivers/net/ethernet/intel/ice/ice_ptp.h')
-rw-r--r--drivers/net/ethernet/intel/ice/ice_ptp.h31
1 files changed, 31 insertions, 0 deletions
diff --git a/drivers/net/ethernet/intel/ice/ice_ptp.h b/drivers/net/ethernet/intel/ice/ice_ptp.h
index afd048d69959..10e396abf130 100644
--- a/drivers/net/ethernet/intel/ice/ice_ptp.h
+++ b/drivers/net/ethernet/intel/ice/ice_ptp.h
@@ -49,6 +49,37 @@ struct ice_perout_channel {
* To allow multiple ports to access the shared register block independently,
* the blocks are split up so that indexes are assigned to each port based on
* hardware logical port number.
+ *
+ * The timestamp blocks are handled differently for E810- and E822-based
+ * devices. In E810 devices, each port has its own block of timestamps, while in
+ * E822 there is a need to logically break the block of registers into smaller
+ * chunks based on the port number to avoid collisions.
+ *
+ * Example for port 5 in E810:
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * |register|register|register|register|register|register|register|register|
+ * | block | block | block | block | block | block | block | block |
+ * | for | for | for | for | for | for | for | for |
+ * | port 0 | port 1 | port 2 | port 3 | port 4 | port 5 | port 6 | port 7 |
+ * +--------+--------+--------+--------+--------+--------+--------+--------+
+ * ^^
+ * ||
+ * |--- quad offset is always 0
+ * ---- quad number
+ *
+ * Example for port 5 in E822:
+ * +-----------------------------+-----------------------------+
+ * | register block for quad 0 | register block for quad 1 |
+ * |+------+------+------+------+|+------+------+------+------+|
+ * ||port 0|port 1|port 2|port 3|||port 0|port 1|port 2|port 3||
+ * |+------+------+------+------+|+------+------+------+------+|
+ * +-----------------------------+-------^---------------------+
+ * ^ |
+ * | --- quad offset*
+ * ---- quad number
+ *
+ * * PHY port 5 is port 1 in quad 1
+ *
*/
/**