gitproxy/RTLPlayground
1
0
Fork 0
mirror of https://github.com/logicog/RTLPlayground.git synced 2026-09-02 15:02:51 +08:00
Code Issues Packages Projects Releases Wiki Activity

doc: move the L2 multicast and tag word details out of the code

Browse Source 
Review asked for this directly: the hardware layout above port_l2mc_set()
would be better as documentation than as a comment, keeping only the two
lines that say what the function does.

doc/l2.md gains a section on static multicast entries, why delivery uses
the forward action rather than the trap, and the SMI layout of the entry.
doc/CpuPort.md gains the layout of the tag's flags and pmask words, with
the byte order trap that cost an afternoon: writing the flags constant raw
instead of through HTONS puts 0x0020 on the wire as 0x2000, which is EFID
rather than LEARN_DIS, and the ASIC then leaves the 0x8899 header on the
frame.

The comments those paragraphs came from are replaced by a pointer to the
file that now holds them.
This commit is contained in:
d00f
2026-08-18 23:29:10 +02:00
committed by d00f
parent 0160b430f4
commit 4a78b2dc8c
4 changed files with 66 additions and 38 deletions
Download Patch File Download Diff File Expand all files Collapse all files
rtl837x_common.h
+2 -12
View File
@@ -71,20 +71,10 @@ struct vlan_tag {
#define VLAN_TAG_SIZE (sizeof (struct vlan_tag))
#define RTL_FRAME_TAG_ID 0x8899
#define RTL_FRAME_TAG_VERSION 0x04
/* Bits of the tag's `flags` word (word2), per Linux DSA tag_rtl8_4:
* bit15 EFID_EN | 14:12 EFID | 11 PRI_EN | 10:8 PRI |
* bit7 KEEP | 6 VSEL | 5 LEARN_DIS | 4:0 VIDX
* NOTE: this word must be written through HTONS like every other tag field -
* writing the constant raw puts the bits in the wrong byte (0x0020 raw lands on
* the wire as 0x2000 = EFID, not LEARN_DIS), the ASIC then fails to parse the
* tag and forwards the frame with the 0x8899 header still on it. */
/* Bits of the tag's `flags` word, see doc/CpuPort.md. */
#define RTL_TAG_LEARN_DIS 0x0020 /* do not learn the CPU's SA on the egress port */
#define RTL_TAG_KEEP 0x0080 /* keep the frame's 802.1Q tag format as injected */
/* The `pmask` word (word3): bit15 ALLOW selects how 14:0 is interpreted.
* ALLOW=0 -> forwarding port mask (directed egress: frame goes exactly to the
* ports set). ALLOW=1 -> allowance mask (permission filter on a normal lookup),
* which for a one-hot mask yields an empty egress set - the frame disappears.
* Directed egress therefore requires ALLOW cleared, as mainline does. */
/* The `pmask` word, see doc/CpuPort.md. */
// For TX, an 8 byte (plus 4 byte padding when when VLAN is enabled)
// header describing the frame to be moved to the Asic is used