From: Ben Greear <greearb@xxxxxxxxxxxxxxx>
This is a tricky beast to understand, so add some notes for
next time someone is looking at this code and trying to compare
against documents.
Signed-off-by: Ben Greear <greearb@xxxxxxxxxxxxxxx>
---
txs and related patches rebased on top of 5.16
.../net/wireless/mediatek/mt76/mt7915/mac.c | 23 +++++++++++++++----
1 file changed, 18 insertions(+), 5 deletions(-)
diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mac.c b/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
index 8e5b87af2efb..6fbd58ae9c88 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
@@ -410,6 +410,7 @@ mt7915_mac_fill_rx(struct mt7915_dev *dev, struct sk_buff *skb)
__le32 *rxd = (__le32 *)skb->data;
__le32 *rxv = NULL;
u32 mode = 0;
+ /* table "PP -> HOST / X-CPU" RX Format */
u32 rxd0 = le32_to_cpu(rxd[0]);
u32 rxd1 = le32_to_cpu(rxd[1]);
u32 rxd2 = le32_to_cpu(rxd[2]);
@@ -489,7 +490,7 @@ mt7915_mac_fill_rx(struct mt7915_dev *dev, struct sk_buff *skb)
rxd += 6;
if (rxd1 & MT_RXD1_NORMAL_GROUP_4) {
- u32 v0 = le32_to_cpu(rxd[0]);
+ u32 v0 = le32_to_cpu(rxd[0]); /* DW6 */
u32 v2 = le32_to_cpu(rxd[2]);
fc = cpu_to_le16(FIELD_GET(MT_RXD6_FRAME_CONTROL, v0));
@@ -502,6 +503,7 @@ mt7915_mac_fill_rx(struct mt7915_dev *dev, struct sk_buff *skb)
}
if (rxd1 & MT_RXD1_NORMAL_GROUP_1) {
+ /* DW10, assuming Group-4 enabled */
u8 *data = (u8 *)rxd;
if (status->flag & RX_FLAG_DECRYPTED) {
@@ -533,6 +535,7 @@ mt7915_mac_fill_rx(struct mt7915_dev *dev, struct sk_buff *skb)
}
if (rxd1 & MT_RXD1_NORMAL_GROUP_2) {
+ /* DW14, assuming group-1,4 */
status->timestamp = le32_to_cpu(rxd[0]);
status->flag |= RX_FLAG_MACTIME_START;
@@ -558,18 +561,22 @@ mt7915_mac_fill_rx(struct mt7915_dev *dev, struct sk_buff *skb)
if (rxd1 & MT_RXD1_NORMAL_GROUP_3) {
u32 v0, v1, v2;
- rxv = rxd;
+ rxv = rxd; /* DW16 assuming group 1,2,3,4 */
rxd += 2;
if ((u8 *)rxd - skb->data >= skb->len)
return -EINVAL;
- v0 = le32_to_cpu(rxv[0]);
+ v0 = le32_to_cpu(rxv[0]); /* DW16, P-VEC1 31:0 */
+ /* DW17, RX_RCPI copied over P-VEC 64:32 Per RX Format doc. */
v1 = le32_to_cpu(rxv[1]);
- v2 = le32_to_cpu(rxv[2]);
+ v2 = le32_to_cpu(rxv[2]); /* first DW of group-5, C-RXV */
if (v0 & MT_PRXV_HT_AD_CODE)
status->enc_flags |= RX_ENC_FLAG_LDPC;
+ /* TODO: When group-5 is enabled, use nss (and stbc) to
+ * calculate chains properly for this particular skb.
+ */
status->chains = mphy->antenna_mask;
status->chain_signal[0] = to_rssi(MT_PRXV_RCPI0, v1);
status->chain_signal[1] = to_rssi(MT_PRXV_RCPI1, v1);
@@ -581,12 +588,18 @@ mt7915_mac_fill_rx(struct mt7915_dev *dev, struct sk_buff *skb)
if (!(status->chains & BIT(i)))
continue;
+ /* TODO: Use db sum logic instead of max. */
status->signal = max(status->signal,
status->chain_signal[i]);
}
- /* RXD Group 5 - C-RXV */
+ /* RXD Group 5 - C-RXV.
+ * Group 5 Not currently enabled for 7915 except in
+ * monitor mode.
+ * See MT_DMA_DCR0_RXD_G5_EN
+ */
if (rxd1 & MT_RXD1_NORMAL_GROUP_5) {
+ /* See RXV document ... */
u8 stbc = FIELD_GET(MT_CRXV_HT_STBC, v2);
u8 gi = FIELD_GET(MT_CRXV_HT_SHORT_GI, v2);
bool cck = false;
--
2.20.1
