ath9k_hw: improve performance for AR934x v1.3+

AR934x v1.3 no longer needs the DCU backoff reduction workaround for
preventing rx overruns, but in turn needs the number of usable Tx
buffers to be reduced slightly.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

3 files changed, 20 insertions, 6 deletions

diff --git a/drivers/net/wireless/ath/ath9k/hw.c b/drivers/net/wireless/ath/ath9k/hw.c
index 01e97ce438ba..15dfefcf2d0f 100644
--- a/drivers/net/wireless/ath/ath9k/hw.c
+++ b/drivers/net/wireless/ath/ath9k/hw.c
@@ -1172,6 +1172,7 @@ u32 ath9k_regd_get_ctl(struct ath_regulatory *reg, struct ath9k_channel *chan)
 static inline void ath9k_hw_set_dma(struct ath_hw *ah)
 {
         struct ath_common *common = ath9k_hw_common(ah);
+        int txbuf_size;
 
         ENABLE_REGWRITE_BUFFER(ah);
 
@@ -1225,13 +1226,17 @@ static inline void ath9k_hw_set_dma(struct ath_hw *ah)
                  * So set the usable tx buf size also to half to
                  * avoid data/delimiter underruns
                  */
-                REG_WRITE(ah, AR_PCU_TXBUF_CTRL,
-                          AR_9285_PCU_TXBUF_CTRL_USABLE_SIZE);
-        } else if (!AR_SREV_9271(ah)) {
-                REG_WRITE(ah, AR_PCU_TXBUF_CTRL,
-                          AR_PCU_TXBUF_CTRL_USABLE_SIZE);
+                txbuf_size = AR_9285_PCU_TXBUF_CTRL_USABLE_SIZE;
+        } else if (AR_SREV_9340_13_OR_LATER(ah)) {
+                /* Uses fewer entries for AR934x v1.3+ to prevent rx overruns */
+                txbuf_size = AR_9340_PCU_TXBUF_CTRL_USABLE_SIZE;
+        } else {
+                txbuf_size = AR_PCU_TXBUF_CTRL_USABLE_SIZE;
         }
 
+        if (!AR_SREV_9271(ah))
+                REG_WRITE(ah, AR_PCU_TXBUF_CTRL, txbuf_size);
+
         REGWRITE_BUFFER_FLUSH(ah);
 
         if (AR_SREV_9300_20_OR_LATER(ah))
diff --git a/drivers/net/wireless/ath/ath9k/mac.c b/drivers/net/wireless/ath/ath9k/mac.c
index 498fee04afa0..566109a40fb3 100644
--- a/drivers/net/wireless/ath/ath9k/mac.c
+++ b/drivers/net/wireless/ath/ath9k/mac.c
@@ -410,7 +410,7 @@ bool ath9k_hw_resettxqueue(struct ath_hw *ah, u32 q)
 
         REG_WRITE(ah, AR_QMISC(q), AR_Q_MISC_DCU_EARLY_TERM_REQ);
 
-        if (AR_SREV_9340(ah))
+        if (AR_SREV_9340(ah) && !AR_SREV_9340_13_OR_LATER(ah))
                 REG_WRITE(ah, AR_DMISC(q),
                           AR_D_MISC_CW_BKOFF_EN | AR_D_MISC_FRAG_WAIT_EN | 0x1);
         else
diff --git a/drivers/net/wireless/ath/ath9k/reg.h b/drivers/net/wireless/ath/ath9k/reg.h
index 9c056a80b85d..f7c90cc58d56 100644
--- a/drivers/net/wireless/ath/ath9k/reg.h
+++ b/drivers/net/wireless/ath/ath9k/reg.h
@@ -798,6 +798,10 @@
 #define AR_SREV_REVISION_9485_10        0
 #define AR_SREV_REVISION_9485_11        1
 #define AR_SREV_VERSION_9340            0x300
+#define AR_SREV_REVISION_9340_10        0
+#define AR_SREV_REVISION_9340_11        1
+#define AR_SREV_REVISION_9340_12        2
+#define AR_SREV_REVISION_9340_13        3
 #define AR_SREV_VERSION_9580            0x1C0
 #define AR_SREV_REVISION_9580_10        4 /* AR9580 1.0 */
 #define AR_SREV_VERSION_9462            0x280
@@ -897,6 +901,10 @@
 #define AR_SREV_9340(_ah) \
         (((_ah)->hw_version.macVersion == AR_SREV_VERSION_9340))
 
+#define AR_SREV_9340_13_OR_LATER(_ah) \
+        (AR_SREV_9340((_ah)) && \
+         ((_ah)->hw_version.macRev >= AR_SREV_REVISION_9340_13))
+
 #define AR_SREV_9285E_20(_ah) \
     (AR_SREV_9285_12_OR_LATER(_ah) && \
      ((REG_READ(_ah, AR_AN_SYNTH9) & 0x7) == 0x1))
@@ -1883,6 +1891,7 @@ enum {
 #define AR_PCU_TXBUF_CTRL_SIZE_MASK     0x7FF
 #define AR_PCU_TXBUF_CTRL_USABLE_SIZE   0x700
 #define AR_9285_PCU_TXBUF_CTRL_USABLE_SIZE   0x380
+#define AR_9340_PCU_TXBUF_CTRL_USABLE_SIZE   0x500
 
 #define AR_PCU_MISC_MODE2               0x8344
 #define AR_PCU_MISC_MODE2_MGMT_CRYPTO_ENABLE           0x00000002