openwrt/package/kernel/mac80211/patches/rt2x00/005-1-v6.8-wifi-rt2x00-introduce-DMA-busy-check-watchdog-for-rt.patch
Shiji Yang 6bcd1c2501 mac80211: sync some rt2x00 patches with wireless-next
Some local patches have been sent to upstream and they are slightly
different from the upstream version. So it's better to replace them
to avoid conflicts with the new mac80211 backport driver. The
different parts have been merged into patch 996.

This commit also includes some additional fixes:
* Fix watchdog function.
* Improve MT7620 register initialization.
* Introduce DMA busy watchdog for rt2800.

P.S.
Sometimes rt2800 series chips may fall into a DMA busy state. The
tx queues become very slow and the client cannot connect to the AP.
Usually, We can see a lot of hostapd warnings at this point:
'hostapd: IEEE 802.11: did not acknowledge authentication response'

The DMA busy watchdog can help the driver automatically recover
from this abnormal state. By the way, setting higer 'cell_density'
and disabling 'disassoc_low_ack' can significantly reduce the
probability of the DMA busy.

Signed-off-by: Shiji Yang <yangshiji66@qq.com>
2023-11-13 00:55:38 +00:00

178 lines
5.7 KiB
Diff

From b1275cdd7456ef811747dfb4f3c46310ddd300cd Mon Sep 17 00:00:00 2001
From: Shiji Yang <yangshiji66@outlook.com>
Date: Sat, 4 Nov 2023 16:57:58 +0800
Subject: wifi: rt2x00: introduce DMA busy check watchdog for rt2800
When I tried to fix the watchdog of rt2800, I found that sometimes
the watchdog can not reset the hung device. This is because the
queue is not completely stuck, it just becomes very slow. The MTK
vendor driver for the new chip MT7603/MT7612 has a DMA busy watchdog
to detect device hangs by checking DMA busy status. This watchdog
implementation is something similar to it. To reduce unnecessary
reset, we can check the INT_SOURCE_CSR register together as I found
that when the radio hung, the RX/TX coherent interrupt will always
stuck at triggered state.
The 'watchdog' module parameter has been extended to control all
watchdogs(0=disabled, 1=hang watchdog, 2=DMA watchdog, 3=both). This
new watchdog function is a slight schedule and it won't affect the
transmission speed. So we can turn on it by default. Due to the
INT_SOURCE_CSR register is invalid on rt2800 USB NICs, the DMA busy
watchdog will be automatically disabled for them.
Tested on MT7620 and RT5350.
Signed-off-by: Shiji Yang <yangshiji66@outlook.com>
Acked-by: Stanislaw Gruszka <stf_xl@wp.pl>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/TYAP286MB0315D7462CE08A119A99DE34BCA4A@TYAP286MB0315.JPNP286.PROD.OUTLOOK.COM
---
drivers/net/wireless/ralink/rt2x00/rt2800.h | 4 ++
drivers/net/wireless/ralink/rt2x00/rt2800lib.c | 77 ++++++++++++++++++++++----
drivers/net/wireless/ralink/rt2x00/rt2x00.h | 3 +
3 files changed, 73 insertions(+), 11 deletions(-)
--- a/drivers/net/wireless/ralink/rt2x00/rt2800.h
+++ b/drivers/net/wireless/ralink/rt2x00/rt2800.h
@@ -3194,4 +3194,8 @@ enum rt2800_eeprom_word {
*/
#define BCN_TBTT_OFFSET 64
+/* Watchdog type mask */
+#define RT2800_WATCHDOG_HANG BIT(0)
+#define RT2800_WATCHDOG_DMA_BUSY BIT(1)
+
#endif /* RT2800_H */
--- a/drivers/net/wireless/ralink/rt2x00/rt2800lib.c
+++ b/drivers/net/wireless/ralink/rt2x00/rt2800lib.c
@@ -30,9 +30,10 @@
#include "rt2800lib.h"
#include "rt2800.h"
-static bool modparam_watchdog;
-module_param_named(watchdog, modparam_watchdog, bool, S_IRUGO);
-MODULE_PARM_DESC(watchdog, "Enable watchdog to detect tx/rx hangs and reset hardware if detected");
+static unsigned int modparam_watchdog = RT2800_WATCHDOG_DMA_BUSY;
+module_param_named(watchdog, modparam_watchdog, uint, 0444);
+MODULE_PARM_DESC(watchdog, "Enable watchdog to recover tx/rx hangs.\n"
+ "\t\t(0=disabled, 1=hang watchdog, 2=DMA watchdog(default), 3=both)");
/*
* Register access.
@@ -1261,15 +1262,12 @@ static void rt2800_update_survey(struct
chan_survey->time_ext_busy += rt2800_register_read(rt2x00dev, CH_BUSY_STA_SEC);
}
-void rt2800_watchdog(struct rt2x00_dev *rt2x00dev)
+static bool rt2800_watchdog_hung(struct rt2x00_dev *rt2x00dev)
{
struct data_queue *queue;
bool hung_tx = false;
bool hung_rx = false;
- if (test_bit(DEVICE_STATE_SCANNING, &rt2x00dev->flags))
- return;
-
rt2800_update_survey(rt2x00dev);
queue_for_each(rt2x00dev, queue) {
@@ -1297,18 +1295,72 @@ void rt2800_watchdog(struct rt2x00_dev *
}
}
+ if (!hung_tx && !hung_rx)
+ return false;
+
if (hung_tx)
rt2x00_warn(rt2x00dev, "Watchdog TX hung detected\n");
if (hung_rx)
rt2x00_warn(rt2x00dev, "Watchdog RX hung detected\n");
- if (hung_tx || hung_rx) {
- queue_for_each(rt2x00dev, queue)
- queue->wd_count = 0;
+ queue_for_each(rt2x00dev, queue)
+ queue->wd_count = 0;
+
+ return true;
+}
+
+static bool rt2800_watchdog_dma_busy(struct rt2x00_dev *rt2x00dev)
+{
+ bool busy_rx, busy_tx;
+ u32 reg_cfg = rt2800_register_read(rt2x00dev, WPDMA_GLO_CFG);
+ u32 reg_int = rt2800_register_read(rt2x00dev, INT_SOURCE_CSR);
+
+ if (rt2x00_get_field32(reg_cfg, WPDMA_GLO_CFG_RX_DMA_BUSY) &&
+ rt2x00_get_field32(reg_int, INT_SOURCE_CSR_RX_COHERENT))
+ rt2x00dev->rxdma_busy++;
+ else
+ rt2x00dev->rxdma_busy = 0;
+ if (rt2x00_get_field32(reg_cfg, WPDMA_GLO_CFG_TX_DMA_BUSY) &&
+ rt2x00_get_field32(reg_int, INT_SOURCE_CSR_TX_COHERENT))
+ rt2x00dev->txdma_busy++;
+ else
+ rt2x00dev->txdma_busy = 0;
+
+ busy_rx = rt2x00dev->rxdma_busy > 30 ? true : false;
+ busy_tx = rt2x00dev->txdma_busy > 30 ? true : false;
+
+ if (!busy_rx && !busy_tx)
+ return false;
+
+ if (busy_rx)
+ rt2x00_warn(rt2x00dev, "Watchdog RX DMA busy detected\n");
+
+ if (busy_tx)
+ rt2x00_warn(rt2x00dev, "Watchdog TX DMA busy detected\n");
+
+ rt2x00dev->rxdma_busy = 0;
+ rt2x00dev->txdma_busy = 0;
+
+ return true;
+}
+
+void rt2800_watchdog(struct rt2x00_dev *rt2x00dev)
+{
+ bool reset = false;
+
+ if (test_bit(DEVICE_STATE_SCANNING, &rt2x00dev->flags))
+ return;
+
+ if (modparam_watchdog & RT2800_WATCHDOG_DMA_BUSY)
+ reset = rt2800_watchdog_dma_busy(rt2x00dev);
+
+ if (modparam_watchdog & RT2800_WATCHDOG_HANG)
+ reset = rt2800_watchdog_hung(rt2x00dev) || reset;
+
+ if (reset)
ieee80211_restart_hw(rt2x00dev->hw);
- }
}
EXPORT_SYMBOL_GPL(rt2800_watchdog);
@@ -12016,6 +12068,9 @@ int rt2800_probe_hw(struct rt2x00_dev *r
__set_bit(REQUIRE_TASKLET_CONTEXT, &rt2x00dev->cap_flags);
}
+ /* USB NICs don't support DMA watchdog as INT_SOURCE_CSR is invalid */
+ if (rt2x00_is_usb(rt2x00dev))
+ modparam_watchdog &= ~RT2800_WATCHDOG_DMA_BUSY;
if (modparam_watchdog) {
__set_bit(CAPABILITY_RESTART_HW, &rt2x00dev->cap_flags);
rt2x00dev->link.watchdog_interval = msecs_to_jiffies(100);
--- a/drivers/net/wireless/ralink/rt2x00/rt2x00.h
+++ b/drivers/net/wireless/ralink/rt2x00/rt2x00.h
@@ -926,6 +926,9 @@ struct rt2x00_dev {
*/
u16 beacon_int;
+ /* Rx/Tx DMA busy watchdog counter */
+ u16 rxdma_busy, txdma_busy;
+
/**
* Timestamp of last received beacon
*/