From: Youghandhar Chintala quic_youghand@quicinc.com
[ Upstream commit acd4324e5f1f11351630234297f95076f0ac9a2f ]
On WCN3990, we are seeing a rare scenario where copy engine hardware is sending a copy complete interrupt to the host driver while still processing the buffer that the driver has sent, this is leading into an SMMU fault triggering kernel panic. This is happening on copy engine channel 3 (CE3) where the driver normally enqueues WMI commands to the firmware. Upon receiving a copy complete interrupt, host driver will immediately unmap and frees the buffer presuming that hardware has processed the buffer. In the issue case, upon receiving copy complete interrupt, host driver will unmap and free the buffer but since hardware is still accessing the buffer (which in this case got unmapped in parallel), SMMU hardware will trigger an SMMU fault resulting in a kernel panic.
In order to avoid this, as a work around, add a delay before unmapping the copy engine source DMA buffer. This is conditionally done for WCN3990 and only for the CE3 channel where issue is seen.
Below is the crash signature:
wifi smmu error: kernel: [ 10.120965] arm-smmu 15000000.iommu: Unhandled context fault: fsr=0x402, iova=0x7fdfd8ac0, fsynr=0x500003,cbfrsynra=0xc1, cb=6 arm-smmu 15000000.iommu: Unhandled context fault:fsr=0x402, iova=0x7fe06fdc0, fsynr=0x710003, cbfrsynra=0xc1, cb=6 qcom-q6v5-mss 4080000.remoteproc: fatal error received: err_qdi.c:1040:EF:wlan_process:0x1:WLAN RT:0x2091: cmnos_thread.c:3998:Asserted in copy_engine.c:AXI_ERROR_DETECTED:2149 remoteproc remoteproc0: crash detected in 4080000.remoteproc: type fatal error <3> remoteproc remoteproc0: handling crash #1 in 4080000.remoteproc
pc : __arm_lpae_unmap+0x500/0x514 lr : __arm_lpae_unmap+0x4bc/0x514 sp : ffffffc011ffb530 x29: ffffffc011ffb590 x28: 0000000000000000 x27: 0000000000000000 x26: 0000000000000004 x25: 0000000000000003 x24: ffffffc011ffb890 x23: ffffffa762ef9be0 x22: ffffffa77244ef00 x21: 0000000000000009 x20: 00000007fff7c000 x19: 0000000000000003 x18: 0000000000000000 x17: 0000000000000004 x16: ffffffd7a357d9f0 x15: 0000000000000000 x14: 00fd5d4fa7ffffff x13: 000000000000000e x12: 0000000000000000 x11: 00000000ffffffff x10: 00000000fffffe00 x9 : 000000000000017c x8 : 000000000000000c x7 : 0000000000000000 x6 : ffffffa762ef9000 x5 : 0000000000000003 x4 : 0000000000000004 x3 : 0000000000001000 x2 : 00000007fff7c000 x1 : ffffffc011ffb890 x0 : 0000000000000000 Call trace: __arm_lpae_unmap+0x500/0x514 __arm_lpae_unmap+0x4bc/0x514 __arm_lpae_unmap+0x4bc/0x514 arm_lpae_unmap_pages+0x78/0xa4 arm_smmu_unmap_pages+0x78/0x104 __iommu_unmap+0xc8/0x1e4 iommu_unmap_fast+0x38/0x48 __iommu_dma_unmap+0x84/0x104 iommu_dma_free+0x34/0x50 dma_free_attrs+0xa4/0xd0 ath10k_htt_rx_free+0xc4/0xf4 [ath10k_core] ath10k_core_stop+0x64/0x7c [ath10k_core] ath10k_halt+0x11c/0x180 [ath10k_core] ath10k_stop+0x54/0x94 [ath10k_core] drv_stop+0x48/0x1c8 [mac80211] ieee80211_do_open+0x638/0x77c [mac80211] ieee80211_open+0x48/0x5c [mac80211] __dev_open+0xb4/0x174 __dev_change_flags+0xc4/0x1dc dev_change_flags+0x3c/0x7c devinet_ioctl+0x2b4/0x580 inet_ioctl+0xb0/0x1b4 sock_do_ioctl+0x4c/0x16c compat_ifreq_ioctl+0x1cc/0x35c compat_sock_ioctl+0x110/0x2ac __arm64_compat_sys_ioctl+0xf4/0x3e0 el0_svc_common+0xb4/0x17c el0_svc_compat_handler+0x2c/0x58 el0_svc_compat+0x8/0x2c
Tested-on: WCN3990 hw1.0 SNOC WLAN.HL.2.0-01387-QCAHLSWMTPLZ-1
Tested-by: Douglas Anderson dianders@chromium.org Signed-off-by: Youghandhar Chintala quic_youghand@quicinc.com Signed-off-by: Kalle Valo quic_kvalo@quicinc.com Link: https://lore.kernel.org/r/20221012142733.32420-1-quic_youghand@quicinc.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/wireless/ath/ath10k/core.c | 16 ++++++++++++++++ drivers/net/wireless/ath/ath10k/htc.c | 9 +++++++++ drivers/net/wireless/ath/ath10k/hw.h | 2 ++ 3 files changed, 27 insertions(+)
diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c index d1ac64026cb3..9a8ea7231a9e 100644 --- a/drivers/net/wireless/ath/ath10k/core.c +++ b/drivers/net/wireless/ath/ath10k/core.c @@ -99,6 +99,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = { .dynamic_sar_support = false, .hw_restart_disconnect = false, .use_fw_tx_credits = true, + .delay_unmap_buffer = false, }, { .id = QCA988X_HW_2_0_VERSION, @@ -138,6 +139,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = { .dynamic_sar_support = false, .hw_restart_disconnect = false, .use_fw_tx_credits = true, + .delay_unmap_buffer = false, }, { .id = QCA9887_HW_1_0_VERSION, @@ -178,6 +180,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = { .dynamic_sar_support = false, .hw_restart_disconnect = false, .use_fw_tx_credits = true, + .delay_unmap_buffer = false, }, { .id = QCA6174_HW_3_2_VERSION, @@ -213,6 +216,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = { .dynamic_sar_support = true, .hw_restart_disconnect = false, .use_fw_tx_credits = true, + .delay_unmap_buffer = false, }, { .id = QCA6174_HW_2_1_VERSION, @@ -252,6 +256,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = { .dynamic_sar_support = false, .hw_restart_disconnect = false, .use_fw_tx_credits = true, + .delay_unmap_buffer = false, }, { .id = QCA6174_HW_2_1_VERSION, @@ -291,6 +296,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = { .dynamic_sar_support = false, .hw_restart_disconnect = false, .use_fw_tx_credits = true, + .delay_unmap_buffer = false, }, { .id = QCA6174_HW_3_0_VERSION, @@ -330,6 +336,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = { .dynamic_sar_support = false, .hw_restart_disconnect = false, .use_fw_tx_credits = true, + .delay_unmap_buffer = false, }, { .id = QCA6174_HW_3_2_VERSION, @@ -373,6 +380,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = { .dynamic_sar_support = true, .hw_restart_disconnect = false, .use_fw_tx_credits = true, + .delay_unmap_buffer = false, }, { .id = QCA99X0_HW_2_0_DEV_VERSION, @@ -418,6 +426,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = { .dynamic_sar_support = false, .hw_restart_disconnect = false, .use_fw_tx_credits = true, + .delay_unmap_buffer = false, }, { .id = QCA9984_HW_1_0_DEV_VERSION, @@ -470,6 +479,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = { .dynamic_sar_support = false, .hw_restart_disconnect = false, .use_fw_tx_credits = true, + .delay_unmap_buffer = false, }, { .id = QCA9888_HW_2_0_DEV_VERSION, @@ -519,6 +529,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = { .dynamic_sar_support = false, .hw_restart_disconnect = false, .use_fw_tx_credits = true, + .delay_unmap_buffer = false, }, { .id = QCA9377_HW_1_0_DEV_VERSION, @@ -558,6 +569,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = { .dynamic_sar_support = false, .hw_restart_disconnect = false, .use_fw_tx_credits = true, + .delay_unmap_buffer = false, }, { .id = QCA9377_HW_1_1_DEV_VERSION, @@ -599,6 +611,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = { .dynamic_sar_support = false, .hw_restart_disconnect = false, .use_fw_tx_credits = true, + .delay_unmap_buffer = false, }, { .id = QCA9377_HW_1_1_DEV_VERSION, @@ -631,6 +644,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = { .dynamic_sar_support = false, .hw_restart_disconnect = false, .use_fw_tx_credits = true, + .delay_unmap_buffer = false, }, { .id = QCA4019_HW_1_0_DEV_VERSION, @@ -677,6 +691,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = { .dynamic_sar_support = false, .hw_restart_disconnect = false, .use_fw_tx_credits = true, + .delay_unmap_buffer = false, }, { .id = WCN3990_HW_1_0_DEV_VERSION, @@ -709,6 +724,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = { .dynamic_sar_support = true, .hw_restart_disconnect = true, .use_fw_tx_credits = false, + .delay_unmap_buffer = true, }, };
diff --git a/drivers/net/wireless/ath/ath10k/htc.c b/drivers/net/wireless/ath/ath10k/htc.c index 6d1784f74bea..5bfeecb95fca 100644 --- a/drivers/net/wireless/ath/ath10k/htc.c +++ b/drivers/net/wireless/ath/ath10k/htc.c @@ -56,6 +56,15 @@ void ath10k_htc_notify_tx_completion(struct ath10k_htc_ep *ep, ath10k_dbg(ar, ATH10K_DBG_HTC, "%s: ep %d skb %pK\n", __func__, ep->eid, skb);
+ /* A corner case where the copy completion is reaching to host but still + * copy engine is processing it due to which host unmaps corresponding + * memory and causes SMMU fault, hence as workaround adding delay + * the unmapping memory to avoid SMMU faults. + */ + if (ar->hw_params.delay_unmap_buffer && + ep->ul_pipe_id == 3) + mdelay(2); + hdr = (struct ath10k_htc_hdr *)skb->data; ath10k_htc_restore_tx_skb(ep->htc, skb);
diff --git a/drivers/net/wireless/ath/ath10k/hw.h b/drivers/net/wireless/ath/ath10k/hw.h index 1b99f3a39a11..9643031a4427 100644 --- a/drivers/net/wireless/ath/ath10k/hw.h +++ b/drivers/net/wireless/ath/ath10k/hw.h @@ -637,6 +637,8 @@ struct ath10k_hw_params { bool hw_restart_disconnect;
bool use_fw_tx_credits; + + bool delay_unmap_buffer; };
struct htt_resp;