From d4626f91739b76633dbb3013e843e178c4a26618 Mon Sep 17 00:00:00 2001 From: Mordechay Goodstein Date: Tue, 30 Mar 2021 16:24:57 +0300 Subject: [PATCH] iwlwifi: pcie: clear only FH bits handle in the interrupt For simplicity we assume that msix has 2 IRQ lines one used for rx data called msix_non_share, and another used for one bit flags messages (alive, hw error, sw error, rx data flag) called msix_share. Every time the FW has data to send it puts it on the RX queue and HW turns on the flags in msix_share (inta_fw) indicating about rx data, and HW sends an interrupt a bit later to the msix_non_share _unless_ the msix_shared RX data bit was cleared. Currently in the code every time we get an msix_shared we clear all bits including rx data queue bits. So we can have a race ---------------------------------------------------- DRIVER | HW | FW ---------------------------------------------------- - send host cmd to FW | | | | - handle message | | and put a response | | on the RX queue | - RX flag on | | | - send alive msix | - alive flag on | | - interrupt | | msix_share driver | - handle msix_shared | | and clear all flags | | bits | | | - don't send an | | interrupt on | | msix_non_shared | | (driver cleared) | - driver timeout on | | waiting for host cmd | | respond | | | | ---------------------------------------------------- The change is to clear only the msi_shared flags that are handled in the msix_shared flow, which will cause the hardware to send an interrupt on the msix_non_share line as well, when it has data. Signed-off-by: Mordechay Goodstein Signed-off-by: Luca Coelho Link: https://lore.kernel.org/r/iwlwifi.20210330162204.a1cdda2fa270.I02a82312679f4541f30bb8db8747a797dbb70ee7@changeid Signed-off-by: Luca Coelho --- drivers/net/wireless/intel/iwlwifi/iwl-csr.h | 3 +++ drivers/net/wireless/intel/iwlwifi/pcie/rx.c | 9 ++++++++- 2 files changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/net/wireless/intel/iwlwifi/iwl-csr.h b/drivers/net/wireless/intel/iwlwifi/iwl-csr.h index 6ccde7e..db312ab 100644 --- a/drivers/net/wireless/intel/iwlwifi/iwl-csr.h +++ b/drivers/net/wireless/intel/iwlwifi/iwl-csr.h @@ -578,6 +578,9 @@ enum msix_fh_int_causes { MSIX_FH_INT_CAUSES_FH_ERR = BIT(21), }; +/* The low 16 bits are for rx data queue indication */ +#define MSIX_FH_INT_CAUSES_DATA_QUEUE 0xffff + /* * Causes for the HW register interrupts */ diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c index 2bec971..0cbc799 100644 --- a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c +++ b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c @@ -2194,9 +2194,16 @@ irqreturn_t iwl_pcie_irq_msix_handler(int irq, void *dev_id) struct iwl_trans_pcie *trans_pcie = iwl_pcie_get_trans_pcie(entry); struct iwl_trans *trans = trans_pcie->trans; struct isr_statistics *isr_stats = &trans_pcie->isr_stats; + u32 inta_fh_msk = ~MSIX_FH_INT_CAUSES_DATA_QUEUE; u32 inta_fh, inta_hw; bool polling = false; + if (trans_pcie->shared_vec_mask & IWL_SHARED_IRQ_NON_RX) + inta_fh_msk |= MSIX_FH_INT_CAUSES_Q0; + + if (trans_pcie->shared_vec_mask & IWL_SHARED_IRQ_FIRST_RSS) + inta_fh_msk |= MSIX_FH_INT_CAUSES_Q1; + lock_map_acquire(&trans->sync_cmd_lockdep_map); spin_lock_bh(&trans_pcie->irq_lock); @@ -2205,7 +2212,7 @@ irqreturn_t iwl_pcie_irq_msix_handler(int irq, void *dev_id) /* * Clear causes registers to avoid being handling the same cause. */ - iwl_write32(trans, CSR_MSIX_FH_INT_CAUSES_AD, inta_fh); + iwl_write32(trans, CSR_MSIX_FH_INT_CAUSES_AD, inta_fh & inta_fh_msk); iwl_write32(trans, CSR_MSIX_HW_INT_CAUSES_AD, inta_hw); spin_unlock_bh(&trans_pcie->irq_lock); -- 2.7.4