From: Mordechay Goodstein <mordechay.goodstein@xxxxxxxxx>
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 <mordechay.goodstein@xxxxxxxxx>
Signed-off-by: Luca Coelho <luciano.coelho@xxxxxxxxx>
---
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 6ccde7e30211..db312abd2e09 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 2bec97133119..0cbc79949982 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);
--
2.31.0
