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/openbmc/linux/drivers/net/wireless/intel/iwlwifi/
H A Diwl-csr.hd4626f91 Tue Mar 30 08:24:57 CDT 2021 Mordechay Goodstein <mordechay.goodstein@intel.com> 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 <mordechay.goodstein@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210330162204.a1cdda2fa270.I02a82312679f4541f30bb8db8747a797dbb70ee7@changeid
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
/openbmc/linux/drivers/net/wireless/intel/iwlwifi/pcie/
H A Drx.cd4626f91 Tue Mar 30 08:24:57 CDT 2021 Mordechay Goodstein <mordechay.goodstein@intel.com> 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 <mordechay.goodstein@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210330162204.a1cdda2fa270.I02a82312679f4541f30bb8db8747a797dbb70ee7@changeid
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>