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SAP version 4 uses larger Host to MEI notification queue.
Since it is unknown which SAP version is used by the CSME firmware
when the driver loads, try version 4 first. In case the CSME firmware
uses version 3, the memory allocation will fail. In this case the
driver will try again to allocate the memory for version 3.
Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20240729201718.8372e040282f.Ia0085784e08a35159c9293f986c3d2774038f4c4@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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In case the SAP connection is established before the interface is
added, the mac address is still not set. Don't send the nic info
SAP message in this case since it will result in sending an invalid
mac address. The nic info message will be sent with a valid mac
address when the interface is added.
Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230822103048.a49436bed387.I0ca88d72456e6e9f939bbc2e0c52ffb173fbc97e@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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When wiamt is disabled the driver up SAP message is not sent, so
there is no need to send the driver down message as well.
Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230822103048.100f41b84656.I583d3e18ea65793f53aa710af13e47f8af82b53d@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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The HOST_GOES_DOWN message should be sent even if wiamt is disabled.
Otherwise wiamt may still use the shared memory (e.g. if enabled
later) while it's no longer valid.
Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230822103048.2baad50eb1c3.If7b7c1dc2d6bfc6bacf7f6c72972f19714d9d973@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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SAP messages should not be sent when AMT is disabled.
Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230822103048.db16b55c27c1.I48834c14f5af8d31792f5048b3023509cba191dd@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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The feature is still disabled (depends on BROKEN), but
the code had a compilation error after one of the merges.
Fix that.
Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230531085033.216028-1-gregory.greenman@intel.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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When CSME takes ownership, the driver sets RFKILL on, and this
triggers driver unload and sending the confirmation SAP message.
However, when IWL_MVM_MEI_REPORT_RFKILL is set, RFKILL was not
reported and as a result, the driver did not confirm the ownership
transition. Fix it.
Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230418122405.29ac3cd3df73.I96b32bc274bfe1e3871e54d3fa29c7ac4f40446f@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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When the host disconnects from the AP CSME takes ownership right away.
Since the driver never asks for ownership again wifi is left in rfkill
until CSME releases the NIC, although in many cases the host could
re-connect shortly after the disconnection. To allow the host to
recover from occasional disconnection, re-ask for ownership to let
the host connect again.
Allow one minute before re-asking for ownership to avoid too frequent
ownership transitions.
Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230418122405.a6c6ebc48f2d.I8a17003b86e71b3567521cc69864b9cbe9553ea9@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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The rfkill() callback was invoked with wrong parameters.
It was missed since MEI is defined now as depending on BROKEN.
Fix that.
Fixes: d288067ede4b ("wifi: iwlwifi: mei: avoid blocking sap messages handling due to rtnl lock")
Fixes: 5aa7ce31bd84 ("wifi: iwlwifi: mei: make sure ownership confirmed message is sent")
Fixes: 95170a46b7dd ("wifi: iwlwifi: mei: don't send SAP commands if AMT is disabled")
Link: https://lore.kernel.org/r/20230126222821.305122-2-gregory.greenman@intel.com
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
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SPDX
*.h use /* */ style comments
Spelling replacements
commnunication to communication
adsress to address
procotol to protocol
addtional to additional
kown to know
negotiaion to negotiation
mssage to message
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20221205102808.f1ff5aff270b.Ie4ba3f980a35455ed95e7c0cae854231fccc89e2@changeid
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When iwlmei driver is removed, it removes all the interfaces
since CSME will take over the NIC while there is no SAP connection.
When the iwlmei driver is removed due to the host being suspended,
this results in the interface being down after resume since the
interface was removed on suspend so mac80211 will not try to bring it
up on resume.
Since on suspend the mac is stopped anyway by mac80211, there is
no need to remove the interface in this case. Wait for the mac
to stop instead. Once the mac is stopped, the driver will not
access the NIC anymore so it is safe for CSME to take over.
Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20221102165239.371102f04586.I813a964607b3e92ea275a0cf56df57227c11ae88@changeid
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Disconnections are reported to CSME as long link down. As a result,
CSME will take ownership right away so the host doesn't have a
chance to reconnect, although in many cases it could quickly reconnect
and preserve host connectivity.
Report disconnections as temporary so CSME will give the host some
grace time to reconnect.
Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20221102165239.401665457652.Ie5de9eacc5a51cf0965a08c202caf3fbc3a91ec4@changeid
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wait_event_timeout() return value indicates whether the condition
evaluated to true or not, so no need to re-take the lock and
check the got_ownership flag.
Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20221102165239.33159054626f.Ief9e2dc42f96f8044c197d32172003a5ead0f8d3@changeid
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If the FW needs to do OTP re-read, the driver must notify CSME before
loading the FW so CSME will not try to access the NIC during the
re-read. Once the alive notification is received, CSME is notified
that NIC access is allowed again.
Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20221102165239.49eb8c6d455f.I7f0a5debb2d3d662a4151199bbec24613f324c13@changeid
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The AMT_STATE sap message handler tries to take the rtnl lock.
This means that in case the rtnl lock is already taken, sap messages
will not be processed.
When an interface is brought up, the host requests ownership from
csme. However, since the rtnl lock is already held, if there is a
pending amt state message, the host will not be able to read the
ownership confirm message because the amt state message handler
is pending. As a result, the host fails to get ownership although
csme granted it.
Fix it by moving the part that needs the rtnl lock into a dedicated
worker, so handling sap messages can continue.
Fixes: 2da4366f9e2c ("iwlwifi: mei: add the driver to allow cooperation with CSME")
Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20221030191011.8599f2b4e9dd.I518f79e9099bf815c5f8d90235b4ce3250f59970@changeid
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We should not send any SAP command to CSME if AMT is disabled.
Reported-by: Toke Høiland-Jørgensen <toke@toke.dk>
Fixes: 2da4366f9e2c ("iwlwifi: mei: add the driver to allow cooperation with CSME")
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20221030191011.ea222d41c781.Ifc90ddc3e35187683ff7f59371d792b61c8854c8@changeid
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It is possible that CSME will try to take ownership while the driver
is stopping. In this case, if the CSME takes ownership message arrives
after the driver started unregistering, the iwl_mei_cache->ops is
already invalid, so the host will not answer with the ownership
confirmed message.
Similarly, if the take ownership message arrived after the mac was
stopped or when iwl_mvm_up() failed, setting rfkill will not trigger
sending the confirm message. As a result, CSME will not take
ownership, which will result in a disconnection.
Fix it by sending the ownership confirmed message immediately in such
cases.
Fixes: 2da4366f9e2c ("iwlwifi: mei: add the driver to allow cooperation with CSME")
Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20221030191011.b2a4c009e3e6.I7f931b7ee8b168e8ac88b11f23bff98b7ed3cb19@changeid
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If SKB allocation fails, continue rather than using the NULL
pointer.
Coverity CID: 1497650
Cc: stable@vger.kernel.org
Fixes: 2da4366f9e2c ("iwlwifi: mei: add the driver to allow cooperation with CSME")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20220517120045.90c1b1fd534e.Ibb42463e74d0ec7d36ec81df22e171ae1f6268b0@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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The SAP data header has some fields that are marked as reserved
but are actually in use by CSME. Clear those fields before sending
the data to avoid having random values in those fields.
Cc: stable@vger.kernel.org
Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20220517120045.8dd3423cf683.I02976028eaa6aab395cb2e701fa7127212762eb7@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless-next
Johannes Berg says:
====================
brcmfmac
* add BCM43454/6 support
rtw89
* add support for 160 MHz channels and 6 GHz band
* hardware scan support
iwlwifi
* support UHB TAS enablement via BIOS
* remove a bunch of W=1 warnings
* add support for channel switch offload
* support 32 Rx AMPDU sessions in newer devices
* add support for a couple of new devices
* add support for band disablement via BIOS
mt76
* mt7915 thermal management improvements
* SAR support for more mt76 drivers
* mt7986 wmac support on mt7915
ath11k
* debugfs interface to configure firmware debug log level
* debugfs interface to test Target Wake Time (TWT)
* provide 802.11ax High Efficiency (HE) data via radiotap
ath9k
* use hw_random API instead of directly dumping into random.c
wcn36xx
* fix wcn3660 to work on 5 GHz band
ath6kl
* add device ID for WLU5150-D81
cfg80211/mac80211
* initial EHT (from 802.11be) support
(EHT rates, 320 MHz, larger block-ack)
* support disconnect on HW restart
* tag 'wireless-next-2022-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless-next: (247 commits)
mac80211: Add support to trigger sta disconnect on hardware restart
mac80211: fix potential double free on mesh join
mac80211: correct legacy rates check in ieee80211_calc_rx_airtime
nl80211: fix typo of NL80211_IF_TYPE_OCB in documentation
mac80211: Use GFP_KERNEL instead of GFP_ATOMIC when possible
mac80211: replace DEFINE_SIMPLE_ATTRIBUTE with DEFINE_DEBUGFS_ATTRIBUTE
rtw89: 8852c: process logic efuse map
rtw89: 8852c: process efuse of phycap
rtw89: support DAV efuse reading operation
rtw89: 8852c: add chip::dle_mem
rtw89: add page_regs to handle v1 chips
rtw89: add chip_info::{h2c,c2h}_reg to support more chips
rtw89: add hci_func_en_addr to support variant generation
rtw89: add power_{on/off}_func
rtw89: read chip version depends on chip ID
rtw89: pci: use a struct to describe all registers address related to DMA channel
rtw89: pci: add V1 of PCI channel address
rtw89: pci: add struct rtw89_pci_info
rtw89: 8852c: add 8852c empty files
MAINTAINERS: add devicetree bindings entry for mt76
...
====================
Link: https://lore.kernel.org/r/20220311124029.213470-1-johannes@sipsolutions.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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There's another field and so W=2 warns about this code, but
in general it's nicer to use C99 initializers anyway to make
the code easier to read.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20220204122220.b5efbbd83c9c.I908128aa8249565ff1c5496ca5c5597efea7cb39@changeid
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
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These cause extra warnings (at least with W=3), avoid them.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20220130115024.59d00c6e5f09.I331bf18af0b80b5cc41b379ff0cc1b26a89dd915@changeid
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
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When we register and we are in link protection passive, meaning
that the host can't touch the device, report RFKILL immediately
upon register() and don't wait for the CSME firmware to let us
know again about the link protection state.
What happens if we wait is that the host will not see RFKILL soon
enough and we'll have a window of time during which it can bring
up the device which will request ownership.
Fixes: 2da4366f9e2c ("iwlwifi: mei: add the driver to allow cooperation with CSME")
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/iwlwifi.20220128142706.a136f9f46336.Ief7506dc3b1813a1943a5a639aa45d8e5f284f31@changeid
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The shared area is a DMA memory allocated in the host and
mapped so that the host and the CSME firmware can
exchange data. It is mapped through a dedicated PCI device
that is driven by the mei bus driver.
The bus driver is in charge of allocating and mapping this
memory. It also needs to configure the CSME firmware with
a specific set of commands, so that the CSME firmware will
know that this memory is meant to be used by its internal
WLAN module.
For this, the CSME firmware first needs to completely
initialize its WLAN module and only then get the mapping
request.
The problem is that the mei bus enumeration completes
before the WLAN is completely ready. This means that
the WLAN module's initialization is racing with iwlmei's
allocation and mapping flow.
Testing showed a problem in resume flows where iwlmei
was too fast and the DMA mapping failed.
Add a retry mechanism to make sure that we will succeed
to map the memory.
Fixes: 2da4366f9e2c ("iwlwifi: mei: add the driver to allow cooperation with CSME")
Fixes: bcbddc4f9d02 ("iwlwifi: mei: wait before mapping the shared area")
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/iwlwifi.20220128142706.cc51e6a6d635.I4b74a082eb8d89f9e4f556a27c4339c15444dc6c@changeid
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git://git.kernel.org/pub/scm/linux/kernel/git/iwlwifi/iwlwifi-next
wlwifi patches for v5.17 v2
* Support for Time-Aware-SAR (TAS) as read from the BIOS;
* Fix scan timeout issue when 6GHz is enabled;
* Work continues for new HW family Bz;
* Support for Optimized Connectivity Experience (OCE) scan;
* A bunch of FW debugging improvements and fixes;
* Fix one 32-bit compilation issue;
* Some RX changes for new HW family
* Some fixes for 6 GHz scan;
* Fix SAR table fixes with newer platforms;
* Fix early restart crash;
* Small fix in the debugging code;
* Add new Killer device IDs;
* Datapath updates for Bz family continues;
* A couple of important fixes in iwlmei;
* Some other small fixes, clean-ups and improvements.
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The shared area is a DMA memory allocated in the host and
mapped so that the host and the CSME firmware can
exchange data. It is mapped through a dedicated PCI device
that is driven by the mei bus driver.
The bus driver is in charge of allocating and mapping this
memory. It also needs to configure the CSME firmware with
a specific set of commands, so that the CSME firmware will
know that this memory is meant to be used by its internal
WLAN module.
For this, the CSME firmware first needs to completely
initialize its WLAN module and only then get the mapping
request.
The problem is that the mei bus enumeration completes
before the WLAN is completely ready. This means that
the WLAN module's initialization is racing with iwlmei's
allocation and mapping flow.
Testing showed a problem in resume flows where iwlmei
was too fast and the DMA mapping failed.
Add a delay to avoid this. This is still racy, but our
measurements showed that we have a good margin and we
should now be safe.
Fixes: 2da4366f9e2c ("iwlwifi: mei: add the driver to allow cooperation with CSME")
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20211220142940.8b6279e3d0be.I6fe128b0b86149a85535104822c8355b367887c8@changeid
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
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When the driver is unregistered, CSME will take ownership on the
device. Reflect this in the iwlmei object so that we will remember
to re-ask for ownership when the driver will register again.
Not doing so will cause CSME not to give the host ownership and
we will see the following error message when trying to bring up
the interface:
iwlwifi 0000:a9:00.0: iwl_pcie_prepare_card_hw iwl_trans_prepare_card_hw enter
iwlwifi 0000:a9:00.0: iwl_pcie_set_hw_ready hardware not ready
iwlwifi 0000:a9:00.0: iwl_pcie_set_hw_ready hardware not ready
iwlwifi 0000:a9:00.0: iwl_pcie_prepare_card_hw Couldn't prepare the card but SAP is connected
iwlwifi 0000:a9:00.0: Error while preparing HW: -16
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20211220142940.c7bb5b7644df.I48498d9fd6e3959562205af67aa5f1a822eb762d@changeid
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
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There are a few warnings due to kernel-doc not understanding
the constructs the way they're done here, fix them.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/iwlwifi.20211219110000.1ef2bb24771c.I6a59ad2d64f719d3e27398951c8f1b678b0b1092@changeid
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Smatch spot a possible NULL pointer dereference. Fix it.
__iwl_mvm_mac_set_key can be called with sta = NULL
Also add a NULL pointer check after memory allocation.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Link: https://lore.kernel.org/r/20211130105951.85539-1-emmanuel.grumbach@intel.com
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
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There is a spelling mistake in a debugfs filename. Fix it.
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20211129124921.11817-1-colin.i.king@gmail.com
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
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If CSME is compromised, it could report a bigger queue size
in the share area and make the host perform an out of bound
access.
Instead of reading the size of the queue from the shared area,
store it in the regular context which is not accessible by CSME.
While at it, fix a small typo in an error print.
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Link: https://lore.kernel.org/r/20211128121509.3952-1-emmanuel.grumbach@intel.com
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
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Add three debugfs hooks:
* status: Check if we have a connection with the CSME
firwmare. This hook is a read only.
* req_ownership: Send a SAP command to request ownership. This
flow should be triggered by iwlwifi (from user space through
vendor commands really), but being able to trigger an ownership
request from debugfs allows us to request ownership without
connecting afterwards. This is an "error" flow that the CSME
firmware is designed to handle this way:
+ Grant ownership since the host asked for it
+ Wait 3 seconds to let the host connect
+ If the host didn't connect, take the device back (forcefully).
+ Don't grant any new ownership request in the following 30
seconds.
This debugfs hook allows us to test this flow.
* send_start_message: Restart the communication with the CSME
firmware from the very beginning. At the very beginning (upon
iwlwifi start), iwlmei send a special message: SAP_ME_MSG_START.
This hook allows to send it again and this will retrigger the
whole flow. It is important to test this restart in the middle
of normal operation since it can happen (in case the CSME
firmware decided to reset for example).
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20211112062814.7502-3-emmanuel.grumbach@intel.com
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CSME in two words
-----------------
CSME stands for Converged Security and Management Engine. It is
a CPU on the chipset and runs a dedicated firmware.
AMT (Active Management Technology) is one of the applications
that run on that CPU. AMT allows to control the platform remotely.
Here is a partial list of the use cases:
* View the screen of the plaform, with keyboard and mouse (KVM)
* Attach a remote IDE device
* Have a serial console to the device
* Query the state of the platform
* Reset / shut down / boot the platform
Networking in CSME
------------------
For those uses cases, CSME's firmware has an embedded network
stack and is able to use the network devices of the system: LAN
and WLAN. This is thanks to the CSME's firmware WLAN driver.
One can add a profile (SSID / key / certificate) to the CSME's OS
and CSME will connect to that profile. Then, one can use the WLAN
link to access the applications that run on CSME (AMT is one of
them). Note that CSME is active during power state and power state
transitions. For example, it is possible to have a KVM session
open to the system while the system is rebooting and actually
configure the BIOS remotely over WLAN thanks to AMT.
How all this is related to Linux
--------------------------------
In Linux, there is a driver that allows the OS to talk to the
CSME firmware, this driver is drivers/misc/mei. This driver
advertises a bus that allows other kernel drivers or even user
space) to talk to components inside the CSME firmware.
In practice, the system advertises a PCI device that allows
to send / receive data to / from the CSME firmware. The mei
bus drivers in drivers/misc/mei is an abstration on top of
this PCI device.
The driver being added here is called iwlmei and talks to the
WLAN driver inside the CSME firmware through the mei bus driver.
Note that the mei bus driver only gives bus services, it doesn't
define the content of the communication.
Why do we need this driver?
--------------------------
CSME uses the same WLAN device that the OS is expecting to see
hence we need an arbitration mechanism. This is what iwlmei is
in charge of. iwlmei maintains the communication with the CSME
firmware's WLAN driver. The language / protocol that is used
between the CSME's firmware WLAN driver and iwlmei is OS agnostic
and is called SAP which stands for Software Abritration Protocol.
With SAP, iwlmei will be able to tell the CSME firmware's WLAN
driver:
1) Please give me the device.
2) Please note that the SW/HW rfkill state change.
3) Please note that I am now associated to X.
4) Please note that I received this packet.
etc...
There are messages that go the opposite direction as well:
1) Please note that AMT is en/disable.
2) Please note that I believe the OS is broken and hence I'll take
the device *now*, whether you like it or not, to make sure that
connectivity is preserved.
3) Please note that I am willing to give the device if the OS
needs it.
4) Please give me any packet that is sent on UDP / TCP on IP address
XX.XX.XX.XX and an port ZZ.
5) Please send this packet.
etc...
Please check drivers/net/wireless/intel/iwlwifi/mei/sap.h for the
full protocol specification.
Arbitration is not the only purpose of iwlmei and SAP. SAP also
allows to maintain the AMT's functionality even when the OS owns
the device. To connect to AMT, one needs to initiate an HTTP
connection to port 16992. iwlmei will listen to the Rx path and
forward (through SAP) to the CSME firmware the data it got. Then,
the embedded HTTP server in the chipset will reply to the request
and send a SAP notification to ask iwlmei to send the reply.
This way, AMT running on the CSME can still work.
In practice this means that all the use cases quoted above (KVM,
remote IDE device, etc...) will work even when the OS uses the
WLAN device.
How to disable all this?
---------------------------
iwlmei won't be able to do anything if the CSME's networking stack
is not enabled. By default, CSME's networking stack is disabled (this
is a BIOS setting).
In case the CSME's networking stack is disabled, iwlwifi will just
get access to the device because there is no contention with any other
actor and, hence, no arbitration is needed.
In this patch, I only add the iwlmei driver. Integration with
iwlwifi will be implemented in the next one.
Co-Developed-by: Ayala Beker <ayala.beker@intel.com>
Signed-off-by: Ayala Beker <ayala.beker@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
v2: fix a few warnings raised by the different bots
v3: rewrite the commit message
v4: put the debugfs content in a different patch
v5: fix a NULL pointer dereference upon DHCP TX if SAP is connected
since we now have the required cfg80211 bits in wl-drv-next, add
the RFKILL handling patch to this series.
v6: change the SAP API to inherit the values from iwl-mei.h removing
the need to ensure the values are equal with a BUILD_BUG_ON.
This was suggested by Arend
v7: * fix a locking issue in case of CSME firmware reset:
When the CSME firmware resets, we need to unregister the
netdev, first take the mutex, and only then, rely on it
being taken.
* Add a comment to explain why it is ok to have static variables
(iwlmei can't have more than a single instance).
* Add a define for 26 + 8 + 8
* Add a define SEND_SAP_MAX_WAIT_ITERATION
* make struct const
* Reword a bit the Kconfig help message
* Ayala added her Signed-off
* fixed an RCU annotation
v8: do not require ownership upfront, use NIC_OWNER instead. This fixes
a deadlock when CSME does not have the right WiFi FW.
Add more documentation about the owernship transition
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20211112062814.7502-2-emmanuel.grumbach@intel.com
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