On 6/6/2024 6:50 PM, Kalle Valo wrote:
Harshitha Prem <quic_hprem@xxxxxxxxxxx> writes:
From: Karthikeyan Periyasamy <quic_periyasa@xxxxxxxxxxx>
Currently, single device is probed and once firmware is ready, the device
is registered to mac80211. For multi-link operation, different bands of
different devices or same device would be part of a single wiphy and for
this, hardware device group abstraction would be helpful.
Hardware device group abstraction - when there are multiple devices (with
single radio or dual radio) that are connected by any means of interface
for communicating between them, then these devices can be combined
together as a single group using a group id to form a group abstraction
and register to mac80211.
The grouping information of multiple devices would be based on device tree
during device probe. If no such information is available then a single
device will be part of group abstraction and registered to mac80211 else
multiple devices advertised in device tree are combined and then registered
to mac80211.
For device group abstraction, a base structure named ath12k_hw_group (ag)
and the following helpers are introduced:
ath12k_core_hw_group_alloc() : allocate ath12k_hw_group (ag)
based on group id and number
of devices that are going to
be part of this group.
ath12k_core_hw_group_free() : free ag during deinit.
ath12k_core_assign_hw_group() : assign/map the details of group
to ath12k_base (ab).
ath12k_core_unassign_hw_group() : unassign/unmap the details of ag
in ath12k_base (ab).
ath12k_core_hw_group_create() : create the devices which are part
of group (ag).
ath12k_core_hw_group_destroy() : cleanup the devices in ag
These helpers are used during device probe and mapping the group to the
devices involved.
Please find the illustration of how multiple devices might be combined
together in future based on group id.
Grouping of multiple devices (in future)
+------------------------------------------------------------------------+
| +-------------------------------------+ +-------------------+ |
| | +-----------+ | | +-----------+ | | +-----------+ | |
| | | ar (2GHz) | | | | ar (5GHz) | | | | ar (6GHz) | | |
| | +-----------+ | | +-----------+ | | +-----------+ | |
| | ath12k_base (ab) | | ath12k_base (ab) | |
| | (Dual band device) | | | |
| +-------------------------------------+ +-------------------+ |
| ath12k_hw_group (ag) based on group id |
+------------------------------------------------------------------------+
This is a good diagram, thanks for that. But how does struct ath12k_hw
fit into the diagram?
Currently with this base device group series, ath12k_hw sits above
ath12k_base.
Please find the representation below:
+-----------------------------------------------+
| +-------------------+ +-------------------+ |
| | +---------+ | | +---------+ | |
| | | | | | | | | |
| | | mac80211| | | | mac80211| | |
| | | hw->priv| | | | hw->priv| | |
| | | | | | | | | |
| | +---------+ | | +---------+ | |
| | +---------+ | | +---------+ | |
| | | | | | | | | |
| | |ath12k_hw| | | |ath12k_hw| | |
| | | (ah) | | | | (ah) | | |
| | | | | | | | | |
| | +---------+ | | +---------+ | |
| | ^ | | ^ | |
| | +------|--------+ | | +------|--------+ | |
| | | | | | | | | | | |
| | | +----------+ | | | | +----------+ | | |
| | | | ar | | | | | | ar | | | |
| | | | 5 GHz | | | | | | 6 GHz | | | |
| | | | | | | | | | | | | |
| | | +----------+ | | | | +----------+ | | |
| | | ath12k_base | | | | ath12k_base | | |
| | | (ab) | | | | (ab) | | |
| | +---------------+ | | +---------------+ | |
| | ath12k_hw_group | | ath12k_hw_group | |
| +-------------------+ +-------------------+ |
+-----------------------------------------------+
As multiple device grouping is not yet brought in with this patch, this
is how it might look like.
In the above representation, two devices are combined into single group
based on group id.
Add base code changes where single device would be part of a group with an
invalid group id forming an group abstraction. Multi device grouping will
be introduced in future.
Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.0.1-00029-QCAHKSWPL_SILICONZ-1
Tested-on: WCN7850 hw2.0 PCI
WLAN.HMT.1.0-03427-QCAHMTSWPL_V1.0_V2.0_SILICONZ-1.15378.4
Signed-off-by: Karthikeyan Periyasamy <quic_periyasa@xxxxxxxxxxx>
Co-developed-by: Harshitha Prem <quic_hprem@xxxxxxxxxxx>
Signed-off-by: Harshitha Prem <quic_hprem@xxxxxxxxxxx>
Acked-by: Jeff Johnson <quic_jjohnson@xxxxxxxxxxx>
Like I have said before, for adding any new locks there needs to be a
proper analysis for the locking and good justifications why new locks
are needed. I don't see any of that above.
Sure, Kalle. Will add the details for new locks. As grouping has to be
done in synchronous manner lock was introduced.
BTW I will from now on require proper analysis also for additions to
enum ath12k_dev_flags.
Sure, Will update the details.
There are few racy conditions with mutiple device grouping which needed
these flags.
One such instance is, if a reboot is triggered between core_init and
core_start, some of the devices in ath12k_hw_group would have already
started and completed till FW ready but some would not even reached QMI
firmware ready event. But, during reboot as part of pci shutdown group
clean up would try to do core stop for all devices in group. This will
lead to crashes as for some devices core start is yet to do but we tried
to invoked core stop.
--- a/drivers/net/wireless/ath/ath12k/core.c
+++ b/drivers/net/wireless/ath/ath12k/core.c
@@ -21,6 +21,9 @@ unsigned int ath12k_debug_mask;
module_param_named(debug_mask, ath12k_debug_mask, uint, 0644);
MODULE_PARM_DESC(debug_mask, "Debugging mask");
+static DEFINE_MUTEX(ath12k_hw_lock);
+static struct list_head ath12k_hw_groups = LIST_HEAD_INIT(ath12k_hw_groups);
I can somehow understand/guess why this mutex is needed (even though
there's no documentation) but the naming is not really clear as we
already have struct ath12k_hw::hw_mutex.
This lock is for device group list handling. Will modify the name
accordingly and update the documentation. Thanks.
+/* Holds info on the group of devices that are registered as a single wiphy */
+struct ath12k_hw_group {
+ struct list_head list;
+ u8 id;
+ u8 num_devices;
+ u8 num_probed;
+ struct ath12k_base *ab[ATH12K_MAX_SOCS];
+ /* To synchronize group create, assign, start, stop */
+ struct mutex mutex_lock;
+};
But why we really need this mutex? And does it really justify the extra
complexity it creates?
This lock is necessary because for some QMI handling and WMI MLO
handling should happen only after all the devices in group are probed
and devices are started. In those WMI & QMI MLO handshake, it requires
the partner details.
QMI firmware ready can come from any device in a group and may not be
synchronous but the group has to be registered only after all the
devices have received QMI firmware ready. Similarly, core stop, firmware
recovery scenarios. To handle this the ag lock is needed. Will update
the details.
Thanks,
Harshitha
