Quite some controller drivers use the defines from the internal header
already. This prevents controller drivers outside the mailbox directory.
Move the defines to the public controller header to allow this again as
the defines are not strictly internal anyhow.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Sudeep Holla <sudeep.holla@kernel.org>
Reviewed-by: Daniel Baluta <daniel.baluta@nxp.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
The PCC code currently specifies IRQF_ONESHOT if the interrupt could
potentially be shared but doesn't actually use request_threaded_irq() and
the interrupt handler does not use IRQ_WAKE_THREAD so IRQF_ONESHOT is
never relevant. Since commit aef30c8d56 ("genirq: Warn about using
IRQF_ONESHOT without a threaded handler") specifying it has resulted in a
WARN_ON(), fix this by removing IRQF_ONESHOT.
Reported-by: Aishwarya TCV <Aishwarya.TCV@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
Some platforms may leave a responder interrupt pending from earlier
transactions. If a PCC responder channel has a pending interrupt when
the controller starts up, enabling the IRQ line without first clearing
the condition can lead to a spurious interrupt which could disrupt other
transmissions if the IRQ is shared.
Explicitly clear any pending responder interrupt before enabling the IRQ
to ensure a clean start. Acknowledge the responder channel via
pcc_chan_acknowledge() in startup before requesting/enablement of the
IRQ. This ensures a clean baseline for the first transfer/receiption
of the notification/response.
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Adam Young <admiyo@os.amperecomputing.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
The PCC channel's shared memory region must be set up before the
mailbox controller binds the channel with the client, as the binding
process may trigger client operations like startup() that may rely on
SHMEM being initialized.
Reorder the setup sequence to ensure the shared memory is ready before
binding. Initialize and map the PCC shared memory (SHMEM) prior to
calling mbox_bind_client() so that clients never observe an uninitialized
or NULL SHMEM during bind-time callbacks or early use in startup().
This makes the PCC mailbox channel bring-up order consistent and
eliminates a race between SHMEM setup and client binding.
This will be needed in channel startup to clear/acknowledge any pending
interrupts before enabling them.
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: lihuisong@huawei.com
Tested-by: Adam Young <admiyo@os.amperecomputing.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
The PCC IRQ handler clears channel-in-use and notifies clients with
mbox_chan_received_data(), but it does not explicitly mark the
transmit as complete. In IRQ completion mode this could leave Tx complete
waiters hanging or lead to generic timeouts in the mailbox core.
Invoke mbox_chan_txdone() in the IRQ path once the platform has
acknowledged the transfer so the core can wake any waiters and update
state accordingly.
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Adam Young <admiyo@os.amperecomputing.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
The PCC controller currently enables txdone via IRQ if the PCCT exposes
platform capability to generate command completion interrupt, but it
leaves txdone_poll unchanged. Make the behaviour explicit:
- If ACPI_PCCT_DOORBELL is present, use txdone_irq and disable polling.
- Otherwise, disable txdone_irq and fall back to txdone_poll.
Configure the PCC mailbox to use interrupt-based completion for PCC types
that signal completion via IRQ using TXDONE_BY_IRQ, and fall back to
polling for others using TXDONE_BY_POLL.
This ensures the PCC driver uses the appropriate completion mechanism
according to the PCCT table definition and makes the completion mode
unambiguous avoiding mixed signalling when the platform lacks a doorbell
flag set.
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Adam Young <admiyo@os.amperecomputing.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
Some PCC users poll for completion between transfers and benefit from
the knowledge of previous Tx completion check through the mailbox
framework's ->last_tx_done() op.
Hook up the last_tx_done callback in the PCC mailbox driver so the mailbox
framework can correctly query the completion status of the last transmitted
message. This aligns PCC with other controllers that already implement such
last_tx_done status query.
No functional change unless callers use ->last_tx_done(). Normal Tx and
IRQ paths are unchanged. This change just improves synchronization and
avoids unnecessary timeouts for non-interrupt driven channels by ensuring
correct completion detection for PCC channels that don’t rely on interrupts.
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Adam Young <admiyo@os.amperecomputing.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
This reverts commit 5378bdf6a6.
Commit 5378bdf6a6 ("mailbox/pcc: support mailbox management of the shared buffer")
attempted to introduce generic helpers for managing the PCC shared memory,
but it largely duplicates functionality already provided by the mailbox
core and leaves gaps:
1. TX preparation: The mailbox framework already supports this via
->tx_prepare callback for mailbox clients. The patch adds
pcc_write_to_buffer() and expects clients to toggle pchan->chan.manage_writes,
but no drivers set manage_writes, so pcc_write_to_buffer() has no users.
2. RX handling: Data reception is already delivered through
mbox_chan_received_data() and client ->rx_callback. The patch adds an
optional pchan->chan.rx_alloc, which again has no users and duplicates
the existing path.
3. Completion handling: While adding last_tx_done is directionally useful,
the implementation only covers Type 3/4 and fails to handle the absence
of a command_complete register, so it is incomplete for other types.
Given the duplication and incomplete coverage, revert this change. Any new
requirements should be addressed in focused follow-ups rather than bundling
multiple behavioral changes together.
Fixes: 5378bdf6a6 ("mailbox/pcc: support mailbox management of the shared buffer")
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
The error status mask for a type 3/4 subspace is used for reading the
error status, and the bitwise inverse is used for clearing the error
with the intent being to preserve any of the non-error bits. However,
we were previously applying the mask to extract the status and then
applying the inverse to the result which ended up clearing all bits.
Instead, store the inverse mask in the preserve mask and then use that
on the original value read from the error status so that only the error
is cleared.
Fixes: c45ded7e11 ("mailbox: pcc: Add support for PCCT extended PCC subspaces(type 3/4)")
Signed-off-by: Jamie Iles <jamie.iles@oss.qualcomm.com>
Signed-off-by: Punit Agrawal <punit.agrawal@oss.qualcomm.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
Define a new, optional, callback that allows the driver to
specify how the return data buffer is allocated. If that callback
is set, mailbox/pcc.c is now responsible for reading from and
writing to the PCC shared buffer.
This also allows for proper checks of the Commnand complete flag
between the PCC sender and receiver.
For Type 4 channels, initialize the command complete flag prior
to accepting messages.
Since the mailbox does not know what memory allocation scheme
to use for response messages, the client now has an optional
callback that allows it to allocate the buffer for a response
message.
When an outbound message is written to the buffer, the mailbox
checks for the flag indicating the client wants an tx complete
notification via IRQ. Upon receipt of the interrupt It will
pair it with the outgoing message. The expected use is to
free the kernel memory buffer for the previous outgoing message.
Signed-off-by: Adam Young <admiyo@os.amperecomputing.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
The existing check_and_ack() function had unnecessary complexity. The
logic could be streamlined to improve code readability and maintainability.
The command update register needs to be updated in order to acknowledge
the platform notification through type 4 channel. So it can be done
unconditionally. Currently it is complicated just to make use of
pcc_send_data() which also executes the same updation.
In order to simplify, let us just ring the doorbell directly from
check_and_ack() instead of calling into pcc_send_data(). While at it,
rename it into pcc_chan_check_and_ack() to maintain consistency in the
driver.
Acked-by: Huisong Li <lihuisong@huawei.com>
Tested-by: Adam Young <admiyo@os.amperecomputing.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
Currently the shared memory communication address was mapped by the
mailbox client drivers leading to all sorts of inconsistencies.
It also has resulted in the inconsistent attributes used while mapping
the shared memory regions.
In order to remove/eliminate any issues, let us ensures the shared
memory address is always mapped and unmapped when the PCC channels are
requested and release.
We need to map them as the ACPI PCCT associates these shared memory
with each channel subspace and may need use the status or the flags in
the headers of those shared memory communication address regions to
manage the transport/channel.
Note, until all the drivers using PCC start using this mapped shmem,
there might be double mapping of the shared memory address. This
shouldn't have any impact on existing mbox client drivers.
Since there are no users of pcc_chan_ioremap() and also it is mapped
by default, we can stop exporting it and merge the functionality into
pcc_mbox_request_channel().
Acked-by: Huisong Li <lihuisong@huawei.com>
Tested-by: Huisong Li <lihuisong@huawei.com>
Tested-by: Adam Young <admiyo@os.amperecomputing.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
The existing error handling logic in pcc_mbox_irq() is intermixed with the
main flow of the function. The command complete check and the complete
complete update/acknowledgment are nicely factored into separate functions.
Moves error detection and clearing logic into a separate function called:
pcc_mbox_error_check_and_clear() by extracting error-handling logic from
pcc_mbox_irq().
This ensures error checking and clearing are handled separately and it
improves maintainability by keeping the IRQ handler focused on processing
events.
Acked-by: Huisong Li <lihuisong@huawei.com>
Tested-by: Huisong Li <lihuisong@huawei.com>
Tested-by: Adam Young <admiyo@os.amperecomputing.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
The Platform Communication Channel (PCC) mailbox driver currently uses
ioremap() to map channel shared memory regions. However it is preferred
to use acpi_os_ioremap(), which is mapping function specific to EFI/ACPI
defined memory regions. It ensures that the correct memory attributes
are applied when mapping ACPI-provided regions.
While at it, also add checks for handling any errors with the mapping.
Acked-by: Huisong Li <lihuisong@huawei.com>
Tested-by: Huisong Li <lihuisong@huawei.com>
Tested-by: Adam Young <admiyo@os.amperecomputing.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
pcc_mbox_cmd_complete_check() accesses pchan->cmd_complete.gas to check
command completion status. Even if GAS is NULL, pcc_chan_reg_read() gets
called which returns success doing nothing and then we return.
Add an early return if pchan->cmd_complete.gas == NULL before performing
any operations.
Acked-by: Huisong Li <lihuisong@huawei.com>
Tested-by: Huisong Li <lihuisong@huawei.com>
Tested-by: Adam Young <admiyo@os.amperecomputing.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
The Sparse static checker flags a type mismatch warning related to
endianness conversion:
| warning: incorrect type in argument 1 (different base types)
| expected restricted __le32 const [usertype] *p
| got unsigned int *
This is because an explicit endianness conversion (le32_to_cpu()) was
applied unnecessarily to a pcc_hdr.flags field that is already in
little-endian format.
The PCC driver is only enabled on little-endian kernels due to its
dependency on ACPI and EFI, making the explicit conversion unnecessary.
The redundant conversion occurs in pcc_chan_check_and_ack() for the
pcc_hdr.flags field. Drop this unnecessary endianness conversion of
pcc_hdr.flags.
Also drop the redundant PCC_ACK_FLAG_MASK definition and use the
more appropriate and already defined PCC_CMD_COMPLETION_NOTIFY.
Acked-by: Huisong Li <lihuisong@huawei.com>
Tested-by: Adam Young <admiyo@os.amperecomputing.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
The PCC mailbox interrupt handler (pcc_mbox_irq()) currently checks
for command completion flags and any error status before clearing the
interrupt.
The below sequence highlights an issue in the handling of PCC mailbox
interrupts, specifically when dealing with doorbell notifications and
acknowledgment between the OSPM and the platform where type3 and type4
channels are sharing the interrupt.
-------------------------------------------------------------------------
| T | Platform Firmware | OSPM/Linux PCC driver |
|---|---------------------------------|---------------------------------|
| 1 | | Build message in shmem |
| 2 | | Ring Type3 chan doorbell |
| 3 | Receives the doorbell interrupt | |
| 4 | Process the message from OSPM | |
| 5 | Build response for the message | |
| 6 | Ring Platform ACK interrupt on | |
| | Type3 chan to OSPM | Received the interrupt |
| 7 | Build Notification in Type4 Chan| |
| 8 | | Start processing interrupt in |
| | | pcc_mbox_irq() handler |
| 9 | | Enter PCC handler for Type4 chan|
|10 | | Check command complete cleared |
|11 | | Read the notification |
|12 | | Clear Platform ACK interrupt |
| | No effect from the previous step yet as the Platform ACK |
| | interrupt has not yet been triggered for this channel |
|13 | Ring Platform ACK interrupt on | |
| | Type4 chan to OSPM | |
|14 | | Enter PCC handler for Type3 chan|
|15 | | Command complete is set. |
|16 | | Read the response. |
|17 | | Clear Platform ACK interrupt |
|18 | | Leave PCC handler for Type3 |
|19 | | Leave pcc_mbox_irq() handler |
|20 | | Re-enter pcc_mbox_irq() handler |
|21 | | Enter PCC handler for Type4 chan|
|22 | | Leave PCC handler for Type4 chan|
|23 | | Enter PCC handler for Type3 chan|
|24 | | Leave PCC handler for Type3 chan|
|25 | | Leave pcc_mbox_irq() handler |
-------------------------------------------------------------------------
The key issue occurs when OSPM tries to acknowledge platform ack
interrupt for a notification which is ready to be read and processed
but the interrupt itself is not yet triggered by the platform.
This ineffective acknowledgment leads to an issue later in time where
the interrupt remains pending as we exit the interrupt handler without
clearing the platform ack interrupt as there is no pending response or
notification. The interrupt acknowledgment order is incorrect.
To resolve this issue, the platform acknowledgment interrupt should
always be cleared before processing the interrupt for any notifications
or response.
Reported-by: Robbie King <robbiek@xsightlabs.com>
Reviewed-by: Huisong Li <lihuisong@huawei.com>
Tested-by: Huisong Li <lihuisong@huawei.com>
Tested-by: Adam Young <admiyo@os.amperecomputing.com>
Tested-by: Robbie King <robbiek@xsightlabs.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
The function mbox_chan_received_data() calls the Rx callback of the
mailbox client driver. The callback might set chan_in_use flag from
pcc_send_data(). This flag's status determines whether the PCC channel
is in use.
However, there is a potential race condition where chan_in_use is
updated incorrectly due to concurrency between the interrupt handler
(pcc_mbox_irq()) and the command sender(pcc_send_data()).
The 'chan_in_use' flag of a channel is set to true after sending a
command. And the flag of the new command may be cleared erroneous by
the interrupt handler afer mbox_chan_received_data() returns,
As a result, the interrupt being level triggered can't be cleared in
pcc_mbox_irq() and it will be disabled after the number of handled times
exceeds the specified value. The error log is as follows:
| kunpeng_hccs HISI04B2:00: PCC command executed timeout!
| kunpeng_hccs HISI04B2:00: get port link status info failed, ret = -110
| irq 13: nobody cared (try booting with the "irqpoll" option)
| Call trace:
| dump_backtrace+0x0/0x210
| show_stack+0x1c/0x2c
| dump_stack+0xec/0x130
| __report_bad_irq+0x50/0x190
| note_interrupt+0x1e4/0x260
| handle_irq_event+0x144/0x17c
| handle_fasteoi_irq+0xd0/0x240
| __handle_domain_irq+0x80/0xf0
| gic_handle_irq+0x74/0x2d0
| el1_irq+0xbc/0x140
| mnt_clone_write+0x0/0x70
| file_update_time+0xcc/0x160
| fault_dirty_shared_page+0xe8/0x150
| do_shared_fault+0x80/0x1d0
| do_fault+0x118/0x1a4
| handle_pte_fault+0x154/0x230
| __handle_mm_fault+0x1ac/0x390
| handle_mm_fault+0xf0/0x250
| do_page_fault+0x184/0x454
| do_translation_fault+0xac/0xd4
| do_mem_abort+0x44/0xb4
| el0_da+0x40/0x74
| el0_sync_handler+0x60/0xb4
| el0_sync+0x168/0x180
| handlers:
| pcc_mbox_irq
| Disabling IRQ #13
To solve this issue, pcc_mbox_irq() must clear 'chan_in_use' flag before
the call to mbox_chan_received_data().
Tested-by: Adam Young <admiyo@os.amperecomputing.com>
Tested-by: Robbie King <robbiek@xsightlabs.com>
Signed-off-by: Huisong Li <lihuisong@huawei.com>
(sudeep.holla: Minor updates to the subject, commit message and comment)
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
Type 4 PCC channels have an option to send back a response
to the platform when they are done processing the request.
The flag to indicate whether or not to respond is inside
the message body, and thus is not available to the pcc
mailbox.
If the flag is not set, still set command completion
bit after processing message.
In order to read the flag, this patch maps the shared
buffer to virtual memory. To avoid duplication of mapping
the shared buffer is then made available to be used by
the driver that uses the mailbox.
Signed-off-by: Adam Young <admiyo@os.amperecomputing.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
If the platform acknowledge interrupt is level triggered, then it can
be shared by multiple subspaces provided each one has a unique platform
interrupt ack preserve and ack set masks.
If it can be shared, then we can request the irq with IRQF_SHARED and
IRQF_ONESHOT flags. The first one indicating it can be shared and the
latter one to keep the interrupt disabled until the hardirq handler
finished.
Further, since there is no way to detect if the interrupt is for a given
channel as the interrupt ack preserve and ack set masks are for clearing
the interrupt and not for reading the status(in case Irq Ack register
may be write-only on some platforms), we need a way to identify if the
given channel is in use and expecting the interrupt.
PCC type0, type1 and type5 do not support shared level triggered interrupt.
The methods of determining whether a given channel for remaining types
should respond to an interrupt are as follows:
- type2: Whether the interrupt belongs to a given channel is only
determined by the status field in Generic Communications Channel
Shared Memory Region, which is done in rx_callback of PCC client.
- type3: This channel checks chan_in_use flag first and then checks the
command complete bit(value '1' indicates that the command has
been completed).
- type4: Platform ensure that the default value of the command complete
bit corresponding to the type4 channel is '1'. This command
complete bit is '0' when receive a platform notification.
The new field, 'chan_in_use' is used by the type only support the
communication from OSPM to Platform (like type3) and should be completely
ignored by other types so as to avoid too many type unnecessary checks in
IRQ handler.
Signed-off-by: Huisong Li <lihuisong@huawei.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Link: https://lore.kernel.org/r/20230801063827.25336-3-lihuisong@huawei.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Currently, PCC driver doesn't support the processing of platform
notification for type 4 PCC subspaces.
According to ACPI specification, if platform sends a notification
to OSPM, it must clear the command complete bit and trigger platform
interrupt. OSPM needs to check whether the command complete bit is
cleared, clear platform interrupt, process command, and then set the
command complete and ring doorbell to the Platform.
Let us stash the value of the pcc type and use the same while processing
the interrupt of the channel. We also need to set the command complete
bit and ring doorbell in the interrupt handler for the type 4 channel to
complete the communication flow after processing the notification from
the Platform.
Signed-off-by: Huisong Li <lihuisong@huawei.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Link: https://lore.kernel.org/r/20230801063827.25336-2-lihuisong@huawei.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Use generic mbox_bind_client() to bind omap mailbox channel to a client.
mbox_bind_client is identical to the replaced lines, except that it:
- Does the operation under con_mutex which prevents possible races in
removal path
- Sets TXDONE_BY_ACK if pcc uses TXDONE_BY_POLL and the client knows
when tx is done. TXDONE_BY_ACK is already set if there's no interrupt,
so this is not applicable.
- Calls chan->mbox->ops->startup. This is usecase for requesting irq:
move the devm_request_irq into the startup callback and unregister it
in the shutdown path.
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
Currently, 'pcc_chan_count' is remains set to a non-zero value if PCC
subspaces are parsed successfully but something else fail later during
the initial PCC probing phase. This will result in pcc_mbox_request_channel
trying to access the resources that are not initialised or allocated and
may end up in a system crash.
Reset pcc_chan_count to 0 when the PCC probe fails in order to prevent
the possible issue as described above.
Fixes: ce028702dd ("mailbox: pcc: Move bulk of PCCT parsing into pcc_mbox_probe")
Signed-off-by: Huisong Li <lihuisong@huawei.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
`pcc_mailbox_probe` doesn't initialize all memory that has been allocated
before the first time that one of it's members `txdone_irq` may be
accessed.
This leads to a an invalid load any time that this member is accessed:
[ 2.429769] UBSAN: invalid-load in drivers/mailbox/pcc.c:684:22
[ 2.430324] UBSAN: invalid-load in drivers/mailbox/mailbox.c:486:12
[ 4.276782] UBSAN: invalid-load in drivers/acpi/cppc_acpi.c:314:45
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215587
Fixes: ce028702dd ("mailbox: pcc: Move bulk of PCCT parsing into pcc_mbox_probe")
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
Wolfram SangandJassi Brar
Mark BrownandJassi Brar
Sudeep HollaandJassi Brar
Jamie IlesandJassi Brar
Adam YoungandJassi Brar
Huisong LiandJassi Brar
Elliot BermanandJassi Brar
Colin Ian KingandJassi Brar
Mario LimoncielloandJassi Brar