When clearing up the channel context after client drivers are
done using channels, the configuration is currently not being
reset entirely. Ensure this is done to appropriately handle
issues where clients unaware of the context state end up calling
functions which expect a context.
Signed-off-by: NBhaumik Bhatt <bbhatt@codeaurora.org>
Reviewed-by: NHemant Kumar <hemantk@codeaurora.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/1617311778-1254-7-git-send-email-bbhatt@codeaurora.orgSigned-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Improve the channel handling state machine such that all commands
go through a common function and a validation process to ensure
that the state machine is not violated in any way and adheres to
the MHI specification. Using this common function allows MHI to
eliminate some unnecessary debug messages and code duplication.
Signed-off-by: NBhaumik Bhatt <bbhatt@codeaurora.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/1617311778-1254-4-git-send-email-bbhatt@codeaurora.orgSigned-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

If a channel was explicitly stopped but not reset and a driver
remove is issued, clean up the channel context such that it is
reflected on the device. This move is useful if a client driver
module is unloaded or a device crash occurs with the host having
placed the channel in a stopped state.
Signed-off-by: NBhaumik Bhatt <bbhatt@codeaurora.org>
Reviewed-by: NHemant Kumar <hemantk@codeaurora.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/1617311778-1254-3-git-send-email-bbhatt@codeaurora.orgSigned-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Some controllers can choose to skip preparation for power up.
In that case, device context is initialized based on the pre_init
flag not being set during mhi_prepare_for_power_up(). There is no
reason MHI host driver should maintain and provide controllers
with two separate paths for preparing MHI.

Going forward, all controllers will be required to call the
mhi_prepare_for_power_up() API followed by their choice of sync
or async power up. This allows MHI host driver to get rid of the
pre_init flag and sets up a common way for all controllers to use
MHI. This also helps controllers fail early on during preparation
phase in some failure cases.
Signed-off-by: NBhaumik Bhatt <bbhatt@codeaurora.org>
Reviewed-by: NHemant Kumar <hemantk@codeaurora.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/1617313309-24035-1-git-send-email-bbhatt@codeaurora.orgSigned-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

As of now abbreviations are being used for many state and
execution environment strings. Improve and expand those such that
debug messages are clear.
Signed-off-by: NBhaumik Bhatt <bbhatt@codeaurora.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: NLoic Poulain <loic.poulain@linaro.org>
Link: https://lore.kernel.org/r/1617067704-28850-8-git-send-email-bbhatt@codeaurora.orgSigned-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

MHI WWAN modems support downloading firmware to NAND or eMMC
using Firehose protocol with process as follows:
1. Modem boots up, enters AMSS execution environment and the
device later enters EDL (Emergency Download) mode through any
mechanism host can use such as a diag command.
2. Modem enters SYS_ERROR, MHI host handles SYS_ERROR transition.
3. EDL image for device to enter 'Flash Programmer' execution
environment is then flashed via BHI interface from host.
4. Modem enters MHI READY -> M0 and sends the Flash Programmer
execution environment change to host.
5. Following that, EDL/FIREHOSE channels (34, 35) are made
available from the host.
6. User space tool for downloading firmware image to modem over
the EDL channels using Firehose protocol. Link to USB flashing
tool: https://git.linaro.org/landing-teams/working/qualcomm/qdl.git/

Make the necessary changes to allow for this sequence to occur and
allow using the Flash Programmer execution environment.
Signed-off-by: NCarl Yin <carl.yin@quectel.com>
Co-developed-by: NBhaumik Bhatt <bbhatt@codeaurora.org>
Signed-off-by: NBhaumik Bhatt <bbhatt@codeaurora.org>
Reviewed-by: NLoic Poulain <loic.poulain@linaro.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/1617067704-28850-5-git-send-email-bbhatt@codeaurora.orgSigned-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

As per documentation, fields marked as (required) in an MHI
controller structure need to be populated by the controller driver
before calling mhi_register_controller(). Ensure all required
pointers and non-zero fields are present in the controller before
proceeding with the registration.
Signed-off-by: NBhaumik Bhatt <bbhatt@codeaurora.org>
Reviewed-by: NJeffrey Hugo <jhugo@codeaurora.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/1615315490-36017-1-git-send-email-bbhatt@codeaurora.orgSigned-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

A recent change created a dedicated workqueue for the state-change work
with WQ_HIGHPRI (no strong reason for that) and WQ_MEM_RECLAIM flags,
but the state-change work (mhi_pm_st_worker) does not guarantee forward
progress under memory pressure, and will even wait on various memory
allocations when e.g. creating devices, loading firmware, etc... The
work is then not part of a memory reclaim path...

Moreover, this causes a warning in check_flush_dependency() since we end
up in code that flushes a non-reclaim workqueue:

[   40.969601] workqueue: WQ_MEM_RECLAIM mhi_hiprio_wq:mhi_pm_st_worker [mhi] is flushing !WQ_MEM_RECLAIM events_highpri:flush_backlog
[   40.969612] WARNING: CPU: 4 PID: 158 at kernel/workqueue.c:2607 check_flush_dependency+0x11c/0x140
[   40.969733] Call Trace:
[   40.969740]  __flush_work+0x97/0x1d0
[   40.969745]  ? wake_up_process+0x15/0x20
[   40.969749]  ? insert_work+0x70/0x80
[   40.969750]  ? __queue_work+0x14a/0x3e0
[   40.969753]  flush_work+0x10/0x20
[   40.969756]  rollback_registered_many+0x1c9/0x510
[   40.969759]  unregister_netdevice_queue+0x94/0x120
[   40.969761]  unregister_netdev+0x1d/0x30
[   40.969765]  mhi_net_remove+0x1a/0x40 [mhi_net]
[   40.969770]  mhi_driver_remove+0x124/0x250 [mhi]
[   40.969776]  device_release_driver_internal+0xf0/0x1d0
[   40.969778]  device_release_driver+0x12/0x20
[   40.969782]  bus_remove_device+0xe1/0x150
[   40.969786]  device_del+0x17b/0x3e0
[   40.969791]  mhi_destroy_device+0x9a/0x100 [mhi]
[   40.969796]  ? mhi_unmap_single_use_bb+0x50/0x50 [mhi]
[   40.969799]  device_for_each_child+0x5e/0xa0
[   40.969804]  mhi_pm_st_worker+0x921/0xf50 [mhi]

Fixes: 8f703978 ("bus: mhi: core: Move to using high priority workqueue")
Signed-off-by: NLoic Poulain <loic.poulain@linaro.org>
Reviewed-by: NBhaumik Bhatt <bbhatt@codeaurora.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/1614161930-8513-1-git-send-email-loic.poulain@linaro.orgSigned-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

The wake_db register presence is highly speculative and can fuze MHI
devices. Indeed, currently the wake_db register address is defined at
entry 127 of the 'Channel doorbell array', thus writing to this address
is equivalent to ringing the doorbell for channel 127, causing trouble
with some devics (e.g. SDX24 based modems) that get an unexpected
channel 127 doorbell interrupt.

This change fixes that issue by setting wake get/put as no-op for
pci_generic devices. The wake device sideband mechanism seems really
specific to each device, and is AFAIK not defined by the MHI spec.

It also removes zeroing initialization of wake_db register during MMIO
initialization, the register being set via wake_get/put accessors few
cycles later during M0 transition.
Signed-off-by: NLoic Poulain <loic.poulain@linaro.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/1614971808-22156-4-git-send-email-loic.poulain@linaro.orgSigned-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

mhi_deinit_chan_ctxt functionthat takes care of unitializing channel
resources, including unmapping coherent MHI areas, can be called
from different path in case of controller unregistering/removal:
 - From a client driver remove callback, via mhi_unprepare_channel
 - From mhi_driver_remove that unitialize all channels

mhi_driver_remove()
|-> driver->remove()
|    |-> mhi_unprepare_channel()
|        |-> mhi_deinit_chan_ctxt()
|...
|-> mhi_deinit_chan_ctxt()

This leads to double dma freeing...

Fix that by preventing deinit for already uninitialized channel.

Link: https://lore.kernel.org/r/1612894264-15956-1-git-send-email-loic.poulain@linaro.org
Fixes: a7f422f2 ("bus: mhi: Fix channel close issue on driver remove")
Reported-by: NKalle Valo <kvalo@codeaurora.org>
Tested-by: NKalle Valo <kvalo@codeaurora.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: NLoic Poulain <loic.poulain@linaro.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20210210082538.2494-2-manivannan.sadhasivam@linaro.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

If controller driver has specified the irq_flags, mhi uses this specified
irq_flags. Otherwise, mhi uses default irq_flags.

The purpose of this change is to support one MSI vector for QCA6390.
MHI will use one same MSI vector too in this scenario.

In case of one MSI vector, IRQ_NO_BALANCING is needed when irq handler
is requested. The reason is if irq migration happens, the msi_data may
change too. However, the msi_data is already programmed to QCA6390
hardware during initialization phase. This msi_data inconsistence will
result in crash in kernel.

Another issue is in case of one MSI vector, IRQF_NO_SUSPEND will trigger
WARNINGS because QCA6390 wants to disable the IRQ during the suspend.

To avoid above two issues, QCA6390 driver specifies the irq_flags in case
of one MSI vector when mhi_register_controller is called.
Signed-off-by: NCarl Huang <cjhuang@codeaurora.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

There are a few problems with the error handling in this function.  They
mostly center around the alloc_ordered_workqueue() allocation.
1) If that allocation fails or if the kcalloc() prior to it fails then
it leads to a NULL dereference when we call
destroy_workqueue(mhi_cntrl->hiprio_wq).
2) The error code is not set.
3) The "mhi_cntrl->mhi_cmd" allocation is not freed.

The error handling was slightly confusing and I re-ordered it to be in
the exact mirror/reverse order of how things were allocated.  I changed
the label names to say what the goto does instead of describing where
the goto comes from.

Fixes: 8f703978 ("bus: mhi: core: Move to using high priority workqueue")
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: NLoic Poulain <loic.poulain@linaro.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

This patch fixes the hierarchical structure of MHI devices. Indeed,
MHI client devices are directly 'enumerated' from the mhi controller
and therefore must be direct descendants/children of their mhi
controller device, in accordance with the Linux Device Model.

Today both MHI clients and controller devices are at the same level,
this patch ensures that MHI controller is parent of its client devices.

The hierarchy is especially important for power management (safe
suspend/resume order). It is also useful for userspace to determine
relationship between MHI client devices and controllers.
Signed-off-by: NLoic Poulain <loic.poulain@linaro.org>
Reviewed-by: NBjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: NHemant Kumar <hemantk@codeaurora.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Today the MHI controller name is simply cloned from the underlying
bus device (its parent), that gives the following device structure
for e.g. a MHI/PCI controller:
devices/pci0000:00/0000:00:01.2/0000:02:00.0/0000:02:00.0
devices/pci0000:00/0000:00:01.2/0000:02:00.0/0000:02:00.0/0000:02:00.0_IPCR
...

That's quite misleading/confusing and can cause device registering
issues because of duplicate dev name (e.g. if a PCI device register
two different MHI instances).

This patch changes MHI core to create indexed mhi controller names
(mhi0, mhi1...) in the same way as other busses (i2c0, usb0...).

The previous example becomes:
devices/pci0000:00/0000:00:01.2/0000:02:00.0/mhi0
devices/pci0000:00/0000:00:01.2/0000:02:00.0/mhi0/mhi0_IPCR
...
 v2: move index field at the end of mhi_controller struct (before bool)
     to avoid breaking well packed alignment.
Signed-off-by: NLoic Poulain <loic.poulain@linaro.org>
Reviewed-by: NJeffrey Hugo <jhugo@codeaurora.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Current design allows a controller to register with MHI successfully
without the need to have any IRQs available for use. If no IRQs are
available, power up requests to MHI can fail after a successful
registration with MHI. Improve the design by checking for the number
of IRQs available sooner within the mhi_regsiter_controller() API as
it is required to be specified by the controller.
Signed-off-by: NBhaumik Bhatt <bbhatt@codeaurora.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

MHI work is currently scheduled on the global/system workqueue and can
encounter delays on a stressed system. To avoid those unforeseen
delays which can hamper bootup or shutdown times, use a dedicated high
priority workqueue instead of the global/system workqueue.
Signed-off-by: NBhaumik Bhatt <bbhatt@codeaurora.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Functions parse_ev_cfg() and parse_ch_cfg() access mhi_cntrl->mhi_dev
before it is set in function mhi_register_controller(),
use cntrl_dev instead of mhi_dev.

Fixes: 0cbf2608 ("bus: mhi: core: Add support for registering MHI controllers")
Signed-off-by: NCarl Yin <carl.yin@quectel.com>
Reviewed-by: NBhaumik Bhatt <bbhatt@codeaurora.org>
Reviewed-by: NHemant Kumar <hemantk@codeaurora.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

There is double acquisition of the pm_lock from mhi_driver_remove()
function. Remove the read_lock_bh/read_unlock_bh calls for pm_lock
taken during a call to mhi_device_put() as the lock is acquired
within the function already. This will help avoid a potential
kernel panic.

Fixes: 189ff97c ("bus: mhi: core: Add support for data transfer")
Reported-by: NShuah Khan <skhan@linuxfoundation.org>
Signed-off-by: NBhaumik Bhatt <bbhatt@codeaurora.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

There is really no point having an auto-start for channels.
This is confusing for the device drivers, some have to enable the
channels, others don't have... and waste resources (e.g. pre allocated
buffers) that may never be used.

This is really up to the MHI device(channel) driver to manage the state
of its channels.

While at it, let's also remove the auto-start option from ath11k mhi
controller.
Signed-off-by: NLoic Poulain <loic.poulain@linaro.org>
Acked-by: NKalle Valo <kvalo@codeaurora.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
[mani: clubbed ath11k change]
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

nr_irqs_req is unused in MHI stack.
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: NLoic Poulain <loic.poulain@linaro.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200929175218.8178-18-manivannan.sadhasivam@linaro.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There is no requirement for using a dedicated IRQ per event ring.
Some systems does not support multiple MSI vectors (e.g. intel
without CONFIG_IRQ_REMAP), In that case the MHI controller can
configure all the event rings to use the same interrupt (as fallback).

Allow this by removing the nr_irqs = ev_ring test and add extra check
in the irq_setup function.
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: NLoic Poulain <loic.poulain@linaro.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200929175218.8178-17-manivannan.sadhasivam@linaro.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Introduce sysfs entries to enable userspace clients the ability to read
the serial number and the OEM PK Hash values obtained from BHI. OEMs
need to read these device-specific hardware information values through
userspace for factory testing purposes and cannot be exposed via degbufs
as it may remain disabled for performance reasons. Also, update the
documentation for ABI to include these entries.
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
[mani: used dev_groups to manage sysfs attributes]
Signed-off-by: NBhaumik Bhatt <bbhatt@codeaurora.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200929175218.8178-16-manivannan.sadhasivam@linaro.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Introduce debugfs entries to show state, register, channel, device,
and event rings information. Allow the host to dump registers,
issue device wake, and change the MHI timeout to help in debug.
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: NBhaumik Bhatt <bbhatt@codeaurora.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200929175218.8178-15-manivannan.sadhasivam@linaro.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

MHI channel, event and controller config data needs to be
treated read only information. Add const qualifier to make
sure config information passed by MHI controller is not
modified by MHI core driver.
Suggested-by: NKalle Valo <kvalo@codeaurora.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: NHemant Kumar <hemantk@codeaurora.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200929175218.8178-12-manivannan.sadhasivam@linaro.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Client devices should use the APIs provided to allocate and free
the MHI controller structure. This will help ensure that the
structure is zero-initialized and there are no false positives
with respect to reading any values such as the serial number or
the OEM PK hash.
Suggested-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: NBhaumik Bhatt <bbhatt@codeaurora.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200929175218.8178-11-manivannan.sadhasivam@linaro.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

An MHI device is not necessarily associated with only channels as we can
have one associated with the controller itself. Hence, the chan_name
field within the mhi_device structure should instead be replaced with a
generic name to accurately reflect any type of MHI device.
Reviewed-by: NJeffrey Hugo <jhugo@codeaurora.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: NBhaumik Bhatt <bbhatt@codeaurora.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200929175218.8178-7-manivannan.sadhasivam@linaro.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Mission mode transition is handled by state worker thread but
power off is not. There is a possibility while mission mode
transition is in progress which calls MHI client driver probe,
power off is issued by MHI controller. This results into client
driver probe and remove running in parallel and causes use after
free situation. By queuing disable transition work when mission
mode is in progress prevents the race condition.
Signed-off-by: NHemant Kumar <hemantk@codeaurora.org>
Reviewed-by: NJeffrey Hugo <jhugo@codeaurora.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200521170249.21795-11-manivannan.sadhasivam@linaro.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove the system error worker thread and instead have the
execution environment worker handle that transition to serialize
processing and avoid any possible race conditions during
shutdown.
Signed-off-by: NHemant Kumar <hemantk@codeaurora.org>
Reviewed-by: NJeffrey Hugo <jhugo@codeaurora.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200521170249.21795-10-manivannan.sadhasivam@linaro.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Upon power up, driver queues firmware worker thread if the execution
environment is PBL. Firmware worker is blocked with a timeout until
state worker gets a chance to run and unblock firmware worker. An
endpoint power up failure can be seen if state worker gets a chance to
run after firmware worker has timed out. Remove this dependency and
handle firmware load directly using state worker thread.
Signed-off-by: NBhaumik Bhatt <bbhatt@codeaurora.org>
Reviewed-by: NJeffrey Hugo <jhugo@codeaurora.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200521170249.21795-6-manivannan.sadhasivam@linaro.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Driver is using zero initialized intmod value from mhi channel when
configuring TRE for bei field. This prevents interrupt moderation to
take effect in case it is supported by an event ring. Fix this by
copying intmod value from associated event ring to mhi channel upon
registering mhi controller.
Signed-off-by: NHemant Kumar <hemantk@codeaurora.org>
Signed-off-by: NBhaumik Bhatt <bbhatt@codeaurora.org>
Reviewed-by: NJeffrey Hugo <jhugo@codeaurora.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200521170249.21795-3-manivannan.sadhasivam@linaro.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix to return negative error code from the error handling case
instead of 0 in mhi_init_dev_ctxt() and mhi_driver_probe().

Fixes: 3000f85b ("bus: mhi: core: Add support for basic PM operations")
Reported-by: NHulk Robot <hulkci@huawei.com>
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200509075654.175002-1-weiyongjun1@huawei.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When reading or writing MHI registers, the core assumes that the physical
link is a memory mapped PCI link.  This assumption may not hold for all
MHI devices.  The controller knows what is the physical link (ie PCI, I2C,
SPI, etc), and therefore knows the proper methods to access that link.
The controller can also handle link specific error scenarios, such as
reading -1 when the PCI link went down.

Therefore, it is appropriate that the MHI core requests the controller to
make register accesses on behalf of the core, which abstracts the core
from link specifics, and end up removing an unnecessary assumption.
Signed-off-by: NJeffrey Hugo <jhugo@codeaurora.org>
Reviewed-by: NHemant Kumar <hemantk@codeaurora.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200430190555.32741-5-manivannan.sadhasivam@linaro.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

If the MHI core detects invalid data due to a PCI read, it calls into
the controller via link_status() to double check that the link is infact
down.  All in all, this is pretty pointless, and racy.  There are no good
reasons for this, and only drawbacks.

Its pointless because chances are, the controller is going to do the same
thing to determine if the link is down - attempt a PCI access and compare
the result.  This does not make the link status decision any smarter.

Its racy because its possible that the link was down at the time of the
MHI core access, but then recovered before the controller access.  In this
case, the controller will indicate the link is not down, and the MHI core
will precede to use a bad value as the MHI core does not attempt to retry
the access.

Retrying the access in the MHI core is a bad idea because again, it is
racy - what if the link is down again?  Furthermore, there may be some
higher level state associated with the link status, that is now invalid
because the link went down.

The only reason why the MHI core could see "invalid" data when doing a PCI
access, that is actually valid, is if the register actually contained the
PCI spec defined sentinel for an invalid access.  In this case, it is
arguable that the MHI implementation broken, and should be fixed, not
worked around.

Therefore, remove the link_status() callback before anyone attempts to
implement it.
Signed-off-by: NJeffrey Hugo <jhugo@codeaurora.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: NHemant Kumar <hemantk@codeaurora.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200430190555.32741-4-manivannan.sadhasivam@linaro.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

For some scenarios like controller suspend and resume, mhi_destroy_device()
will get called without mhi_unregister_controller(). In that case, the
references to the mhi_dev created for the channels will not be dropped
but the channels will be destroyed as per the spec. This will cause issue
during resume as the channels will not be created due to the fact that
mhi_dev is not NULL.

Hence, this change decrements the refcount for mhi_dev in
mhi_destroy_device() for concerned channels and also sets mhi_dev to NULL
in release_device().
Reported-by: NCarl Huang <cjhuang@codeaurora.org>
Reviewed-by: NJeffrey Hugo <jhugo@codeaurora.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200324061050.14845-5-manivannan.sadhasivam@linaro.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The bhie field in mhi_cntrl needs to be initialized to proper register
base in order to make mhi_rddm_prepare() to work. Otherwise,
mhi_rddm_prepare() will cause NULL pointer dereference.

Fixes: 6fdfdd27 ("bus: mhi: core: Add support for downloading RDDM image during panic")
Reported-by: NHemant Kumar <hemantk@codeaurora.org>
Reviewed-by: NJeffrey Hugo <jhugo@codeaurora.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200324061050.14845-4-manivannan.sadhasivam@linaro.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The MHI register base has several registers used for getting the MHI
specific information such as version, family, major, and minor numbers
from the device. This information can be used by the controller drivers
for usecases such as applying quirks for a specific revision etc...

While at it, let's also rearrange the local variables
in mhi_register_controller().
Suggested-by: NHemant Kumar <hemantk@codeaurora.org>
Reviewed-by: NJeffrey Hugo <jhugo@codeaurora.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200324061050.14845-3-manivannan.sadhasivam@linaro.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The module owner field can be used to prevent the removal of kernel
modules when there are any device files associated with it opened in
userspace. Hence, modify the API to pass module owner field. For
convenience, module_mhi_driver() macro is used which takes care of
passing the module owner through THIS_MODULE of the module of the
driver and also avoiding the use of specifying the default MHI client
driver register/unregister routines.
Suggested-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: NBjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20200324061050.14845-2-manivannan.sadhasivam@linaro.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add uevent support to MHI bus so that the client drivers can be autoloaded
by udev when the MHI devices gets created. The client drivers are
expected to provide MODULE_DEVICE_TABLE with the MHI id_table struct so
that the alias can be exported.
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: NJeffrey Hugo <jhugo@codeaurora.org>
Tested-by: NJeffrey Hugo <jhugo@codeaurora.org>
Link: https://lore.kernel.org/r/20200220095854.4804-13-manivannan.sadhasivam@linaro.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add support for transferring data between external modem and host
processor using MHI protocol.

This is based on the patch submitted by Sujeev Dias:
https://lkml.org/lkml/2018/7/9/988Signed-off-by: NSujeev Dias <sdias@codeaurora.org>
Signed-off-by: NSiddartha Mohanadoss <smohanad@codeaurora.org>
[mani: splitted the data transfer patch and cleaned up for upstream]
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: NJeffrey Hugo <jhugo@codeaurora.org>
Tested-by: NJeffrey Hugo <jhugo@codeaurora.org>
Link: https://lore.kernel.org/r/20200220095854.4804-12-manivannan.sadhasivam@linaro.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This commit adds support for processing the MHI data and control
events from the client device. The client device can report various
events such as EE events, state change events by interrupting the
host through IRQ and adding events to the event rings allocated by
the host during initialization.

This is based on the patch submitted by Sujeev Dias:
https://lkml.org/lkml/2018/7/9/988Signed-off-by: NSujeev Dias <sdias@codeaurora.org>
Signed-off-by: NSiddartha Mohanadoss <smohanad@codeaurora.org>
[mani: splitted the data transfer patch and cleaned up for upstream]
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: NJeffrey Hugo <jhugo@codeaurora.org>
Tested-by: NJeffrey Hugo <jhugo@codeaurora.org>
Link: https://lore.kernel.org/r/20200220095854.4804-11-manivannan.sadhasivam@linaro.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>