10 Commits

Author SHA1 Message Date
Jeffrey Hugo
d469d9448a bus: mhi: host: Remove duplicate ee check for syserr
If we detect a system error via intvec, we only process the syserr if the
current ee is different than the last observed ee.  The reason for this
check is to prevent bhie from running multiple times, but with the single
queue handling syserr, that is not possible.

The check can cause an issue with device recovery.  If PBL loads a bad SBL
via BHI, but that SBL hangs before notifying the host of an ee change,
then issuing soc_reset to crash the device and retry (after supplying a
fixed SBL) will not recover the device as the host will observe a PBL->PBL
transition and not process the syserr.  The device will be stuck until
either the driver is reloaded, or the host is rebooted.  Instead, remove
the check so that we can attempt to recover the device.

Fixes: ef2126c4e2ea ("bus: mhi: core: Process execution environment changes serially")
Cc: stable@vger.kernel.org
Signed-off-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Reviewed-by: Carl Vanderlip <quic_carlv@quicinc.com>
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Link: https://lore.kernel.org/r/1681142292-27571-2-git-send-email-quic_jhugo@quicinc.com
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
2023-04-10 21:32:55 +05:30
Vivek Pernamitta
4308c6878a bus: mhi: host: Avoid ringing EV DB if there are no elements to process
Currently, mhi_process_data_event_ring()/mhi_process_ctrl_ev_ring() APIs
are ringing DB even if there are no ring elements to process. This could
cause the device to process the DB event in the absence of ring elements.
So to avoid this unnecessary device processing, let's ring event DB only
if there are any ring elements to process.

Signed-off-by: Vivek Pernamitta <quic_vpernami@quicinc.com>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/1680601458-9105-1-git-send-email-quic_vpernami@quicinc.com
[mani: massaged the commit message a bit]
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
2023-04-10 18:41:38 +05:30
Manivannan Sadhasivam
5da094ac80 bus: mhi: host: Remove mhi_poll() API
mhi_poll() API is not used within the MHI stack and also not by any client
drivers in mainline. So let's remove it until any consumer is available.

Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
2023-03-07 22:04:45 +05:30
Qiang Yu
acc5495bf7 bus: mhi: host: Fix up null pointer access in mhi_irq_handler
The irq handler for a shared IRQ ought to be prepared for running
even now it's being freed. So let's check the pointer used by
mhi_irq_handler to avoid null pointer access since it is probably
released before freeing IRQ.

Fixes: 1227d2a20cd7 ("bus: mhi: host: Move IRQ allocation to controller registration phase")
Signed-off-by: Qiang Yu <quic_qianyu@quicinc.com>
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Tested-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/1658459838-30802-1-git-send-email-quic_qianyu@quicinc.com
[mani: added fixes tag]
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
2022-08-29 22:33:46 +05:30
Bhaumik Bhatt
0bca889fd6 bus: mhi: host: Bail on writing register fields if read fails
Helper API to write register fields relies on successful reads
of the register/address prior to the write. Bail out if a failure
is seen when reading the register before the actual write is
performed.

Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>
Signed-off-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Reviewed-by: Hemant Kumar <hemantk@codeaurora.org>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/1650304226-11080-2-git-send-email-quic_jhugo@quicinc.com
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
2022-04-23 18:57:32 +05:30
Jeffrey Hugo
e565d3efd8 bus: mhi: host: Use cached values for calculating the shared write pointer
mhi_recycle_ev_ring() computes the shared write pointer for the ring
(ctxt_wp) using a read/modify/write pattern where the ctxt_wp value in the
shared memory is read, incremented, and written back.  There are no checks
on the read value, it is assumed that it is kept in sync with the locally
cached value.  Per the MHI spec, this is correct.  The device should only
read ctxt_wp, never write it.

However, there are devices in the wild that violate the spec, and can
update the ctxt_wp in a specific scenario.  This can cause corruption, and
violate the above assumption that the ctxt_wp is in sync with the cached
value.

This can occur when the device has loaded firmware from the host, and is
transitioning from the SBL EE to the AMSS EE.  As part of shutting down
SBL, the SBL flushes it's local MHI context to the shared memory since
the local context will not persist across an EE change.  In the case of
the event ring, SBL will flush its entire context, not just the parts that
it is allowed to update.  This means SBL will write to ctxt_wp, and
possibly corrupt it.

An example:

Host				Device
----				---
Update ctxt_wp to 0x1f0
				SBL observes 0x1f0
Update ctxt_wp to 0x0
				Starts transition to AMSS EE
				Context flush, writes 0x1f0 to ctxt_wp
Update ctxt_wp to 0x200
Update ctxt_wp to 0x210
				AMSS observes 0x210
				0x210 exceeds ring size
				AMSS signals syserr

The reason the ctxt_wp goes off the end of the ring is that the rollover
check is only performed on the cached wp, which is out of sync with
ctxt_wp.

Since the host is the authority of the value of ctxt_wp per the MHI spec,
we can fix this issue by not reading ctxt_wp from the shared memory, and
instead compute it based on the cached value.  If SBL corrupts ctxt_wp,
the host won't observe it, and will correct the value at some point later.

Signed-off-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Reviewed-by: Hemant Kumar <quic_hemantk@quicinc.com>
Reviewed-by: Bhaumik Bhatt <quic_bbhatt@quicinc.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/1649868113-18826-1-git-send-email-quic_jhugo@quicinc.com
[mani: used the quicinc domain for Hemant and Bhaumik]
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
2022-04-23 18:57:31 +05:30
Manivannan Sadhasivam
3a1b8e281a bus: mhi: Make mhi_state_str[] array static inline and move to common.h
mhi_state_str[] array could be used by MHI endpoint stack also. So let's
make the array as "static inline function" and move it inside the
"common.h" header so that the endpoint stack could also make use of it.

Reviewed-by: Hemant Kumar <hemantk@codeaurora.org>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20220301160308.107452-11-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-18 14:02:55 +01:00
Manivannan Sadhasivam
84f5f31f11 bus: mhi: host: Rename "struct mhi_tre" to "struct mhi_ring_element"
Structure "struct mhi_tre" is representing a generic MHI ring element and
not specifically a Transfer Ring Element (TRE). Fix the naming.

Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20220301160308.107452-9-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-18 14:02:55 +01:00
Manivannan Sadhasivam
d28cab4d4a bus: mhi: Use bitfield operations for register read and write
Functions like mhi_read_reg_field(), mhi_poll_reg_field() and
mhi_write_reg_field() could be modified to not depend on the shift value
passed as an argument. Instead, the bitfield operation could be used to
extract the shift value from the mask itself.

This eliminates the need to define _SHIFT (and _SHFT) macros and
simplifies the code a bit. For shift values those cannot be determined
during build time, "__ffs()" helper is used find the shift value during
runtime.

While at it, let's also get rid of 32-bit masks like CHDBOFF_CHDBOFF_MASK
by doing the full 32-bit register read.

Suggested-by: Alex Elder <elder@linaro.org>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20220301160308.107452-6-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-18 14:02:54 +01:00
Manivannan Sadhasivam
a0f5a63066 bus: mhi: Move host MHI code to "host" directory
In preparation of the endpoint MHI support, let's move the host MHI code
to its own "host" directory and adjust the toplevel MHI Kconfig & Makefile.

While at it, let's also move the "pci_generic" driver to "host" directory
as it is a host MHI controller driver.

Reviewed-by: Hemant Kumar <hemantk@codeaurora.org>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20220301160308.107452-5-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-18 14:02:54 +01:00