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path: root/drivers/bus/mhi/host/main.c
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* bus: mhi: host: Fix up null pointer access in mhi_irq_handlerQiang Yu2022-08-291-3/+16
| | | | | | | | | | | | | | | 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>
* bus: mhi: host: Bail on writing register fields if read failsBhaumik Bhatt2022-04-231-3/+6
| | | | | | | | | | | | | | | 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>
* bus: mhi: host: Use cached values for calculating the shared write pointerJeffrey Hugo2022-04-231-7/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* bus: mhi: Make mhi_state_str[] array static inline and move to common.hManivannan Sadhasivam2022-03-181-4/+4
| | | | | | | | | | | | 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>
* bus: mhi: host: Rename "struct mhi_tre" to "struct mhi_ring_element"Manivannan Sadhasivam2022-03-181-10/+10
| | | | | | | | | | 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>
* bus: mhi: Use bitfield operations for register read and writeManivannan Sadhasivam2022-03-181-9/+7
| | | | | | | | | | | | | | | | | | | | | 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>
* bus: mhi: Move host MHI code to "host" directoryManivannan Sadhasivam2022-03-181-0/+1687
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>