4 Commits

Author	SHA1	Message	Date
Elliot Berman	3bf90eca76	firmware: qcom_scm: Move qcom_scm.h to include/linux/firmware/qcom/ ... Move include/linux/qcom_scm.h to include/linux/firmware/qcom/qcom_scm.h. This removes 1 of a few remaining Qualcomm-specific headers into a more approciate subdirectory under include/. Suggested-by: Bjorn Andersson <andersson@kernel.org> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com> Reviewed-by: Guru Das Srinagesh <quic_gurus@quicinc.com> Acked-by: Mukesh Ojha <quic_mojha@quicinc.com> Signed-off-by: Bjorn Andersson <andersson@kernel.org> Link: https://lore.kernel.org/r/20230203210956.3580811-1-quic_eberman@quicinc.com	2023-02-08 19:15:16 -08:00
Guru Das Srinagesh	6bf3259922	firmware: qcom: scm: Add wait-queue handling logic ... When the firmware (FW) supports multiple requests per VM, multiple requests from the same/different VM can reach the firmware at the same time. Since the firmware currently being used has limited resources, it guards them with a resource lock and puts requests on a wait-queue internally and signals to HLOS that it is doing so. It does this by returning a new return value in addition to success or error: SCM_WAITQ_SLEEP. A sleeping SCM call can be woken up by an interrupt that the FW raises. 1) SCM_WAITQ_SLEEP: When an SCM call receives this return value instead of success or error, FW has placed this call on a wait-queue and has signalled HLOS to put it to non-interruptible sleep. Along with this return value, FW also passes to HLOS `wq_ctx` - a unique number (UID) identifying the wait-queue that it has put the call on, internally. This is to help HLOS with its own bookkeeping to wake this sleeping call later. Additionally, FW also passes to HLOS `smc_call_ctx` - a UID identifying the SCM call thus being put to sleep. This is also for HLOS' bookkeeping to wake this call up later. These two additional values are passed via the a1 and a2 registers. N.B.: The "ctx" in the above UID names = "context". The handshake mechanism that HLOS uses to talk to FW about wait-queue operations involves two new SMC calls. 1) get_wq_ctx(): Arguments: None Returns: wq_ctx, flags, more_pending Get the wait-queue context, and wake up either one or all of the sleeping SCM calls associated with that wait-queue. Additionally, repeat this if there are more wait-queues that are ready to have their requests woken up (`more_pending`). 2) wq_resume(smc_call_ctx): Arguments: smc_call_ctx HLOS needs to issue this in response to receiving an IRQ, passing to FW the same smc_call_ctx that FW receives from HLOS via the get_wq_ctx() call. (The mechanism to wake a SMC call back up is described in detail below) VM_1 VM_2 Firmware │ │ │ │ │ │ │ │ │ │ │ │ │ REQUEST_1 │ │ ├────────────────────────┼─────────────────────────────────┤ │ │ │ │ │ ┌──┼──┐ │ │ │ │ │ │ │ REQUEST_2 │ │ │ │ ├──────────────────────────────┼──┤ │ │ │ │ │ │Resource │ │ │ │ │is busy │ │ {WQ_SLEEP} │ │ │ │ │◄─────────────────────────────┼──┤ │ │ │ wq_ctx, smc_call_ctx │ │ │ │ │ └──┼──┘ │ REQUEST_1 COMPLETE │ │ │◄───────────────────────┼─────────────────────────────────┤ │ │ │ │ │ IRQ │ │ │◄─-------------------------------│ │ │ │ │ │ get_wq_ctx() │ │ ├────────────────────────────────►│ │ │ │ │ │ │ │ │◄────────────────────────────────┤ │ │ wq_ctx, flags, and │ │ │ more_pending │ │ │ │ │ │ │ │ │ wq_resume(smc_call_ctx) │ │ ├────────────────────────────────►│ │ │ │ │ │ │ │ │ REQUEST_2 COMPLETE │ │ │◄────────────────────────────────┤ │ │ │ │ │ │ With the exception of get_wq_ctx(), the other SMC call wq_resume() can return WQ_SLEEP (these nested rounds of WQ_SLEEP are not shown in the above diagram for the sake of simplicity). Therefore, introduce a new do-while loop to handle multiple WQ_SLEEP return values for the same parent SCM call. Request Completion in the above diagram refers to either a success return value (zero) or error (and not SMC_WAITQ_SLEEP) Also add the interrupt handler that wakes up a sleeping SCM call. Signed-off-by: Guru Das Srinagesh <quic_gurus@quicinc.com> Co-developed-by: Sibi Sankar <quic_sibis@quicinc.com> Signed-off-by: Sibi Sankar <quic_sibis@quicinc.com> Reviewed-by: Guru Das Srinagesh <quic_gurus@quicinc.com> Signed-off-by: Bjorn Andersson <andersson@kernel.org> Link: https://lore.kernel.org/r/20230113161114.22607-3-quic_sibis@quicinc.com	2023-01-18 21:14:40 -06:00
Stephen Boyd	f6ea568f0d	firmware: qcom_scm: Reduce locking section for __get_convention() ... We shouldn't need to hold this spinlock here around the entire SCM call into the firmware and back. Instead, we should be able to query the firmware, potentially in parallel with other CPUs making the same convention detection firmware call, and then grab the lock to update the calling convention detected. The convention doesn't change at runtime so calling into firmware more than once is possibly wasteful but simpler. Besides, this is the slow path, not the fast path where we've already detected the convention used. More importantly, this allows us to add more logic here to workaround the case where the firmware call to check for availability isn't implemented in the firmware at all. In that case we can check the firmware node compatible string and force a calling convention. Note that we remove the 'has_queried' logic that is repeated twice. That could lead to the calling convention being printed multiple times to the kernel logs if the bool is true but __query_convention() is running on multiple CPUs. We also shorten the time where the lock is held, but we keep the lock held around the printk because it doesn't seem hugely important to drop it for that. Cc: Elliot Berman <eberman@codeaurora.org> Cc: Brian Masney <masneyb@onstation.org> Cc: Stephan Gerhold <stephan@gerhold.net> Cc: Jeffrey Hugo <jhugo@codeaurora.org> Cc: Douglas Anderson <dianders@chromium.org> Fixes: 9a434cee773a ("firmware: qcom_scm: Dynamically support SMCCC and legacy conventions") Signed-off-by: Stephen Boyd <swboyd@chromium.org> Link: https://lore.kernel.org/r/20210223214539.1336155-3-swboyd@chromium.org Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>	2021-04-06 21:25:23 -05:00
Elliot Berman	9a434cee77	firmware: qcom_scm: Dynamically support SMCCC and legacy conventions ... Dynamically support SMCCCC and legacy conventions by detecting which convention to use at runtime. qcom_scm_call_atomic and qcom_scm_call can then be moved in qcom_scm.c and use underlying convention backend as appropriate. Thus, rename qcom_scm-64,-32 to reflect that they are backends for -smc and -legacy, respectively. Also add support for making SCM calls earlier than when SCM driver probes to support use cases such as qcom_scm_set_cold_boot_addr. Support is added by lazily initializing the convention and guarding the query with a spin lock. The limitation of these early SCM calls is that they cannot use DMA, as in the case of >4 arguments for SMC convention and any non-atomic call for legacy convention. Tested-by: Brian Masney <masneyb@onstation.org> # arm32 Tested-by: Stephan Gerhold <stephan@gerhold.net> Signed-off-by: Elliot Berman <eberman@codeaurora.org> Link: https://lore.kernel.org/r/1578431066-19600-18-git-send-email-eberman@codeaurora.org Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>	2020-01-07 22:14:43 -08:00