soc: qcom: rpmh-rsc: Enhance check for VRM in-flight request

commit f592cc5794747b81e53b53dd6e80219ee25f0611 upstream.

Each RPMh VRM accelerator resource has 3 or 4 contiguous 4-byte aligned
addres

soc: qcom: rpmh-rsc: Enhance check for VRM in-flight request

commit f592cc5794747b81e53b53dd6e80219ee25f0611 upstream.

Each RPMh VRM accelerator resource has 3 or 4 contiguous 4-byte aligned
addresses associated with it. These control voltage, enable state, mode,
and in legacy targets, voltage headroom. The current in-flight request
checking logic looks for exact address matches. Requests for different
addresses of the same RPMh resource as thus not detected as in-flight.

Add new cmd-db API cmd_db_match_resource_addr() to enhance the in-flight
request check for VRM requests by ignoring the address offset.

This ensures that only one request is allowed to be in-flight for a given
VRM resource. This is needed to avoid scenarios where request commands are
carried out by RPMh hardware out-of-order leading to LDO regulator
over-current protection triggering.

Fixes: 658628e7ef78 ("drivers: qcom: rpmh-rsc: add RPMH controller for QCOM SoCs")
Cc: stable@vger.kernel.org
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Tested-by: Elliot Berman <quic_eberman@quicinc.com> # sm8650-qrd
Signed-off-by: Maulik Shah <quic_mkshah@quicinc.com>
Link: https://lore.kernel.org/r/20240215-rpmh-rsc-fixes-v4-1-9cbddfcba05b@quicinc.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

soc: qcom: rpmh-rsc: Enhance check for VRM in-flight request

commit f592cc5794747b81e53b53dd6e80219ee25f0611 upstream.

Each RPMh VRM accelerator resource has 3 or 4 contiguous 4-byte aligned
addres

soc: qcom: rpmh-rsc: Enhance check for VRM in-flight request

commit f592cc5794747b81e53b53dd6e80219ee25f0611 upstream.

Each RPMh VRM accelerator resource has 3 or 4 contiguous 4-byte aligned
addresses associated with it. These control voltage, enable state, mode,
and in legacy targets, voltage headroom. The current in-flight request
checking logic looks for exact address matches. Requests for different
addresses of the same RPMh resource as thus not detected as in-flight.

Add new cmd-db API cmd_db_match_resource_addr() to enhance the in-flight
request check for VRM requests by ignoring the address offset.

This ensures that only one request is allowed to be in-flight for a given
VRM resource. This is needed to avoid scenarios where request commands are
carried out by RPMh hardware out-of-order leading to LDO regulator
over-current protection triggering.

Fixes: 658628e7ef78 ("drivers: qcom: rpmh-rsc: add RPMH controller for QCOM SoCs")
Cc: stable@vger.kernel.org
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Tested-by: Elliot Berman <quic_eberman@quicinc.com> # sm8650-qrd
Signed-off-by: Maulik Shah <quic_mkshah@quicinc.com>
Link: https://lore.kernel.org/r/20240215-rpmh-rsc-fixes-v4-1-9cbddfcba05b@quicinc.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

soc: qcom: rpmh-rsc: Enhance check for VRM in-flight request

commit f592cc5794747b81e53b53dd6e80219ee25f0611 upstream.

Each RPMh VRM accelerator resource has 3 or 4 contiguous 4-byte aligned
addres

soc: qcom: rpmh-rsc: Enhance check for VRM in-flight request

commit f592cc5794747b81e53b53dd6e80219ee25f0611 upstream.

Each RPMh VRM accelerator resource has 3 or 4 contiguous 4-byte aligned
addresses associated with it. These control voltage, enable state, mode,
and in legacy targets, voltage headroom. The current in-flight request
checking logic looks for exact address matches. Requests for different
addresses of the same RPMh resource as thus not detected as in-flight.

Add new cmd-db API cmd_db_match_resource_addr() to enhance the in-flight
request check for VRM requests by ignoring the address offset.

This ensures that only one request is allowed to be in-flight for a given
VRM resource. This is needed to avoid scenarios where request commands are
carried out by RPMh hardware out-of-order leading to LDO regulator
over-current protection triggering.

Fixes: 658628e7ef78 ("drivers: qcom: rpmh-rsc: add RPMH controller for QCOM SoCs")
Cc: stable@vger.kernel.org
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Tested-by: Elliot Berman <quic_eberman@quicinc.com> # sm8650-qrd
Signed-off-by: Maulik Shah <quic_mkshah@quicinc.com>
Link: https://lore.kernel.org/r/20240215-rpmh-rsc-fixes-v4-1-9cbddfcba05b@quicinc.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

soc: qcom: rpmh-rsc: Enhance check for VRM in-flight request

commit f592cc5794747b81e53b53dd6e80219ee25f0611 upstream.

Each RPMh VRM accelerator resource has 3 or 4 contiguous 4-byte aligned
addres

soc: qcom: rpmh-rsc: Enhance check for VRM in-flight request

commit f592cc5794747b81e53b53dd6e80219ee25f0611 upstream.

Each RPMh VRM accelerator resource has 3 or 4 contiguous 4-byte aligned
addresses associated with it. These control voltage, enable state, mode,
and in legacy targets, voltage headroom. The current in-flight request
checking logic looks for exact address matches. Requests for different
addresses of the same RPMh resource as thus not detected as in-flight.

Add new cmd-db API cmd_db_match_resource_addr() to enhance the in-flight
request check for VRM requests by ignoring the address offset.

This ensures that only one request is allowed to be in-flight for a given
VRM resource. This is needed to avoid scenarios where request commands are
carried out by RPMh hardware out-of-order leading to LDO regulator
over-current protection triggering.

Fixes: 658628e7ef78 ("drivers: qcom: rpmh-rsc: add RPMH controller for QCOM SoCs")
Cc: stable@vger.kernel.org
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Tested-by: Elliot Berman <quic_eberman@quicinc.com> # sm8650-qrd
Signed-off-by: Maulik Shah <quic_mkshah@quicinc.com>
Link: https://lore.kernel.org/r/20240215-rpmh-rsc-fixes-v4-1-9cbddfcba05b@quicinc.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

soc: qcom: rpmh-rsc: Enhance check for VRM in-flight request

commit f592cc5794747b81e53b53dd6e80219ee25f0611 upstream.

Each RPMh VRM accelerator resource has 3 or 4 contiguous 4-byte aligned
addres

soc: qcom: rpmh-rsc: Enhance check for VRM in-flight request

commit f592cc5794747b81e53b53dd6e80219ee25f0611 upstream.

Each RPMh VRM accelerator resource has 3 or 4 contiguous 4-byte aligned
addresses associated with it. These control voltage, enable state, mode,
and in legacy targets, voltage headroom. The current in-flight request
checking logic looks for exact address matches. Requests for different
addresses of the same RPMh resource as thus not detected as in-flight.

Add new cmd-db API cmd_db_match_resource_addr() to enhance the in-flight
request check for VRM requests by ignoring the address offset.

This ensures that only one request is allowed to be in-flight for a given
VRM resource. This is needed to avoid scenarios where request commands are
carried out by RPMh hardware out-of-order leading to LDO regulator
over-current protection triggering.

Fixes: 658628e7ef78 ("drivers: qcom: rpmh-rsc: add RPMH controller for QCOM SoCs")
Cc: stable@vger.kernel.org
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Tested-by: Elliot Berman <quic_eberman@quicinc.com> # sm8650-qrd
Signed-off-by: Maulik Shah <quic_mkshah@quicinc.com>
Link: https://lore.kernel.org/r/20240215-rpmh-rsc-fixes-v4-1-9cbddfcba05b@quicinc.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

soc: qcom: rpmh-rsc: Include state in trace event

When tracing messages written to the RSC it's very useful to know the
type of TCS being targeted, in particular if/when the code borrows a
WAKE TCS

soc: qcom: rpmh-rsc: Include state in trace event

When tracing messages written to the RSC it's very useful to know the
type of TCS being targeted, in particular if/when the code borrows a
WAKE TCS for ACTIVE votes.

Add the "state" of the message to the traced information.

While at it, drop the "send-msg:" substring, as this is already captured
by the trace event itself.

Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20230620230058.428833-1-quic_bjorande@quicinc.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

show more ...

soc: qcom: rpmh-rsc: drop redundant unsigned >=0 comparision

Unsigned int "minor" is always >= 0 as reported by Smatch:

drivers/soc/qcom/rpmh-rsc.c:1076 rpmh_rsc_probe() warn: always true conditi

soc: qcom: rpmh-rsc: drop redundant unsigned >=0 comparision

Unsigned int "minor" is always >= 0 as reported by Smatch:

drivers/soc/qcom/rpmh-rsc.c:1076 rpmh_rsc_probe() warn: always true condition '(drv->ver.minor >= 0) => (0-u32max >= 0)'

Fixes: 88704a0cd719 ("soc: qcom: rpmh-rsc: Support RSC v3 minor versions")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230513112913.176009-1-krzysztof.kozlowski@linaro.org

show more ...

soc: qcom: rpmh-rsc: Support RSC v3 minor versions

RSC v3 register offsets are same for all minor versions of v3. Fix a
minor version check to pick correct offsets for all v3 minor versions.

Fixes:

soc: qcom: rpmh-rsc: Support RSC v3 minor versions

RSC v3 register offsets are same for all minor versions of v3. Fix a
minor version check to pick correct offsets for all v3 minor versions.

Fixes: 40482e4f7364 ("soc: qcom: rpmh-rsc: Add support for RSC v3 register offsets")
Signed-off-by: Tushar Nimkar <quic_tnimkar@quicinc.com>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230406115732.9293-1-quic_tnimkar@quicinc.com

show more ...

soc: qcom: rpmh-rsc: Avoid unnecessary checks on irq-done response

The RSC interrupt is issued only after the request is complete. For
fire-n-forget requests, the irq-done interrupt is sent after is

soc: qcom: rpmh-rsc: Avoid unnecessary checks on irq-done response

The RSC interrupt is issued only after the request is complete. For
fire-n-forget requests, the irq-done interrupt is sent after issuing the
RPMH request and for response-required request, the interrupt is
triggered only after all the requests are complete.

These unnecessary checks in the interrupt handler issues AHB reads from
a critical path. Lets remove them and clean up error handling in
rpmh_request data structures.

Co-developed-by: Lina Iyer <ilina@codeaurora.org>
Signed-off-by: Lina Iyer <ilina@codeaurora.org>
Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221116112246.2640648-2-abel.vesa@linaro.org

show more ...

soc: qcom: rpmh-rsc: Add support for RSC v3 register offsets

The SM8550 RSC has a new set of register offsets due to its version bump.
So read the version from HW and use the proper register offsets

soc: qcom: rpmh-rsc: Add support for RSC v3 register offsets

The SM8550 RSC has a new set of register offsets due to its version bump.
So read the version from HW and use the proper register offsets based on
that.

Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221116112246.2640648-1-abel.vesa@linaro.org

show more ...

soc: qcom: rpmh-rsc: Write CONTROL_TCS with next timer wakeup

The next wakeup timer value needs to be set in always on domain timer
as the arch timer interrupt can not wakeup the SoC if after the de

soc: qcom: rpmh-rsc: Write CONTROL_TCS with next timer wakeup

The next wakeup timer value needs to be set in always on domain timer
as the arch timer interrupt can not wakeup the SoC if after the deepest
CPUidle states the SoC also enters deepest low power state.

To wakeup the SoC in such scenarios the earliest wakeup time is set in
CONTROL_TCS and the firmware takes care of setting up its own timer in
always on domain with next wakeup time. The timer wakes up the RSC and
sets resources back to wake state.

Signed-off-by: Maulik Shah <quic_mkshah@quicinc.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> # SM8450
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221018152837.619426-7-ulf.hansson@linaro.org

show more ...

soc: qcom: rpmh-rsc: Save base address of drv

Add changes to save drv's base address for rsc. This is
used to read drv's configuration such as solver mode is
supported or to write into CONTROL_TCS r

soc: qcom: rpmh-rsc: Save base address of drv

Add changes to save drv's base address for rsc. This is
used to read drv's configuration such as solver mode is
supported or to write into CONTROL_TCS registers.

Signed-off-by: Maulik Shah <quic_mkshah@quicinc.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> # SM8450
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221018152837.619426-6-ulf.hansson@linaro.org

show more ...

soc: qcom: rpmh-rsc: Attach RSC to cluster PM domain

RSC is part the CPU subsystem and powers off the CPU domains when all
the CPUs and no RPMH transactions are pending from any of the drivers.
The

soc: qcom: rpmh-rsc: Attach RSC to cluster PM domain

RSC is part the CPU subsystem and powers off the CPU domains when all
the CPUs and no RPMH transactions are pending from any of the drivers.
The RSC needs to flush the 'sleep' and 'wake' votes that are critical
for saving power when all the CPUs are in idle.

Let's make RSC part of the CPU PM domains, by attaching it to the
cluster power domain. Registering for PM domain notifications, RSC
driver can be notified that the last CPU is powering down. When the last
CPU is powering down the domain, let's flush the 'sleep' and 'wake'
votes that are stored in the data buffers into the hardware and also
write next wakeup in CONTROL_TCS.

Signed-off-by: Lina Iyer <ilina@codeaurora.org>
Signed-off-by: Maulik Shah <quic_mkshah@quicinc.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> # SM8450
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221018152837.619426-3-ulf.hansson@linaro.org

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soc: qcom: rpmh-rsc: Fix typo in a comment

The double `for' in the comment in line 694 is repeated. Remove one
of them from the comment.

Signed-off-by: Jason Wang <wangborong@cdjrlc.com>
Signed-off

soc: qcom: rpmh-rsc: Fix typo in a comment

The double `for' in the comment in line 694 is repeated. Remove one
of them from the comment.

Signed-off-by: Jason Wang <wangborong@cdjrlc.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20211211090626.248801-1-wangborong@cdjrlc.com

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soc: qcom: rpmh-rsc: Make use of the helper function devm_platform_ioremap_resource_byname()

Use the devm_platform_ioremap_resource_byname() helper instead of
calling platform_get_resource_byname()

soc: qcom: rpmh-rsc: Make use of the helper function devm_platform_ioremap_resource_byname()

Use the devm_platform_ioremap_resource_byname() helper instead of
calling platform_get_resource_byname() and devm_ioremap_resource()
separately

Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20210908080216.1301-6-caihuoqing@baidu.com

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soc: qcom: rpmh-rsc: Fold WARN_ON() into if condition

Move the WARN_ON() into the if condition so the compiler can see that
the branch is unlikely() and possibly optimize it better.

Cc: Maulik Shah

soc: qcom: rpmh-rsc: Fold WARN_ON() into if condition

Move the WARN_ON() into the if condition so the compiler can see that
the branch is unlikely() and possibly optimize it better.

Cc: Maulik Shah <mkshah@codeaurora.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20200521060425.24285-4-swboyd@chromium.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

show more ...

soc: qcom: rpmh-rsc: Loop over fewer bits in irq handler

readl() returns a u32, and BITS_PER_LONG is different on 32-bit vs.
64-bit architectures. Let's loop over the possible bits set in that type

soc: qcom: rpmh-rsc: Loop over fewer bits in irq handler

readl() returns a u32, and BITS_PER_LONG is different on 32-bit vs.
64-bit architectures. Let's loop over the possible bits set in that type
instead of looping over more bits than we ever may need to.

Cc: Maulik Shah <mkshah@codeaurora.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20200521060425.24285-3-swboyd@chromium.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

show more ...

soc: qcom: rpmh-rsc: Remove tcs_is_free() API

This API does very little. Let's replace all the callsites with the
normal operations that would be done on top of the bitmap that
tcs_in_use is. This s

soc: qcom: rpmh-rsc: Remove tcs_is_free() API

This API does very little. Let's replace all the callsites with the
normal operations that would be done on top of the bitmap that
tcs_in_use is. This simplifies and reduces the code size.

Reviewed-by: Maulik Shah <mkshah@codeaurora.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Cc: Maulik Shah <mkshah@codeaurora.org>
Cc: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20200521060425.24285-2-swboyd@chromium.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

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soc: qcom: rpmh: Remove serialization of TCS commands

Requests sent to RPMH can be sent as fire-n-forget or response required,
with the latter ensuring the command has been completed by the hardware

soc: qcom: rpmh: Remove serialization of TCS commands

Requests sent to RPMH can be sent as fire-n-forget or response required,
with the latter ensuring the command has been completed by the hardware
accelerator. Commands in a request with tcs_cmd::wait set, would ensure
that those select commands are sent as response required, even though
the actual TCS request may be fire-n-forget.

Also, commands with .wait flag were also guaranteed to be complete
before the following command in the TCS is sent. This means that the
next command of the same request blocked until the current request is
completed. This could mean waiting for a voltage to settle or series of
NOCs be configured before the next command is sent. But drivers using
this feature have never cared about the serialization aspect. By not
enforcing the serialization we can allow the hardware to run in parallel
improving the performance.

Let's clarify the usage of this member in the tcs_cmd structure to mean
only completion and not serialization. This should also improve the
performance of bus requests where changes could happen in parallel.
Also, CPU resume from deep idle may see benefits from certain wake
requests.

Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Lina Iyer <ilina@codeaurora.org>
Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
Link: https://lore.kernel.org/r/1610008770-13891-1-git-send-email-mkshah@codeaurora.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

show more ...

drivers: qcom: rpmh-rsc: Do not read back the register write on trigger

When triggering a TCS to send its contents, reading back the trigger
value may return an incorrect value. That is because, wri

drivers: qcom: rpmh-rsc: Do not read back the register write on trigger

When triggering a TCS to send its contents, reading back the trigger
value may return an incorrect value. That is because, writing the
trigger may raise an interrupt which could be handled immediately and
the trigger value could be reset in the interrupt handler.

A write_tcs_reg_sync() would read back the value that is written and try
to match it to the value written to ensure that the value is written,
but if that value is different, we may see false error for same.

Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Lina Iyer <ilina@codeaurora.org>
Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
Link: https://lore.kernel.org/r/1606211610-15168-1-git-send-email-mkshah@codeaurora.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

show more ...

soc: qcom: rpmh: Allow RPMH driver to be loaded as a module

This patch allow the rpmh driver to be loaded as a permenent
module. Meaning it can be loaded from a module, but then cannot
be unloaded.

soc: qcom: rpmh: Allow RPMH driver to be loaded as a module

This patch allow the rpmh driver to be loaded as a permenent
module. Meaning it can be loaded from a module, but then cannot
be unloaded.

Ideally, it would include a remove hook and related logic, but
the rpmh driver is fairly core to the system, so once its loaded
with almost anything else to get the system to go, the dependencies
are not likely to ever also be removed.

So making it a permanent module at least improves things slightly
over requiring it to be a built in driver.

Cc: Todd Kjos <tkjos@google.com>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Andy Gross <agross@kernel.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Rajendra Nayak <rnayak@codeaurora.org>
Cc: linux-arm-msm@vger.kernel.org
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
[mkshah: Fix typos in commit message, send after removing _rcuidle trace]
Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/1601877596-32676-3-git-send-email-mkshah@codeaurora.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

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Revert "drivers: qcom: rpmh-rsc: Use rcuidle tracepoints for rpmh"

Commit efde2659b0fe ("drivers: qcom: rpmh-rsc: Use rcuidle tracepoints
for rpmh") was written to fix a bug seen in an unmerged seri

Revert "drivers: qcom: rpmh-rsc: Use rcuidle tracepoints for rpmh"

Commit efde2659b0fe ("drivers: qcom: rpmh-rsc: Use rcuidle tracepoints
for rpmh") was written to fix a bug seen in an unmerged series that
implemented a struct generic_pm_domain::power_off() callback calling
rpmh_flush(). See stack trace below.

Call trace:
dump_backtrace+0x0/0x174
show_stack+0x20/0x2c
dump_stack+0xc8/0x124
lockdep_rcu_suspicious+0xe4/0x104
__tcs_buffer_write+0x230/0x2d0
rpmh_rsc_write_ctrl_data+0x210/0x270
rpmh_flush+0x84/0x24c
rpmh_domain_power_off+0x78/0x98
_genpd_power_off+0x40/0xc0
genpd_power_off+0x168/0x208

Later the final merged solution is to use CPU PM notification to invoke
rpmh_flush() and power_off() callback of genpd is not implemented in the
driver.

CPU PM notifiers are run with RCU enabled/watching (see cpu_pm_notify()
and how it calls rcu_irq_enter_irqson() before calling the notifiers).

Remove this change since RCU will not be idle during CPU PM notifications
hence not required to use _rcuidle tracepoint. Using _rcuidle tracepoint
prevented rpmh driver to be loadable module as these are not exported
symbols.

This reverts commit efde2659b0fe835732047357b2902cca14f054d9.

Cc: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/1601877596-32676-2-git-send-email-mkshah@codeaurora.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

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soc: qcom: rpmh-rsc: Sleep waiting for tcs slots to be free

The busy loop in rpmh_rsc_send_data() is written with the assumption
that the udelay will be preempted by the tcs_tx_done() irq handler wh

soc: qcom: rpmh-rsc: Sleep waiting for tcs slots to be free

The busy loop in rpmh_rsc_send_data() is written with the assumption
that the udelay will be preempted by the tcs_tx_done() irq handler when
the TCS slots are all full. This doesn't hold true when the calling
thread is an irqthread and the tcs_tx_done() irq is also an irqthread.
That's because kernel irqthreads are SCHED_FIFO and thus need to
voluntarily give up priority by calling into the scheduler so that other
threads can run.

I see RCU stalls when I boot with irqthreads on the kernel commandline
because the modem remoteproc driver is trying to send an rpmh async
message from an irqthread that needs to give up the CPU for the rpmh
irqthread to run and clear out tcs slots.

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 0-....: (1 GPs behind) idle=402/1/0x4000000000000002 softirq=2108/2109 fqs=4920
(t=21016 jiffies g=2933 q=590)
Task dump for CPU 0:
irq/11-smp2p R running task 0 148 2 0x00000028
Call trace:
dump_backtrace+0x0/0x154
show_stack+0x20/0x2c
sched_show_task+0xfc/0x108
dump_cpu_task+0x44/0x50
rcu_dump_cpu_stacks+0xa4/0xf8
rcu_sched_clock_irq+0x7dc/0xaa8
update_process_times+0x30/0x54
tick_sched_handle+0x50/0x64
tick_sched_timer+0x4c/0x8c
__hrtimer_run_queues+0x21c/0x36c
hrtimer_interrupt+0xf0/0x22c
arch_timer_handler_phys+0x40/0x50
handle_percpu_devid_irq+0x114/0x25c
__handle_domain_irq+0x84/0xc4
gic_handle_irq+0xd0/0x178
el1_irq+0xbc/0x180
save_return_addr+0x18/0x28
return_address+0x54/0x88
preempt_count_sub+0x40/0x88
_raw_spin_unlock_irqrestore+0x4c/0x6c
___ratelimit+0xd0/0x128
rpmh_rsc_send_data+0x24c/0x378
__rpmh_write+0x1b0/0x208
rpmh_write_async+0x90/0xbc
rpmhpd_send_corner+0x60/0x8c
rpmhpd_aggregate_corner+0x8c/0x124
rpmhpd_set_performance_state+0x8c/0xbc
_genpd_set_performance_state+0xdc/0x1b8
dev_pm_genpd_set_performance_state+0xb8/0xf8
q6v5_pds_disable+0x34/0x60 [qcom_q6v5_mss]
qcom_msa_handover+0x38/0x44 [qcom_q6v5_mss]
q6v5_handover_interrupt+0x24/0x3c [qcom_q6v5]
handle_nested_irq+0xd0/0x138
qcom_smp2p_intr+0x188/0x200
irq_thread_fn+0x2c/0x70
irq_thread+0xfc/0x14c
kthread+0x11c/0x12c
ret_from_fork+0x10/0x18

This busy loop naturally lends itself to using a wait queue so that each
thread that tries to send a message will sleep waiting on the waitqueue
and only be woken up when a free slot is available. This should make
things more predictable too because the scheduler will be able to sleep
tasks that are waiting on a free tcs instead of the busy loop we
currently have today.

Reviewed-by: Maulik Shah <mkshah@codeaurora.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Cc: Douglas Anderson <dianders@chromium.org>
Cc: Maulik Shah <mkshah@codeaurora.org>
Cc: Lina Iyer <ilina@codeaurora.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20200724211711.810009-1-sboyd@kernel.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

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soc: qcom: rpmh-rsc: Don't use ktime for timeout in write_tcs_reg_sync()

The write_tcs_reg_sync() may be called after timekeeping is suspended
so it's not OK to use ktime. The readl_poll_timeout_at

soc: qcom: rpmh-rsc: Don't use ktime for timeout in write_tcs_reg_sync()

The write_tcs_reg_sync() may be called after timekeeping is suspended
so it's not OK to use ktime. The readl_poll_timeout_atomic() macro
implicitly uses ktime. This was causing a warning at suspend time.

Change to just loop 1000000 times with a delay of 1 us between loops.
This may give a timeout of more than 1 second but never less and is
safe even if timekeeping is suspended.

NOTE: I don't have any actual evidence that we need to loop here.
It's possibly that all we really need to do is just read the value
back to ensure that the pipes are cleaned and the looping/comparing is
totally not needed. I never saw the loop being needed in my tests.
However, the loop shouldn't hurt.

Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Reviewed-by: Maulik Shah <mkshah@codeaurora.org>
Fixes: 91160150aba0 ("soc: qcom: rpmh-rsc: Timeout after 1 second in write_tcs_reg_sync()")
Reported-by: Maulik Shah <mkshah@codeaurora.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200528074530.1.Ib86e5b406fe7d16575ae1bb276d650faa144b63c@changeid
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

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soc: qcom: rpmh-rsc: Set suppress_bind_attrs flag

rpmh-rsc driver is fairly core to system and should not be removable
once its probed. However it allows to unbind driver from sysfs using
below comm

soc: qcom: rpmh-rsc: Set suppress_bind_attrs flag

rpmh-rsc driver is fairly core to system and should not be removable
once its probed. However it allows to unbind driver from sysfs using
below command which results into a crash on sc7180.

echo 18200000.rsc > /sys/bus/platform/drivers/rpmh/unbind

Lets prevent unbind at runtime by setting suppress_bind_attrs flag.

Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
Link: https://lore.kernel.org/r/1592808805-2437-1-git-send-email-mkshah@codeaurora.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

show more ...