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Date: Wed, 31 Jan 2024 16:35:02 +0530
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Subject: Re: [PATCH v8 00/10] Add Qualcomm APSS Minidump driver related
 support
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To: <corbet@lwn.net>, <andersson@kernel.org>, <konrad.dybcio@linaro.org>,
        <robh+dt@kernel.org>, <krzysztof.kozlowski+dt@linaro.org>,
        <conor+dt@kernel.org>, <keescook@chromium.org>, <tony.luck@intel.com>,
        <gpiccoli@igalia.com>, <mathieu.poirier@linaro.org>, <vigneshr@ti.com>,
        <nm@ti.com>, <matthias.bgg@gmail.com>, <kgene@kernel.org>,
        <alim.akhtar@samsung.com>, <bmasney@redhat.com>
CC: <linux-doc@vger.kernel.org>, <linux-kernel@vger.kernel.org>
References: <20240131105734.13090-1-quic_mojha@quicinc.com>
From: Mukesh Ojha <quic_mojha@quicinc.com>
In-Reply-To: <20240131105734.13090-1-quic_mojha@quicinc.com>
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Please ignore the series; looks like it got missed quite a few people
and mailing lists. I will resend this.

-Mukesh

On 1/31/2024 4:27 PM, Mukesh Ojha wrote:
> Abstract and PDF here:
> https://lpc.events/event/17/contributions/1468/
> 
> Video:
> https://www.youtube.com/watch?v=3vL3gtAu84s
> 
> Patch 1 deals in detail documentation on minidump.
> Patch 2-4 refactors minidump existing layout and separate it from remoteproc files.
> Patch 6 is the Qualcomm APSS minidump driver.
> Patch 7-10 Enable support to reserve dynamic ramoops and the support to
>    register ramoops region with minidump.
> 
> Detail about Minidump is discussed in documentation patch (1/10) and also briefly
> discussed after below changelog.
> 
> Changes in v8:
>   - Addressed documentation comment made by Randy Dunlap.
>   - Rebased on linux-next tag next-20240130
> 
> Changes in v7:
>   - Addressed comment made by [Pavan.K] to use generic notifiers.
>   - Addresses comment made on Dynamic ramoops about error handling.
>   - Significant change minidump documentation suggested by [Bryan O'Donoghue]
>   - Added Reviewed by from [Bagas]
>   - Renamed ramoops notifiers.
> 
> Changes in v6: https://lore.kernel.org/lkml/1700864395-1479-1-git-send-email-quic_mojha@quicinc.com/
>   - Accumalated the feedback received on v5 and rebase v5 versions in v6.
>   - Removed the exported function as there is no current users of them.
>   - Applied [Pavan.K] suggestion on caller/callee placement of dynamic ramoops reserve memory.
>   - Addressed [krzysztof] comment on sizeof() and to have qcom_apss_md_table_exit().
>   - Addressed [Bagas.S] comment on minidump doc.
>   - Tried to implement [Kees] suggestion in slight different way with callback registration
>     with ramoops instead of pstore core.
> 
> Change in rebase v5: https://lore.kernel.org/lkml/1694429639-21484-1-git-send-email-quic_mojha@quicinc.com/
>   - Rebased it on latest tag available on linux-next
>   - Added missed Poovendhan sign-off on 15/17 and tested-by tag from
>     Kathiravan. Thanks to him for testing and reminding me of missing sign-off.
> 
> Changes in v5: https://lore.kernel.org/lkml/1694290578-17733-1-git-send-email-quic_mojha@quicinc.com/
>   - On suggestion from Pavan.k, to have single function call for minidump collection
>     from remoteproc driver, separated the logic to have separate minidump file called
>     qcom_rproc_minidump.c and also renamed the function from qcom_minidump() to
>     qcom_rproc_minidump(); however, dropped his suggestion about rework on lazy deletion
>     during region unregister in this series, will pursue it in next series.
> 
>   - To simplify the minidump driver, removed the complication for frontend and different
>     backend from Greg suggestion, will pursue this once main driver gets mainlined.
> 
>   - Move the dynamic ramoops region allocation from Device tree approach to command line
>     approch with the introduction command line parsing and memblock reservation during
>     early boot up; Not added documentation about it yet, will add if it gets positive
>     response.
> 
>   - Exporting linux banner from kernel to make minidump build also as module, however,
>     minidump is a debug module and should be kernel built to get most debug information
>     from kernel.
> 
>   - Tried to address comments given on dload patch series.
> 
> Changes in v4: https://lore.kernel.org/lkml/1687955688-20809-1-git-send-email-quic_mojha@quicinc.com/
>   - Redesigned the driver and divided the driver into front end and backend (smem) so
>     that any new backend can be attached easily to avoid code duplication.
>   - Patch reordering as per the driver and subsystem to easier review of the code.
>   - Removed minidump specific code from remoteproc to minidump smem based driver.
>   - Enabled the all the driver as modules.
>   - Address comments made on documentation and yaml and Device tree file [Krzysztof/Konrad]
>   - Address comments made qcom_pstore_minidump driver and given its Device tree
>     same set of properties as ramoops. [Luca/Kees]
>   - Added patch for MAINTAINER file.
>   - Include defconfig change as one patch as per [Krzysztof] suggestion.
>   - Tried to remove the redundant file scope variables from the module as per [Krzysztof] suggestion.
>   - Addressed comments made on dload mode patch v6 version
>     https://lore.kernel.org/lkml/1680076012-10785-1-git-send-email-quic_mojha@quicinc.com/
> 
> Changes in v3: https://lore.kernel.org/lkml/1683133352-10046-1-git-send-email-quic_mojha@quicinc.com/
>   - Addressed most of the comments by Srini on v2 and refactored the minidump driver.
>      - Added platform device support
>      - Unregister region support.
>   - Added update region for clients.
>   - Added pending region support.
>   - Modified the documentation guide accordingly.
>   - Added qcom_pstore_ramdump client driver which happen to add ramoops platform
>     device and also registers ramoops region with minidump.
>   - Added download mode patch series with this minidump series.
>      https://lore.kernel.org/lkml/1680076012-10785-1-git-send-email-quic_mojha@quicinc.com/
> 
> Changes in v2: https://lore.kernel.org/lkml/1679491817-2498-1-git-send-email-quic_mojha@quicinc.com/
>   - Addressed review comment made by [quic_tsoni/bmasney] to add documentation.
>   - Addressed comments made by [srinivas.kandagatla]
>   - Dropped pstore 6/6 from the last series, till i get conclusion to get pstore
>     region in minidump.
>   - Fixed issue reported by kernel test robot.
> 
> Changes in v1: https://lore.kernel.org/lkml/1676978713-7394-1-git-send-email-quic_mojha@quicinc.com/
> 
> Minidump is a best effort mechanism to collect useful and predefined data
> for first level of debugging on end user devices running on Qualcomm SoCs.
> It is built on the premise that System on Chip (SoC) or subsystem part of
> SoC crashes, due to a range of hardware and software bugs.
> 
> Qualcomm devices in engineering mode provides a mechanism for generating
> full system ramdumps for post mortem debugging. But in some cases it's
> however not feasible to capture the entire content of RAM. The minidump
> mechanism provides the means for selecting which snippets should be
> included in the ramdump.
> 
> The core of SMEM based minidump feature is part of Qualcomm's boot
> firmware code. It initializes shared memory (SMEM), which is a part of
> DDR and allocates a small section of SMEM to minidump table i.e also
> called global table of content (G-ToC). Each subsystem (APSS, ADSP, ...)
> has their own table of segments to be included in the minidump and all
> get their reference from G-ToC. Each segment/region has some details
> like name, physical address and it's size etc. and it could be anywhere
> scattered in the DDR.
> 
> Existing upstream Qualcomm remoteproc driver[1] already supports SMEM
> based minidump feature for remoteproc instances like ADSP, MODEM, ...
> where predefined selective segments of subsystem region can be dumped
> as part of coredump collection which generates smaller size artifacts
> compared to complete coredump of subsystem on crash.
> 
> [1]
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/drivers/remoteproc/qcom_common.c#n142
> 
> In addition to managing and querying the APSS minidump description,
> the Linux driver maintains a ELF header in a segment. This segment
> gets updated with section/program header whenever a new entry gets
> registered.
> 
> Support for Minidump enablement on Qualcomm SoCs is pursued separately and
> can be done via below series of changes. For testing, these patches can be
> applied
> 
> https://lore.kernel.org/lkml/1704727654-13999-1-git-send-email-quic_mojha@quicinc.com/
> 
> https://lore.kernel.org/lkml/20240109153200.12848-12-quic_mojha@quicinc.com/
> https://lore.kernel.org/lkml/20240109153200.12848-13-quic_mojha@quicinc.com/
> 
> Testing of these patches has been done on sm8450 target after enabling kernel
> config like CONFIG_PSTORE_RAM/CONFIG_PSTORE_CONSOLE and once the device boots
> up. Below command can be executed from sysfs to enable minidump in the firmware.
> 
>   echo mini > /sys/module/qcom_scm/parameters/download_mode
> 
> Try crashing it via devmem2 0xf11c000(this is known command to create xpu violation
> and put the device crash dump mode) on command prompt.
> 
> Default storage type is set to via USB, so Minidump would be downloaded with the
> help of x86_64 machine (running PCAT tool) attached to Qualcomm product which has
> backed Minidump boot firmware support.
> 
> After that we will see a bunch of predefined registered region as binary blobs files
> starts with md_* downloaded on the x86 machine at configured/default location in PCAT
> tool from the product, more about this can be found in qualcomm minidump guide
> patch.
> 
> Mukesh Ojha (10):
>    docs: qcom: Add qualcomm minidump guide
>    soc: qcom: Add qcom_rproc_minidump module
>    remoteproc: qcom_q6v5_pas: Use qcom_rproc_minidump()
>    remoteproc: qcom: Remove minidump related data from qcom_common.c
>    init: export linux_banner data variable
>    soc: qcom: Add Qualcomm APSS minidump kernel driver
>    MAINTAINERS: Add entry for minidump related files
>    pstore/ram: Add dynamic ramoops region support through commandline
>    pstore/ram: Add ramoops information notifier support
>    soc: qcom: register ramoops region with APSS minidump
> 
>   Documentation/admin-guide/index.rst         |   1 +
>   Documentation/admin-guide/qcom_minidump.rst | 318 +++++++++
>   Documentation/admin-guide/ramoops.rst       |  23 +-
>   MAINTAINERS                                 |  10 +
>   drivers/remoteproc/Kconfig                  |   1 +
>   drivers/remoteproc/qcom_common.c            | 160 -----
>   drivers/remoteproc/qcom_q6v5_pas.c          |   3 +-
>   drivers/soc/qcom/Kconfig                    |  23 +
>   drivers/soc/qcom/Makefile                   |   2 +
>   drivers/soc/qcom/qcom_minidump.c            | 690 ++++++++++++++++++++
>   drivers/soc/qcom/qcom_minidump_internal.h   |  74 +++
>   drivers/soc/qcom/qcom_rproc_minidump.c      | 111 ++++
>   drivers/soc/qcom/smem.c                     |  20 +
>   fs/pstore/Kconfig                           |  15 +
>   fs/pstore/ram.c                             | 180 ++++-
>   include/linux/init.h                        |   3 +
>   include/linux/pstore_ram.h                  |  20 +
>   include/linux/soc/qcom/smem.h               |   2 +
>   include/soc/qcom/qcom_minidump.h            |  41 ++
>   init/main.c                                 |   3 +
>   init/version-timestamp.c                    |   3 +
>   21 files changed, 1538 insertions(+), 165 deletions(-)
>   create mode 100644 Documentation/admin-guide/qcom_minidump.rst
>   create mode 100644 drivers/soc/qcom/qcom_minidump.c
>   create mode 100644 drivers/soc/qcom/qcom_minidump_internal.h
>   create mode 100644 drivers/soc/qcom/qcom_rproc_minidump.c
>   create mode 100644 include/soc/qcom/qcom_minidump.h
> 
> 
> base-commit: 41d66f96d0f15a0a2ad6fa2208f6bac1a66cbd52