[V4,2/3] soc: qcom: boot_stat: Add Driver Support for Boot Stats

All of Qualcomm's proprietary Android boot-loaders capture boot time
stats, like the time when the bootloader started execution and at what
point the bootloader handed over control to the kernel etc. in the IMEM
region. This information is captured in a specific format by this driver
by mapping a structure to the IMEM memory region and then accessing the
members of the structure to show the information within debugfs file.
This information is useful in verifying if the existing boot KPIs have
regressed or not. The information is shown in milliseconds, a sample
log from sm8450(waipio) device is as follows:-

/sys/kernel/debug/146aa6b0.boot_stats # cat abl_time
17898 ms
/sys/kernel/debug/146aa6b0.boot_stats # cat pre_abl_time
2879 ms

The Module Power Manager(MPM) sleep counter starts ticking at the PBL
stage and the timestamp generated by the sleep counter is logged by
the Qualcomm proprietary bootloader(ABL) at two points-> First when it
starts execution which is logged here as "pre_abl_time" and the second
when it is about to load the kernel logged as "abl_time". Documentation
details are also added in Documentation/ABI/testing/debugfs-driver-bootstat

Signed-off-by: Souradeep Chowdhury <quic_schowdhu@quicinc.com>
---
 Documentation/ABI/testing/debugfs-driver-bootstat |  17 ++++
 drivers/soc/qcom/Kconfig                          |   9 ++
 drivers/soc/qcom/Makefile                         |   1 +
 drivers/soc/qcom/boot_stats.c                     | 101 ++++++++++++++++++++++
 4 files changed, 128 insertions(+)
 create mode 100644 Documentation/ABI/testing/debugfs-driver-bootstat
 create mode 100644 drivers/soc/qcom/boot_stats.c

Hi Souradeep,

kernel test robot noticed the following build warnings:

[auto build test WARNING on robh/for-next]
[also build test WARNING on krzk-dt/for-next linus/master v6.3-rc7]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Souradeep-Chowdhury/dt-bindings-sram-qcom-imem-Add-Boot-Stat-region-within-IMEM/20230417-231510
base:   https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next
patch link:    https://lore.kernel.org/r/2ef76ce292c059c144e559123a9a54201ae2d0cf.1681742910.git.quic_schowdhu%40quicinc.com
patch subject: [PATCH V4 2/3] soc: qcom: boot_stat: Add Driver Support for Boot Stats
config: sh-allmodconfig (https://download.01.org/0day-ci/archive/20230418/202304180101.Wxf2Jbjq-lkp@intel.com/config)
compiler: sh4-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/4c8808184261e004f0b258e469415e4eea9c5ad9
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Souradeep-Chowdhury/dt-bindings-sram-qcom-imem-Add-Boot-Stat-region-within-IMEM/20230417-231510
        git checkout 4c8808184261e004f0b258e469415e4eea9c5ad9
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=sh olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=sh SHELL=/bin/bash drivers/soc/qcom/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202304180101.Wxf2Jbjq-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/soc/qcom/boot_stats.c:76:6: warning: no previous prototype for 'boot_stats_remove' [-Wmissing-prototypes]
      76 | void boot_stats_remove(struct platform_device *pdev)
         |      ^~~~~~~~~~~~~~~~~


vim +/boot_stats_remove +76 drivers/soc/qcom/boot_stats.c

    75	
  > 76	void boot_stats_remove(struct platform_device *pdev)
    77	{
    78		struct bs_data *drvdata = platform_get_drvdata(pdev);
    79	
    80		debugfs_remove_recursive(drvdata->dbg_dir);
    81		iounmap(drvdata->b_stats);
    82	}
    83

On 17/04/2023 16:08, Souradeep Chowdhury wrote:
> All of Qualcomm's proprietary Android boot-loaders capture boot time
> stats, like the time when the bootloader started execution and at what
> point the bootloader handed over control to the kernel etc. in the IMEM
> region. This information is captured in a specific format by this driver
> by mapping a structure to the IMEM memory region and then accessing the
> members of the structure to show the information within debugfs file.
> This information is useful in verifying if the existing boot KPIs have
> regressed or not. The information is shown in milliseconds, a sample
> log from sm8450(waipio) device is as follows:-
> 
> /sys/kernel/debug/146aa6b0.boot_stats # cat abl_time
> 17898 ms
> /sys/kernel/debug/146aa6b0.boot_stats # cat pre_abl_time
> 2879 ms
> 
> The Module Power Manager(MPM) sleep counter starts ticking at the PBL
> stage and the timestamp generated by the sleep counter is logged by
> the Qualcomm proprietary bootloader(ABL) at two points-> First when it
> starts execution which is logged here as "pre_abl_time" and the second
> when it is about to load the kernel logged as "abl_time". Documentation
> details are also added in Documentation/ABI/testing/debugfs-driver-bootstat
> 
> Signed-off-by: Souradeep Chowdhury <quic_schowdhu@quicinc.com>

Hi,

[...]
> +
> +static int boot_stats_probe(struct platform_device *pdev)
> +{
> +	struct device *bootstat_dev = &pdev->dev;
> +	struct bs_data *drvdata;
> +
> +	drvdata = devm_kzalloc(bootstat_dev, sizeof(*drvdata), GFP_KERNEL);
> +	platform_set_drvdata(pdev, drvdata);
> +
> +	drvdata->dbg_dir = debugfs_create_dir(dev_name(bootstat_dev), NULL);

This might be better as just "qcom_boot_stats", rather than including
the address.

[...]
> +
> +static const struct of_device_id boot_stats_dt_match[] = {
> +	{ .compatible = "qcom,sm8450-bootstats" },

This driver doesn't only support sm8450, I've tested this on sdm845 and
it works just fine. Can we use a generic compatible here instead?
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, boot_stats_dt_match);
> +
> +static struct platform_driver boot_stat_driver = {
> +	.probe  = boot_stats_probe,
> +	.remove_new = boot_stats_remove,
> +	.driver = {
> +		.name = "qcom-boot-stats",
> +		.of_match_table = boot_stats_dt_match,
> +	},
> +};
> +module_platform_driver(boot_stat_driver);
> +
> +MODULE_DESCRIPTION("Qualcomm Technologies Inc. Boot Stat driver");
> +MODULE_LICENSE("GPL");
> --
> 2.7.4
>

On 17/04/2023 18:08, Souradeep Chowdhury wrote:
> All of Qualcomm's proprietary Android boot-loaders capture boot time
> stats, like the time when the bootloader started execution and at what
> point the bootloader handed over control to the kernel etc. in the IMEM
> region. This information is captured in a specific format by this driver
> by mapping a structure to the IMEM memory region and then accessing the
> members of the structure to show the information within debugfs file.
> This information is useful in verifying if the existing boot KPIs have
> regressed or not. The information is shown in milliseconds, a sample
> log from sm8450(waipio) device is as follows:-
> 
> /sys/kernel/debug/146aa6b0.boot_stats # cat abl_time
> 17898 ms
> /sys/kernel/debug/146aa6b0.boot_stats # cat pre_abl_time
> 2879 ms
> 
> The Module Power Manager(MPM) sleep counter starts ticking at the PBL
> stage and the timestamp generated by the sleep counter is logged by
> the Qualcomm proprietary bootloader(ABL) at two points-> First when it
> starts execution which is logged here as "pre_abl_time" and the second
> when it is about to load the kernel logged as "abl_time". Documentation
> details are also added in Documentation/ABI/testing/debugfs-driver-bootstat
> 
> Signed-off-by: Souradeep Chowdhury <quic_schowdhu@quicinc.com>
> ---
>   Documentation/ABI/testing/debugfs-driver-bootstat |  17 ++++
>   drivers/soc/qcom/Kconfig                          |   9 ++
>   drivers/soc/qcom/Makefile                         |   1 +
>   drivers/soc/qcom/boot_stats.c                     | 101 ++++++++++++++++++++++
>   4 files changed, 128 insertions(+)
>   create mode 100644 Documentation/ABI/testing/debugfs-driver-bootstat
>   create mode 100644 drivers/soc/qcom/boot_stats.c
> 
> diff --git a/Documentation/ABI/testing/debugfs-driver-bootstat b/Documentation/ABI/testing/debugfs-driver-bootstat
> new file mode 100644
> index 0000000..2543029
> --- /dev/null
> +++ b/Documentation/ABI/testing/debugfs-driver-bootstat
> @@ -0,0 +1,17 @@
> +What:		/sys/kernel/debug/...stats/pre_abl_time
> +Date:           April 2023
> +Contact:        Souradeep Chowdhury <quic_schowdhu@quicinc.com>
> +Description:
> +		This file is used to read the KPI value pre abl time.
> +		It shows the time in milliseconds from the starting
> +		point of PBL to the point when the control shifted
> +		to ABL(Qualcomm proprietary bootloader).
> +
> +What:           /sys/kernel/debug/...stats/abl_time
> +Date:           April 2023
> +Contact:        Souradeep Chowdhury <quic_schowdhu@quicinc.com>
> +Description:
> +		This file is used to read the KPI value abl time.
> +		It show the duration in milliseconds from the
> +		time control switched to ABL to the point when
> +		the linux kernel started getting loaded.
> diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
> index a8f2830..0d2cbd3 100644
> --- a/drivers/soc/qcom/Kconfig
> +++ b/drivers/soc/qcom/Kconfig
> @@ -16,6 +16,15 @@ config QCOM_AOSS_QMP
>   	  subsystems as well as controlling the debug clocks exposed by the Always On
>   	  Subsystem (AOSS) using Qualcomm Messaging Protocol (QMP).
>   
> +config QCOM_BOOTSTAT
> +	tristate "Qualcomm Technologies, Boot Stat driver"
> +	depends on ARCH_QCOM || COMPILE_TEST
> +	help
> +	  This option enables driver support for boot stats. Boot stat driver logs
> +	  the kernel bootloader information by accessing the imem region. These
> +	  information are exposed in the form of debugfs files. This is used to
> +	  determine if there is any regression in boot timings.
> +
>   config QCOM_COMMAND_DB
>   	tristate "Qualcomm Command DB"
>   	depends on ARCH_QCOM || COMPILE_TEST
> diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
> index 6e88da8..bdaa41a 100644
> --- a/drivers/soc/qcom/Makefile
> +++ b/drivers/soc/qcom/Makefile
> @@ -1,6 +1,7 @@
>   # SPDX-License-Identifier: GPL-2.0
>   CFLAGS_rpmh-rsc.o := -I$(src)
>   obj-$(CONFIG_QCOM_AOSS_QMP) +=	qcom_aoss.o
> +obj-$(CONFIG_QCOM_BOOTSTAT) += boot_stats.o
>   obj-$(CONFIG_QCOM_GENI_SE) +=	qcom-geni-se.o
>   obj-$(CONFIG_QCOM_COMMAND_DB) += cmd-db.o
>   obj-$(CONFIG_QCOM_CPR)		+= cpr.o
> diff --git a/drivers/soc/qcom/boot_stats.c b/drivers/soc/qcom/boot_stats.c
> new file mode 100644
> index 0000000..7fa8efb
> --- /dev/null
> +++ b/drivers/soc/qcom/boot_stats.c
> @@ -0,0 +1,101 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2013-2019, 2021 The Linux Foundation. All rights reserved.
> + * Copyright (c) 2023 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +
> +#include <linux/debugfs.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/platform_device.h>
> +
> +#define TO_MS(timestamp) ((timestamp * 1000) / 32768)

Some of the platforms DTs define 32KHz clock instead of 32.768 KHz What 
should be the divisor in this case?

> +
> +/**
> + *  struct boot_stats - timestamp information related to boot stats
> + *  @abl_start: Time for the starting point of the abl
> + *  @abl_end: Time when the kernel starts loading from abl
> + */
> +struct boot_stats {
> +	u32 abl_start;
> +	u32 abl_end;
> +} __packed;
> +
> +struct bs_data {
> +	struct boot_stats __iomem *b_stats;
> +	struct dentry *dbg_dir;
> +};
> +
> +static int abl_time_show(struct seq_file *seq, void *v)
> +{
> +	struct boot_stats *boot_stats = seq->private;
> +	u32 abl_time = TO_MS(boot_stats->abl_end) - TO_MS(boot_stats->abl_start);
> +
> +	seq_printf(seq, "%u ms\n", abl_time);
> +	return 0;
> +}
> +DEFINE_SHOW_ATTRIBUTE(abl_time);
> +
> +static int pre_abl_time_show(struct seq_file *seq, void *v)
> +{
> +	struct boot_stats *boot_stats = seq->private;
> +
> +	seq_printf(seq, "%u ms\n", TO_MS(boot_stats->abl_start));

It would be better to move the unit to the file name and include just 
the number.

> +	return 0;
> +}
> +DEFINE_SHOW_ATTRIBUTE(pre_abl_time);
> +
> +static int boot_stats_probe(struct platform_device *pdev)
> +{
> +	struct device *bootstat_dev = &pdev->dev;
> +	struct bs_data *drvdata;
> +
> +	drvdata = devm_kzalloc(bootstat_dev, sizeof(*drvdata), GFP_KERNEL);
> +	platform_set_drvdata(pdev, drvdata);
> +
> +	drvdata->dbg_dir = debugfs_create_dir(dev_name(bootstat_dev), NULL);
> +	if (IS_ERR(drvdata->dbg_dir))
> +		return dev_err_probe(bootstat_dev, -ENOENT, "failed to create debugfs directory");
> +
> +	drvdata->b_stats = devm_of_iomap(bootstat_dev, bootstat_dev->of_node, 0, NULL);
> +	if (!drvdata->b_stats)
> +		return dev_err_probe(bootstat_dev, -ENOMEM, "failed to map imem region\n");
> +
> +	debugfs_create_file("pre_abl_time", 0200, drvdata->dbg_dir,
> +			    drvdata->b_stats, &pre_abl_time_fops);
> +	debugfs_create_file("abl_time", 0200, drvdata->dbg_dir, drvdata->b_stats, &abl_time_fops);
> +
> +	return 0;
> +}
> +
> +void boot_stats_remove(struct platform_device *pdev)
> +{
> +	struct bs_data *drvdata = platform_get_drvdata(pdev);
> +
> +	debugfs_remove_recursive(drvdata->dbg_dir);
> +	iounmap(drvdata->b_stats);
> +}
> +
> +static const struct of_device_id boot_stats_dt_match[] = {
> +	{ .compatible = "qcom,sm8450-bootstats" },

Is it specific to sm8450 only?

> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, boot_stats_dt_match);
> +
> +static struct platform_driver boot_stat_driver = {
> +	.probe  = boot_stats_probe,
> +	.remove_new = boot_stats_remove,
> +	.driver = {
> +		.name = "qcom-boot-stats",
> +		.of_match_table = boot_stats_dt_match,
> +	},
> +};
> +module_platform_driver(boot_stat_driver);
> +
> +MODULE_DESCRIPTION("Qualcomm Technologies Inc. Boot Stat driver");
> +MODULE_LICENSE("GPL");