Re: [PATCH V6 2/3] soc: qcom: boot_stat: Add Driver Support for Boot Stats

[Souradeep Chowdhury]

On 5/9/2023 6:31 PM, Dmitry Baryshkov wrote:
> On Tue, 9 May 2023 at 15:27, Souradeep Chowdhury
> <quic_schowdhu@xxxxxxxxxxx> wrote:
> > On 5/9/2023 5:09 PM, Dmitry Baryshkov wrote:
> > > On Tue, 9 May 2023 at 13:53, Souradeep Chowdhury
> > > <quic_schowdhu@xxxxxxxxxxx> wrote:
>
>
> > > > diff --git a/drivers/soc/qcom/boot_stats.c b/drivers/soc/qcom/boot_stats.c
> > > > new file mode 100644
> > > > index 000000000000..ca67b6b5d8eb
> > > > --- /dev/null
> > > > +++ b/drivers/soc/qcom/boot_stats.c
> > > > @@ -0,0 +1,100 @@
> > > > +// 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)
> > >
> > > Quoting v4 question, which got no answer:
> > >
> > > Some of the platforms DTs define 32KHz clock instead of 32.768 KHz
> > > What should be the divisor in this case?
> >
> > This is the standard divisor used to calculate the pre_abl and abl times
> > across most QCOM SoCs. Can you give an example where the sleep_stat
> > counter has a different frequency?
>
> Following SoCs declare 37000 as sleep_clk frequency:
> ipq6018, qdu1000, qru1000, sc7280, sm6125, sm6375, sm8350, sm8450, sm8550.
>
> This might be an error in the dtsi, or might be not.

This sleep_clk is different from the sleep_stats counter of the module 
power manager(MPM) which is used to log the timestamps. This driver is 
tested and verified with sm8450(waipio) which uses the same
frequency(32768).


> > > > +
> > > > +/**
> > > > + *  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 void populate_boot_stats(char *abl_str, char *pre_abl_str, struct bs_data *drvdata)
> > > > +{
> > > > +        u32 abl_time, pre_abl_time;
> > > > +
> > > > +        abl_time = TO_MS(drvdata->b_stats->abl_end) - TO_MS(drvdata->b_stats->abl_start);
> > > > +        sprintf(abl_str, "%u ms", abl_time);
> > > > +
> > > > +        pre_abl_time =  TO_MS(drvdata->b_stats->abl_start);
> > > > +        sprintf(pre_abl_str, "%u ms", pre_abl_time);
> > >
> > > Another point from v4:
> > >
> > > It would be better to move the unit to the file name and include just
> > > the number.
> >
> > Clarified from your first comment
> >
> > > > +}
> > > > +
> > > > +static int boot_stats_probe(struct platform_device *pdev)
> > > > +{
> > > > +       char abl_str[20], pre_abl_str[20], *abl, *pre_abl;
> > > > +       struct device *bootstat_dev = &pdev->dev;
> > > > +       struct bs_data *drvdata;
> > > > +
> > > > +       drvdata = devm_kzalloc(bootstat_dev, sizeof(*drvdata), GFP_KERNEL);
> > > > +       if (!drvdata)
> > > > +               return dev_err_probe(bootstat_dev, -ENOMEM, "failed to allocate memory");
> > > > +       platform_set_drvdata(pdev, drvdata);
> > > > +
> > > > +       drvdata->b_stats = devm_of_iomap(bootstat_dev, bootstat_dev->of_node, 0, NULL);
> > > > +       if (IS_ERR(drvdata->b_stats))
> > > > +               return dev_err_probe(bootstat_dev, PTR_ERR(drvdata->b_stats),
> > > > +                                    "failed to map imem region");
> > > > +
> > > > +       drvdata->dbg_dir = debugfs_create_dir("qcom_boot_stats", NULL);
> > > > +       if (IS_ERR(drvdata->dbg_dir))
> > > > +               return dev_err_probe(bootstat_dev, PTR_ERR(drvdata->dbg_dir),
> > > > +                                    "failed to create debugfs directory");
> > > > +
> > > > +       populate_boot_stats(abl_str, pre_abl_str, drvdata);
> > > > +       abl = abl_str;
> > > > +       pre_abl = pre_abl_str;
> > > > +
> > > > +       debugfs_create_str("pre_abl_time", 0400, drvdata->dbg_dir, (char **)&pre_abl);
> > > > +       debugfs_create_str("abl_time", 0400, drvdata->dbg_dir, (char **)&abl);
> > > > +
> > > > +       return 0;
> > > > +}
> > > > +
> > > > +void boot_stats_remove(struct platform_device *pdev)
> > > > +{
> > > > +       struct bs_data *drvdata = platform_get_drvdata(pdev);
> > > > +
> > > > +       debugfs_remove_recursive(drvdata->dbg_dir);
> > > > +}
> > > > +
> > > > +static const struct of_device_id boot_stats_dt_match[] = {
> > > > +       { .compatible = "qcom,imem-bootstats" },
> > > > +       { }
> > > > +};
> > > > +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");
> > > > --
> > > > 2.17.1