linux-kernel - Re: [PATCH v2 3/6] drivers/thermal/exynos: improve sanitize_temp

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAPLW+4mN5sntZj5UcXXazZq6a_Ra7Ssuz-qLJk9N0egp1W9r=A@mail.gmail.com>
Date: Fri, 26 Jul 2024 13:27:26 -0500
From: Sam Protsenko <semen.protsenko@...aro.org>
To: Mateusz Majewski <m.majewski2@...sung.com>
Cc: linux-pm@...r.kernel.org, linux-samsung-soc@...r.kernel.org, 
	devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	linux-kernel@...r.kernel.org, Bartlomiej Zolnierkiewicz <bzolnier@...il.com>, 
	Krzysztof Kozlowski <krzk@...nel.org>, "Rafael J. Wysocki" <rafael@...nel.org>, 
	Daniel Lezcano <daniel.lezcano@...aro.org>, Zhang Rui <rui.zhang@...el.com>, 
	Lukasz Luba <lukasz.luba@....com>, Rob Herring <robh@...nel.org>, 
	Conor Dooley <conor+dt@...nel.org>, Alim Akhtar <alim.akhtar@...sung.com>, 
	Anand Moon <linux.amoon@...il.com>
Subject: Re: [PATCH v2 3/6] drivers/thermal/exynos: improve sanitize_temp_error

On Fri, Jul 26, 2024 at 6:01 AM Mateusz Majewski
<m.majewski2@...sung.com> wrote:
>
> There are two minor issues regarding this function.
>
> One is that it attempts to calculate the second calibration value even
> if 1-point trimming is being used; in this case, the calculated value is
> probably not useful and is never used anyway. Changing this also
> requires a minor reordering in Exynos5433 initialization function, so
> that we know which type of trimming is used before we call
> sanitize_temp_error.
>
> The second issue is that the function is not very consistent when it
> comes to the use of Exynos7-specific parameters. This seems to not be an
> issue in practice, in part because some of these issues are related to
> the mentioned calculation of the second calibration value. However,
> fixing this makes the code a bit less confusing, and will be required
> for Exynos850 which has 9-bit temperature values and uses 2-point
> trimming.
>
> Signed-off-by: Mateusz Majewski <m.majewski2@...sung.com>
> ---

Reviewed-by: Sam Protsenko <semen.protsenko@...aro.org>

> v1 -> v2: reworked to change shift instead of only mask and to also fix
>   the 2-point trimming issue.
>
>  drivers/thermal/samsung/exynos_tmu.c | 23 ++++++++++++++---------
>  1 file changed, 14 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/thermal/samsung/exynos_tmu.c b/drivers/thermal/samsung/exynos_tmu.c
> index b68e9755c933..087a09628e23 100644
> --- a/drivers/thermal/samsung/exynos_tmu.c
> +++ b/drivers/thermal/samsung/exynos_tmu.c
> @@ -111,6 +111,7 @@
>  #define EXYNOS7_TMU_REG_EMUL_CON               0x160
>
>  #define EXYNOS7_TMU_TEMP_MASK                  0x1ff
> +#define EXYNOS7_TMU_TEMP_SHIFT                 9
>  #define EXYNOS7_PD_DET_EN_SHIFT                        23
>  #define EXYNOS7_TMU_INTEN_RISE0_SHIFT          0
>  #define EXYNOS7_EMUL_DATA_SHIFT                        7
> @@ -234,20 +235,23 @@ static void sanitize_temp_error(struct exynos_tmu_data *data, u32 trim_info)
>         u16 tmu_temp_mask =
>                 (data->soc == SOC_ARCH_EXYNOS7) ? EXYNOS7_TMU_TEMP_MASK
>                                                 : EXYNOS_TMU_TEMP_MASK;
> +       int tmu_85_shift =
> +               (data->soc == SOC_ARCH_EXYNOS7) ? EXYNOS7_TMU_TEMP_SHIFT
> +                                               : EXYNOS_TRIMINFO_85_SHIFT;
>
>         data->temp_error1 = trim_info & tmu_temp_mask;
> -       data->temp_error2 = ((trim_info >> EXYNOS_TRIMINFO_85_SHIFT) &
> -                               EXYNOS_TMU_TEMP_MASK);
> -
>         if (!data->temp_error1 ||
>             (data->min_efuse_value > data->temp_error1) ||
>             (data->temp_error1 > data->max_efuse_value))
> -               data->temp_error1 = data->efuse_value & EXYNOS_TMU_TEMP_MASK;
> +               data->temp_error1 = data->efuse_value & tmu_temp_mask;
>
> -       if (!data->temp_error2)
> -               data->temp_error2 =
> -                       (data->efuse_value >> EXYNOS_TRIMINFO_85_SHIFT) &
> -                       EXYNOS_TMU_TEMP_MASK;
> +       if (data->cal_type == TYPE_TWO_POINT_TRIMMING) {
> +               data->temp_error2 = (trim_info >> tmu_85_shift) & tmu_temp_mask;
> +               if (!data->temp_error2)
> +                       data->temp_error2 =
> +                               (data->efuse_value >> tmu_85_shift) &
> +                               tmu_temp_mask;
> +       }
>  }
>
>  static int exynos_tmu_initialize(struct platform_device *pdev)
> @@ -510,7 +514,6 @@ static void exynos5433_tmu_initialize(struct platform_device *pdev)
>         int sensor_id, cal_type;
>
>         trim_info = readl(data->base + EXYNOS_TMU_REG_TRIMINFO);
> -       sanitize_temp_error(data, trim_info);
>
>         /* Read the temperature sensor id */
>         sensor_id = (trim_info & EXYNOS5433_TRIMINFO_SENSOR_ID_MASK)
> @@ -532,6 +535,8 @@ static void exynos5433_tmu_initialize(struct platform_device *pdev)
>                 break;
>         }
>
> +       sanitize_temp_error(data, trim_info);
> +
>         dev_info(&pdev->dev, "Calibration type is %d-point calibration\n",
>                         cal_type ?  2 : 1);
>  }
> --
> 2.45.1
>