| 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
| ||
|
Message-ID: <b22ca322-c8f2-d17c-75ff-54ee26b0041b@roeck-us.net>
Date: Thu, 17 Feb 2022 10:11:32 -0800
From: Guenter Roeck <linux@...ck-us.net>
To: Zev Weiss <zev@...ilderbeest.net>,
Jean Delvare <jdelvare@...e.com>, linux-hwmon@...r.kernel.org
Cc: openbmc@...ts.ozlabs.org,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
linux-kernel@...r.kernel.org, Mark Brown <broonie@...nel.org>,
Liam Girdwood <lgirdwood@...il.com>
Subject: Re: [PATCH 1/4] hwmon: (pmbus) Add get_error_flags support to
regulator ops
On 2/17/22 02:44, Zev Weiss wrote:
> The various PMBus status bits don't all map perfectly to the more
> limited set of REGULATOR_ERROR_* flags, but there's a reasonable
> number where they correspond well enough.
>
> Signed-off-by: Zev Weiss <zev@...ilderbeest.net>
> ---
> drivers/hwmon/pmbus/pmbus_core.c | 97 ++++++++++++++++++++++++++++++++
> 1 file changed, 97 insertions(+)
>
> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
> index 776ee2237be2..a274e8e524a5 100644
> --- a/drivers/hwmon/pmbus/pmbus_core.c
> +++ b/drivers/hwmon/pmbus/pmbus_core.c
> @@ -2417,10 +2417,107 @@ static int pmbus_regulator_disable(struct regulator_dev *rdev)
> return _pmbus_regulator_on_off(rdev, 0);
> }
>
> +/* A PMBus status flag and the corresponding REGULATOR_ERROR_* flag */
> +struct pmbus_regulator_status_assoc {
> + int pflag, rflag;
> +};
> +
> +/* PMBus->regulator bit mappings for a PMBus status register */
> +struct pmbus_regulator_status_category {
> + int func;
> + int reg;
> + const struct pmbus_regulator_status_assoc *bits; /* zero-terminated */
> +};
> +
> +static const struct pmbus_regulator_status_category pmbus_regulator_flag_map[] = {
> + {
> + .func = PMBUS_HAVE_STATUS_VOUT,
> + .reg = PMBUS_STATUS_VOUT,
> + .bits = (const struct pmbus_regulator_status_assoc[]) {
> + { PB_VOLTAGE_UV_WARNING, REGULATOR_ERROR_UNDER_VOLTAGE_WARN },
> + { PB_VOLTAGE_UV_FAULT, REGULATOR_ERROR_UNDER_VOLTAGE },
> + { PB_VOLTAGE_OV_WARNING, REGULATOR_ERROR_OVER_VOLTAGE_WARN },
> + { PB_VOLTAGE_OV_FAULT, REGULATOR_ERROR_REGULATION_OUT },
> + { },
> + },
> + }, {
> + .func = PMBUS_HAVE_STATUS_IOUT,
> + .reg = PMBUS_STATUS_IOUT,
> + .bits = (const struct pmbus_regulator_status_assoc[]) {
> + { PB_IOUT_OC_WARNING, REGULATOR_ERROR_OVER_CURRENT_WARN },
> + { PB_IOUT_OC_FAULT, REGULATOR_ERROR_OVER_CURRENT },
> + { PB_IOUT_OC_LV_FAULT, REGULATOR_ERROR_OVER_CURRENT },
> + { },
> + },
> + }, {
> + .func = PMBUS_HAVE_STATUS_TEMP,
> + .reg = PMBUS_STATUS_TEMPERATURE,
> + .bits = (const struct pmbus_regulator_status_assoc[]) {
> + { PB_TEMP_OT_WARNING, REGULATOR_ERROR_OVER_TEMP_WARN },
> + { PB_TEMP_OT_FAULT, REGULATOR_ERROR_OVER_TEMP },
> + { },
> + },
> + },
> +};
> +
> +static int pmbus_regulator_get_error_flags(struct regulator_dev *rdev, unsigned int *flags)
> +{
> + int i, status, statusreg;
> + const struct pmbus_regulator_status_category *cat;
> + const struct pmbus_regulator_status_assoc *bit;
> + struct device *dev = rdev_get_dev(rdev);
> + struct i2c_client *client = to_i2c_client(dev->parent);
> + struct pmbus_data *data = i2c_get_clientdata(client);
> + u8 page = rdev_get_id(rdev);
> + int func = data->info->func[page];
> +
> + *flags = 0;
> +
> + for (i = 0; i < ARRAY_SIZE(pmbus_regulator_flag_map); i++) {
> + cat = &pmbus_regulator_flag_map[i];
> + if (!(func & cat->func))
> + continue;
> +
> + status = pmbus_read_byte_data(client, page, cat->reg);
> + if (status < 0)
> + return status;
> +
> + for (bit = cat->bits; bit->pflag; bit++) {
> + if (status & bit->pflag)
> + *flags |= bit->rflag;
> + }
> + }
> +
> + /*
> + * Map what bits of STATUS_{WORD,BYTE} we can to REGULATOR_ERROR_*
> + * bits. Some of the other bits are tempting (especially for cases
> + * where we don't have the relevant PMBUS_HAVE_STATUS_*
> + * functionality), but there's an unfortunate ambiguity in that
> + * they're defined as indicating a fault *or* a warning, so we can't
> + * easily determine whether to report REGULATOR_ERROR_<foo> or
> + * REGULATOR_ERROR_<foo>_WARN.
> + */
> + statusreg = data->has_status_word ? PMBUS_STATUS_WORD : PMBUS_STATUS_BYTE;
> + status = pmbus_get_status(client, page, statusreg);
> +
pmbus_get_status() calls data->read_status if PMBUS_STATUS_WORD is provided
as parameter, and data->read_status is set to pmbus_read_status_byte()
if reading the word status is not supported. Given that, why not just call
pmbus_get_status(client, page, PMBUS_STATUS_WORD) ?
> + if (status < 0)
> + return status;
> +
> + if (pmbus_regulator_is_enabled(rdev) && (status & PB_STATUS_OFF))
> + *flags |= REGULATOR_ERROR_FAIL;
> + if (status & PB_STATUS_IOUT_OC)
> + *flags |= REGULATOR_ERROR_OVER_CURRENT;
If the current status register is supported, this effectively means that
an overcurrent warning is always reported as both REGULATOR_ERROR_OVER_CURRENT
and REGULATOR_ERROR_OVER_CURRENT_WARN. Is that intentional ?
> + if (status & PB_STATUS_VOUT_OV)
> + *flags |= REGULATOR_ERROR_REGULATION_OUT;
Same for voltage. On the other side, temperature limit violations are not
reported at all unless the temperature status register exists.
That seems to be a bit inconsistent to me.
> +
> + return 0;
> +}
> +
> const struct regulator_ops pmbus_regulator_ops = {
> .enable = pmbus_regulator_enable,
> .disable = pmbus_regulator_disable,
> .is_enabled = pmbus_regulator_is_enabled,
> + .get_error_flags = pmbus_regulator_get_error_flags,
> };
> EXPORT_SYMBOL_NS_GPL(pmbus_regulator_ops, PMBUS);
>
Powered by blists - more mailing lists