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SubjectRe: [PATCH v7 1/2] hwmon: (asus_wmi_ec_sensors) Support B550 Asus WMI.
Date
On 10/15/21 1:21 AM, Andy Shevchenko wrote:
> On Fri, Oct 15, 2021 at 8:58 AM Denis Pauk <pauk.denis@gmail.com> wrote:
>>
>> Linux HWMON sensors driver for ASUS motherboards to read
>> sensors from the embedded controller.
>>
>> Many ASUS motherboards do not publish all the available
>> sensors via the Super I/O chip but the missing ones are
>> available through the embedded controller (EC) registers.
>>
>> This driver implements reading those sensor data via the
>> WMI method BREC, which is known to be present in all ASUS
>> motherboards based on the AMD 500 series chipsets (and
>> probably is available in other models too). The driver
>> needs to know exact register addresses for the sensors and
>> thus support for each motherboard has to be added explicitly.
>>
>> The EC registers do not provide critical values for the
>> sensors and as such they are not published to the HWMON.
>>
>> Supported motherboards:
>> * PRIME X570-PRO
>> * Pro WS X570-ACE
>> * ROG CROSSHAIR VIII HERO
>> * ROG CROSSHAIR VIII DARK HERO
>> * ROG CROSSHAIR VIII FORMULA
>> * ROG STRIX X570-E GAMING
>> * ROG STRIX B550-E GAMING
>
> ...
>
>> Reported-by: kernel test robot <lkp@intel.com>
>
> New code can't be reported as regression. Or what did you mean by that?
>
Some people include that after 0-day reported a bug in an earlier
revision of the patch. No idea why (it's like expecting submitters
to add "Reported-by:" for everyone providing code review feedback).

Guenter

> ...
>
>> +Kernel driver asus-wmi-ec-sensors
>> +=================================
>> +
>> +Supported boards:
>> + * PRIME X570-PRO,
>> + * Pro WS X570-ACE,
>> + * ROG CROSSHAIR VIII DARK HERO,
>> + * ROG CROSSHAIR VIII FORMULA,
>> + * ROG CROSSHAIR VIII HERO,
>> + * ROG STRIX B550-E GAMING,
>> + * ROG STRIX X570-E GAMING.
>> +
>
>> +Authors:
>> + Eugene Shalygin <eugene.shalygin@gmail.com>
>
> reST has a special keyword for that.
>
> ...
>
>> +/*
>> + * HWMON driver for ASUS B550/X570 motherboards that publish sensor
>> + * values via the embedded controller registers.
>> + *
>> + * Copyright (C) 2021 Eugene Shalygin <eugene.shalygin@gmail.com>
>> + * Copyright (C) 2018-2019 Ed Brindley <kernel@maidavale.org>
>> + *
>> + * EC provides:
>> + * Chipset temperature,
>> + * CPU temperature,
>> + * Motherboard temperature,
>> + * T_Sensor temperature,
>> + * VRM temperature,
>> + * Water In temperature,
>> + * Water Out temperature,
>> + * CPU Optional Fan RPM,
>> + * Chipset Fan RPM,
>> + * Water Flow Fan RPM,
>> + * CPU current.
>
>> + *
>
> Redundant line.
>
>> + */
>
>> +#include <asm/unaligned.h>
>
> The common rule is to go from generic to particular, hence
> linux/*
> followed by
> asm/*
> followed by local subsystem / local headers like
> linux/hwmon*
>
> with a blank line between each group.
>
>> +#include <linux/acpi.h>
>> +#include <linux/dmi.h>
>> +#include <linux/hwmon.h>
>> +#include <linux/hwmon-sysfs.h>
>> +#include <linux/init.h>
>> +#include <linux/jiffies.h>
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/mutex.h>
>> +#include <linux/nls.h>
>> +#include <linux/units.h>
>> +#include <linux/wmi.h>
>
> ...
>
>> +/* BLOCK_READ_EC */
>
> Not sure what this means, but...
>
>> +#define ASUSWMI_METHODID_BREC 0x42524543
>
> ...above has definitely an ASCII combination in hex format, care to
> decode it in the comment?
>
> ...
>
>> +/* from the ASUS DSDT source */
>
> Keep the same style for all comments, i.e. here "From ..."
>
> ...
>
>> +#define MAKE_SENSOR_ADDRESS(size_i, bank_i, index_i) \
>> + { .size = size_i,\
>> + .bank = bank_i,\
>> + .index = index_i}
>
> You should choose one style for all macros. Here is one, there is
> another... I would recommend to use one of
>
> #define ... { \
> ... \
> }
>
> or
>
> #define ... \
> { \
> ... \
> }
>
> In the second case the indentation of the {} is defined by the
> semantics of the macro: in case of function-like macro it starts from
> the first column, in case of data structure filler usually with one
> TAB.
>
> ...
>
>> +/*
>> + * All the known sensors for ASUS EC controllers
>> + */
>
> One line and "All known sensors..."
>
> ...
>
>> +struct asus_wmi_ec_info {
>> + struct ec_sensor sensors[SENSOR_MAX];
>
>> + char read_arg[((ASUSWMI_BREC_REGISTERS_MAX * 4) + 1) * 2];
>
> Too many parentheses.
>
>> + u8 read_buffer[ASUSWMI_BREC_REGISTERS_MAX];
>> + unsigned int nr_sensors;
>> + unsigned int nr_registers;
>> + unsigned long last_updated;
>> +};
>
> ...
>
>> + for (i = 0; i < SENSOR_MAX && bsi[i] != SENSOR_MAX; i++) {
>> + s[i].info_index = bsi[i];
>
>> + s[i].cached_value = 0;
>
> Isn't it filled by kzalloc() or alike?
>
>> + ec->nr_sensors++;
>> + ec->nr_registers += known_ec_sensors[bsi[i]].addr.size;
>> + }
>
> ...
>
>> +/*
>> + * The next four functions converts to/from BRxx string argument format
>> + * The format of the string is as follows:
>> + * The string consists of two-byte UTF-16 characters
>> + * The value of the very first byte int the string is equal to the total length
>> + * of the next string in bytes, thus excluding the first two-byte character
>> + * The rest of the string encodes pairs of (bank, index) pairs, where both
>> + * values are byte-long (0x00 to 0xFF)
>> + * Numbers are encoded as UTF-16 hex values
>
> The comment above misses a lot of punctuation. Also it would be nice
> to indent the list of items if any and so on.
>
>> + */
>> +static void asus_wmi_ec_decode_reply_buffer(const u8 *inp, u8 *out, u32 length)
>> +{
>> + char buffer[ASUSWMI_MAX_BUF_LEN * 2];
>> + const char *pos = buffer;
>> + const u8 *data = inp + 2;
>> + unsigned int i;
>> + u32 len;
>
>> + len = min3((u32)ASUSWMI_MAX_BUF_LEN, (length - 2) / 4, (u32)inp[0] / 4);
>
> Instead I would prefer to have to min_t() calls without adding castings.
> Also might be useful to have a short comment explaining this choice.
>
>> + utf16s_to_utf8s((wchar_t *)data, len * 2, UTF16_LITTLE_ENDIAN, buffer, len * 2);
>
>> + for (i = 0; i < len; i++, pos += 2)
>> + out[i] = (hex_to_bin(pos[0]) << 4) + hex_to_bin(pos[1]);
>
> NIH hex2bin().
>
>> +}
>
> ...
>
>> + for (i = 0; i < len; i++) {
>> + byte = registers[i] >> 8;
>> + *pos = hex_asc_hi(byte);
>> + pos++;
>> + *pos = hex_asc_lo(byte);
>> + pos++;
>> + byte = registers[i];
>> + *pos = hex_asc_hi(byte);
>> + pos++;
>> + *pos = hex_asc_lo(byte);
>> + pos++;
>> + }
>
> NIH bin2hex()
>
> ...
>
>> + for (j = 0; j < si->addr.size;
>> + j++, register_idx++) {
>
> One line.
>
>> + registers[register_idx] = (si->addr.bank << 8) + si->addr.index + j;
>> + }
>
> ...
>
>> + /* the first byte of the BRxx() argument string has to be the string size */
>
> Comment style.
>
> ...
>
>> + input.length = (acpi_size)query[0] + 2;
>
> Why is casting needed?
>
> ...
>
>> + status = wmi_evaluate_method(ASUSWMI_MONITORING_GUID, 0, method_id, &input,
>> + &output);
>
> Logically better to keep &input and &output on the same line, i.e.
> second one here.
>
>> + obj = output.pointer;
>> + if (!obj || obj->type != ACPI_TYPE_BUFFER) {
>
>> + acpi_os_free(obj);
>
> What's the point of calling acpi_os_free(obj) when you already know it's NULL?
>
> On top of that is the acpi_os_free() high-level enough API for this?
>
>> + return -EIO;
>> + }
>> + asus_wmi_ec_decode_reply_buffer(obj->buffer.pointer, out, obj->buffer.length);
>
>> + acpi_os_free(obj);
>
> Ditto.
>
> ...
>
>> + switch (data_type) {
>> + case hwmon_curr:
>> + case hwmon_temp:
>> + case hwmon_in:
>
>> + return value * KILO;
>
> Thanks for using KILO, but do you think it's the correct one and not MILLI?
> MILLI means that we got value in <units> and we would like to convert
> it to <milliunits>.
> KILO would mean the opposite, like we got in <milliunits> and we would
> like to have <units>.
>
>> + default:
>> + return value;
>> + }
>
> ...
>
>> +/*
>> + * Now follow the functions that implement the hwmon interface
>> + */
>
> One line.
>
> ...
>
>> + int index;
>> + const struct asus_wmi_sensors *sensor_data = drvdata;
>
> Here and elsewhere, perhaps reversed xmas tree order?
>
> ...
>
>> + int nr_count[hwmon_max] = { 0 }, nr_types = 0;
>
> {} will work as well.
>
> ...
>
>> + /*
>> + * if we can get values for all the registers in a single query,
>> + * the query will not change from call to call
>
> "If..."
> And period at the end since it's a multi-line comment.
>
>> + */
>
> ...
>
>> + sensor_data = devm_kzalloc(dev, sizeof(struct asus_wmi_sensors),
>> + GFP_KERNEL);
>
> One line?
>
> ...
>
>> + /* ec init */
>
> Usefulness of this comment?
>
>> + return asus_wmi_ec_configure_sensor_setup(dev,
>> + sensor_data, bsi);
>
> One line?
>
> ...
>
>> + .driver = {
>
>> + .name = KBUILD_MODNAME,
>
> It's kinda semi-ABI, please be not dependent on compile-time variables.
>
>> + },
>

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