Hi Badal,
[...]
> +static ssize_t
> +xe_hwmon_power1_max_interval_store(struct device *dev, struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + struct xe_hwmon *hwmon = dev_get_drvdata(dev);
> + u32 x, y, rxy, x_w = 2; /* 2 bits */
> + u64 tau4, r, max_win;
> + unsigned long val;
> + int ret;
> +
> + ret = kstrtoul(buf, 0, &val);
> + if (ret)
> + return ret;
> +
> + /*
> + * Max HW supported tau in '1.x * power(2,y)' format, x = 0, y = 0x12
> + * The hwmon->scl_shift_time default of 0xa results in a max tau of 256 seconds
> + */
> +#define PKG_MAX_WIN_DEFAULT 0x12ull
> +
> + /*
> + * val must be < max in hwmon interface units. The steps below are
> + * explained in xe_hwmon_power1_max_interval_show()
> + */
> + r = FIELD_PREP(PKG_MAX_WIN, PKG_MAX_WIN_DEFAULT);
> + x = REG_FIELD_GET(PKG_MAX_WIN_X, r);
> + y = REG_FIELD_GET(PKG_MAX_WIN_Y, r);
> + tau4 = ((1 << x_w) | x) << y;
> + max_win = mul_u64_u32_shr(tau4, SF_TIME, hwmon->scl_shift_time + x_w);
> +
> + if (val > max_win)
> + return -EINVAL;
> +
> + /* val in hw units */
> + val = DIV_ROUND_CLOSEST_ULL((u64)val << hwmon->scl_shift_time, SF_TIME);
> + /* Convert to 1.x * power(2,y) */
> + if (!val) {
> + /* Avoid ilog2(0) */
> + y = 0;
> + x = 0;
> + } else {
> + y = ilog2(val);
> + /* x = (val - (1 << y)) >> (y - 2); */
this is some spurious development comment, can you please remove
it?
> + x = (val - (1ul << y)) << x_w >> y;
> + }
> +
> + rxy = REG_FIELD_PREP(PKG_PWR_LIM_1_TIME_X, x) | REG_FIELD_PREP(PKG_PWR_LIM_1_TIME_Y, y);
> +
> + xe_device_mem_access_get(gt_to_xe(hwmon->gt));
> +
> + mutex_lock(&hwmon->hwmon_lock);
> +
> + xe_hwmon_process_reg(hwmon, REG_PKG_RAPL_LIMIT, REG_RMW, (u32 *)&r,
> + PKG_PWR_LIM_1_TIME, rxy);
> +
> + mutex_unlock(&hwmon->hwmon_lock);
why are we locking here?
Andi
> +
> + xe_device_mem_access_put(gt_to_xe(hwmon->gt));
> +
> + return count;
> +}
