Hi Badal,
On Wed, Aug 02, 2023 at 07:22:37PM +0530, Badal Nilawar wrote:
> Expose power_max (pl1) and power_rated_max (tdp) attributes.
can you please write a few words more here to explain the
interface being exposed and what these powers are?
> +/* SPDX-License-Identifier: MIT */
> +/*
> + * Copyright © 2023 Intel Corporation
> + */
> +
> +#ifndef _XE_MCHBAR_REGS_H__
> +#define _XE_MCHBAR_REGS_H_
there is an extra '_' in the ifndef
> +
[...]
> #include <linux/hwmon.h>
>
> #include <drm/drm_managed.h>
> +#include "regs/xe_mchbar_regs.h"
> #include "regs/xe_gt_regs.h"
> #include "xe_device.h"
> #include "xe_hwmon.h"
> +#include "xe_mmio.h"
> +#include "xe_gt.h"
can we keep these in alphabetical order?
> +enum hwmon_reg_name {
> + REG_PKG_RAPL_LIMIT,
> + REG_PKG_POWER_SKU,
> + REG_PKG_POWER_SKU_UNIT,
> +};
Are these names or id's? With name I understand string/
> +enum hwmon_reg_operation {
> + REG_READ,
> + REG_WRITE,
> + REG_RMW,
> +};
I'm not checking on the prefixes here... I let someone more
experienced than me comment if there anything wrong.
> +/*
> + * SF_* - scale factors for particular quantities according to hwmon spec.
> + * - power - microwatts
> + */
this comment looks a bit off to me, what does
" - power - microwatts" stand for?
> +#define SF_POWER 1000000
>
> struct xe_hwmon_data {
> struct device *hwmon_dev;
> @@ -18,13 +39,268 @@ struct xe_hwmon_data {
>
> struct xe_hwmon {
> struct xe_hwmon_data ddat;
> - struct mutex hwmon_lock;
> + struct mutex hwmon_lock; /* rmw operations*/
please put this change in the previous patch.
> + bool reset_in_progress;
> + wait_queue_head_t waitq;
> + int scl_shift_power;
> };
>
> +#define ddat_to_xe_hwmon(ddat) ({ container_of(ddat, struct xe_hwmon, ddat); })
Any particular reason for the ({ ... }) ?
> +static int process_hwmon_reg(struct xe_hwmon_data *ddat, enum hwmon_reg_name reg_name,
> + enum hwmon_reg_operation operation, u32 *value,
> + u32 clr, u32 set)
> +{
> + struct xe_reg reg;
> + int ret = 0;
> +
> + reg.raw = hwmon_get_reg(ddat, reg_name);
> +
> + if (!reg.raw)
> + return -EOPNOTSUPP;
> +
> + switch (operation) {
> + case REG_READ:
> + *value = xe_mmio_read32(ddat->gt, reg);
> + break;
> + case REG_WRITE:
> + xe_mmio_write32(ddat->gt, reg, *value);
> + break;
> + case REG_RMW:
> + *value = xe_mmio_rmw32(ddat->gt, reg, clr, set);
> + break;
> + default:
> + XE_MISSING_CASE(operation);
> + ret = -EOPNOTSUPP;
you could just return 0 or return -EOPNOTSUPP everywhere and save
"ret" and a return (maybe not needed).
Just a personal preference, feel free to ignro and do as you like
it.
> + break;
> + }
> +
> + return ret;
> +}
[...]
> +static int hwmon_power_max_read(struct xe_hwmon_data *ddat, long *value)
> +{
> + struct xe_hwmon *hwmon = ddat_to_xe_hwmon(ddat);
> + u32 reg_val;
> + u64 r, min, max;
> +
> + process_hwmon_reg(ddat, REG_PKG_RAPL_LIMIT, REG_READ, ®_val, 0, 0);
> + /* Check if PL1 limit is disabled */
> + if (!(reg_val & PKG_PWR_LIM_1_EN)) {
> + *value = PL1_DISABLE;
> + return 0;
> + }
> +
> + reg_val = REG_FIELD_GET(PKG_PWR_LIM_1, reg_val);
> + *value = mul_u64_u32_shr(reg_val, SF_POWER, hwmon->scl_shift_power);
> +
> + process_hwmon_reg_read64(ddat, REG_PKG_POWER_SKU, &r);
> + min = REG_FIELD_GET(PKG_MIN_PWR, r);
> + min = mul_u64_u32_shr(min, SF_POWER, hwmon->scl_shift_power);
> + max = REG_FIELD_GET(PKG_MAX_PWR, r);
> + max = mul_u64_u32_shr(max, SF_POWER, hwmon->scl_shift_power);
> +
> + if (min && max)
> + *value = clamp_t(u64, *value, min, max);
> +
> + return 0;
you are returning '0' in any case, can we make this void?
> +}
> +
> +static inline bool check_reset_in_progress(struct xe_hwmon *hwmon)
> +{
> + mutex_lock(&hwmon->hwmon_lock);
> + if (!hwmon->reset_in_progress)
> + return true;
> + mutex_unlock(&hwmon->hwmon_lock);
> + return false;
This is a bit scary (apart from the indentation) and without a
strong explanation I can't let this go.
I'm pretty sure that we don't need this... can you explain?
> +}
> +
> +static int hwmon_power_max_write(struct xe_hwmon_data *ddat, long value)
> +{
> + struct xe_hwmon *hwmon = ddat_to_xe_hwmon(ddat);
> + DEFINE_WAIT(wait);
> + int ret = 0;
> + u32 nval;
> +
> + /* hwmon->hwmon_lock remain held till rmw operation is over */
> + wait_event(hwmon->waitq, check_reset_in_progress(hwmon));
> +
> + /* Disable PL1 limit and verify, as limit cannot be disabled on all platforms */
> + if (value == PL1_DISABLE) {
> + process_hwmon_reg(ddat, REG_PKG_RAPL_LIMIT, REG_RMW, &nval,
> + PKG_PWR_LIM_1_EN, 0);
> + process_hwmon_reg(ddat, REG_PKG_RAPL_LIMIT, REG_READ, &nval,
> + PKG_PWR_LIM_1_EN, 0);
> +
> + if (nval & PKG_PWR_LIM_1_EN)
> + ret = -ENODEV;
> + goto unlock;
> + }
> +
> + /* Computation in 64-bits to avoid overflow. Round to nearest. */
> + nval = DIV_ROUND_CLOSEST_ULL((u64)value << hwmon->scl_shift_power, SF_POWER);
> + nval = PKG_PWR_LIM_1_EN | REG_FIELD_PREP(PKG_PWR_LIM_1, nval);
> +
> + process_hwmon_reg(ddat, REG_PKG_RAPL_LIMIT, REG_RMW, &nval,
> + PKG_PWR_LIM_1_EN | PKG_PWR_LIM_1, nval);
> +unlock:
> + mutex_unlock(&hwmon->hwmon_lock);
Where is this lock taken? Are you relying on the fact that this
lock might not be taken? In any case it is not allowed to unlock
a without previously locking.
It's very error prone when you lock in a function and unlock in
another function and in the rare cases when this is done it has
to be written in the function name.
> + return 0;
> +}
> +
> +static int hwmon_power_rated_max_read(struct xe_hwmon_data *ddat, long *value)
> +{
> + struct xe_hwmon *hwmon = ddat_to_xe_hwmon(ddat);
> + u32 reg_val;
> +
> + process_hwmon_reg(ddat, REG_PKG_POWER_SKU, REG_READ, ®_val, 0, 0);
> + reg_val = REG_FIELD_GET(PKG_PKG_TDP, reg_val);
> + *value = mul_u64_u32_shr(reg_val, SF_POWER, hwmon->scl_shift_power);
> +
> + return 0;
Can this function be void?
> +}
[...]
> +void xe_hwmon_power_max_disable(struct xe_device *xe, bool *old)
> +{
> + struct xe_hwmon *hwmon = xe->hwmon;
> + struct xe_hwmon_data *ddat = &hwmon->ddat;
> + u32 r;
> +
> + if (!(hwmon && hwmon_get_reg(ddat, REG_PKG_RAPL_LIMIT)))
> + return;
> +
> + xe_device_assert_mem_access(gt_to_xe(ddat->gt));
> +
> + mutex_lock(&hwmon->hwmon_lock);
> +
> + hwmon->reset_in_progress = true;
> +
> + process_hwmon_reg(ddat, REG_PKG_RAPL_LIMIT, REG_RMW, &r,
> + PKG_PWR_LIM_1_EN, 0);
> + *old = !!(r & PKG_PWR_LIM_1_EN);
do we need to place under lock these last to lines?
> + mutex_unlock(&hwmon->hwmon_lock);
> +}
> +
> +void xe_hwmon_power_max_restore(struct xe_device *xe, bool old)
> +{
> + struct xe_hwmon *hwmon = xe->hwmon;
> + struct xe_hwmon_data *ddat = &hwmon->ddat;
> + u32 r;
> +
> + if (!(hwmon && hwmon_get_reg(ddat, REG_PKG_RAPL_LIMIT)))
> + return;
> +
> + xe_device_assert_mem_access(gt_to_xe(ddat->gt));
> +
> + mutex_lock(&hwmon->hwmon_lock);
> +
> + process_hwmon_reg(ddat, REG_PKG_RAPL_LIMIT, REG_RMW, &r,
> + PKG_PWR_LIM_1_EN, old ? PKG_PWR_LIM_1_EN : 0);
> +
> + hwmon->reset_in_progress = false;
> + wake_up_all(&hwmon->waitq);
does the wake up need to be under lock?
Now... does it eve happen that "check_reset_in_progress()"
returns false and therefore unlocks the mutex?
> +
> + mutex_unlock(&hwmon->hwmon_lock);
> +}
[...]
> void xe_hwmon_register(struct xe_device *xe)
> @@ -128,13 +425,16 @@ void xe_hwmon_register(struct xe_device *xe)
>
> hwmon_get_preregistration_info(xe);
>
> + init_waitqueue_head(&hwmon->waitq);
> +
> drm_dbg(&xe->drm, "Register xe hwmon interface\n");
>
> - /* hwmon_dev points to device hwmon<i> */
> + /* hwmon_dev points to device hwmon<i> */
Please this change needs to go in the previous patch.
What is <i>?
> hwmon_dev = devm_hwmon_device_register_with_info(dev, ddat->name,
> ddat,
> &hwmon_chip_info,
> NULL);
> +
This change in the previous patch.
> if (IS_ERR(hwmon_dev)) {
> drm_warn(&xe->drm, "Fail to register xe hwmon, Err:%ld\n", PTR_ERR(hwmon_dev));
> xe->hwmon = NULL;
> diff --git a/drivers/gpu/drm/xe/xe_hwmon.h b/drivers/gpu/drm/xe/xe_hwmon.h
> index a078eeb0a68b..a5dc693569c5 100644
> --- a/drivers/gpu/drm/xe/xe_hwmon.h
> +++ b/drivers/gpu/drm/xe/xe_hwmon.h
> @@ -14,9 +14,13 @@ struct xe_device;
> #if IS_REACHABLE(CONFIG_HWMON)
> void xe_hwmon_register(struct xe_device *xe);
> void xe_hwmon_unregister(struct xe_device *xe);
> +void xe_hwmon_power_max_disable(struct xe_device *xe, bool *old);
> +void xe_hwmon_power_max_restore(struct xe_device *xe, bool old);
> #else
> static inline void xe_hwmon_register(struct xe_device *xe) { };
> static inline void xe_hwmon_unregister(struct xe_device *xe) { };
> +static inline void xe_hwmon_power_max_disable(struct xe_device *xe, bool *old) { };
> +static inline void xe_hwmon_power_max_restore(struct xe_device *xe, bool old) { };
> #endif
>
> #endif /* __XE_HWMON_H__ */
> diff --git a/drivers/gpu/drm/xe/xe_macros.h b/drivers/gpu/drm/xe/xe_macros.h
> index daf56c846d03..030296f8f863 100644
> --- a/drivers/gpu/drm/xe/xe_macros.h
> +++ b/drivers/gpu/drm/xe/xe_macros.h
> @@ -15,4 +15,7 @@
> "Ioctl argument check failed at %s:%d: %s", \
> __FILE__, __LINE__, #cond), 1))
>
> +#define XE_MISSING_CASE(x) WARN(1, "Missing case (%s == %ld)\n", \
> + __stringify(x), (long)(x))
> +
Should this have its own patch?
Andi
> #endif
