linux/drivers/gpu/drm/i915/intel_uncore.h
Chris Wilson c9e0c6da53 drm/i915: Keep the forcewake timer alive for 1ms past the most recent use
Currently the timer is armed for 1ms after the first use and is killed
immediately, dropping the forcewake as early as possible. However, for
very frequent operations the forcewake dance has a large impact on
latency and keeping the timer alive until we are idle is preferred. To
achieve this, if we call intel_uncore_forcewake_get whilst the timer is
alive (repeated use), then set a flag to restart the timer on expiry
rather than drop the forcewake usage count. The timer is racy, the
consequence of the race is to expire the timer earlier than is now
desired but does not impact on correct behaviour. The offset the race
slightly, we set the active flag again on intel_uncore_forcewake_put.

The effect should be to reduce the jitter of reacquiring the fw every
1ms on a busy system. However, the cost is to keep the timer alive for
an extra 1ms on a nearly idle system. We chose to incur the jitter
previously to keep the timer off for as much as possible.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170526132209.14640-1-chris@chris-wilson.co.uk
2017-05-26 15:58:21 +01:00

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C

/*
* Copyright © 2017 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*
*/
#ifndef __INTEL_UNCORE_H__
#define __INTEL_UNCORE_H__
struct drm_i915_private;
enum forcewake_domain_id {
FW_DOMAIN_ID_RENDER = 0,
FW_DOMAIN_ID_BLITTER,
FW_DOMAIN_ID_MEDIA,
FW_DOMAIN_ID_COUNT
};
enum forcewake_domains {
FORCEWAKE_RENDER = BIT(FW_DOMAIN_ID_RENDER),
FORCEWAKE_BLITTER = BIT(FW_DOMAIN_ID_BLITTER),
FORCEWAKE_MEDIA = BIT(FW_DOMAIN_ID_MEDIA),
FORCEWAKE_ALL = (FORCEWAKE_RENDER |
FORCEWAKE_BLITTER |
FORCEWAKE_MEDIA)
};
struct intel_uncore_funcs {
void (*force_wake_get)(struct drm_i915_private *dev_priv,
enum forcewake_domains domains);
void (*force_wake_put)(struct drm_i915_private *dev_priv,
enum forcewake_domains domains);
uint8_t (*mmio_readb)(struct drm_i915_private *dev_priv,
i915_reg_t r, bool trace);
uint16_t (*mmio_readw)(struct drm_i915_private *dev_priv,
i915_reg_t r, bool trace);
uint32_t (*mmio_readl)(struct drm_i915_private *dev_priv,
i915_reg_t r, bool trace);
uint64_t (*mmio_readq)(struct drm_i915_private *dev_priv,
i915_reg_t r, bool trace);
void (*mmio_writeb)(struct drm_i915_private *dev_priv,
i915_reg_t r, uint8_t val, bool trace);
void (*mmio_writew)(struct drm_i915_private *dev_priv,
i915_reg_t r, uint16_t val, bool trace);
void (*mmio_writel)(struct drm_i915_private *dev_priv,
i915_reg_t r, uint32_t val, bool trace);
};
struct intel_forcewake_range {
u32 start;
u32 end;
enum forcewake_domains domains;
};
struct intel_uncore {
spinlock_t lock; /** lock is also taken in irq contexts. */
const struct intel_forcewake_range *fw_domains_table;
unsigned int fw_domains_table_entries;
struct notifier_block pmic_bus_access_nb;
struct intel_uncore_funcs funcs;
unsigned int fifo_count;
enum forcewake_domains fw_domains;
enum forcewake_domains fw_domains_active;
u32 fw_set;
u32 fw_clear;
u32 fw_reset;
struct intel_uncore_forcewake_domain {
enum forcewake_domain_id id;
enum forcewake_domains mask;
unsigned int wake_count;
bool active;
struct hrtimer timer;
i915_reg_t reg_set;
i915_reg_t reg_ack;
} fw_domain[FW_DOMAIN_ID_COUNT];
int unclaimed_mmio_check;
};
/* Iterate over initialised fw domains */
#define for_each_fw_domain_masked(domain__, mask__, dev_priv__, tmp__) \
for (tmp__ = (mask__); \
tmp__ ? (domain__ = &(dev_priv__)->uncore.fw_domain[__mask_next_bit(tmp__)]), 1 : 0;)
#define for_each_fw_domain(domain__, dev_priv__, tmp__) \
for_each_fw_domain_masked(domain__, (dev_priv__)->uncore.fw_domains, dev_priv__, tmp__)
void intel_uncore_sanitize(struct drm_i915_private *dev_priv);
void intel_uncore_init(struct drm_i915_private *dev_priv);
bool intel_uncore_unclaimed_mmio(struct drm_i915_private *dev_priv);
bool intel_uncore_arm_unclaimed_mmio_detection(struct drm_i915_private *dev_priv);
void intel_uncore_fini(struct drm_i915_private *dev_priv);
void intel_uncore_suspend(struct drm_i915_private *dev_priv);
void intel_uncore_resume_early(struct drm_i915_private *dev_priv);
u64 intel_uncore_edram_size(struct drm_i915_private *dev_priv);
void assert_forcewakes_inactive(struct drm_i915_private *dev_priv);
const char *intel_uncore_forcewake_domain_to_str(const enum forcewake_domain_id id);
enum forcewake_domains
intel_uncore_forcewake_for_reg(struct drm_i915_private *dev_priv,
i915_reg_t reg, unsigned int op);
#define FW_REG_READ (1)
#define FW_REG_WRITE (2)
void intel_uncore_forcewake_get(struct drm_i915_private *dev_priv,
enum forcewake_domains domains);
void intel_uncore_forcewake_put(struct drm_i915_private *dev_priv,
enum forcewake_domains domains);
/* Like above but the caller must manage the uncore.lock itself.
* Must be used with I915_READ_FW and friends.
*/
void intel_uncore_forcewake_get__locked(struct drm_i915_private *dev_priv,
enum forcewake_domains domains);
void intel_uncore_forcewake_put__locked(struct drm_i915_private *dev_priv,
enum forcewake_domains domains);
int intel_wait_for_register(struct drm_i915_private *dev_priv,
i915_reg_t reg,
u32 mask,
u32 value,
unsigned int timeout_ms);
int __intel_wait_for_register_fw(struct drm_i915_private *dev_priv,
i915_reg_t reg,
u32 mask,
u32 value,
unsigned int fast_timeout_us,
unsigned int slow_timeout_ms,
u32 *out_value);
static inline
int intel_wait_for_register_fw(struct drm_i915_private *dev_priv,
i915_reg_t reg,
u32 mask,
u32 value,
unsigned int timeout_ms)
{
return __intel_wait_for_register_fw(dev_priv, reg, mask, value,
2, timeout_ms, NULL);
}
#endif /* !__INTEL_UNCORE_H__ */