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Commit 23fdbdd7 authored by Sean Paul's avatar Sean Paul
Browse files

drm/i915: Add more control to wait_for routines 



This patch adds a little more control to a couple wait_for routines such
that we can avoid open-coding read/wait/timeout patterns which:
 - need the value of the register after the wait_for
 - run arbitrary operation for the read portion

This patch also chooses the correct sleep function (based on
timers-howto.txt) for the polling interval the caller specifies.

Changes in v2:
- Added to the series
Changes in v3:
- Rebased on drm-intel-next-queued and the new Wmin/max _wait_for
- Removed msleep option
Changes in v4:
- Removed ; for OP in _wait_for (Chris)
- Moved reg_value definition above ret (Chris)
Changes in v4:
- checkpatch whitespace fix
Changes in v5:
- None
Changes in v6:
- None

Suggested-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: default avatarSean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20180108195545.218615-3-seanpaul@chromium.org
parent 716719a3

drivers/gpu/drm/i915/intel_drv.h

+10 −7
Original line number Diff line number Diff line
@@ -41,20 +41,21 @@ 
#include <drm/drm_atomic.h>



/**

 * _wait_for - magic (register) wait macro

 * __wait_for - magic wait macro

 *

 * Does the right thing for modeset paths when run under kdgb or similar atomic

 * contexts. Note that it's important that we check the condition again after

 * having timed out, since the timeout could be due to preemption or similar and

 * we've never had a chance to check the condition before the timeout.

 * Macro to help avoid open coding check/wait/timeout patterns. Note that it's

 * important that we check the condition again after having timed out, since the

 * timeout could be due to preemption or similar and we've never had a chance to

 * check the condition before the timeout.

 */

#define _wait_for(COND, US, Wmin, Wmax) ({ \

#define __wait_for(OP, COND, US, Wmin, Wmax) ({ \

	unsigned long timeout__ = jiffies + usecs_to_jiffies(US) + 1;	\

	long wait__ = (Wmin); /* recommended min for usleep is 10 us */	\

	int ret__;							\

	might_sleep();							\

	for (;;) {							\

		bool expired__ = time_after(jiffies, timeout__);	\

		OP;							\

		if (COND) {						\

			ret__ = 0;					\

			break;						\
@@ -70,6 +71,8 @@ 
	ret__;								\

})



#define _wait_for(COND, US, Wmin, Wmax)	__wait_for(, (COND), (US), (Wmin), \

						   (Wmax))

#define wait_for(COND, MS)		_wait_for((COND), (MS) * 1000, 10, 1000)



/* If CONFIG_PREEMPT_COUNT is disabled, in_atomic() always reports false. */

drivers/gpu/drm/i915/intel_uncore.c

+16 −7
Original line number Diff line number Diff line
@@ -1767,12 +1767,14 @@ int __intel_wait_for_register_fw(struct drm_i915_private *dev_priv, 
}



/**

 * intel_wait_for_register - wait until register matches expected state

 * __intel_wait_for_register - wait until register matches expected state

 * @dev_priv: the i915 device

 * @reg: the register to read

 * @mask: mask to apply to register value

 * @value: expected value

 * @timeout_ms: timeout in millisecond

 * @fast_timeout_us: fast timeout in microsecond for atomic/tight wait

 * @slow_timeout_ms: slow timeout in millisecond

 * @out_value: optional placeholder to hold registry value

 *

 * This routine waits until the target register @reg contains the expected

 * @value after applying the @mask, i.e. it waits until ::
@@ -1783,14 +1785,17 @@ int __intel_wait_for_register_fw(struct drm_i915_private *dev_priv, 
 *

 * Returns 0 if the register matches the desired condition, or -ETIMEOUT.

 */

int intel_wait_for_register(struct drm_i915_private *dev_priv,

int __intel_wait_for_register(struct drm_i915_private *dev_priv,

			    i915_reg_t reg,

			    u32 mask,

			    u32 value,

			    unsigned int timeout_ms)

			    unsigned int fast_timeout_us,

			    unsigned int slow_timeout_ms,

			    u32 *out_value)

{

	unsigned fw =

		intel_uncore_forcewake_for_reg(dev_priv, reg, FW_REG_READ);

	u32 reg_value;

	int ret;



	might_sleep();
@@ -1800,14 +1805,18 @@ int intel_wait_for_register(struct drm_i915_private *dev_priv, 


	ret = __intel_wait_for_register_fw(dev_priv,

					   reg, mask, value,

					   2, 0, NULL);

					   fast_timeout_us, 0, &reg_value);



	intel_uncore_forcewake_put__locked(dev_priv, fw);

	spin_unlock_irq(&dev_priv->uncore.lock);



	if (ret)

		ret = wait_for((I915_READ_NOTRACE(reg) & mask) == value,

			       timeout_ms);

		ret = __wait_for(reg_value = I915_READ_NOTRACE(reg),

				 (reg_value & mask) == value,

				 slow_timeout_ms * 1000, 10, 1000);



	if (out_value)

		*out_value = reg_value;



	return ret;

}

drivers/gpu/drm/i915/intel_uncore.h

+13 −1
Original line number Diff line number Diff line
@@ -163,11 +163,23 @@ void intel_uncore_forcewake_put__locked(struct drm_i915_private *dev_priv, 
void intel_uncore_forcewake_user_get(struct drm_i915_private *dev_priv);

void intel_uncore_forcewake_user_put(struct drm_i915_private *dev_priv);



int __intel_wait_for_register(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(struct drm_i915_private *dev_priv,

			    i915_reg_t reg,

			    u32 mask,

			    u32 value,

			    unsigned int timeout_ms);

			    unsigned int timeout_ms)

{

	return __intel_wait_for_register(dev_priv, reg, mask, value, 2,

					 timeout_ms, NULL);

}

int __intel_wait_for_register_fw(struct drm_i915_private *dev_priv,

				 i915_reg_t reg,

				 u32 mask,