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
Suggested-by: Chris Wilson chris@chris-wilson.co.uk Signed-off-by: Sean Paul seanpaul@chromium.org --- drivers/gpu/drm/i915/intel_drv.h | 17 ++++++++++++----- drivers/gpu/drm/i915/intel_uncore.c | 23 ++++++++++++++++------- drivers/gpu/drm/i915/intel_uncore.h | 14 +++++++++++++- 3 files changed, 41 insertions(+), 13 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h index 69aab324aaa1..191c80fc4314 100644 --- a/drivers/gpu/drm/i915/intel_drv.h +++ b/drivers/gpu/drm/i915/intel_drv.h @@ -41,19 +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 + * Macro to help avoid open coding check/wait/timeout patterns, will do the + * right think wrt to choosing msleep vs usleep_range based on how long the wait + * interval is. 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, W) ({ \ +#define __wait_for(OP, COND, US, W) ({ \ unsigned long timeout__ = jiffies + usecs_to_jiffies(US) + 1; \ int ret__; \ might_sleep(); \ for (;;) { \ bool expired__ = time_after(jiffies, timeout__); \ + OP; \ if (COND) { \ ret__ = 0; \ break; \ @@ -62,11 +64,16 @@ ret__ = -ETIMEDOUT; \ break; \ } \ - usleep_range((W), (W) * 2); \ + if (W > (20 * 1000)) \ + msleep(W / 1000); \ + else \ + usleep_range((W), (W) * 2); \ } \ ret__; \ })
+#define _wait_for(COND, US, W) __wait_for(;,(COND), US, W) + #define wait_for(COND, MS) _wait_for((COND), (MS) * 1000, 1000)
/* If CONFIG_PREEMPT_COUNT is disabled, in_atomic() always reports false. */ diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c index b4621271e7a2..c851b0c0602d 100644 --- a/drivers/gpu/drm/i915/intel_uncore.c +++ b/drivers/gpu/drm/i915/intel_uncore.c @@ -1770,12 +1770,14 @@ 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 :: @@ -1786,15 +1788,18 @@ 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); int ret; + u32 reg_value;
might_sleep();
@@ -1803,14 +1808,18 @@ 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, ®_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, 1000); + + if (out_value) + *out_value = reg_value;
return ret; } diff --git a/drivers/gpu/drm/i915/intel_uncore.h b/drivers/gpu/drm/i915/intel_uncore.h index 9ce079b5dd0d..bed019ef000f 100644 --- a/drivers/gpu/drm/i915/intel_uncore.h +++ b/drivers/gpu/drm/i915/intel_uncore.h @@ -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,