Commit 42a71bba authored by Nirmoy Das's avatar Nirmoy Das
Browse files

drm/i915: Introduce intel_gt_mcr_lock_sanitize() 



Implement intel_gt_mcr_lock_sanitize() to provide a mechanism
for cleaning the steer semaphore when absolutely necessary.

v2: remove unnecessary lock(Andi, Matt)
    improve the kernel doc(Matt)
    s/intel_gt_mcr_lock_clear/intel_gt_mcr_lock_sanitize

Signed-off-by: default avatarNirmoy Das <nirmoy.das@intel.com>
Reviewed-by: default avatarAndi Shyti <andi.shyti@linux.intel.com>
Reviewed-by: default avatarMatt Roper <matthew.d.roper@intel.com>
Reviewed-by: default avatarAndrzej Hajda <andrzej.hajda@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230928130015.6758-1-nirmoy.das@intel.com
parent 03d68141

drivers/gpu/drm/i915/gt/intel_gt_mcr.c

+22 −0
Original line number Diff line number Diff line
@@ -419,6 +419,28 @@ void intel_gt_mcr_unlock(struct intel_gt *gt, unsigned long flags) 
		intel_uncore_write_fw(gt->uncore, MTL_STEER_SEMAPHORE, 0x1);

}



/**

 * intel_gt_mcr_lock_sanitize - Sanitize MCR steering lock

 * @gt: GT structure

 *

 * This will be used to sanitize the initial status of the hardware lock

 * during driver load and resume since there won't be any concurrent access

 * from other agents at those times, but it's possible that boot firmware

 * may have left the lock in a bad state.

 *

 */

void intel_gt_mcr_lock_sanitize(struct intel_gt *gt)

{

	/*

	 * This gets called at load/resume time, so we shouldn't be

	 * racing with other driver threads grabbing the mcr lock.

	 */

	lockdep_assert_not_held(&gt->mcr_lock);



	if (GRAPHICS_VER_FULL(gt->i915) >= IP_VER(12, 70))

		intel_uncore_write_fw(gt->uncore, MTL_STEER_SEMAPHORE, 0x1);

}



/**

 * intel_gt_mcr_read - read a specific instance of an MCR register

 * @gt: GT structure

drivers/gpu/drm/i915/gt/intel_gt_mcr.h

+1 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
void intel_gt_mcr_init(struct intel_gt *gt);

void intel_gt_mcr_lock(struct intel_gt *gt, unsigned long *flags);

void intel_gt_mcr_unlock(struct intel_gt *gt, unsigned long flags);

void intel_gt_mcr_lock_sanitize(struct intel_gt *gt);



u32 intel_gt_mcr_read(struct intel_gt *gt,

		      i915_mcr_reg_t reg,