Commit 851435ec authored by Matt Roper's avatar Matt Roper
Browse files

drm/i915/gt: Add intel_gt_mcr_multicast_rmw() operation 



There are cases where we wish to read from any non-terminated MCR
register instance (or the primary instance in the case of GAM ranges),
clear/set some bits, and then write the value back out to the register
in a multicast manner.  Adding a "multicast RMW" will avoid the need to
open-code this.

v2:
 - Return a u32 to align with the recent change to intel_uncore_rmw.

Signed-off-by: default avatarMatt Roper <matthew.d.roper@intel.com>
Reviewed-by: default avatarBalasubramani Vivekanandan <balasubramani.vivekanandan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221014230239.1023689-6-matthew.d.roper@intel.com
parent e4abeab9

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

+28 −0
Original line number Diff line number Diff line
@@ -302,6 +302,34 @@ void intel_gt_mcr_multicast_write_fw(struct intel_gt *gt, i915_reg_t reg, u32 va 
	intel_uncore_write_fw(gt->uncore, reg, value);

}



/**

 * intel_gt_mcr_multicast_rmw - Performs a multicast RMW operations

 * @gt: GT structure

 * @reg: the MCR register to read and write

 * @clear: bits to clear during RMW

 * @set: bits to set during RMW

 *

 * Performs a read-modify-write on an MCR register in a multicast manner.

 * This operation only makes sense on MCR registers where all instances are

 * expected to have the same value.  The read will target any non-terminated

 * instance and the write will be applied to all instances.

 *

 * This function assumes the caller is already holding any necessary forcewake

 * domains; use intel_gt_mcr_multicast_rmw() in cases where forcewake should

 * be obtained automatically.

 *

 * Returns the old (unmodified) value read.

 */

u32 intel_gt_mcr_multicast_rmw(struct intel_gt *gt, i915_reg_t reg,

			       u32 clear, u32 set)

{

	u32 val = intel_gt_mcr_read_any(gt, reg);



	intel_gt_mcr_multicast_write(gt, reg, (val & ~clear) | set);



	return val;

}



/*

 * reg_needs_read_steering - determine whether a register read requires

 *     explicit steering

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

+3 −0
Original line number Diff line number Diff line
@@ -24,6 +24,9 @@ void intel_gt_mcr_multicast_write(struct intel_gt *gt, 
void intel_gt_mcr_multicast_write_fw(struct intel_gt *gt,

				     i915_reg_t reg, u32 value);



u32 intel_gt_mcr_multicast_rmw(struct intel_gt *gt, i915_reg_t reg,

			       u32 clear, u32 set);



void intel_gt_mcr_get_nonterminated_steering(struct intel_gt *gt,

					     i915_reg_t reg,

					     u8 *group, u8 *instance);