drm/xe/display: Implement display support

As for display, the intent is to share the display code with the i915
driver so that there is maximum reuse there.

We do this by recompiling i915/display code twice.
Now that i915 has been adapted to support the Xe build, we can add
the xe/display support.

This initial work is a collaboration of many people and unfortunately
this squashed patch won't fully honor the proper credits.
But let's try to add a few from the squashed patches:

Co-developed-by: Matthew Brost <matthew.brost@intel.com>
Co-developed-by: Jani Nikula <jani.nikula@intel.com>
Co-developed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Co-developed-by: Matt Roper <matthew.d.roper@intel.com>
Co-developed-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Co-developed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Co-developed-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>

2 files changed, 99 insertions, 0 deletions

diff --git a/drivers/gpu/drm/xe/display/ext/i915_irq.c b/drivers/gpu/drm/xe/display/ext/i915_irq.c
new file mode 100644
index 000000000000..bee191a4a97d
--- /dev/null
+++ b/drivers/gpu/drm/xe/display/ext/i915_irq.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2023 Intel Corporation
+ */
+
+#include "i915_drv.h"
+#include "i915_irq.h"
+#include "i915_reg.h"
+#include "intel_uncore.h"
+
+void gen3_irq_reset(struct intel_uncore *uncore, i915_reg_t imr,
+		    i915_reg_t iir, i915_reg_t ier)
+{
+	intel_uncore_write(uncore, imr, 0xffffffff);
+	intel_uncore_posting_read(uncore, imr);
+
+	intel_uncore_write(uncore, ier, 0);
+
+	/* IIR can theoretically queue up two events. Be paranoid. */
+	intel_uncore_write(uncore, iir, 0xffffffff);
+	intel_uncore_posting_read(uncore, iir);
+	intel_uncore_write(uncore, iir, 0xffffffff);
+	intel_uncore_posting_read(uncore, iir);
+}
+
+/*
+ * We should clear IMR at preinstall/uninstall, and just check at postinstall.
+ */
+void gen3_assert_iir_is_zero(struct intel_uncore *uncore, i915_reg_t reg)
+{
+	struct xe_device *xe = container_of(uncore, struct xe_device, uncore);
+	u32 val = intel_uncore_read(uncore, reg);
+
+	if (val == 0)
+		return;
+
+	drm_WARN(&xe->drm, 1,
+		 "Interrupt register 0x%x is not zero: 0x%08x\n",
+		 i915_mmio_reg_offset(reg), val);
+	intel_uncore_write(uncore, reg, 0xffffffff);
+	intel_uncore_posting_read(uncore, reg);
+	intel_uncore_write(uncore, reg, 0xffffffff);
+	intel_uncore_posting_read(uncore, reg);
+}
+
+void gen3_irq_init(struct intel_uncore *uncore,
+		   i915_reg_t imr, u32 imr_val,
+		   i915_reg_t ier, u32 ier_val,
+		   i915_reg_t iir)
+{
+	gen3_assert_iir_is_zero(uncore, iir);
+
+	intel_uncore_write(uncore, ier, ier_val);
+	intel_uncore_write(uncore, imr, imr_val);
+	intel_uncore_posting_read(uncore, imr);
+}
+
+bool intel_irqs_enabled(struct xe_device *xe)
+{
+	/*
+	 * XXX: i915 has a racy handling of the irq.enabled, since it doesn't
+	 * lock its transitions. Because of that, the irq.enabled sometimes
+	 * is not read with the irq.lock in place.
+	 * However, the most critical cases like vblank and page flips are
+	 * properly using the locks.
+	 * We cannot take the lock in here or run any kind of assert because
+	 * of i915 inconsistency.
+	 * But at this point the xe irq is better protected against races,
+	 * although the full solution would be protecting the i915 side.
+	 */
+	return xe->irq.enabled;
+}
+
+void intel_synchronize_irq(struct xe_device *xe)
+{
+	synchronize_irq(to_pci_dev(xe->drm.dev)->irq);
+}
diff --git a/drivers/gpu/drm/xe/display/ext/i915_utils.c b/drivers/gpu/drm/xe/display/ext/i915_utils.c
new file mode 100644
index 000000000000..981edc2788bc
--- /dev/null
+++ b/drivers/gpu/drm/xe/display/ext/i915_utils.c
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2023 Intel Corporation
+ */
+
+#include "i915_drv.h"
+
+bool i915_vtd_active(struct drm_i915_private *i915)
+{
+	if (device_iommu_mapped(i915->drm.dev))
+		return true;
+
+	/* Running as a guest, we assume the host is enforcing VT'd */
+	return i915_run_as_guest();
+}
+
+/* i915 specific, just put here for shutting it up */
+int __i915_inject_probe_error(struct drm_i915_private *i915, int err,
+			      const char *func, int line)
+{
+	return 0;
+}