1 files changed, 279 insertions, 0 deletions
diff --git a/drivers/gpu/drm/xe/xe_guc_id_mgr.c b/drivers/gpu/drm/xe/xe_guc_id_mgr.c
new file mode 100644
index 000000000000..0fb7c6b78c31
--- /dev/null
+++ b/drivers/gpu/drm/xe/xe_guc_id_mgr.c
@@ -0,0 +1,279 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2024 Intel Corporation
+ */
+
+#include <linux/bitmap.h>
+#include <linux/mutex.h>
+
+#include <drm/drm_managed.h>
+
+#include "xe_assert.h"
+#include "xe_gt_printk.h"
+#include "xe_guc.h"
+#include "xe_guc_id_mgr.h"
+#include "xe_guc_types.h"
+
+static struct xe_guc *idm_to_guc(struct xe_guc_id_mgr *idm)
+{
+	return container_of(idm, struct xe_guc, submission_state.idm);
+}
+
+static struct xe_gt *idm_to_gt(struct xe_guc_id_mgr *idm)
+{
+	return guc_to_gt(idm_to_guc(idm));
+}
+
+static struct xe_device *idm_to_xe(struct xe_guc_id_mgr *idm)
+{
+	return gt_to_xe(idm_to_gt(idm));
+}
+
+#define idm_assert(idm, cond)		xe_gt_assert(idm_to_gt(idm), cond)
+#define idm_mutex(idm)			(&idm_to_guc(idm)->submission_state.lock)
+
+static void idm_print_locked(struct xe_guc_id_mgr *idm, struct drm_printer *p, int indent);
+
+static void __fini_idm(struct drm_device *drm, void *arg)
+{
+	struct xe_guc_id_mgr *idm = arg;
+
+	mutex_lock(idm_mutex(idm));
+
+	if (IS_ENABLED(CONFIG_DRM_XE_DEBUG)) {
+		unsigned int weight = bitmap_weight(idm->bitmap, idm->total);
+
+		if (weight) {
+			struct drm_printer p = xe_gt_info_printer(idm_to_gt(idm));
+
+			xe_gt_err(idm_to_gt(idm), "GUC ID manager unclean (%u/%u)\n",
+				  weight, idm->total);
+			idm_print_locked(idm, &p, 1);
+		}
+	}
+
+	bitmap_free(idm->bitmap);
+	idm->bitmap = NULL;
+	idm->total = 0;
+	idm->used = 0;
+
+	mutex_unlock(idm_mutex(idm));
+}
+
+/**
+ * xe_guc_id_mgr_init() - Initialize GuC context ID Manager.
+ * @idm: the &xe_guc_id_mgr to initialize
+ * @limit: number of IDs to manage
+ *
+ * The bare-metal or PF driver can pass ~0 as &limit to indicate that all
+ * context IDs supported by the GuC firmware are available for use.
+ *
+ * Only VF drivers will have to provide explicit number of context IDs
+ * that they can use.
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int xe_guc_id_mgr_init(struct xe_guc_id_mgr *idm, unsigned int limit)
+{
+	int ret;
+
+	idm_assert(idm, !idm->bitmap);
+	idm_assert(idm, !idm->total);
+	idm_assert(idm, !idm->used);
+
+	if (limit == ~0)
+		limit = GUC_ID_MAX;
+	else if (limit > GUC_ID_MAX)
+		return -ERANGE;
+	else if (!limit)
+		return -EINVAL;
+
+	idm->bitmap = bitmap_zalloc(limit, GFP_KERNEL);
+	if (!idm->bitmap)
+		return -ENOMEM;
+	idm->total = limit;
+
+	ret = drmm_add_action_or_reset(&idm_to_xe(idm)->drm, __fini_idm, idm);
+	if (ret)
+		return ret;
+
+	xe_gt_info(idm_to_gt(idm), "using %u GUC ID(s)\n", idm->total);
+	return 0;
+}
+
+static unsigned int find_last_zero_area(unsigned long *bitmap,
+					unsigned int total,
+					unsigned int count)
+{
+	unsigned int found = total;
+	unsigned int rs, re, range;
+
+	for_each_clear_bitrange(rs, re, bitmap, total) {
+		range = re - rs;
+		if (range < count)
+			continue;
+		found = rs + (range - count);
+	}
+	return found;
+}
+
+static int idm_reserve_chunk_locked(struct xe_guc_id_mgr *idm,
+				    unsigned int count, unsigned int retain)
+{
+	int id;
+
+	idm_assert(idm, count);
+	lockdep_assert_held(idm_mutex(idm));
+
+	if (!idm->total)
+		return -ENODATA;
+
+	if (retain) {
+		/*
+		 * For IDs reservations (used on PF for VFs) we want to make
+		 * sure there will be at least 'retain' available for the PF
+		 */
+		if (idm->used + count + retain > idm->total)
+			return -EDQUOT;
+		/*
+		 * ... and we want to reserve highest IDs close to the end.
+		 */
+		id = find_last_zero_area(idm->bitmap, idm->total, count);
+	} else {
+		/*
+		 * For regular IDs reservations (used by submission code)
+		 * we start searching from the lower range of IDs.
+		 */
+		id = bitmap_find_next_zero_area(idm->bitmap, idm->total, 0, count, 0);
+	}
+	if (id >= idm->total)
+		return -ENOSPC;
+
+	bitmap_set(idm->bitmap, id, count);
+	idm->used += count;
+
+	return id;
+}
+
+static void idm_release_chunk_locked(struct xe_guc_id_mgr *idm,
+				     unsigned int start, unsigned int count)
+{
+	idm_assert(idm, count);
+	idm_assert(idm, count <= idm->used);
+	idm_assert(idm, start < idm->total);
+	idm_assert(idm, start + count - 1 < idm->total);
+	lockdep_assert_held(idm_mutex(idm));
+
+	if (IS_ENABLED(CONFIG_DRM_XE_DEBUG)) {
+		unsigned int n;
+
+		for (n = 0; n < count; n++)
+			idm_assert(idm, test_bit(start + n, idm->bitmap));
+	}
+	bitmap_clear(idm->bitmap, start, count);
+	idm->used -= count;
+}
+
+/**
+ * xe_guc_id_mgr_reserve_locked() - Reserve one or more GuC context IDs.
+ * @idm: the &xe_guc_id_mgr
+ * @count: number of IDs to allocate (can't be 0)
+ *
+ * This function is dedicated for the use by the GuC submission code,
+ * where submission lock is already taken.
+ *
+ * Return: ID of allocated GuC context or a negative error code on failure.
+ */
+int xe_guc_id_mgr_reserve_locked(struct xe_guc_id_mgr *idm, unsigned int count)
+{
+	return idm_reserve_chunk_locked(idm, count, 0);
+}
+
+/**
+ * xe_guc_id_mgr_release_locked() - Release one or more GuC context IDs.
+ * @idm: the &xe_guc_id_mgr
+ * @id: the GuC context ID to release
+ * @count: number of IDs to release (can't be 0)
+ *
+ * This function is dedicated for the use by the GuC submission code,
+ * where submission lock is already taken.
+ */
+void xe_guc_id_mgr_release_locked(struct xe_guc_id_mgr *idm, unsigned int id,
+				  unsigned int count)
+{
+	return idm_release_chunk_locked(idm, id, count);
+}
+
+/**
+ * xe_guc_id_mgr_reserve() - Reserve a range of GuC context IDs.
+ * @idm: the &xe_guc_id_mgr
+ * @count: number of GuC context IDs to reserve (can't be 0)
+ * @retain: number of GuC context IDs to keep available (can't be 0)
+ *
+ * This function is dedicated for the use by the PF driver which expects that
+ * reserved range of IDs will be contiguous and that there will be at least
+ * &retain IDs still available for the PF after this reservation.
+ *
+ * Return: starting ID of the allocated GuC context ID range or
+ *         a negative error code on failure.
+ */
+int xe_guc_id_mgr_reserve(struct xe_guc_id_mgr *idm,
+			  unsigned int count, unsigned int retain)
+{
+	int ret;
+
+	idm_assert(idm, count);
+	idm_assert(idm, retain);
+
+	mutex_lock(idm_mutex(idm));
+	ret = idm_reserve_chunk_locked(idm, count, retain);
+	mutex_unlock(idm_mutex(idm));
+
+	return ret;
+}
+
+/**
+ * xe_guc_id_mgr_release() - Release a range of GuC context IDs.
+ * @idm: the &xe_guc_id_mgr
+ * @start: the starting ID of GuC context range to release
+ * @count: number of GuC context IDs to release
+ */
+void xe_guc_id_mgr_release(struct xe_guc_id_mgr *idm,
+			   unsigned int start, unsigned int count)
+{
+	mutex_lock(idm_mutex(idm));
+	idm_release_chunk_locked(idm, start, count);
+	mutex_unlock(idm_mutex(idm));
+}
+
+static void idm_print_locked(struct xe_guc_id_mgr *idm, struct drm_printer *p, int indent)
+{
+	unsigned int rs, re;
+
+	lockdep_assert_held(idm_mutex(idm));
+
+	drm_printf_indent(p, indent, "total %u\n", idm->total);
+	if (!idm->bitmap)
+		return;
+
+	drm_printf_indent(p, indent, "used %u\n", idm->used);
+	for_each_set_bitrange(rs, re, idm->bitmap, idm->total)
+		drm_printf_indent(p, indent, "range %u..%u (%u)\n", rs, re - 1, re - rs);
+}
+
+/**
+ * xe_guc_id_mgr_print() - Print status of GuC ID Manager.
+ * @idm: the &xe_guc_id_mgr to print
+ * @p: the &drm_printer to print to
+ * @indent: tab indentation level
+ */
+void xe_guc_id_mgr_print(struct xe_guc_id_mgr *idm, struct drm_printer *p, int indent)
+{
+	mutex_lock(idm_mutex(idm));
+	idm_print_locked(idm, p, indent);
+	mutex_unlock(idm_mutex(idm));
+}
+
+#if IS_BUILTIN(CONFIG_DRM_XE_KUNIT_TEST)
+#include "tests/xe_guc_id_mgr_test.c"
+#endif