drm/xe/guc: Add basic KLV encoding helpers

We plan to encode more data as KLVs. Add helpers for that.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Michał Winiarski <michal.winiarski@intel.com>
Link: https://patch.msgid.link/20260707220816.677-4-michal.wajdeczko@intel.com

2 files changed, 59 insertions, 0 deletions

diff --git a/drivers/gpu/drm/xe/xe_guc_klv_helpers.c b/drivers/gpu/drm/xe/xe_guc_klv_helpers.c
index d0663c226e87..667c4c119541 100644
--- a/drivers/gpu/drm/xe/xe_guc_klv_helpers.c
+++ b/drivers/gpu/drm/xe/xe_guc_klv_helpers.c
@@ -189,3 +189,59 @@ int xe_guc_klv_count(const u32 *klvs, u32 num_dwords)
 
 	return num_dwords ? -ENODATA : num_klvs;
 }
+
+static u16 to_num_dwords(size_t size)
+{
+	return round_up(size, sizeof(u32)) / sizeof(u32);
+}
+
+/**
+ * xe_guc_klv_encode_u32() - Encode 32-bit value as KLV.
+ * @klvs: the buffer where to place KLV
+ * @avail: number of dwords (u32) available in the buffer
+ * @key: key to be used
+ * @value: value to be encoded
+ *
+ * Return: pointer to the buffer location past the encoded KLV or
+ *         an ERR_PTR if there was no space to encode the KLV.
+ */
+u32 *xe_guc_klv_encode_u32(u32 *klvs, u32 avail, u16 key, u32 value)
+{
+	u16 len = to_num_dwords(sizeof(u32));
+
+	if (IS_ERR(klvs))
+		return klvs;
+
+	if (avail < GUC_KLV_LEN_MIN + len)
+		return ERR_PTR(-ENOSPC);
+
+	*klvs++ = PREP_GUC_KLV(key, len);
+	*klvs++ = value;
+	return klvs;
+}
+
+/**
+ * xe_guc_klv_encode_u64() - Encode 64-bit value as KLV.
+ * @klvs: the buffer where to place KLV
+ * @avail: number of dwords (u32) available in the buffer
+ * @key: key to be used
+ * @value: value to be encoded
+ *
+ * Return: pointer to the buffer location past the encoded KLV or
+ *         an ERR_PTR if there was no space to encode the KLV.
+ */
+u32 *xe_guc_klv_encode_u64(u32 *klvs, u32 avail, u16 key, u64 value)
+{
+	u16 len = to_num_dwords(sizeof(u64));
+
+	if (IS_ERR(klvs))
+		return klvs;
+
+	if (avail < GUC_KLV_LEN_MIN + len)
+		return ERR_PTR(-ENOSPC);
+
+	*klvs++ = PREP_GUC_KLV(key, len);
+	*klvs++ = lower_32_bits(value);
+	*klvs++ = upper_32_bits(value);
+	return klvs;
+}
diff --git a/drivers/gpu/drm/xe/xe_guc_klv_helpers.h b/drivers/gpu/drm/xe/xe_guc_klv_helpers.h
index c7b7e61c1250..713ef7f7b9f2 100644
--- a/drivers/gpu/drm/xe/xe_guc_klv_helpers.h
+++ b/drivers/gpu/drm/xe/xe_guc_klv_helpers.h
@@ -17,6 +17,9 @@ void xe_guc_klv_print_one(u16 key, u16 len, const u32 *value, struct drm_printer
 void xe_guc_klv_print(const u32 *klvs, u32 num_dwords, struct drm_printer *p);
 int xe_guc_klv_count(const u32 *klvs, u32 num_dwords);
 
+u32 *xe_guc_klv_encode_u32(u32 *klvs, u32 avail, u16 key, u32 value);
+u32 *xe_guc_klv_encode_u64(u32 *klvs, u32 avail, u16 key, u64 value);
+
 /**
  * PREP_GUC_KLV - Prepare KLV header value based on provided key and len.
  * @key: KLV key