Merge tag 'ffa-fix-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux into arm/fixes

Arm FF-A fix for v6.18

The FF-A driver was updated to support specification version 1.2 but omitted
support for the 16-byte implementation-defined (IMPDEF) field introduced in
FF-A v1.2 within the Endpoint Memory Access Descriptor (EMAD). This omission
breaks all memory interfaces.

This change updates the EMAD sizing and offset logic to correctly handle the
FF-A v1.2 layout while preserving backward compatibility with older versions.

* tag 'ffa-fix-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux:
firmware: arm_ffa: Add support for IMPDEF value in the memory access descriptor

Signed-off-by: Arnd Bergmann <[e-mail]>

drivers/firmware/arm_ffa/driver.c

···
 	return FFA_MEM_NORMAL | FFA_MEM_WRITE_BACK | FFA_MEM_INNER_SHAREABLE;
 }
 
+static void ffa_emad_impdef_value_init(u32 version, void *dst, void *src)
+{
+	struct ffa_mem_region_attributes *ep_mem_access;
+
+	if (FFA_EMAD_HAS_IMPDEF_FIELD(version))
+		memcpy(dst, src, sizeof(ep_mem_access->impdef_val));
+}
+
+static void
+ffa_mem_region_additional_setup(u32 version, struct ffa_mem_region *mem_region)
+{
+	if (!FFA_MEM_REGION_HAS_EP_MEM_OFFSET(version)) {
+		mem_region->ep_mem_size = 0;
+	} else {
+		mem_region->ep_mem_size = ffa_emad_size_get(version);
+		mem_region->ep_mem_offset = sizeof(*mem_region);
+		memset(mem_region->reserved, 0, 12);
+	}
+}
+
 static int
 ffa_setup_and_transmit(u32 func_id, void *buffer, u32 max_fragsize,
 		       struct ffa_mem_ops_args *args)
···
 	mem_region->flags = args->flags;
 	mem_region->sender_id = drv_info->vm_id;
 	mem_region->attributes = ffa_memory_attributes_get(func_id);
-	ep_mem_access = buffer +
-			ffa_mem_desc_offset(buffer, 0, drv_info->version);
 	composite_offset = ffa_mem_desc_offset(buffer, args->nattrs,
 					       drv_info->version);
 
-	for (idx = 0; idx < args->nattrs; idx++, ep_mem_access++) {
+	for (idx = 0; idx < args->nattrs; idx++) {
+		ep_mem_access = buffer +
+			ffa_mem_desc_offset(buffer, idx, drv_info->version);
 		ep_mem_access->receiver = args->attrs[idx].receiver;
 		ep_mem_access->attrs = args->attrs[idx].attrs;
 		ep_mem_access->composite_off = composite_offset;
 		ep_mem_access->flag = 0;
 		ep_mem_access->reserved = 0;
+		ffa_emad_impdef_value_init(drv_info->version,
+					   ep_mem_access->impdef_val,
+					   args->attrs[idx].impdef_val);
 	}
 	mem_region->handle = 0;
 	mem_region->ep_count = args->nattrs;
-	if (drv_info->version <= FFA_VERSION_1_0) {
-		mem_region->ep_mem_size = 0;
-	} else {
-		mem_region->ep_mem_size = sizeof(*ep_mem_access);
-		mem_region->ep_mem_offset = sizeof(*mem_region);
-		memset(mem_region->reserved, 0, 12);
-	}
+	ffa_mem_region_additional_setup(drv_info->version, mem_region);
 
 	composite = buffer + composite_offset;
 	composite->total_pg_cnt = ffa_get_num_pages_sg(args->sg);

include/linux/arm_ffa.h

···
 	 * an `struct ffa_mem_region_addr_range`.
 	 */
 	u32 composite_off;
+	u8 impdef_val[16];
 	u64 reserved;
 };
 
···
 #define CONSTITUENTS_OFFSET(x)	\
 	(offsetof(struct ffa_composite_mem_region, constituents[x]))
 
+#define FFA_EMAD_HAS_IMPDEF_FIELD(version)	((version) >= FFA_VERSION_1_2)
+#define FFA_MEM_REGION_HAS_EP_MEM_OFFSET(version) ((version) > FFA_VERSION_1_0)
+
+static inline u32 ffa_emad_size_get(u32 ffa_version)
+{
+	u32 sz;
+	struct ffa_mem_region_attributes *ep_mem_access;
+
+	if (FFA_EMAD_HAS_IMPDEF_FIELD(ffa_version))
+		sz = sizeof(*ep_mem_access);
+	else
+		sz = sizeof(*ep_mem_access) - sizeof(ep_mem_access->impdef_val);
+
+	return sz;
+}
+
 static inline u32
 ffa_mem_desc_offset(struct ffa_mem_region *buf, int count, u32 ffa_version)
 {
-	u32 offset = count * sizeof(struct ffa_mem_region_attributes);
+	u32 offset = count * ffa_emad_size_get(ffa_version);
 	/*
 	 * Earlier to v1.1, the endpoint memory descriptor array started at
 	 * offset 32(i.e. offset of ep_mem_offset in the current structure)
 	 */
-	if (ffa_version <= FFA_VERSION_1_0)
+	if (!FFA_MEM_REGION_HAS_EP_MEM_OFFSET(ffa_version))
 		offset += offsetof(struct ffa_mem_region, ep_mem_offset);
 	else
 		offset += sizeof(struct ffa_mem_region);