x86: Simplify the fsp hob access functions

Remove the troublesome union hob_pointers so that some annoying casts
are no longer needed in those hob access routines. This also improves
the readability.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>

5 files changed, 101 insertions, 100 deletions

diff --git a/arch/x86/cpu/queensbay/fsp_support.c b/arch/x86/cpu/queensbay/fsp_support.c
index ef1916b..4764e3c 100644
--- a/arch/x86/cpu/queensbay/fsp_support.c
+++ b/arch/x86/cpu/queensbay/fsp_support.c
@@ -231,26 +231,28 @@ u32 fsp_notify(struct fsp_header *fsp_hdr, u32 phase)
 
 u32 fsp_get_usable_lowmem_top(const void *hob_list)
 {
-	union hob_pointers hob;
+	const struct hob_header *hdr;
+	struct hob_res_desc *res_desc;
 	phys_addr_t phys_start;
 	u32 top;
 
 	/* Get the HOB list for processing */
-	hob.raw = (void *)hob_list;
+	hdr = hob_list;
 
 	/* * Collect memory ranges */
 	top = FSP_LOWMEM_BASE;
-	while (!end_of_hob(hob)) {
-		if (get_hob_type(hob) == HOB_TYPE_RES_DESC) {
-			if (hob.res_desc->type == RES_SYS_MEM) {
-				phys_start = hob.res_desc->phys_start;
+	while (!end_of_hob(hdr)) {
+		if (get_hob_type(hdr) == HOB_TYPE_RES_DESC) {
+			res_desc = (struct hob_res_desc *)hdr;
+			if (res_desc->type == RES_SYS_MEM) {
+				phys_start = res_desc->phys_start;
 				/* Need memory above 1MB to be collected here */
 				if (phys_start >= FSP_LOWMEM_BASE &&
 				    phys_start < (phys_addr_t)FSP_HIGHMEM_BASE)
-					top += (u32)(hob.res_desc->len);
+					top += (u32)(res_desc->len);
 			}
 		}
-		hob.raw = get_next_hob(hob);
+		hdr = get_next_hob(hdr);
 	}
 
 	return top;
@@ -258,25 +260,27 @@ u32 fsp_get_usable_lowmem_top(const void *hob_list)
 
 u64 fsp_get_usable_highmem_top(const void *hob_list)
 {
-	union hob_pointers hob;
+	const struct hob_header *hdr;
+	struct hob_res_desc *res_desc;
 	phys_addr_t phys_start;
 	u64 top;
 
 	/* Get the HOB list for processing */
-	hob.raw = (void *)hob_list;
+	hdr = hob_list;
 
 	/* Collect memory ranges */
 	top = FSP_HIGHMEM_BASE;
-	while (!end_of_hob(hob)) {
-		if (get_hob_type(hob) == HOB_TYPE_RES_DESC) {
-			if (hob.res_desc->type == RES_SYS_MEM) {
-				phys_start = hob.res_desc->phys_start;
+	while (!end_of_hob(hdr)) {
+		if (get_hob_type(hdr) == HOB_TYPE_RES_DESC) {
+			res_desc = (struct hob_res_desc *)hdr;
+			if (res_desc->type == RES_SYS_MEM) {
+				phys_start = res_desc->phys_start;
 				/* Need memory above 1MB to be collected here */
 				if (phys_start >= (phys_addr_t)FSP_HIGHMEM_BASE)
-					top += (u32)(hob.res_desc->len);
+					top += (u32)(res_desc->len);
 			}
 		}
-		hob.raw = get_next_hob(hob);
+		hdr = get_next_hob(hdr);
 	}
 
 	return top;
@@ -285,24 +289,26 @@ u64 fsp_get_usable_highmem_top(const void *hob_list)
 u64 fsp_get_reserved_mem_from_guid(const void *hob_list, u64 *len,
 				   struct efi_guid *guid)
 {
-	union hob_pointers hob;
+	const struct hob_header *hdr;
+	struct hob_res_desc *res_desc;
 
 	/* Get the HOB list for processing */
-	hob.raw = (void *)hob_list;
+	hdr = hob_list;
 
 	/* Collect memory ranges */
-	while (!end_of_hob(hob)) {
-		if (get_hob_type(hob) == HOB_TYPE_RES_DESC) {
-			if (hob.res_desc->type == RES_MEM_RESERVED) {
-				if (compare_guid(&hob.res_desc->owner, guid)) {
+	while (!end_of_hob(hdr)) {
+		if (get_hob_type(hdr) == HOB_TYPE_RES_DESC) {
+			res_desc = (struct hob_res_desc *)hdr;
+			if (res_desc->type == RES_MEM_RESERVED) {
+				if (compare_guid(&res_desc->owner, guid)) {
 					if (len)
-						*len = (u32)(hob.res_desc->len);
+						*len = (u32)(res_desc->len);
 
-					return (u64)(hob.res_desc->phys_start);
+					return (u64)(res_desc->phys_start);
 				}
 			}
 		}
-		hob.raw = get_next_hob(hob);
+		hdr = get_next_hob(hdr);
 	}
 
 	return 0;
@@ -336,44 +342,45 @@ u32 fsp_get_tseg_reserved_mem(const void *hob_list, u32 *len)
 	return base;
 }
 
-void *fsp_get_next_hob(u16 type, const void *hob_list)
+const struct hob_header *fsp_get_next_hob(u16 type, const void *hob_list)
 {
-	union hob_pointers hob;
+	const struct hob_header *hdr;
 
-	assert(hob_list != NULL);
-
-	hob.raw = (u8 *)hob_list;
+	hdr = hob_list;
 
 	/* Parse the HOB list until end of list or matching type is found */
-	while (!end_of_hob(hob)) {
-		if (get_hob_type(hob) == type)
-			return hob.raw;
+	while (!end_of_hob(hdr)) {
+		if (get_hob_type(hdr) == type)
+			return hdr;
 
-		hob.raw = get_next_hob(hob);
+		hdr = get_next_hob(hdr);
 	}
 
 	return NULL;
 }
 
-void *fsp_get_next_guid_hob(const struct efi_guid *guid, const void *hob_list)
+const struct hob_header *fsp_get_next_guid_hob(const struct efi_guid *guid,
+					       const void *hob_list)
 {
-	union hob_pointers hob;
-
-	hob.raw = (u8 *)hob_list;
-	while ((hob.raw = fsp_get_next_hob(HOB_TYPE_GUID_EXT,
-			hob.raw)) != NULL) {
-		if (compare_guid(guid, &hob.guid->name))
+	const struct hob_header *hdr;
+	struct hob_guid *guid_hob;
+
+	hdr = hob_list;
+	while ((hdr = fsp_get_next_hob(HOB_TYPE_GUID_EXT,
+			hdr)) != NULL) {
+		guid_hob = (struct hob_guid *)hdr;
+		if (compare_guid(guid, &(guid_hob->name)))
 			break;
-		hob.raw = get_next_hob(hob);
+		hdr = get_next_hob(hdr);
 	}
 
-	return hob.raw;
+	return hdr;
 }
 
 void *fsp_get_guid_hob_data(const void *hob_list, u32 *len,
 			    struct efi_guid *guid)
 {
-	u8 *guid_hob;
+	const struct hob_header *guid_hob;
 
 	guid_hob = fsp_get_next_guid_hob(guid, hob_list);
 	if (guid_hob == NULL) {
diff --git a/arch/x86/cpu/queensbay/tnc_dram.c b/arch/x86/cpu/queensbay/tnc_dram.c
index 8e97c9b..b669dbc 100644
--- a/arch/x86/cpu/queensbay/tnc_dram.c
+++ b/arch/x86/cpu/queensbay/tnc_dram.c
@@ -14,17 +14,19 @@ DECLARE_GLOBAL_DATA_PTR;
 int dram_init(void)
 {
 	phys_size_t ram_size = 0;
-	union hob_pointers hob;
+	const struct hob_header *hdr;
+	struct hob_res_desc *res_desc;
 
-	hob.raw = gd->arch.hob_list;
-	while (!end_of_hob(hob)) {
-		if (get_hob_type(hob) == HOB_TYPE_RES_DESC) {
-			if (hob.res_desc->type == RES_SYS_MEM ||
-			    hob.res_desc->type == RES_MEM_RESERVED) {
-				ram_size += hob.res_desc->len;
+	hdr = gd->arch.hob_list;
+	while (!end_of_hob(hdr)) {
+		if (get_hob_type(hdr) == HOB_TYPE_RES_DESC) {
+			res_desc = (struct hob_res_desc *)hdr;
+			if (res_desc->type == RES_SYS_MEM ||
+			    res_desc->type == RES_MEM_RESERVED) {
+				ram_size += res_desc->len;
 			}
 		}
-		hob.raw = get_next_hob(hob);
+		hdr = get_next_hob(hdr);
 	}
 
 	gd->ram_size = ram_size;
@@ -55,22 +57,23 @@ ulong board_get_usable_ram_top(ulong total_size)
 unsigned install_e820_map(unsigned max_entries, struct e820entry *entries)
 {
 	unsigned num_entries = 0;
+	const struct hob_header *hdr;
+	struct hob_res_desc *res_desc;
 
-	union hob_pointers hob;
+	hdr = gd->arch.hob_list;
 
-	hob.raw = gd->arch.hob_list;
+	while (!end_of_hob(hdr)) {
+		if (get_hob_type(hdr) == HOB_TYPE_RES_DESC) {
+			res_desc = (struct hob_res_desc *)hdr;
+			entries[num_entries].addr = res_desc->phys_start;
+			entries[num_entries].size = res_desc->len;
 
-	while (!end_of_hob(hob)) {
-		if (get_hob_type(hob) == HOB_TYPE_RES_DESC) {
-			entries[num_entries].addr = hob.res_desc->phys_start;
-			entries[num_entries].size = hob.res_desc->len;
-
-			if (hob.res_desc->type == RES_SYS_MEM)
+			if (res_desc->type == RES_SYS_MEM)
 				entries[num_entries].type = E820_RAM;
-			else if (hob.res_desc->type == RES_MEM_RESERVED)
+			else if (res_desc->type == RES_MEM_RESERVED)
 				entries[num_entries].type = E820_RESERVED;
 		}
-		hob.raw = get_next_hob(hob);
+		hdr = get_next_hob(hdr);
 		num_entries++;
 	}
 
diff --git a/arch/x86/include/asm/arch-queensbay/fsp/fsp_hob.h b/arch/x86/include/asm/arch-queensbay/fsp/fsp_hob.h
index 380b64e..5110361 100644
--- a/arch/x86/include/asm/arch-queensbay/fsp/fsp_hob.h
+++ b/arch/x86/include/asm/arch-queensbay/fsp/fsp_hob.h
@@ -182,15 +182,6 @@ struct hob_guid {
 	/* GUID specific data goes here */
 };
 
-/* Union of all the possible HOB Types */
-union hob_pointers {
-	struct hob_header	*hdr;
-	struct hob_mem_alloc	*mem_alloc;
-	struct hob_res_desc	*res_desc;
-	struct hob_guid		*guid;
-	u8			*raw;
-};
-
 /**
  * get_hob_type() - return the type of a HOB
  *
@@ -201,9 +192,9 @@ union hob_pointers {
  *
  * @return: HOB type.
  */
-static inline u16 get_hob_type(union hob_pointers hob)
+static inline u16 get_hob_type(const struct hob_header *hdr)
 {
-	return hob.hdr->type;
+	return hdr->type;
 }
 
 /**
@@ -216,9 +207,9 @@ static inline u16 get_hob_type(union hob_pointers hob)
  *
  * @return: HOB length.
  */
-static inline u16 get_hob_length(union hob_pointers hob)
+static inline u16 get_hob_length(const struct hob_header *hdr)
 {
-	return hob.hdr->len;
+	return hdr->len;
 }
 
 /**
@@ -227,13 +218,13 @@ static inline u16 get_hob_length(union hob_pointers hob)
  * This macro returns a pointer to HOB that follows the HOB specified by hob
  * in the HOB List.
  *
- * @hob:    A pointer to a HOB.
+ * @hdr:    A pointer to a HOB.
  *
  * @return: A pointer to the next HOB in the HOB list.
  */
-static inline void *get_next_hob(union hob_pointers hob)
+static inline const struct hob_header *get_next_hob(const struct hob_header *hdr)
 {
-	return (void *)(*(u8 **)&(hob) + get_hob_length(hob));
+	return (const struct hob_header *)((u32)hdr + get_hob_length(hdr));
 }
 
 /**
@@ -243,14 +234,14 @@ static inline void *get_next_hob(union hob_pointers hob)
  * HOB list.  If hob is last HOB in the HOB list, then true is returned.
  * Otherwise, false is returned.
  *
- * @hob:          A pointer to a HOB.
+ * @hdr:          A pointer to a HOB.
  *
- * @retval true:  The HOB specified by hob is the last HOB in the HOB list.
- * @retval false: The HOB specified by hob is not the last HOB in the HOB list.
+ * @retval true:  The HOB specified by hdr is the last HOB in the HOB list.
+ * @retval false: The HOB specified by hdr is not the last HOB in the HOB list.
  */
-static inline bool end_of_hob(union hob_pointers hob)
+static inline bool end_of_hob(const struct hob_header *hdr)
 {
-	return get_hob_type(hob) == HOB_TYPE_EOH;
+	return get_hob_type(hdr) == HOB_TYPE_EOH;
 }
 
 /**
@@ -260,13 +251,13 @@ static inline bool end_of_hob(union hob_pointers hob)
  * This macro returns a pointer to the data buffer in a HOB specified by hob.
  * hob is assumed to be a HOB of type HOB_TYPE_GUID_EXT.
  *
- * @hob:    A pointer to a HOB.
+ * @hdr:    A pointer to a HOB.
  *
  * @return: A pointer to the data buffer in a HOB.
  */
-static inline void *get_guid_hob_data(u8 *hob)
+static inline void *get_guid_hob_data(const struct hob_header *hdr)
 {
-	return (void *)(hob + sizeof(struct hob_guid));
+	return (void *)((u32)hdr + sizeof(struct hob_guid));
 }
 
 /**
@@ -276,14 +267,13 @@ static inline void *get_guid_hob_data(u8 *hob)
  * This macro returns the size, in bytes, of the data buffer in a HOB
  * specified by hob. hob is assumed to be a HOB of type HOB_TYPE_GUID_EXT.
  *
- * @hob:    A pointer to a HOB.
+ * @hdr:    A pointer to a HOB.
  *
  * @return: The size of the data buffer.
  */
-static inline u16 get_guid_hob_data_size(u8 *hob)
+static inline u16 get_guid_hob_data_size(const struct hob_header *hdr)
 {
-	union hob_pointers hob_p = *(union hob_pointers *)hob;
-	return get_hob_length(hob_p) - sizeof(struct hob_guid);
+	return get_hob_length(hdr) - sizeof(struct hob_guid);
 }
 
 /* FSP specific GUID HOB definitions */
diff --git a/arch/x86/include/asm/arch-queensbay/fsp/fsp_support.h b/arch/x86/include/asm/arch-queensbay/fsp/fsp_support.h
index 3ae1b66..2a3e987 100644
--- a/arch/x86/include/asm/arch-queensbay/fsp/fsp_support.h
+++ b/arch/x86/include/asm/arch-queensbay/fsp/fsp_support.h
@@ -145,7 +145,7 @@ u32 fsp_get_tseg_reserved_mem(const void *hob_list, u32 *len);
  *
  * @retval:   A HOB object with matching type; Otherwise NULL.
  */
-void *fsp_get_next_hob(u16 type, const void *hob_list);
+const struct hob_header *fsp_get_next_hob(u16 type, const void *hob_list);
 
 /**
  * Returns the next instance of the matched GUID HOB from the starting HOB.
@@ -155,7 +155,8 @@ void *fsp_get_next_hob(u16 type, const void *hob_list);
  *
  * @retval:   A HOB object with matching GUID; Otherwise NULL.
  */
-void *fsp_get_next_guid_hob(const struct efi_guid *guid, const void *hob_list);
+const struct hob_header *fsp_get_next_guid_hob(const struct efi_guid *guid,
+					       const void *hob_list);
 
 /**
  * This function retrieves a GUID HOB data buffer and size.
diff --git a/arch/x86/lib/cmd_hob.c b/arch/x86/lib/cmd_hob.c
index b552fe6..8d1f038 100644
--- a/arch/x86/lib/cmd_hob.c
+++ b/arch/x86/lib/cmd_hob.c
@@ -28,20 +28,20 @@ static char *hob_type[] = {
 
 int do_hob(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
-	union hob_pointers hob;
+	const struct hob_header *hdr;
 	u16 type;
 	char *desc;
 	int i = 0;
 
-	hob.raw = (u8 *)gd->arch.hob_list;
+	hdr = gd->arch.hob_list;
 
-	printf("HOB list address: 0x%08x\n\n", (unsigned int)hob.raw);
+	printf("HOB list address: 0x%08x\n\n", (unsigned int)hdr);
 
 	printf("No. | Address  | Type                | Length in Bytes\n");
 	printf("----|----------|---------------------|----------------\n");
-	while (!end_of_hob(hob)) {
-		printf("%-3d | %08x | ", i, (unsigned int)hob.raw);
-		type = get_hob_type(hob);
+	while (!end_of_hob(hdr)) {
+		printf("%-3d | %08x | ", i, (unsigned int)hdr);
+		type = get_hob_type(hdr);
 		if (type == HOB_TYPE_UNUSED)
 			desc = "*Unused*";
 		else if (type == HOB_TYPE_EOH)
@@ -50,8 +50,8 @@ int do_hob(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 			desc = hob_type[type];
 		else
 			desc = "*Invalid Type*";
-		printf("%-19s | %-15d\n", desc, get_hob_length(hob));
-		hob.raw = get_next_hob(hob);
+		printf("%-19s | %-15d\n", desc, get_hob_length(hdr));
+		hdr = get_next_hob(hdr);
 		i++;
 	}