[U-Boot] [PATCH v2] cfi_flash: Fix unaligned accesses to cfi_qry structure

[Andrew Gabbasov]

Packed structure cfi_qry contains unaligned 16- and 32-bits members,
accessing which causes problems when cfi_flash driver is compiled with
-munaligned-access option: flash initialization hangs, probably
due to data error.

Since the structure is supposed to replicate the actual data layout
in CFI Flash chips, the alignment issue can't be fixed in the structure.
So, unaligned fields need using of explicit unaligned access macros.

Signed-off-by: Andrew Gabbasov <andrew_gabbasov at mentor.com>
---
 drivers/mtd/cfi_flash.c |   15 +++++++++------
 include/mtd/cfi_flash.h |   18 +++++++++++-------
 2 files changed, 20 insertions(+), 13 deletions(-)

diff --git a/drivers/mtd/cfi_flash.c b/drivers/mtd/cfi_flash.c
index 22d8440..f6759a8 100644
--- a/drivers/mtd/cfi_flash.c
+++ b/drivers/mtd/cfi_flash.c
@@ -38,6 +38,7 @@
 #include <asm/processor.h>
 #include <asm/io.h>
 #include <asm/byteorder.h>
+#include <asm/unaligned.h>
 #include <environment.h>
 #include <mtd/cfi_flash.h>
 #include <watchdog.h>
@@ -1640,9 +1641,10 @@ static void cfi_reverse_geometry(struct cfi_qry *qry)
 	u32 tmp;
 
 	for (i = 0, j = qry->num_erase_regions - 1; i < j; i++, j--) {
-		tmp = qry->erase_region_info[i];
-		qry->erase_region_info[i] = qry->erase_region_info[j];
-		qry->erase_region_info[j] = tmp;
+		tmp = get_unaligned(&(qry->erase_region_info[i]));
+		put_unaligned(get_unaligned(&(qry->erase_region_info[j])),
+			      &(qry->erase_region_info[i]));
+		put_unaligned(tmp, &(qry->erase_region_info[j]));
 	}
 }
 
@@ -2073,8 +2075,8 @@ ulong flash_get_size (phys_addr_t base, int banknum)
 	info->start[0] = (ulong)map_physmem(base, info->portwidth, MAP_NOCACHE);
 
 	if (flash_detect_cfi (info, &qry)) {
-		info->vendor = le16_to_cpu(qry.p_id);
-		info->ext_addr = le16_to_cpu(qry.p_adr);
+		info->vendor = le16_to_cpu(get_unaligned(&(qry.p_id)));
+		info->ext_addr = le16_to_cpu(get_unaligned(&(qry.p_adr)));
 		num_erase_regions = qry.num_erase_regions;
 
 		if (info->ext_addr) {
@@ -2163,7 +2165,8 @@ ulong flash_get_size (phys_addr_t base, int banknum)
 				break;
 			}
 
-			tmp = le32_to_cpu(qry.erase_region_info[i]);
+			tmp = le32_to_cpu(get_unaligned(
+						&(qry.erase_region_info[i])));
 			debug("erase region %u: 0x%08lx\n", i, tmp);
 
 			erase_region_count = (tmp & 0xffff) + 1;
diff --git a/include/mtd/cfi_flash.h b/include/mtd/cfi_flash.h
index 966b5e0..b644b91 100644
--- a/include/mtd/cfi_flash.h
+++ b/include/mtd/cfi_flash.h
@@ -129,12 +129,16 @@ typedef union {
 } cfiword_t;
 
 /* CFI standard query structure */
+/* The offsets and sizes of this packed structure members correspond
+ * to the actual layout in CFI Flash chips. Some 16- and 32-bit members
+ * are unaligned and must be accessed with explicit unaligned access macros.
+ */
 struct cfi_qry {
 	u8	qry[3];
-	u16	p_id;
-	u16	p_adr;
-	u16	a_id;
-	u16	a_adr;
+	u16	p_id;			/* unaligned */
+	u16	p_adr;			/* unaligned */
+	u16	a_id;			/* unaligned */
+	u16	a_adr;			/* unaligned */
 	u8	vcc_min;
 	u8	vcc_max;
 	u8	vpp_min;
@@ -148,10 +152,10 @@ struct cfi_qry {
 	u8	block_erase_timeout_max;
 	u8	chip_erase_timeout_max;
 	u8	dev_size;
-	u16	interface_desc;
-	u16	max_buf_write_size;
+	u16	interface_desc;		/* aligned */
+	u16	max_buf_write_size;	/* aligned */
 	u8	num_erase_regions;
-	u32	erase_region_info[NUM_ERASE_REGIONS];
+	u32	erase_region_info[NUM_ERASE_REGIONS];	/* unaligned */
 } __attribute__((packed));
 
 struct cfi_pri_hdr {
-- 
1.7.10.4