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

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Submitter Andrew Gabbasov
Date May 14, 2013, 5:27 p.m.
Message ID <1368552472-12931-1-git-send-email-andrew_gabbasov@mentor.com>
Download mbox | patch
Permalink /patch/243791/
State Awaiting Upstream
Delegated to: Stefan Roese
Headers show

Comments

Andrew Gabbasov - May 14, 2013, 5:27 p.m.
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@mentor.com>
---
 drivers/mtd/cfi_flash.c |   15 +++++++++------
 include/mtd/cfi_flash.h |   18 +++++++++++-------
 2 files changed, 20 insertions(+), 13 deletions(-)
Albert ARIBAUD - May 22, 2013, 6:50 p.m.
Hi Andrew,

On Tue, 14 May 2013 12:27:52 -0500, Andrew Gabbasov
<andrew_gabbasov@mentor.com> wrote:

> 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@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 {

Reviewed-By: Albert ARIBAUD <albert.u.boot@aribaud.net>

Seems ok to me.

Now, seeing as this is global to all architectures, yet motivated by
ARM alignment considerations, which repo should this go to?

Amicalement,
Stefan Roese - May 23, 2013, 6:16 a.m.
Hi Albert,

On 05/22/2013 08:50 PM, Albert ARIBAUD wrote:

<snip>

>> @@ -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 {
> 
> Reviewed-By: Albert ARIBAUD <albert.u.boot@aribaud.net>
> 
> Seems ok to me.
> 
> Now, seeing as this is global to all architectures, yet motivated by
> ARM alignment considerations, which repo should this go to?

I'm responsible for cfi-flash. I'll look at it today.

Thanks,
Stefan
Stefan Roese - May 23, 2013, 7:49 a.m.
On 05/14/2013 07:27 PM, Andrew Gabbasov wrote:
> 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.

Applied to u-boot-cfi-flash/master.

Thanks,
Stefan

Patch

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 {