FAT: Properly align buffers to allow cache operations

Align the FAT FS buffers so DMA on various systems can directly pick them.

Signed-off-by Marek Vasut<[email protected]>

---
  fs/fat/fat.c |   12 ++++++------
  1 files changed, 6 insertions(+), 6 deletions(-)

fs/fat/fat.c +6 -6

index 1f95eb4..d709e59 100644
@@ -31,6 +31,7 @@
  #include<fat.h>
  #include<asm/byteorder.h>
  #include<part.h>
+#include<malloc.h>
 
  /*
   * Convert a string to lowercase.

@@ -62,7 +63,7 @@ static int disk_read(__u32 block, __u32 nr_blocks, void *buf)
 
  int fat_register_device (block_dev_desc_t * dev_desc, int part_no)
  {
-	unsigned char buffer[dev_desc->blksz];
+	ALLOC_CACHE_ALIGN_BUFFER(unsigned char, buffer, dev_desc->blksz);
 
  	/* First close any currently found FAT filesystem */
  	cur_dev = NULL;

@@ -293,9 +294,10 @@ get_cluster (fsdata *mydata, __u32 clustnum, __u8 *buffer,
  		return -1;
  	}
  	if (size % mydata->sect_size) {
-		__u8 tmpbuf[mydata->sect_size];
+		ALLOC_CACHE_ALIGN_BUFFER(unsigned char, tmpbuf, mydata->sect_size);
 
  		idx = size / mydata->sect_size;
+
  		ret = disk_read(startsect + idx, 1, tmpbuf);
  		if (ret != 1) {
  			debug("Error reading data (got %d)\n", ret);

@@ -709,7 +711,7 @@ read_bootsectandvi (boot_sector *bs, volume_info *volinfo, int *fatsize)
  		return -1;
  	}
 
-	block = malloc(cur_dev->blksz);
+	block = memalign(ARCH_DMA_MINALIGN, cur_dev->blksz);
  	if (block == NULL) {
  		debug("Error: allocating block\n");
  		return -1;

@@ -765,9 +767,6 @@ exit:
  	return ret;
  }
 
-__attribute__ ((__aligned__ (__alignof__ (dir_entry))))
-__u8 do_fat_read_block[MAX_CLUSTSIZE];
-
  long
  do_fat_read (const char *filename, void *buffer, unsigned long maxsize,
  	     int dols)

@@ -788,6 +787,7 @@ do_fat_read (const char *filename, void *buffer, unsigned long maxsize,
  	__u32 root_cluster = 0;
  	int rootdir_size = 0;
  	int j;
+	uint8_t do_fat_read_block[MAX_CLUSTSIZE] __attribute__((aligned(32)));
 
  	if (read_bootsectandvi(&bs,&volinfo,&mydata->fatsize)) {
  		debug("Error: reading boot sector\n");

Quoted 2 lines

Align the FAT FS buffers so DMA on various systems can directly pick them.

Just fyi:

http://lists.denx.de/pipermail/u-boot/2012-March/119311.html

http://lists.denx.de/pipermail/u-boot/2012-March/119309.html

Best regards

Dirk

Dear Dirk Behme,

Quoted 6 lines · Marek Vasut

Quoted 2 lines

Align the FAT FS buffers so DMA on various systems can directly pick them.

Just fyi:

Quoted 3 lines

http://lists.denx.de/pipermail/u-boot/2012-March/119311.html

http://lists.denx.de/pipermail/u-boot/2012-March/119309.html

Heh, nice! :-)

I've been so dug up in debugging the USB cache issues I didn't bother to look around the list for previous efforts. So obviously, apply Eric's patch! :-)

Quoted 12 lines

Dear Dirk Behme,

Quoted 9 lines · Marek Vasut

Quoted 2 lines

Align the FAT FS buffers so DMA on various systems can directly pick them.

Just fyi:

http://lists.denx.de/pipermail/u-boot/2012-March/119311.html

http://lists.denx.de/pipermail/u-boot/2012-March/119309.html

Quoted 5 lines

Heh, nice! :-)

I've been so dug up in debugging the USB cache issues I didn't bother to look around the list for previous efforts. So obviously, apply Eric's patch! :-)

Do you need this for 2012.04? Or is the stuff which needs this scheduled for -next?

Best regards

Dirk

Dear Dirk Behme,

Quoted 6 lines · Marek Vasut

Quoted 2 lines

Align the FAT FS buffers so DMA on various systems can directly pick them.

Just fyi:

Quoted 3 lines

http://lists.denx.de/pipermail/u-boot/2012-March/119311.html

http://lists.denx.de/pipermail/u-boot/2012-March/119309.html

Heh, nice! :-)

I've been so dug up in debugging the USB cache issues I didn't bother to look around the list for previous efforts. So obviously, apply Eric's patch! :-)

Quoted 8 lines

fs/fat/fat.c +0 -3

@@ -765,9 +767,6 @@
 
-__attribute__ ((__aligned__ (__alignof__ (dir_entry))))
-__u8 do_fat_read_block[MAX_CLUSTSIZE];
-
 

@@ -788,6 +787,7 @@ do_fat_read (const char *filename, void *buffer,
 

fs/fat/fat.c do_fat_read (const char *filename, void *buffer, unsigned long maxsize,

Quoted 4 lines

fs/fat/fat.c +1 -0

 	int rootdir_size = 0;
 	int j;
 
+	uint8_t do_fat_read_block[MAX_CLUSTSIZE] __attribute__((aligned(32)));

what's going on here exactly ? the old code had the advantage of being in the bss and the linker taking care of the alignment. this new code has an incorrectly hard-coded "32", and puts a 64KiB array onto the *stack*.

Dear Mike Frysinger,

Quoted 12 lines · On Monday 09 April 2012 02:45:03 Marek Vasut wrote:

Quoted 11 lines

fs/fat/fat.c +0 -3

@@ -765,9 +767,6 @@
 
-__attribute__ ((__aligned__ (__alignof__ (dir_entry))))
-__u8 do_fat_read_block[MAX_CLUSTSIZE];
-
 

@@ -788,6 +787,7 @@ do_fat_read (const char *filename, void *buffer,
 
  	int rootdir_size = 0;
  	int j;
 

Quoted 5 lines

fs/fat/fat.c do_fat_read (const char *filename, void *buffer, unsigned long maxsize, · line 790

Quoted 1 line

fs/fat/fat.c +1 -0

+	uint8_t do_fat_read_block[MAX_CLUSTSIZE] __attribute__((aligned(32)));

what's going on here exactly ? the old code had the advantage of being in the bss and the linker taking care of the alignment. this new code has an incorrectly hard-coded "32", and puts a 64KiB array onto the *stack*.

This will be probably fixed in Eric's patch

Quoted 23 lines · Marek Vasut

Dear Mike Frysinger,

Quoted 20 lines · On Monday 09 April 2012 02:45:03 Marek Vasut wrote:

fs/fat/fat.c do_fat_read (const char *filename, void *buffer, · line 792

Quoted 13 lines

fs/fat/fat.c +1 -3

@@ -765,9 +767,6 @@
 
-__attribute__ ((__aligned__ (__alignof__ (dir_entry))))
-__u8 do_fat_read_block[MAX_CLUSTSIZE];
-
 

@@ -788,6 +787,7 @@ do_fat_read (const char *filename, void *buffer,
 
 int rootdir_size = 0;
 int j;
 
+ uint8_t do_fat_read_block[MAX_CLUSTSIZE]
 __attribute__((aligned(32)));

what's going on here exactly ? the old code had the advantage of being in
the bss and the linker taking care of the alignment. this new code has an
incorrectly hard-coded "32", and puts a 64KiB array onto the *stack*.

Quoted 2 lines

This will be probably fixed in Eric's patch

Yep. I left it in bss space.

Sorry guys, but I'm confused now.

We have two patches, Eric's [1] and Marek's [2]. Which one should we take? With the discussion here and [3] I'm somehow under the impression that both patches [1] [2] are not complete?

Do I miss anything? Or do we need a new version ("best of [1] & [2]")?

Dear Dirk,

Quoted 2 lines · In message<[email protected]> you wrote:

Sorry guys, but I'm confused now.

Heh. Me too ;-)

Quoted 5 lines

We have two patches, Eric's [1] and Marek's [2]. Which one should we take? With the discussion here and [3] I'm somehow under the impression that both patches [1] [2] are not complete?

Do I miss anything? Or do we need a new version ("best of [1]& [2]")?

I'm waiting for Eric to post an updated patch that includes 1+2+3.