nand: fix buffer alignment in new verification feature

From: Stephen Warren <[email protected]>

On systems with caches enabled, NAND I/O may need to flush/invalidate the cache during read/write operations. For this to work correctly, all buffers must be cache-aligned. Fix nand_verify*() to allocate aligned buffers.

This prevents cache alignment warnings from being spewed when using U-Boot to write an updated version of itself to flash on NVIDIA Tegra Seaboard (after perturbation of stack/data layout in current u-boot-dm/next branch).

I have validatd (executed) nand_verify(), but I don't think I've executed nand_verify_page_oob(); testing of that would be useful.

Cc Peter Tyser <[email protected]>

Cc Heiko Schocher <[email protected]>

Cc Scott Wood <[email protected]>

Fixes 59b5a2ad83df ("nand: Add verification functions")

Signed-off-by Stephen Warren <[email protected]>

Reviewed-by Simon Glass <[email protected]>

Acked-by Scott Wood <[email protected]>

---
Resending to Tom for direct application, including reviewed-/acked-by tags from others.

As an aside, I think this patch demonstrates why new features shouldn't be merged just a couple weeks before the release; there's not enough time to detect regressions and patch them. The merge window is for new features.

v2: Use memalign() rather than ALLOC_CACHE_ALIGN_BUFFER() so that the buffer is allocated from the heap not on the stack, to reduce stack usage.

  drivers/mtd/nand/nand_util.c | 4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

drivers/mtd/nand/nand_util.c +2 -2

index 12dd26a33fac..ee2c24df3b85 100644
@@ -483,7 +483,7 @@ int nand_verify_page_oob(nand_info_t *nand, struct mtd_oob_ops *ops, loff_t ofs)
 
  	memcpy(&vops, ops, sizeof(vops));
 
-	vops.datbuf = malloc(verlen);
+	vops.datbuf = memalign(ARCH_DMA_MINALIGN, verlen);
 
  	if (!vops.datbuf)
  		return -ENOMEM;

@@ -520,7 +520,7 @@ int nand_verify(nand_info_t *nand, loff_t ofs, size_t len, u_char *buf)
  	int rval = 0;
  	size_t verofs;
  	size_t verlen = nand->writesize;
-	uint8_t *verbuf = malloc(verlen);
+	uint8_t *verbuf = memalign(ARCH_DMA_MINALIGN, verlen);
 
  	if (!verbuf)
  		return -ENOMEM;

Hello Stephen,

Am 06.05.2015 18:01, schrieb Stephen Warren:

Quoted 14 lines

From: Stephen Warren <[email protected]>

On systems with caches enabled, NAND I/O may need to flush/invalidate the cache during read/write operations. For this to work correctly, all buffers must be cache-aligned. Fix nand_verify*() to allocate aligned buffers.

This prevents cache alignment warnings from being spewed when using U-Boot to write an updated version of itself to flash on NVIDIA Tegra Seaboard (after perturbation of stack/data layout in current u-boot-dm/next branch).

I have validatd (executed) nand_verify(), but I don't think I've executed nand_verify_page_oob(); testing of that would be useful.

Quoted 12 lines

Cc Peter Tyser <[email protected]>

Cc Heiko Schocher <[email protected]>

Cc Scott Wood <[email protected]>

Fixes 59b5a2ad83df ("nand: Add verification functions")

Signed-off-by Stephen Warren <[email protected]>

Reviewed-by Simon Glass <[email protected]>

Acked-by Scott Wood <[email protected]>

---
Resending to Tom for direct application, including reviewed-/acked-by tags
from others.

Quoted 4 lines

As an aside, I think this patch demonstrates why new features shouldn't be
merged just a couple weeks before the release; there's not enough time to detect regressions and patch them. The merge window is for new features.

Yes, with new features we should be more conservative.

Quoted 6 lines

v2: Use memalign() rather than ALLOC_CACHE_ALIGN_BUFFER() so that the buffer is allocated from the heap not on the stack, to reduce stack usage.

  drivers/mtd/nand/nand_util.c | 4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

Thanks for detecting this.

Acked-by Heiko Schocher <[email protected]>

bye,
Heiko

Quoted 26 lines

drivers/mtd/nand/nand_util.c +1 -1

index 12dd26a33fac..ee2c24df3b85 100644
@@ -483,7 +483,7 @@ int nand_verify_page_oob(nand_info_t *nand, struct
 mtd_oob_ops *ops, loff_t ofs)
 
      memcpy(&vops, ops, sizeof(vops));
 
-    vops.datbuf = malloc(verlen);
+    vops.datbuf = memalign(ARCH_DMA_MINALIGN, verlen);
 
      if (!vops.datbuf)

          return -ENOMEM;

drivers/mtd/nand/nand_util.c +1 -1

@@ -520,7 +520,7 @@ int nand_verify(nand_info_t *nand, loff_t ofs,
 size_t len, u_char *buf)
      int rval = 0;
      size_t verofs;
      size_t verlen = nand->writesize;
-    uint8_t *verbuf = malloc(verlen);
+    uint8_t *verbuf = memalign(ARCH_DMA_MINALIGN, verlen);
 
      if (!verbuf)

          return -ENOMEM;

Quoted 15 lines · Heiko Schocher

Hello Stephen,

Am 06.05.2015 18:01, schrieb Stephen Warren:

Quoted 12 lines

From: Stephen Warren <[email protected]>

On systems with caches enabled, NAND I/O may need to flush/invalidate the cache during read/write operations. For this to work correctly, all buffers must be cache-aligned. Fix nand_verify*() to allocate aligned buffers.

This prevents cache alignment warnings from being spewed when using U-Boot to write an updated version of itself to flash on NVIDIA Tegra Seaboard (after perturbation of stack/data layout in current u-boot-dm/next branch).

Quoted 2 lines

Quoted 2 lines

I have validatd (executed) nand_verify(), but I don't think I've executed nand_verify_page_oob(); testing of that would be useful.

Is there any chance of this being applied? It's been 5 weeks since it was first sent.