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NOR/CFI: simplify bufferwsize computation 

Review and simplify computation of bufferwsize.
Add comments about variables' meaning.

The same code is present 3 times in the file.
Current patch updates all the 3 instances.

Step 1)
  Replace "switch(bank->chip_width) {...}".
  Illegal values of bank->chip_width are already dropped.
  For legal values, the code is equivalent to:
        bufferwsize = buffersize / bank->chip_width;

Step 2)
  The above code replacement plus the following line:
        bufferwsize /= (bank->bus_width / bank->chip_width);
  is merged in a single formula:
        bufferwsize = (buffersize / bank->chip_width) /
                (bank->bus_width / bank->chip_width);
  and simplified as:
        bufferwsize = buffersize / bank->bus_width;

Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
__archive__
Antonio Borneo 2010-04-19 16:40:08 +08:00 committed by Øyvind Harboe
parent c7b269ace1
commit 89747f81f2
1 changed files with 10 additions and 39 deletions
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49
src/flash/nor/cfi.c
View File

@ -1604,9 +1604,11 @@ static int cfi_intel_write_words(struct flash_bank *bank, uint8_t *word, uint32_
struct target *target = bank->target;
/* Calculate buffer size and boundary mask */
/* buffersize is (buffer size per chip) * (number of chips) */
/* bufferwsize is buffersize in words */
uint32_t buffersize = (1UL << cfi_info->max_buf_write_size) * (bank->bus_width / bank->chip_width);
uint32_t buffermask = buffersize-1;
uint32_t bufferwsize;
uint32_t bufferwsize = buffersize / bank->bus_width;
/* Check for valid range */
if (address & buffermask)
@ -1615,18 +1617,6 @@ static int cfi_intel_write_words(struct flash_bank *bank, uint8_t *word, uint32_
bank->base, address, cfi_info->max_buf_write_size);
return ERROR_FLASH_OPERATION_FAILED;
}
switch (bank->chip_width)
{
case 4 : bufferwsize = buffersize / 4; break;
case 2 : bufferwsize = buffersize / 2; break;
case 1 : bufferwsize = buffersize; break;
default:
LOG_ERROR("Unsupported chip width %d", bank->chip_width);
return ERROR_FLASH_OPERATION_FAILED;
}
bufferwsize/=(bank->bus_width / bank->chip_width);
/* Check for valid size */
if (wordcount > bufferwsize)
@ -1733,9 +1723,11 @@ static int cfi_spansion_write_words(struct flash_bank *bank, uint8_t *word, uint
struct cfi_spansion_pri_ext *pri_ext = cfi_info->pri_ext;
/* Calculate buffer size and boundary mask */
/* buffersize is (buffer size per chip) * (number of chips) */
/* bufferwsize is buffersize in words */
uint32_t buffersize = (1UL << cfi_info->max_buf_write_size) * (bank->bus_width / bank->chip_width);
uint32_t buffermask = buffersize-1;
uint32_t bufferwsize;
uint32_t bufferwsize = buffersize / bank->bus_width;
/* Check for valid range */
if (address & buffermask)
@ -1743,17 +1735,6 @@ static int cfi_spansion_write_words(struct flash_bank *bank, uint8_t *word, uint
LOG_ERROR("Write address at base 0x%" PRIx32 ", address %" PRIx32 " not aligned to 2^%d boundary", bank->base, address, cfi_info->max_buf_write_size);
return ERROR_FLASH_OPERATION_FAILED;
}
switch (bank->chip_width)
{
case 4 : bufferwsize = buffersize / 4; break;
case 2 : bufferwsize = buffersize / 2; break;
case 1 : bufferwsize = buffersize; break;
default:
LOG_ERROR("Unsupported chip width %d", bank->chip_width);
return ERROR_FLASH_OPERATION_FAILED;
}
bufferwsize/=(bank->bus_width / bank->chip_width);
/* Check for valid size */
if (wordcount > bufferwsize)
@ -1950,22 +1931,12 @@ static int cfi_write(struct flash_bank *bank, uint8_t *buffer, uint32_t offset,
{
if (retval == ERROR_TARGET_RESOURCE_NOT_AVAILABLE)
{
//adjust buffersize for chip width
/* Calculate buffer size and boundary mask */
/* buffersize is (buffer size per chip) * (number of chips) */
/* bufferwsize is buffersize in words */
uint32_t buffersize = (1UL << cfi_info->max_buf_write_size) * (bank->bus_width / bank->chip_width);
uint32_t buffermask = buffersize-1;
uint32_t bufferwsize;
switch (bank->chip_width)
{
case 4 : bufferwsize = buffersize / 4; break;
case 2 : bufferwsize = buffersize / 2; break;
case 1 : bufferwsize = buffersize; break;
default:
LOG_ERROR("Unsupported chip width %d", bank->chip_width);
return ERROR_FLASH_OPERATION_FAILED;
}
bufferwsize/=(bank->bus_width / bank->chip_width);
uint32_t bufferwsize = buffersize / bank->bus_width;
/* fall back to memory writes */
while (count >= (uint32_t)bank->bus_width)