Hi,
in src/flash/nor/cfi.c the mathematics around computing "bufferwsize"
variable is quite obscure.
Current code is the result of one year old patch to introduce
multi-chip flash support.
In the attached patch I try to simplify the code and comment what the
variable is and how it is computed.
Please review it.
Best Regards,
Antonio Borneo
From a0a8eccae54591524a7577fae6ecaef92df8ed13 Mon Sep 17 00:00:00 2001
From: Antonio Borneo <borneo.anto...@gmail.com>
Date: Thu, 25 Mar 2010 00:29:10 +0800
Subject: [PATCH] CFI: simplify bufferwsize computation
Review and simplify computation of bufferwsize.
Added comments about variables.
Signed-off-by: Antonio Borneo <borneo.anto...@gmail.com>
---
src/flash/nor/cfi.c | 49 ++++++++++---------------------------------------
1 files changed, 10 insertions(+), 39 deletions(-)
diff --git a/src/flash/nor/cfi.c b/src/flash/nor/cfi.c
index 5f7ed1e..e53be0c 100644
--- a/src/flash/nor/cfi.c
+++ b/src/flash/nor/cfi.c
@@ -1562,9 +1562,11 @@ 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)
@@ -1573,18 +1575,6 @@ 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)
@@ -1691,9 +1681,11 @@ 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)
@@ -1701,17 +1693,6 @@ 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)
@@ -1908,22 +1889,12 @@ int cfi_write(struct flash_bank *bank, uint8_t *buffer, uint32_t offset, uint32_
{
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)
--
1.5.2.2
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