From: David Brownell <david-b@pacbell.net>
To: Linux MTD <linux-mtd@lists.infradead.org>
Cc: lkml <linux-kernel@vger.kernel.org>, Chen Gong <g.chen@freescale.com>
Subject: [patch/resend 2.6.28-rc5] mtd m25p80: chip erase != block erase != sector erase
Date: Mon, 17 Nov 2008 11:38:48 -0800 [thread overview]
Message-ID: <200811171138.48884.david-b@pacbell.net> (raw)
From: Chen Gong <g.chen@freescale.com>
This fixes broken terminology added in the "m25p80.c erase enhance" patch,
which added a chip erase command but called it "block erase". There are
already two block erase commands; blocks are 4KiB or 32KiB. There's also
a sector erase (usually 64 KiB). Chip erase typically covers Megabytes.
OPCODE_BE ==> OPCODE_CHIP_ERASE
erase_block ==> erase_chip
[dbrownell@users.sourceforge.net: update sector erase comments too ]
Signed-Off-by: Chen Gong <clumsycg@gmail.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
---
drivers/mtd/devices/m25p80.c | 23 +++++++++++++----------
1 file changed, 13 insertions(+), 10 deletions(-)
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -37,9 +37,9 @@
#define OPCODE_NORM_READ 0x03 /* Read data bytes (low frequency) */
#define OPCODE_FAST_READ 0x0b /* Read data bytes (high frequency) */
#define OPCODE_PP 0x02 /* Page program (up to 256 bytes) */
-#define OPCODE_BE_4K 0x20 /* Erase 4KiB block */
+#define OPCODE_BE_4K 0x20 /* Erase 4KiB block */
#define OPCODE_BE_32K 0x52 /* Erase 32KiB block */
-#define OPCODE_BE 0xc7 /* Erase whole flash block */
+#define OPCODE_CHIP_ERASE 0xc7 /* Erase whole flash block */
#define OPCODE_SE 0xd8 /* Sector erase (usually 64KiB) */
#define OPCODE_RDID 0x9f /* Read JEDEC ID */
@@ -167,7 +167,7 @@ static int wait_till_ready(struct m25p *
*
* Returns 0 if successful, non-zero otherwise.
*/
-static int erase_block(struct m25p *flash)
+static int erase_chip(struct m25p *flash)
{
DEBUG(MTD_DEBUG_LEVEL3, "%s: %s %dKiB\n",
flash->spi->dev.bus_id, __func__,
@@ -181,7 +181,7 @@ static int erase_block(struct m25p *flas
write_enable(flash);
/* Set up command buffer. */
- flash->command[0] = OPCODE_BE;
+ flash->command[0] = OPCODE_CHIP_ERASE;
spi_write(flash->spi, flash->command, 1);
@@ -250,15 +250,18 @@ static int m25p80_erase(struct mtd_info
mutex_lock(&flash->lock);
- /* REVISIT in some cases we could speed up erasing large regions
- * by using OPCODE_SE instead of OPCODE_BE_4K
- */
-
- /* now erase those sectors */
- if (len == flash->mtd.size && erase_block(flash)) {
+ /* whole-chip erase? */
+ if (len == flash->mtd.size && erase_chip(flash)) {
instr->state = MTD_ERASE_FAILED;
mutex_unlock(&flash->lock);
return -EIO;
+
+ /* REVISIT in some cases we could speed up erasing large regions
+ * by using OPCODE_SE instead of OPCODE_BE_4K. We may have set up
+ * to use "small sector erase", but that's not always optimal.
+ */
+
+ /* "sector"-at-a-time erase */
} else {
while (len) {
if (erase_sector(flash, addr)) {
reply other threads:[~2008-11-17 21:12 UTC|newest]
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