Re: [PATCH 7/8] mtd: spi-nor: factor out write_enable() for erase commands

Huang Shijie
2014-08-12T00:59:31Z

On Mon, Aug 11, 2014 at 11:48:18AM -0700, Brian Norris wrote:
> On Sat, Aug 09, 2014 at 06:52:34PM +0800, Huang Shijie wrote:
> > On Wed, Aug 06, 2014 at 06:17:01PM -0700, Brian Norris wrote:
> > > write_enable() was being duplicated to both m25p80.c and fsl-quadspi.c.
> > > But this should be handled within the spi-nor abstraction layer.
> > >
> > > At the same time, let's add write_disable() after erasing, so we don't
> > > leave the flash in a write-enabled state afterward.
> > >
> > > Signed-off-by: Brian Norris <computersforpeace@gmail.com>
> > > ---
> > > drivers/mtd/devices/m25p80.c | 5 -----
> > > drivers/mtd/spi-nor/fsl-quadspi.c | 5 -----
> > > drivers/mtd/spi-nor/spi-nor.c | 7 ++++---
> > > 3 files changed, 4 insertions(+), 13 deletions(-)
> > >
> > > diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
> > > index 96226ea69f90..116d979ffdb9 100644
> > > --- a/drivers/mtd/devices/m25p80.c
> > > +++ b/drivers/mtd/devices/m25p80.c
> > > @@ -158,11 +158,6 @@ static int m25p80_erase(struct spi_nor *nor, loff_t offset)
> > > dev_dbg(nor->dev, "%dKiB at 0x%08x\n",
> > > flash->mtd.erasesize / 1024, (u32)offset);
> > >
> > > - /* Send write enable, then erase commands. */
> > > - ret = nor->write_reg(nor, SPINOR_OP_WREN, NULL, 0, 0);
> > > - if (ret)
> > > - return ret;
> > > -
> > > /* Set up command buffer. */
> > > flash->command[0] = nor->erase_opcode;
> > > m25p_addr2cmd(nor, offset, flash->command);
> > > diff --git a/drivers/mtd/spi-nor/fsl-quadspi.c b/drivers/mtd/spi-nor/fsl-quadspi.c
> > > index 9c13622a0c7a..07fbfb0a7738 100644
> > > --- a/drivers/mtd/spi-nor/fsl-quadspi.c
> > > +++ b/drivers/mtd/spi-nor/fsl-quadspi.c
> > > @@ -738,11 +738,6 @@ static int fsl_qspi_erase(struct spi_nor *nor, loff_t offs)
> > > dev_dbg(nor->dev, "%dKiB at 0x%08x:0x%08x\n",
> > > nor->mtd->erasesize / 1024, q->chip_base_addr, (u32)offs);
> > >
> > > - /* Send write enable, then erase commands. */
> > > - ret = nor->write_reg(nor, SPINOR_OP_WREN, NULL, 0, 0);
> > > - if (ret)
> > > - return ret;
> > > -
> > This write-enable is used for per-sector-erase, not for the whole chip
> > erase.
> >
> > So if you really want to remove this code, you should add an extra write-enable
> > in the spi_nor_erase.
>
> I don't understand your comment.
>
> Before this patch, there is a write-enable command in:
> * m25p80.c, per-sector erase
> * fsl-quadspi, per-sector erase
> * spi-nor.c, whole-chip erase
>
> With this patch, I am factoring all of these out into spi_nor_erase().
>
> What is the problem?
Hi Brian:
For the spi_nor_erase(), the patch should like this:

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index c130bf7..26c48bc 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -324,6 +324,7 @@ static int spi_nor_erase(struct mtd_info *mtd, struct erase_info *instr)

/* whole-chip erase? */
if (len == mtd->size) {
+ write_enable(nor);
if (erase_chip(nor)) {
ret = -EIO;
goto erase_err;
@@ -337,6 +338,7 @@ static int spi_nor_erase(struct mtd_info *mtd, struct erase_info *instr)
/* "sector"-at-a-time erase */
} else {
while (len) {
+ write_enable(nor);
if (nor->erase(nor, addr)) {
ret = -EIO;
goto erase_err;

thanks
Huang Shijie