Message ID | 1361182768-31919-1-git-send-email-u.kleine-koenig@pengutronix.de |
---|---|
State | New, archived |
Headers | show |
On Mon, 2013-02-18 at 11:19 +0100, Uwe Kleine-König wrote: > Before this patch mtd_read_fact_prot_reg was used to check availability > for both MTD_OTP_FACTORY and MTD_OTP_USER access. This made accessing > user otp for chips that don't have a factory otp area impossible. So use > the right wrapper depending on the intended area to be accessed. > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > --- > Hello, > > I'm currently working on accessing the user otp area of MT29F2G nand > flash that doesn't have a factory otp. Reading and writing are not ready > yet, but this change is an obvious prerequisite. > > Best regards > Uwe > > drivers/mtd/mtdchar.c | 30 +++++++++++++++++++----------- > 1 file changed, 19 insertions(+), 11 deletions(-) > > diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c > index a6e7451..1f4034a 100644 > --- a/drivers/mtd/mtdchar.c > +++ b/drivers/mtd/mtdchar.c > @@ -371,26 +371,34 @@ static int otp_select_filemode(struct mtd_file_info *mfi, int mode) > struct mtd_info *mtd = mfi->mtd; > size_t retlen; > int ret = 0; > - > - /* > - * Make a fake call to mtd_read_fact_prot_reg() to check if OTP > - * operations are supported. > - */ > - if (mtd_read_fact_prot_reg(mtd, -1, 0, &retlen, NULL) == -EOPNOTSUPP) > - return -EOPNOTSUPP; > + int (*func)(struct mtd_info *, loff_t, size_t, size_t *, u_char *) = > + NULL; > + enum mtd_file_modes outmode = MTD_FILE_MODE_NORMAL; In this particular case when we only have 2 modes I'd prefer to not introduce a function pointer variable but directly call the function. > > switch (mode) { > case MTD_OTP_FACTORY: > - mfi->mode = MTD_FILE_MODE_OTP_FACTORY; > + outmode = MTD_FILE_MODE_OTP_FACTORY; > + func = mtd_read_fact_prot_reg; > break; > case MTD_OTP_USER: > - mfi->mode = MTD_FILE_MODE_OTP_USER; > + outmode = MTD_FILE_MODE_OTP_USER; > + func = mtd_read_user_prot_reg; > break; > - default: > - ret = -EINVAL; > case MTD_OTP_OFF: > break; > + default: > + ret = -EINVAL; Probably in this case you need to 'return -EINVAL', otherwise you modify 'mfi->mode' below which is an unexpected side-effect of '-EINVAL'. > } > + > + /* > + * Make a fake call to mtd_read_fact_prot_reg() or > + * mtd_read_user_prot_reg() to check if OTP operations are supported. > + */ > + if (func && func(mtd, -1, 0, &retlen, NULL) == -EOPNOTSUPP) > + return -EOPNOTSUPP; > + > + mfi->mode = outmode; > + > return ret; > } > #else
Hello, On Sat, Mar 02, 2013 at 05:41:24PM +0200, Artem Bityutskiy wrote: > On Mon, 2013-02-18 at 11:19 +0100, Uwe Kleine-König wrote: > > Before this patch mtd_read_fact_prot_reg was used to check availability > > for both MTD_OTP_FACTORY and MTD_OTP_USER access. This made accessing > > user otp for chips that don't have a factory otp area impossible. So use > > the right wrapper depending on the intended area to be accessed. > > > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > > --- > > Hello, > > > > I'm currently working on accessing the user otp area of MT29F2G nand > > flash that doesn't have a factory otp. Reading and writing are not ready > > yet, but this change is an obvious prerequisite. > > > > Best regards > > Uwe > > > > drivers/mtd/mtdchar.c | 30 +++++++++++++++++++----------- > > 1 file changed, 19 insertions(+), 11 deletions(-) > > > > diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c > > index a6e7451..1f4034a 100644 > > --- a/drivers/mtd/mtdchar.c > > +++ b/drivers/mtd/mtdchar.c > > @@ -371,26 +371,34 @@ static int otp_select_filemode(struct mtd_file_info *mfi, int mode) > > struct mtd_info *mtd = mfi->mtd; > > size_t retlen; > > int ret = 0; > > - > > - /* > > - * Make a fake call to mtd_read_fact_prot_reg() to check if OTP > > - * operations are supported. > > - */ > > - if (mtd_read_fact_prot_reg(mtd, -1, 0, &retlen, NULL) == -EOPNOTSUPP) > > - return -EOPNOTSUPP; > > + int (*func)(struct mtd_info *, loff_t, size_t, size_t *, u_char *) = > > + NULL; > > + enum mtd_file_modes outmode = MTD_FILE_MODE_NORMAL; > > In this particular case when we only have 2 modes I'd prefer to not > introduce a function pointer variable but directly call the function. I choosed the function pointer to reduce code duplication. Do function pointer have a bad characteristic that I don't know? But actually I don't care much and can resend without the function pointer. > > > > switch (mode) { > > case MTD_OTP_FACTORY: > > - mfi->mode = MTD_FILE_MODE_OTP_FACTORY; > > + outmode = MTD_FILE_MODE_OTP_FACTORY; > > + func = mtd_read_fact_prot_reg; > > break; > > case MTD_OTP_USER: > > - mfi->mode = MTD_FILE_MODE_OTP_USER; > > + outmode = MTD_FILE_MODE_OTP_USER; > > + func = mtd_read_user_prot_reg; > > break; > > - default: > > - ret = -EINVAL; > > case MTD_OTP_OFF: > > break; > > + default: > > + ret = -EINVAL; > > Probably in this case you need to 'return -EINVAL', otherwise you modify > 'mfi->mode' below which is an unexpected side-effect of '-EINVAL'. I don't remember, but I think I convinced myself that it doesn't hurt. Still it's less surprising to not modify mfi, so OK. Uwe > > } > > + > > + /* > > + * Make a fake call to mtd_read_fact_prot_reg() or > > + * mtd_read_user_prot_reg() to check if OTP operations are supported. > > + */ > > + if (func && func(mtd, -1, 0, &retlen, NULL) == -EOPNOTSUPP) > > + return -EOPNOTSUPP; > > + > > + mfi->mode = outmode; > > + > > return ret; > > } > > #else > > -- > Best Regards, > Artem Bityutskiy > >
diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c index a6e7451..1f4034a 100644 --- a/drivers/mtd/mtdchar.c +++ b/drivers/mtd/mtdchar.c @@ -371,26 +371,34 @@ static int otp_select_filemode(struct mtd_file_info *mfi, int mode) struct mtd_info *mtd = mfi->mtd; size_t retlen; int ret = 0; - - /* - * Make a fake call to mtd_read_fact_prot_reg() to check if OTP - * operations are supported. - */ - if (mtd_read_fact_prot_reg(mtd, -1, 0, &retlen, NULL) == -EOPNOTSUPP) - return -EOPNOTSUPP; + int (*func)(struct mtd_info *, loff_t, size_t, size_t *, u_char *) = + NULL; + enum mtd_file_modes outmode = MTD_FILE_MODE_NORMAL; switch (mode) { case MTD_OTP_FACTORY: - mfi->mode = MTD_FILE_MODE_OTP_FACTORY; + outmode = MTD_FILE_MODE_OTP_FACTORY; + func = mtd_read_fact_prot_reg; break; case MTD_OTP_USER: - mfi->mode = MTD_FILE_MODE_OTP_USER; + outmode = MTD_FILE_MODE_OTP_USER; + func = mtd_read_user_prot_reg; break; - default: - ret = -EINVAL; case MTD_OTP_OFF: break; + default: + ret = -EINVAL; } + + /* + * Make a fake call to mtd_read_fact_prot_reg() or + * mtd_read_user_prot_reg() to check if OTP operations are supported. + */ + if (func && func(mtd, -1, 0, &retlen, NULL) == -EOPNOTSUPP) + return -EOPNOTSUPP; + + mfi->mode = outmode; + return ret; } #else
Before this patch mtd_read_fact_prot_reg was used to check availability for both MTD_OTP_FACTORY and MTD_OTP_USER access. This made accessing user otp for chips that don't have a factory otp area impossible. So use the right wrapper depending on the intended area to be accessed. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> --- Hello, I'm currently working on accessing the user otp area of MT29F2G nand flash that doesn't have a factory otp. Reading and writing are not ready yet, but this change is an obvious prerequisite. Best regards Uwe drivers/mtd/mtdchar.c | 30 +++++++++++++++++++----------- 1 file changed, 19 insertions(+), 11 deletions(-)