| Message ID | 1385500515-5376-1-git-send-email-u.kleine-koenig@pengutronix.de |
|---|---|
| State | Superseded, archived |
| Headers | show |
+ Pekon, Ezequiel Can one of you see how this patch works with your BeagleBones w/ x16 NAND? Also, do you think on of you could take a look at killing the nand_chip.read_word() callback, as Artem was originally requesting with this patch? It only has one user (for bad block checking in nand_block_bad(), which is currently only used when there is no BBT at all), and it looks like it could be replaced with a call to read_buf(mtd, buf, 2). Hi Uwe, On Tue, Nov 26, 2013 at 10:15:15PM +0100, Uwe Kleine-König wrote: > According to the Open NAND Flash Interface Specification (ONFI) Revision > 3.1 "Parameters are always transferred on the lower 8-bits of the data > bus." for the Get Features and Set Features commands. > > So using read_buf and write_buf is wrong for 16-bit wide nand chips as > they use I/O[15:0]. The Get Features command is easily fixed using 4 > times the read_byte callback. For Set Features implement a new > overwritable callback "write_byte". Still I expect the default to work > just fine for all controllers and making it overwriteable was just done > for symmetry. > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > --- > drivers/mtd/nand/nand_base.c | 61 +++++++++++++++++++++++++++++++++++++++++--- > include/linux/mtd/nand.h | 3 +++ > 2 files changed, 60 insertions(+), 4 deletions(-) > > diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c > index bd39f7b..27d755b 100644 > --- a/drivers/mtd/nand/nand_base.c > +++ b/drivers/mtd/nand/nand_base.c ... > @@ -2706,7 +2751,7 @@ static int nand_block_markbad(struct mtd_info *mtd, loff_t ofs) > } > > /** > - * nand_onfi_set_features- [REPLACEABLE] set features for ONFI nand > + * nand_onfi_set_features - [REPLACEABLE] set features for ONFI nand This change is unrelated. (Yes, the whitespace should be fixed, but probably not in this patch.) > * @mtd: MTD device structure > * @chip: nand chip info structure > * @addr: feature address. ... > @@ -2731,7 +2779,7 @@ static int nand_onfi_set_features(struct mtd_info *mtd, struct nand_chip *chip, > } > > /** > - * nand_onfi_get_features- [REPLACEABLE] get features for ONFI nand > + * nand_onfi_get_features - [REPLACEABLE] get features for ONFI nand Ditto. > * @mtd: MTD device structure > * @chip: nand chip info structure > * @addr: feature address. ... > @@ -2812,6 +2863,8 @@ static void nand_set_defaults(struct nand_chip *chip, int busw) > chip->block_markbad = nand_default_block_markbad; > if (!chip->write_buf || chip->write_buf == nand_write_buf) > chip->write_buf = busw ? nand_write_buf16 : nand_write_buf; > + if (!chip->write_byte) This check should be: if (!chip->write_byte || chip->write_byte == nand_write_byte) in order to match the rest of the functions, so they can be reset if the buswidth is detected to be x16, and we re-call nand_set_defaults() (e.g., when using NAND_BUSWIDTH_AUTO). See the comment: /* If called twice, pointers that depend on busw may need to be reset */ I know it's kind of ugly, but that's what we have for now. > + chip->write_byte = busw ? nand_write_byte16 : nand_write_byte; > if (!chip->read_buf || chip->read_buf == nand_read_buf) > chip->read_buf = busw ? nand_read_buf16 : nand_read_buf; > if (!chip->scan_bbt) Brian
Brian, On Tue, Nov 26, 2013 at 11:35:12PM -0800, Brian Norris wrote: > + Pekon, Ezequiel > > Can one of you see how this patch works with your BeagleBones w/ x16 > NAND? > > Also, do you think on of you could take a look at killing the > nand_chip.read_word() callback, as Artem was originally requesting with > this patch? It only has one user (for bad block checking in > nand_block_bad(), which is currently only used when there is no BBT at > all), and it looks like it could be replaced with a call to > read_buf(mtd, buf, 2). > Sure, sounds doable. > Hi Uwe, > Uwe, If you're preparing a v4 to address Brian's feedback, then I'll see about testing it with 8/16-bit flashes on my AM335x. > On Tue, Nov 26, 2013 at 10:15:15PM +0100, Uwe Kleine-König wrote: > > According to the Open NAND Flash Interface Specification (ONFI) Revision > > 3.1 "Parameters are always transferred on the lower 8-bits of the data > > bus." for the Get Features and Set Features commands. > > > > So using read_buf and write_buf is wrong for 16-bit wide nand chips as > > they use I/O[15:0]. The Get Features command is easily fixed using 4 > > times the read_byte callback. For Set Features implement a new > > overwritable callback "write_byte". Still I expect the default to work > > just fine for all controllers and making it overwriteable was just done > > for symmetry. > > > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > > --- > > drivers/mtd/nand/nand_base.c | 61 +++++++++++++++++++++++++++++++++++++++++--- > > include/linux/mtd/nand.h | 3 +++ > > 2 files changed, 60 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c > > index bd39f7b..27d755b 100644 > > --- a/drivers/mtd/nand/nand_base.c > > +++ b/drivers/mtd/nand/nand_base.c > ... > > @@ -2706,7 +2751,7 @@ static int nand_block_markbad(struct mtd_info *mtd, loff_t ofs) > > } > > > > /** > > - * nand_onfi_set_features- [REPLACEABLE] set features for ONFI nand > > + * nand_onfi_set_features - [REPLACEABLE] set features for ONFI nand > > This change is unrelated. (Yes, the whitespace should be fixed, but > probably not in this patch.) > > > * @mtd: MTD device structure > > * @chip: nand chip info structure > > * @addr: feature address. > ... > > @@ -2731,7 +2779,7 @@ static int nand_onfi_set_features(struct mtd_info *mtd, struct nand_chip *chip, > > } > > > > /** > > - * nand_onfi_get_features- [REPLACEABLE] get features for ONFI nand > > + * nand_onfi_get_features - [REPLACEABLE] get features for ONFI nand > > Ditto. > > > * @mtd: MTD device structure > > * @chip: nand chip info structure > > * @addr: feature address. > ... > > @@ -2812,6 +2863,8 @@ static void nand_set_defaults(struct nand_chip *chip, int busw) > > chip->block_markbad = nand_default_block_markbad; > > if (!chip->write_buf || chip->write_buf == nand_write_buf) > > chip->write_buf = busw ? nand_write_buf16 : nand_write_buf; > > + if (!chip->write_byte) > > This check should be: > > if (!chip->write_byte || chip->write_byte == nand_write_byte) > > in order to match the rest of the functions, so they can be reset if the > buswidth is detected to be x16, and we re-call nand_set_defaults() > (e.g., when using NAND_BUSWIDTH_AUTO). See the comment: > > /* If called twice, pointers that depend on busw may need to be reset */ > > I know it's kind of ugly, but that's what we have for now. > > > + chip->write_byte = busw ? nand_write_byte16 : nand_write_byte; > > if (!chip->read_buf || chip->read_buf == nand_read_buf) > > chip->read_buf = busw ? nand_read_buf16 : nand_read_buf; > > if (!chip->scan_bbt) > > Brian
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index bd39f7b..27d755b 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -202,6 +202,51 @@ static void nand_select_chip(struct mtd_info *mtd, int chipnr) } /** + * nand_write_byte - [DEFAULT] write single byte to chip + * @mtd: MTD device structure + * @byte: value to write + * + * Default function to write a byte to I/O[7:0] + */ +static void nand_write_byte(struct mtd_info *mtd, uint8_t byte) +{ + struct nand_chip *chip = mtd->priv; + + chip->write_buf(mtd, &byte, 1); +} + +/** + * nand_write_byte16 - [DEFAULT] write single byte to a chip with width 16 + * @mtd: MTD device structure + * @byte: value to write + * + * Default function to write a byte to I/O[7:0] on a 16-bit wide chip. + */ +static void nand_write_byte16(struct mtd_info *mtd, uint8_t byte) +{ + struct nand_chip *chip = mtd->priv; + uint16_t word = byte; + + /* + * It's not entirely clear what should happen to I/O[15:8] when writing + * a byte. The ONFi spec (Revision 3.1; 2012-09-19, Section 2.16) reads: + * + * When the host supports a 16-bit bus width, only data is + * transferred at the 16-bit width. All address and command line + * transfers shall use only the lower 8-bits of the data bus. During + * command transfers, the host may place any value on the upper + * 8-bits of the data bus. During address transfers, the host shall + * set the upper 8-bits of the data bus to 00h. + * + * One user of the write_byte callback is nand_onfi_set_features. The + * four parameters are specified to be written to I/O[7:0], but this is + * neither an address nor a command transfer. Let's assume a 0 on the + * upper I/O lines is OK. + */ + chip->write_buf(mtd, &word, 2); +} + +/** * nand_write_buf - [DEFAULT] write buffer to chip * @mtd: MTD device structure * @buf: data buffer @@ -2706,7 +2751,7 @@ static int nand_block_markbad(struct mtd_info *mtd, loff_t ofs) } /** - * nand_onfi_set_features- [REPLACEABLE] set features for ONFI nand + * nand_onfi_set_features - [REPLACEABLE] set features for ONFI nand * @mtd: MTD device structure * @chip: nand chip info structure * @addr: feature address. @@ -2716,6 +2761,7 @@ static int nand_onfi_set_features(struct mtd_info *mtd, struct nand_chip *chip, int addr, uint8_t *subfeature_param) { int status; + int i; if (!chip->onfi_version || !(le16_to_cpu(chip->onfi_params.opt_cmd) @@ -2723,7 +2769,9 @@ static int nand_onfi_set_features(struct mtd_info *mtd, struct nand_chip *chip, return -EINVAL; chip->cmdfunc(mtd, NAND_CMD_SET_FEATURES, addr, -1); - chip->write_buf(mtd, subfeature_param, ONFI_SUBFEATURE_PARAM_LEN); + for (i = 0; i < ONFI_SUBFEATURE_PARAM_LEN; ++i) + chip->write_byte(mtd, subfeature_param[i]); + status = chip->waitfunc(mtd, chip); if (status & NAND_STATUS_FAIL) return -EIO; @@ -2731,7 +2779,7 @@ static int nand_onfi_set_features(struct mtd_info *mtd, struct nand_chip *chip, } /** - * nand_onfi_get_features- [REPLACEABLE] get features for ONFI nand + * nand_onfi_get_features - [REPLACEABLE] get features for ONFI nand * @mtd: MTD device structure * @chip: nand chip info structure * @addr: feature address. @@ -2740,6 +2788,8 @@ static int nand_onfi_set_features(struct mtd_info *mtd, struct nand_chip *chip, static int nand_onfi_get_features(struct mtd_info *mtd, struct nand_chip *chip, int addr, uint8_t *subfeature_param) { + int i; + if (!chip->onfi_version || !(le16_to_cpu(chip->onfi_params.opt_cmd) & ONFI_OPT_CMD_SET_GET_FEATURES)) @@ -2749,7 +2799,8 @@ static int nand_onfi_get_features(struct mtd_info *mtd, struct nand_chip *chip, memset(subfeature_param, 0, ONFI_SUBFEATURE_PARAM_LEN); chip->cmdfunc(mtd, NAND_CMD_GET_FEATURES, addr, -1); - chip->read_buf(mtd, subfeature_param, ONFI_SUBFEATURE_PARAM_LEN); + for (i = 0; i < ONFI_SUBFEATURE_PARAM_LEN; ++i) + *subfeature_param++ = chip->read_byte(mtd); return 0; } @@ -2812,6 +2863,8 @@ static void nand_set_defaults(struct nand_chip *chip, int busw) chip->block_markbad = nand_default_block_markbad; if (!chip->write_buf || chip->write_buf == nand_write_buf) chip->write_buf = busw ? nand_write_buf16 : nand_write_buf; + if (!chip->write_byte) + chip->write_byte = busw ? nand_write_byte16 : nand_write_byte; if (!chip->read_buf || chip->read_buf == nand_read_buf) chip->read_buf = busw ? nand_read_buf16 : nand_read_buf; if (!chip->scan_bbt) diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h index 9e6c8f9..e843942 100644 --- a/include/linux/mtd/nand.h +++ b/include/linux/mtd/nand.h @@ -432,6 +432,8 @@ struct nand_buffers { * flash device. * @read_byte: [REPLACEABLE] read one byte from the chip * @read_word: [REPLACEABLE] read one word from the chip + * @write_byte [REPLACEABLE] write a single byte to the chip on the + * low 8 I/O lines * @write_buf: [REPLACEABLE] write data from the buffer to the chip * @read_buf: [REPLACEABLE] read data from the chip into the buffer * @select_chip: [REPLACEABLE] select chip nr @@ -521,6 +523,7 @@ struct nand_chip { uint8_t (*read_byte)(struct mtd_info *mtd); u16 (*read_word)(struct mtd_info *mtd); + void (*write_byte)(struct mtd_info *mtd, uint8_t byte); void (*write_buf)(struct mtd_info *mtd, const uint8_t *buf, int len); void (*read_buf)(struct mtd_info *mtd, uint8_t *buf, int len); void (*select_chip)(struct mtd_info *mtd, int chip);
According to the Open NAND Flash Interface Specification (ONFI) Revision 3.1 "Parameters are always transferred on the lower 8-bits of the data bus." for the Get Features and Set Features commands. So using read_buf and write_buf is wrong for 16-bit wide nand chips as they use I/O[15:0]. The Get Features command is easily fixed using 4 times the read_byte callback. For Set Features implement a new overwritable callback "write_byte". Still I expect the default to work just fine for all controllers and making it overwriteable was just done for symmetry. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> --- drivers/mtd/nand/nand_base.c | 61 +++++++++++++++++++++++++++++++++++++++++--- include/linux/mtd/nand.h | 3 +++ 2 files changed, 60 insertions(+), 4 deletions(-)