| Message ID | 20200930185732.6201-8-p.yadav@ti.com |
|---|---|
| State | Superseded |
| Delegated to: | Ambarus Tudor |
| Headers | show |
| Series | mtd: spi-nor: add xSPI Octal DTR support | expand |
On 9/30/20 9:57 PM, Pratyush Yadav wrote: > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > > Some controllers, like the cadence qspi controller, have trouble reading > only 1 byte in DTR mode. So, do 2 byte reads for SR and FSR commands in > DTR mode, and then discard the second byte. > > Signed-off-by: Pratyush Yadav <p.yadav@ti.com> Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com> > --- > drivers/mtd/spi-nor/core.c | 15 +++++++++++++-- > 1 file changed, 13 insertions(+), 2 deletions(-) > > diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c > index 1465cf80f978..73a26e7e32c2 100644 > --- a/drivers/mtd/spi-nor/core.c > +++ b/drivers/mtd/spi-nor/core.c > @@ -370,7 +370,7 @@ int spi_nor_write_disable(struct spi_nor *nor) > * spi_nor_read_sr() - Read the Status Register. > * @nor: pointer to 'struct spi_nor'. > * @sr: pointer to a DMA-able buffer where the value of the > - * Status Register will be written. > + * Status Register will be written. Should be at least 2 bytes. > * > * Return: 0 on success, -errno otherwise. > */ > @@ -388,6 +388,11 @@ static int spi_nor_read_sr(struct spi_nor *nor, u8 *sr) > if (nor->reg_proto == SNOR_PROTO_8_8_8_DTR) { > op.addr.nbytes = nor->params->rdsr_addr_nbytes; > op.dummy.nbytes = nor->params->rdsr_dummy; > + /* > + * We don't want to read only one byte in DTR mode. So, > + * read 2 and then discard the second byte. > + */ > + op.data.nbytes = 2; > } > > spi_nor_spimem_setup_op(nor, &op, nor->reg_proto); > @@ -408,7 +413,8 @@ static int spi_nor_read_sr(struct spi_nor *nor, u8 *sr) > * spi_nor_read_fsr() - Read the Flag Status Register. > * @nor: pointer to 'struct spi_nor' > * @fsr: pointer to a DMA-able buffer where the value of the > - * Flag Status Register will be written. > + * Flag Status Register will be written. Should be at least 2 > + * bytes. > * > * Return: 0 on success, -errno otherwise. > */ > @@ -426,6 +432,11 @@ static int spi_nor_read_fsr(struct spi_nor *nor, u8 *fsr) > if (nor->reg_proto == SNOR_PROTO_8_8_8_DTR) { > op.addr.nbytes = nor->params->rdsr_addr_nbytes; > op.dummy.nbytes = nor->params->rdsr_dummy; > + /* > + * We don't want to read only one byte in DTR mode. So, > + * read 2 and then discard the second byte. > + */ > + op.data.nbytes = 2; > } > > spi_nor_spimem_setup_op(nor, &op, nor->reg_proto); > -- > 2.28.0 >
diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c index 1465cf80f978..73a26e7e32c2 100644 --- a/drivers/mtd/spi-nor/core.c +++ b/drivers/mtd/spi-nor/core.c @@ -370,7 +370,7 @@ int spi_nor_write_disable(struct spi_nor *nor) * spi_nor_read_sr() - Read the Status Register. * @nor: pointer to 'struct spi_nor'. * @sr: pointer to a DMA-able buffer where the value of the - * Status Register will be written. + * Status Register will be written. Should be at least 2 bytes. * * Return: 0 on success, -errno otherwise. */ @@ -388,6 +388,11 @@ static int spi_nor_read_sr(struct spi_nor *nor, u8 *sr) if (nor->reg_proto == SNOR_PROTO_8_8_8_DTR) { op.addr.nbytes = nor->params->rdsr_addr_nbytes; op.dummy.nbytes = nor->params->rdsr_dummy; + /* + * We don't want to read only one byte in DTR mode. So, + * read 2 and then discard the second byte. + */ + op.data.nbytes = 2; } spi_nor_spimem_setup_op(nor, &op, nor->reg_proto); @@ -408,7 +413,8 @@ static int spi_nor_read_sr(struct spi_nor *nor, u8 *sr) * spi_nor_read_fsr() - Read the Flag Status Register. * @nor: pointer to 'struct spi_nor' * @fsr: pointer to a DMA-able buffer where the value of the - * Flag Status Register will be written. + * Flag Status Register will be written. Should be at least 2 + * bytes. * * Return: 0 on success, -errno otherwise. */ @@ -426,6 +432,11 @@ static int spi_nor_read_fsr(struct spi_nor *nor, u8 *fsr) if (nor->reg_proto == SNOR_PROTO_8_8_8_DTR) { op.addr.nbytes = nor->params->rdsr_addr_nbytes; op.dummy.nbytes = nor->params->rdsr_dummy; + /* + * We don't want to read only one byte in DTR mode. So, + * read 2 and then discard the second byte. + */ + op.data.nbytes = 2; } spi_nor_spimem_setup_op(nor, &op, nor->reg_proto);
Some controllers, like the cadence qspi controller, have trouble reading only 1 byte in DTR mode. So, do 2 byte reads for SR and FSR commands in DTR mode, and then discard the second byte. Signed-off-by: Pratyush Yadav <p.yadav@ti.com> --- drivers/mtd/spi-nor/core.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-)