| Message ID | 20210531181757.19458-3-p.yadav@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Avoid odd length/address read/writes in 8D-8D-8D mode. | expand |
Am 2021-05-31 20:17, schrieb Pratyush Yadav: > The Octal DTR configuration is stored in the CFR5V register. This > register is 1 byte wide. But 1 byte long transactions are not allowed > in > 8D-8D-8D mode. Since the next byte address does not contain any > register, it is safe to write any value to it. Write a 0 to it. > > Signed-off-by: Pratyush Yadav <p.yadav@ti.com> > --- Can't say much, because there is no public datasheet, is there? But looks sane. Same for patch 3/6.
On 01/06/21 02:47PM, Michael Walle wrote: > Am 2021-05-31 20:17, schrieb Pratyush Yadav: > > The Octal DTR configuration is stored in the CFR5V register. This > > register is 1 byte wide. But 1 byte long transactions are not allowed in > > 8D-8D-8D mode. Since the next byte address does not contain any > > register, it is safe to write any value to it. Write a 0 to it. > > > > Signed-off-by: Pratyush Yadav <p.yadav@ti.com> > > --- > > Can't say much, because there is no public datasheet, is there? https://www.cypress.com/file/513996/download > > But looks sane. Same for patch 3/6.
On 5/31/21 9:17 PM, Pratyush Yadav wrote: > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > > The Octal DTR configuration is stored in the CFR5V register. This > register is 1 byte wide. But 1 byte long transactions are not allowed in > 8D-8D-8D mode. Since the next byte address does not contain any > register, it is safe to write any value to it. Write a 0 to it. > > Signed-off-by: Pratyush Yadav <p.yadav@ti.com> > --- > > (no changes since v1) > > drivers/mtd/spi-nor/spansion.c | 18 +++++++++++++----- > 1 file changed, 13 insertions(+), 5 deletions(-) > > diff --git a/drivers/mtd/spi-nor/spansion.c b/drivers/mtd/spi-nor/spansion.c > index ee82dcd75310..e6bf5c9eee6a 100644 > --- a/drivers/mtd/spi-nor/spansion.c > +++ b/drivers/mtd/spi-nor/spansion.c > @@ -65,10 +65,18 @@ static int spi_nor_cypress_octal_dtr_enable(struct spi_nor *nor, bool enable) > if (ret) > return ret; > > - if (enable) > - *buf = SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_EN; > - else > - *buf = SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_DS; > + if (enable) { > + buf[0] = SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_EN; > + } else { > + /* > + * The register is 1-byte wide, but 1-byte transactions are not > + * allowed in 8D-8D-8D mode. Since there is no register at the > + * next location, just initialize the value to 0 and let the > + * transaction go on. > + */ > + buf[0] = SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_DS; > + buf[1] = 0; how about writing 0xff instead? > + } > > op = (struct spi_mem_op) > SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WR_ANY_REG, 1), > @@ -76,7 +84,7 @@ static int spi_nor_cypress_octal_dtr_enable(struct spi_nor *nor, bool enable) > SPINOR_REG_CYPRESS_CFR5V, > 1), > SPI_MEM_OP_NO_DUMMY, > - SPI_MEM_OP_DATA_OUT(1, buf, 1)); > + SPI_MEM_OP_DATA_OUT(enable ? 1 : 2, buf, 1)); > > if (!enable) > spi_nor_spimem_setup_op(nor, &op, SNOR_PROTO_8_8_8_DTR); > -- > 2.30.0 >
On 12/23/21 3:06 PM, Tudor Ambarus wrote: > On 5/31/21 9:17 PM, Pratyush Yadav wrote: >> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe >> >> The Octal DTR configuration is stored in the CFR5V register. This >> register is 1 byte wide. But 1 byte long transactions are not allowed in >> 8D-8D-8D mode. Since the next byte address does not contain any >> register, it is safe to write any value to it. Write a 0 to it. >> >> Signed-off-by: Pratyush Yadav <p.yadav@ti.com> >> --- >> >> (no changes since v1) >> >> drivers/mtd/spi-nor/spansion.c | 18 +++++++++++++----- >> 1 file changed, 13 insertions(+), 5 deletions(-) >> >> diff --git a/drivers/mtd/spi-nor/spansion.c b/drivers/mtd/spi-nor/spansion.c >> index ee82dcd75310..e6bf5c9eee6a 100644 >> --- a/drivers/mtd/spi-nor/spansion.c >> +++ b/drivers/mtd/spi-nor/spansion.c >> @@ -65,10 +65,18 @@ static int spi_nor_cypress_octal_dtr_enable(struct spi_nor *nor, bool enable) >> if (ret) >> return ret; >> >> - if (enable) >> - *buf = SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_EN; >> - else >> - *buf = SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_DS; >> + if (enable) { >> + buf[0] = SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_EN; >> + } else { >> + /* >> + * The register is 1-byte wide, but 1-byte transactions are not >> + * allowed in 8D-8D-8D mode. Since there is no register at the >> + * next location, just initialize the value to 0 and let the >> + * transaction go on. >> + */ >> + buf[0] = SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_DS; >> + buf[1] = 0; > > how about writing 0xff instead? patches 1, 2 and 3 look fine, except for this comment. Would you resend them, or you want me to do the change locally when applying? Send me an updated comment if so. > >> + } >> >> op = (struct spi_mem_op) >> SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WR_ANY_REG, 1), >> @@ -76,7 +84,7 @@ static int spi_nor_cypress_octal_dtr_enable(struct spi_nor *nor, bool enable) >> SPINOR_REG_CYPRESS_CFR5V, >> 1), >> SPI_MEM_OP_NO_DUMMY, >> - SPI_MEM_OP_DATA_OUT(1, buf, 1)); >> + SPI_MEM_OP_DATA_OUT(enable ? 1 : 2, buf, 1)); >> >> if (!enable) >> spi_nor_spimem_setup_op(nor, &op, SNOR_PROTO_8_8_8_DTR); >> -- >> 2.30.0 >> >
On 12/23/21 3:06 PM, Tudor.Ambarus@microchip.com wrote: > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > > On 5/31/21 9:17 PM, Pratyush Yadav wrote: >> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe >> >> The Octal DTR configuration is stored in the CFR5V register. This >> register is 1 byte wide. But 1 byte long transactions are not allowed in >> 8D-8D-8D mode. Since the next byte address does not contain any >> register, it is safe to write any value to it. Write a 0 to it. >> >> Signed-off-by: Pratyush Yadav <p.yadav@ti.com> >> --- >> >> (no changes since v1) >> >> drivers/mtd/spi-nor/spansion.c | 18 +++++++++++++----- >> 1 file changed, 13 insertions(+), 5 deletions(-) >> >> diff --git a/drivers/mtd/spi-nor/spansion.c b/drivers/mtd/spi-nor/spansion.c >> index ee82dcd75310..e6bf5c9eee6a 100644 >> --- a/drivers/mtd/spi-nor/spansion.c >> +++ b/drivers/mtd/spi-nor/spansion.c >> @@ -65,10 +65,18 @@ static int spi_nor_cypress_octal_dtr_enable(struct spi_nor *nor, bool enable) >> if (ret) >> return ret; >> >> - if (enable) >> - *buf = SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_EN; >> - else >> - *buf = SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_DS; >> + if (enable) { >> + buf[0] = SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_EN; >> + } else { >> + /* >> + * The register is 1-byte wide, but 1-byte transactions are not >> + * allowed in 8D-8D-8D mode. Since there is no register at the >> + * next location, just initialize the value to 0 and let the >> + * transaction go on. >> + */ >> + buf[0] = SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_DS; >> + buf[1] = 0; > > how about writing 0xff instead? it doesn't matter, it's a register. Will apply first 3. > >> + } >> >> op = (struct spi_mem_op) >> SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WR_ANY_REG, 1), >> @@ -76,7 +84,7 @@ static int spi_nor_cypress_octal_dtr_enable(struct spi_nor *nor, bool enable) >> SPINOR_REG_CYPRESS_CFR5V, >> 1), >> SPI_MEM_OP_NO_DUMMY, >> - SPI_MEM_OP_DATA_OUT(1, buf, 1)); >> + SPI_MEM_OP_DATA_OUT(enable ? 1 : 2, buf, 1)); >> >> if (!enable) >> spi_nor_spimem_setup_op(nor, &op, SNOR_PROTO_8_8_8_DTR); >> -- >> 2.30.0 >> > > ______________________________________________________ > Linux MTD discussion mailing list > http://lists.infradead.org/mailman/listinfo/linux-mtd/ >
diff --git a/drivers/mtd/spi-nor/spansion.c b/drivers/mtd/spi-nor/spansion.c index ee82dcd75310..e6bf5c9eee6a 100644 --- a/drivers/mtd/spi-nor/spansion.c +++ b/drivers/mtd/spi-nor/spansion.c @@ -65,10 +65,18 @@ static int spi_nor_cypress_octal_dtr_enable(struct spi_nor *nor, bool enable) if (ret) return ret; - if (enable) - *buf = SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_EN; - else - *buf = SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_DS; + if (enable) { + buf[0] = SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_EN; + } else { + /* + * The register is 1-byte wide, but 1-byte transactions are not + * allowed in 8D-8D-8D mode. Since there is no register at the + * next location, just initialize the value to 0 and let the + * transaction go on. + */ + buf[0] = SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_DS; + buf[1] = 0; + } op = (struct spi_mem_op) SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WR_ANY_REG, 1), @@ -76,7 +84,7 @@ static int spi_nor_cypress_octal_dtr_enable(struct spi_nor *nor, bool enable) SPINOR_REG_CYPRESS_CFR5V, 1), SPI_MEM_OP_NO_DUMMY, - SPI_MEM_OP_DATA_OUT(1, buf, 1)); + SPI_MEM_OP_DATA_OUT(enable ? 1 : 2, buf, 1)); if (!enable) spi_nor_spimem_setup_op(nor, &op, SNOR_PROTO_8_8_8_DTR);
The Octal DTR configuration is stored in the CFR5V register. This register is 1 byte wide. But 1 byte long transactions are not allowed in 8D-8D-8D mode. Since the next byte address does not contain any register, it is safe to write any value to it. Write a 0 to it. Signed-off-by: Pratyush Yadav <p.yadav@ti.com> --- (no changes since v1) drivers/mtd/spi-nor/spansion.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-)