| Message ID | 20240201094353.33281-3-jaimeliao.tw@gmail.com |
|---|---|
| State | Changes Requested |
| Delegated to: | Ambarus Tudor |
| Headers | show |
| Series | Add octal DTR support for Macronix flash | expand |
On Thu, Feb 01, 2024 at 05:43:46PM +0800, Jaime Liao wrote: > From: JaimeLiao <jaimeliao@mxic.com.tw> > > There are NOR flashes (Macronix) that swap the bytes on a 16-bit > boundary when configured in Octal DTR mode. The byte order of > 16-bit words is swapped when read or written in Octal Double > Transfer Rate (DTR) mode compared to Single Transfer Rate (STR) > modes. If one writes D0 D1 D2 D3 bytes using 1-1-1 mode, and uses Acked-by: Mark Brown <broonie@kernel.org>
Hi, > From: JaimeLiao <jaimeliao@mxic.com.tw> I think Tudor told you to keep his name/mail here. > There are NOR flashes (Macronix) that swap the bytes on a 16-bit > boundary when configured in Octal DTR mode. The byte order of > 16-bit words is swapped when read or written in Octal Double > Transfer Rate (DTR) mode compared to Single Transfer Rate (STR) > modes. If one writes D0 D1 D2 D3 bytes using 1-1-1 mode, and uses > 8D-8D-8D SPI mode for reading, it will read back D1 D0 D3 D2. > Swapping the bytes may introduce some endianness problems. It can > affect the boot sequence if the entire boot sequence is not handled > in either 8D-8D-8D mode or 1-1-1 mode. So we must swap the bytes > back to have the same byte order as in STR modes. Fortunately there > are controllers that could swap the bytes back at runtime, > addressing the flash's endiannesses requirements. Provide a way for > the upper layers to specify the byte order in Octal DTR mode. > > Merge Tudor's patch and add modifications for suiting newer version > of Linux kernel. > > Suggested-by: Michael Walle <mwalle@kernel.org> > Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org> > Signed-off-by: JaimeLiao <jaimeliao@mxic.com.tw> > --- > drivers/spi/spi-mem.c | 4 ++++ > include/linux/spi/spi-mem.h | 6 ++++++ > 2 files changed, 10 insertions(+) > > diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c > index 2dc8ceb85374..f8120f6b288f 100644 > --- a/drivers/spi/spi-mem.c > +++ b/drivers/spi/spi-mem.c > @@ -172,6 +172,10 @@ bool spi_mem_default_supports_op(struct spi_mem > *mem, > if (!spi_mem_controller_is_capable(ctlr, dtr)) > return false; > > + if (op->data.swap16 && > + !spi_mem_controller_is_capable(ctlr, swap16)) Since you need to redo this anyway (see below): This can now be one line. Please keep in mind that the 80char limit was extended to 100 chars some time ago. And I think this reads better if its just one line. > + return false; > + > if (op->cmd.nbytes != 2) > return false; > } else { > diff --git a/include/linux/spi/spi-mem.h b/include/linux/spi/spi-mem.h > index f866d5c8ed32..8df44fbc9d99 100644 > --- a/include/linux/spi/spi-mem.h > +++ b/include/linux/spi/spi-mem.h > @@ -89,6 +89,8 @@ enum spi_mem_data_dir { > * @dummy.dtr: whether the dummy bytes should be sent in DTR mode or > not > * @data.buswidth: number of IO lanes used to send/receive the data > * @data.dtr: whether the data should be sent in DTR mode or not > + * @data.swap16: whether the byte order of 16-bit words is swapped > when read > + * or written in Octal DTR mode compared to STR mode. I think this was ordered alphabetically in the former patch, but since you've renamed it to swap16 now the order would change. I don't have any preference here, just wanted to point that out. I just noticed because the new member "swap16" in spi_controller_mem_caps was added in the middle, which looked odd. > * @data.ecc: whether error correction is required or not > * @data.dir: direction of the transfer > * @data.nbytes: number of data bytes to send/receive. Can be zero if > the > @@ -123,6 +125,7 @@ struct spi_mem_op { > struct { > u8 buswidth; > u8 dtr : 1; > + u8 swap16 : 1; > u8 ecc : 1; > u8 __pad : 6; Still wrong, please go over all the previous remarks, to be clear you have to use "__pad : 5" here. Otherwise looks good. So with the above fixed: Reviewed-by: Michael Walle <mwalle@kernel.org> -michael > enum spi_mem_data_dir dir; > @@ -296,10 +299,13 @@ struct spi_controller_mem_ops { > /** > * struct spi_controller_mem_caps - SPI memory controller capabilities > * @dtr: Supports DTR operations > + * @swap16: Supports swapping bytes on a 16 bit boundary when > configured in > + * Octal DTR > * @ecc: Supports operations with error correction > */ > struct spi_controller_mem_caps { > bool dtr; > + bool swap16; > bool ecc; > };
diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c index 2dc8ceb85374..f8120f6b288f 100644 --- a/drivers/spi/spi-mem.c +++ b/drivers/spi/spi-mem.c @@ -172,6 +172,10 @@ bool spi_mem_default_supports_op(struct spi_mem *mem, if (!spi_mem_controller_is_capable(ctlr, dtr)) return false; + if (op->data.swap16 && + !spi_mem_controller_is_capable(ctlr, swap16)) + return false; + if (op->cmd.nbytes != 2) return false; } else { diff --git a/include/linux/spi/spi-mem.h b/include/linux/spi/spi-mem.h index f866d5c8ed32..8df44fbc9d99 100644 --- a/include/linux/spi/spi-mem.h +++ b/include/linux/spi/spi-mem.h @@ -89,6 +89,8 @@ enum spi_mem_data_dir { * @dummy.dtr: whether the dummy bytes should be sent in DTR mode or not * @data.buswidth: number of IO lanes used to send/receive the data * @data.dtr: whether the data should be sent in DTR mode or not + * @data.swap16: whether the byte order of 16-bit words is swapped when read + * or written in Octal DTR mode compared to STR mode. * @data.ecc: whether error correction is required or not * @data.dir: direction of the transfer * @data.nbytes: number of data bytes to send/receive. Can be zero if the @@ -123,6 +125,7 @@ struct spi_mem_op { struct { u8 buswidth; u8 dtr : 1; + u8 swap16 : 1; u8 ecc : 1; u8 __pad : 6; enum spi_mem_data_dir dir; @@ -296,10 +299,13 @@ struct spi_controller_mem_ops { /** * struct spi_controller_mem_caps - SPI memory controller capabilities * @dtr: Supports DTR operations + * @swap16: Supports swapping bytes on a 16 bit boundary when configured in + * Octal DTR * @ecc: Supports operations with error correction */ struct spi_controller_mem_caps { bool dtr; + bool swap16; bool ecc; };