| Message ID | 20240201131710.797505-2-f.suligoi@asem.it |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [1/1] mtd: spi-nor: everspin: add em004lxb entry | expand |
Hi, > Add the Everspin EM0004LXB 4Mb (512KB) Industrial STT-MRAM Persistent > Memory. Out of curiosity, what is your use case here? Usually, I push back on this small MRAM devices in SPI-NOR in favor of the at25 driver. But this datasheet lists octal dtr with 200mhz, which seems a bit ridiculous for 512kB. The at25 driver only supports single bit SPI of course. I'm not sure in which mode you are using this device, though. The DS shows a non-volatile configuration register (Table 10, offset 0) and it's default value is single bit SPI. > This device is JEDEC compatible (JESD251 and JESD251-1), but it is not > able to provide SFDP information. > > Link: https://www.everspin.com/file/158244/download No newline. > Signed-off-by: Flavio Suligoi <f.suligoi@asem.it> > --- > drivers/mtd/spi-nor/everspin.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/mtd/spi-nor/everspin.c > b/drivers/mtd/spi-nor/everspin.c > index 5f321e24ae7d..4741930ce9a8 100644 > --- a/drivers/mtd/spi-nor/everspin.c > +++ b/drivers/mtd/spi-nor/everspin.c > @@ -31,6 +31,14 @@ static const struct flash_info everspin_nor_parts[] > = { > .size = SZ_512K, > .sector_size = SZ_512K, > .flags = SPI_NOR_NO_ERASE | SPI_NOR_NO_FR, > + }, { > + .id = SNOR_ID(0x6b, 0xbb, 0x13), > + .name = "em004lxb", No name. We prefer to only have the ID for parts which has JEDED IDs. > + .size = SZ_512K, > + .sector_size = SZ_512K, This should probably be removed (and then default to the 64k erase size). > + .flags = SPI_NOR_NO_ERASE | SPI_NOR_NO_FR | SPI_NOR_HAS_LOCK | Don't use SPI_NOR_NO_ERASE for new devices. Eventually, I like to get rid of this flag. This device is emulating the erase instruction, so it should work without. SPI_NOR_NO_FR is wrong here. The DS says it supports fast read. Please also have a look at [1] for the required tests. -michael > + SPI_NOR_HAS_TB | SPI_NOR_4BIT_BP | SPI_NOR_BP3_SR_BIT6, > + .no_sfdp_flags = SPI_NOR_SKIP_SFDP, > } > }; [1] https://docs.kernel.org/driver-api/mtd/spi-nor.html
Hi Michael, ... > Subject: Re: [PATCH 1/1] mtd: spi-nor: everspin: add em004lxb entry > > Hi, > > > Add the Everspin EM0004LXB 4Mb (512KB) Industrial STT-MRAM Persistent > > Memory. > > Out of curiosity, what is your use case here? Usually, I push back on this small > MRAM devices in SPI-NOR in favor of the at25 driver. But this datasheet lists > octal dtr with 200mhz, which seems a bit ridiculous for 512kB. The at25 driver > only supports single bit SPI of course. > > I'm not sure in which mode you are using this device, though. The DS shows a > non-volatile configuration register (Table 10, offset 0) and it's default value is > single bit SPI. ... We adopted the MRAM to save some important application data in case of power loss (there are some super-capacitors to maintain the power for a few seconds). We use this MRAM in single SPI mode (MISO, MOSI, clock and CS). About the SPI frequency, we use only 30MHz, because it is a hw limit of the MX8MP CPU. I used the SPI-NOR driver, instead of at25, because in everspin.c there are other Everspin MRAMs devices (already used in other our boards). Best regards, Flavio
diff --git a/drivers/mtd/spi-nor/everspin.c b/drivers/mtd/spi-nor/everspin.c index 5f321e24ae7d..4741930ce9a8 100644 --- a/drivers/mtd/spi-nor/everspin.c +++ b/drivers/mtd/spi-nor/everspin.c @@ -31,6 +31,14 @@ static const struct flash_info everspin_nor_parts[] = { .size = SZ_512K, .sector_size = SZ_512K, .flags = SPI_NOR_NO_ERASE | SPI_NOR_NO_FR, + }, { + .id = SNOR_ID(0x6b, 0xbb, 0x13), + .name = "em004lxb", + .size = SZ_512K, + .sector_size = SZ_512K, + .flags = SPI_NOR_NO_ERASE | SPI_NOR_NO_FR | SPI_NOR_HAS_LOCK | + SPI_NOR_HAS_TB | SPI_NOR_4BIT_BP | SPI_NOR_BP3_SR_BIT6, + .no_sfdp_flags = SPI_NOR_SKIP_SFDP, } };
Add the Everspin EM0004LXB 4Mb (512KB) Industrial STT-MRAM Persistent Memory. This device is JEDEC compatible (JESD251 and JESD251-1), but it is not able to provide SFDP information. Link: https://www.everspin.com/file/158244/download Signed-off-by: Flavio Suligoi <f.suligoi@asem.it> --- drivers/mtd/spi-nor/everspin.c | 8 ++++++++ 1 file changed, 8 insertions(+)