Hello! On 04/23/2019 01:48 PM, Vignesh Raghavendra wrote: > HyperFlash devices are compliant with CFI AMD/Fujitsu Extended Command > Set(0x0002) for flash operations, therefore drivers/mtd/chips/cfi_cmdset_0002.c > can be used as is. But these devices do not support DQ polling method of > determining chip ready/good status. These flashes provide Status > Register whose bits can be polled to know status of flash operation. > > Cypress HyperFlash datasheet here[1], talks about CFI Amd/Fujitsu > Extended Query version 1.5. Bit 0 of "Software Features supported" field > of CFI Primary Vendor-Specific Extended Query table indicates > presence/absence of status register and Bit 1 indicates whether or not > DQ polling is supported. Using these bits, its possible to determine > whether flash supports DQ polling or need to use Status Register. > > Add support for polling Status Register to know device ready/status of > erase/write operations when DQ polling is not supported. > Print error messages on erase/program failure by looking at related > Status Register bits. > > [1] https://www.cypress.com/file/213346/download > > Signed-off-by: Vignesh Raghavendra <vigneshr@xxxxxx> Sorry, only superficial review, I'm not an MTD expert. :-) > --- > drivers/mtd/chips/cfi_cmdset_0002.c | 90 +++++++++++++++++++++++++++++ > include/linux/mtd/cfi.h | 5 ++ > 2 files changed, 95 insertions(+) > > diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c b/drivers/mtd/chips/cfi_cmdset_0002.c > index 7b7286b4d81e..55c4d81098d5 100644 > --- a/drivers/mtd/chips/cfi_cmdset_0002.c > +++ b/drivers/mtd/chips/cfi_cmdset_0002.c > @@ -49,6 +49,16 @@ > #define SST49LF008A 0x005a > #define AT49BV6416 0x00d6 > > +/* > + * Status Register bit description. Used by flash devices that don't > + * support DQ polling (Eg.: HyperFlash) It's "e.g. " :-) [...] > @@ -97,6 +107,48 @@ static struct mtd_chip_driver cfi_amdstd_chipdrv = { > .module = THIS_MODULE > }; > > +/* > + * Use status register to poll for Erase/write completion when DQ is not > + * supported. This is indicated by Bit[1:0] of SoftwareFeatures field in > + * CFI Primary Vendor-Specific Extended Query table 1.5 > + */ > +static int cfi_use_status_reg(struct cfi_private *cfi) > +{ > + struct cfi_pri_amdstd *extp = cfi->cmdset_priv; > + > + return (extp->MinorVersion >= '5') && Parens not needed here, especially as the next operator isn't enclosed. > + (extp->SoftwareFeatures & 0x3) == 0x1; > +} [...] MBR, Sergei
