[PATCH v3 0/3] spi-nor: Add support for Intel SPI serial flash controller

[Stefan Roese]

Hi Mika,

On 15.08.2016 09:10, Mika Westerberg wrote:
> This is third version of the series. Previous versions can be found:
> 
>   v2: http://lists.infradead.org/pipermail/linux-mtd/2016-June/068277.html
>   v1: https://lkml.org/lkml/2016/6/14/269
> 
> This series adds support for the Intel SPI serial flash controller found on
> many recent Intel CPUs including Baytrail and Braswell. This driver makes
> it possible to access the BIOS and other platform data which is stored on
> the SPI serial flash. It is also possible to upgrade the BIOS using this
> driver if it has not been protected by special hardware bits.
> 
> The patch [1/3] includes documentation how to upgrade BIOS on MinnowBoard
> MAX.
> 
> Since poking the SPI serial flash can brick the machine, this driver can
> only be enabled when CONFIG_EXPERT=y and even then it will remain read-only
> unless instructed othwerwise by module parameter.

I'm currently testing this driver on a BayTrail based board with
a common 8MiB SPI NOR chip. Something special to note is, that I'm
using U-Boot as bootloader instead of some BIOS. Accessing the
SPI NOR in U-Boot works without problems. Also I'm able to access
the SPI NOR in Linux via the flashrom tool just fine.

I've now applied your v3 patchset on top of v4.8 and got the SPI NOR
driver loaded. But the SPI NOR device is not detected correctly. Here
the output of the driver with DEBUG enabled:

...
[    3.675891] intel-spi intel-spi: BFPREG=0x07ff0300
[    3.675894] intel-spi intel-spi: HSFSTS_CTL=0x00006000
[    3.675897] intel-spi intel-spi: FADDR=0x006effc0
[    3.675900] intel-spi intel-spi: DLOCK=0x00000000
[    3.675902] intel-spi intel-spi: FDATA(0)=0x00000000
[    3.675905] intel-spi intel-spi: FDATA(1)=0x00000000
[    3.675908] intel-spi intel-spi: FDATA(2)=0x00000000
[    3.675910] intel-spi intel-spi: FDATA(3)=0x00000000
[    3.675913] intel-spi intel-spi: FDATA(4)=0x00000000
[    3.675916] intel-spi intel-spi: FDATA(5)=0x00000000
[    3.675918] intel-spi intel-spi: FDATA(6)=0x00000000
[    3.675921] intel-spi intel-spi: FDATA(7)=0x00000000
[    3.675923] intel-spi intel-spi: FDATA(8)=0x00000000
[    3.675926] intel-spi intel-spi: FDATA(9)=0x00000000
[    3.675929] intel-spi intel-spi: FDATA(10)=0x00000000
[    3.675931] intel-spi intel-spi: FDATA(11)=0x00000000
[    3.675934] intel-spi intel-spi: FDATA(12)=0x00000000
[    3.675941] intel-spi intel-spi: FDATA(13)=0x00000000
[    3.675943] intel-spi intel-spi: FDATA(14)=0x00000000
[    3.675946] intel-spi intel-spi: FDATA(15)=0x00000000
[    3.675949] intel-spi intel-spi: FRACC=0x0000ffff
[    3.675951] intel-spi intel-spi: FREG(0)=0x00000000
[    3.675954] intel-spi intel-spi: FREG(1)=0x07ff0300
[    3.675957] intel-spi intel-spi: FREG(2)=0x02ff0001
[    3.675959] intel-spi intel-spi: FREG(3)=0x00001fff
[    3.675962] intel-spi intel-spi: FREG(4)=0x00001fff
[    3.675965] intel-spi intel-spi: PR(0)=0x00000000
[    3.675967] intel-spi intel-spi: PR(1)=0x00000000
[    3.675970] intel-spi intel-spi: PR(2)=0x00000000
[    3.675972] intel-spi intel-spi: PR(3)=0x00000000
[    3.675975] intel-spi intel-spi: PR(4)=0x00000000
[    3.675978] intel-spi intel-spi: PR(5)=0x00000000
[    3.675980] intel-spi intel-spi: SSFSTS_CTL=0xf87f00c0
[    3.675983] intel-spi intel-spi: PREOP_OPTYPE=0x00020000
[    3.675985] intel-spi intel-spi: OPMENU0=0x0000000b
[    3.675988] intel-spi intel-spi: OPMENU1=0x00000000
[    3.675990] intel-spi intel-spi: BCR=0x00000009
[    3.675992] intel-spi intel-spi: Protected regions:
[    3.675997] intel-spi intel-spi: Flash regions:
[    3.676001] intel-spi intel-spi:  00 base: 0x00000000 limit: 0x00000fff
[    3.676004] intel-spi intel-spi:  01 base: 0x00300000 limit: 0x007fffff
[    3.676007] intel-spi intel-spi:  02 base: 0x00001000 limit: 0x002fffff
[    3.676009] intel-spi intel-spi:  03 disabled
[    3.676012] intel-spi intel-spi:  04 disabled
[    3.676014] intel-spi intel-spi: Using HW sequencer for register access
[    3.679294] intel-spi intel-spi: unrecognized JEDEC id bytes: 00, 00, 00
[    3.686002] intel-spi intel-spi: failed to locate the chip
[    3.691505] intel-spi: probe of intel-spi failed with error -2
... 

Do you have a quick guess on what might go wrong here? Anything
that I should change / test?

Thanks,
Stefan