[flashrom] [Patch] Added SST25LF080A Flash Chip

[Stefan Tauner]

On Wed, 13 Apr 2011 21:04:38 +0200
Stefan Tauner <stefan.tauner at student.tuwien.ac.at> wrote:

> On Wed, 13 Apr 2011 14:11:00 -0400
> Zeus Castro <thezeusjuice at gmail.com> wrote:
> 
> 
> > > disclamer: this is my first patch review for flashrom.
> > disclamer: this is my first patch ever :-)
> > Also, although I'm a decent programmer, my knowledge of C is pretty
> > limited.
> > 
> > Based on the datasheets of both, the SST25LF080A is basically a larger
> > version of the SST25LF040A.
> > However, flashrom had an entry for SST25LF040A, but not for
> > SST25LF080A. As such, I modeled it after the entry for SST25LF040A,
> > and altered the values that differed.
> thought so. that's what i and probably all without better insights
> usually do. my comments were mostly meant to show what i think is the
> right thing to do, not in your patch alone but on the whole in the code
> related to it. that's probably the wrong stand when one reviews a
> concrete patch, but it feels natural and the reviews i received were
> similar. in this case my patch would probably be very similar to yours.
> with the exception of the .RES _REMS suffices:
> 
> > >> +             .name           = "SST25LF080A.RES",
> > > i dont see a reason why you are using .RES here.
> > > according to the datasheet REMS work as well as RES.
> > > but maybe i dont know some detail.
> > >
> > >> +             .probe          = probe_spi_res2,
> > > ok, or probe_spi_rems
> > >
> > I was confused as well as to why the oscillation between REMS, RES,
> > and RES2 in the SST25LF040A entry, but figured that there was probably
> > a reason I did not understand, and copied it over in the same manner.
> > So, you recommend I change it all to REMS?
> i would remove the .RES from the name, the probe method is ok.
> i dont understand it either, maybe someone else can clear that up.
> 
> > >> Index: flashchips.h
> > >
> > >> -#define SST_SST25VF080_REMS  0x80    /* REMS or RES opcode */
> > >> +#define SST_SST25VF080_REMS  0x80    /* REMS or RES opcode, same
> > >> as SST25LF080A */
> > >
> > > since the SST25VF080 is not implemented and that define is not used
> > > at all as far as i (and grep) can see, there is no reason to use
> > > the rems suffix imho.
> > >
> > Apparently SST25VFxxx and SST25LFxxx chips often share the same
> > REMS/RES device id. And since the one for  SST25LF040A was "tacked on"
> > to the define for SST25VF040_REMS (since they use the same byte), and
> > there was an already existing define for SST25VF080_REMS (which uses
> > the same byte as I was planning to include for the SST25LF080A), I
> > just "tacked on" the SST25LF080A in the same manner. So, you recommend
> > I change it to read?:
> > #define SST_SST25LF080A  0x80"
> i dont like the _REMS suffix, just like above.
> the "same as xyz"-strategy is used all over in flashrom.h and is ok.
> 
> > >> +             .tested         = TEST_UNTESTED,
> > > did you really not test it? why have you added it?
> > >
> > The only sample I have is currently inside my laptop, and flashrom
> > access to it is being blocked by the EC/KBC (an ENE KB926).
> > Besides, there are about 170 untested chips in flashchips.c, so I
> > figured one more, especially based on an incremental upgrade to a
> > probe-tested chip (SST25LF040A), wouldn't be problematic.
> no problem at all, i just wanted to know.
> 
> > >> +             .unlock         = spi_disable_blockprotect,
> > > this will not work if bit 7 (BPL) is set
> > > some of the at25* write protections are similar. one might use them.
> > >
> > spi_disable_blockprotect is sufficient for this chip:
> > The important bits are 2-5 (although this chip only cares about 2 and
> > 3). If those bits are 0, the chip isn't protected.
> > If there is protection, spi_disable_blockprotect correctly attempts to
> > set them to 0, and checks if it succeeded.
> > The only way it can fail is if bit 7 is set and the Write Protect Pin
> > (WP#) is being pulled low, in which case there is nothing that can be
> > done (block protection cannot be disabled without reseting the chip)
> > and spi_disable_blockprotect returns 1.
> > No additional functionality is possible.
> > 
> correct. i missed the point, that WRSR is not possible when BPL is set.
> 
> all in all it looks ok, thanks for your effort!
> due to the rems/res stuff someone else needs to take a look (i dont
> have commit rights anyway).
> 

i have sorted out the naming problems, moved the definition a bit up
and committed in r1415. thank you!

-- 
Kind regards/Mit freundlichen Grüßen, Stefan Tauner