Re: [PATCH] mtd: spi-nor: Add support for S3AN spi-nor devices

[Boris Brezillon <boris.brezillon@free-electrons.com>]

On Wed, 21 Sep 2016 09:57:23 +0200
Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> wrote:

> Hi Boris
> 
> On Wed, Sep 21, 2016 at 9:07 AM, Boris Brezillon
> <boris.brezillon@free-electrons.com> wrote:
> > Hi Ricardo,
> >
> > Please try to pass the version in your subject prefix (pass
> > --subject-prefix="PATCH vX" to git format-patch).
> >  
> 
> Sorry about that.
> 
> 
> > On Tue, 20 Sep 2016 17:45:51 +0200
> > Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> wrote:  
> 
> >>  /*
> >> + * This code converts an address to the Default Address Mode, that has non
> >> + * power of two page sizes. We must support this mode because it is the default
> >> + * mode supported by Xilinx tools, it can access the whole flash area and
> >> + * changing over to the Power-of-two mode is irreversible and corrupts the
> >> + * original data.
> >> + */
> >> +static loff_t spi_nor_s3an_addr_convert(struct spi_nor *nor, unsigned int addr)
> >> +{
> >> +     unsigned int offset;
> >> +
> >> +     offset = (nor->page_size == 264) ? (addr % 264) : (addr % 528);  
> >
> > Can you send a new version with
> >
> >         offset = addr % nor->page_size;
> >
> > to see if kbuild test robot still complains.
> >  
> 
> This code:
> 
> static loff_t spi_nor_s3an_addr_convert(struct spi_nor *nor, loff_t addr)
> {
> unsigned int offset;
> 
> offset = addr % nor->page_size;
> 
> return ((addr - offset) << 1) | offset;
> }
> 
> 
> When built like:
> 
>    wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross
> -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # save the attached .config to linux build tree
>         make.cross ARCH=blackfin
> 
> Produces this error:
> 
> 
> drivers/built-in.o: In function `spi_nor_write':
> drivers/mtd/spi-nor/spi-nor.c:(.text+0xfeb8): undefined reference to `__moddi3'
> drivers/built-in.o: In function `spi_nor_read':
> drivers/mtd/spi-nor/spi-nor.c:(.text+0x10248): undefined reference to `__moddi3'
> drivers/built-in.o: In function `spi_nor_erase':
> drivers/mtd/spi-nor/spi-nor.c:(.text+0x1034e): undefined reference to `__moddi3'
> Makefile:956: recipe for target 'vmlinux' failed
> 
> 
> But I think I found the right combination:
> 
> 
> static loff_t spi_nor_s3an_addr_convert(struct spi_nor *nor, loff_t addr)
> {
> unsigned int offset = addr;
> 
> offset %= nor->page_size;
> 
> return ((addr - offset) << 1) | offset;
> }
> 
> 
> This one works fine on x86 and blackfin
> 
> Sending v7

Wait. If you really want to manipulate an loff_t variable, you can do

	offset = do_div(addr, nor->page_size);