[U-Boot] Flag -mno-cache-volatile to bypass the cache

[ivanchuklist ivanchu]

I feel like a fool :S. If i didn't miss anything spi_xfer is defined in
include/spi.h and that function is implemented in cpu related code. I see
also that atmel has put their code in drivers/spi and drivers/mmc. Finally i
took as example cpu/pxa/mmc.c where i found functions (defined in
include/mmc.h) to provide access to the mmc card with the commands cp and
mmc (if CONFIG_CMD_MMC is defined). Then, i chose to put my code in
cpu/nios2/mmc_spi.c to implement the following functions,

Functions used in common/cmd_mmc.c,
mmc_read: return -1 (cp error)
mmc_write: return -1 (cp error)
mmc2info: return -1 (cp error)
mmc_init: it initializes the card in spi mode and it fills the
block_dev_desc_t structure (mmc command).

Functions used to access the block device,
mmc_block_read: it reads a block in spi mode and its passed as a pointer in
the field block_read in block_dev_desc_t (used in fs/fat/fat.c to access the
partition table)
mmc_get_dev: to give a pointer to the block_dev_desc_t variable (needed by
disk/part.c because CONFIG_MMC is defined).

Because i had to write functions to manage the spi core, i thought that
spi_xfer() should be used to access the core in mmc_block_read.
I'm a little lost because there are some implementations that places the
code in cpu/ and others in drivers/. Is the code well placed in cpu/?. I
would like to write the code as it should be written and i wouldn't like to
mess up the code tree.

Regards,
Ivan Llopard.

2009/2/5 Wolfgang Denk <wd at denx.de>

> Dear ivanchuklist ivanchu,
>
> In message <51a313240902051201k1977196cu314e60a1cfcd0e11 at mail.gmail.com>
> you wrote:
> >
> > I see also in cpu/nios an implementation of the spi core, it uses
> volatiles
> > variables to access hardware, so it will not work. Nevertheless the
> > implementation is correct.
>
> I'm not a NIOS expert - but if it doesn't work, this should be fixed.
> Patches welcome.
>
> > I'm adding sd access by spi protocol to u-boot, so i created a new file
> > called mmc_spi.c in cpu/nios2. I faced many problems. I just want to have
> > access to the fat partition, then i wrote mmc_get_dev and mmc_read_block
> but
> > i need to initialize the card so i implemented mmc_init (which add mmc
> > command) and i don't want to write mmc_read/write/2info. Should i
> implement
> > those functions?. In the other hand, should i use spi_xfer() to do spi
> > transactions?.
>
> Sorry, I don't know any of this code,
>
> Best regards,
>
> Wolfgang Denk
>
> --
> DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
> Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
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> "There are no good ways."
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>