Re: problem with converting from at91_spi to atmel_spi (AT91RM9200)

[Ivan Kuten <ivan.kuten-NihHnkIkDZhBDgjK7y7TUQ@public.gmane.org>]

Hi David, 

> 
> This is AT91rm9200, yes?
> 

Correct, it's AT91RM9200.

While trying to catch your thought regarding chip selects & errata, I just note 
that in mach-at91/*.c there are some boards which use dataflash and "mtd_dataflash" driver with
SPI chip select 0, for example board-ek.c, board-carmeva.c, board-dk.c. I can't believe 
all of them has non-working dataflash (certainly at they was tested).

Best regards, Ivan



On Wed, 23 May 2007 09:06:12 -0700
David Brownell wrote:

> On Wednesday 23 May 2007, Ivan Kuten wrote:
> > 
> > Hello,
> > 
> > I'm trying to convert from legacy at91_spi to newer atmel_spi driver in my board.
> > Linux kernel 2.6.22rc2 + corresponding patch from maxim.org.za/at91_26.html
> 
> This is AT91rm9200, yes?
> 
> 
> > board specific spi info :
> > 
> > static struct spi_board_info chub_spi_devices[] = {
> >         {       /* DataFlash chip */
> >                 .modalias       = "mtd_dataflash",
> >                 .chip_select    = 0,
> 
> Chipselect zero ... I've had one report that this driver has some issues
> on that chipselect.  There seem to be two errata in conflict here:
> 
>   - One saying that when the controller manages chipselects, it
>     does so incorrectly ... releasing it before it's told to do so,
>     which prematurely terminates transactions.  ("NPCSx rises if
>     no data is to be transmitted")
> 
>   - Another saying that if it does *not* manage chipselects, then
>     broken mode fault detect logic kicks in; this could be what
>     you're seeing.  ("Mode Fault does not allow more than one
>     master on Chip Select 0")
> 
> I've CC'd the relevant folk from Atmel.  Seems that maybe rm9200
> needs to have a special case whereby chipselect zero is managed
> by the hardware despite the first erratum.  And maybe that because
> of that erratum, the DMA chaining needs to be made to work... else
> root-on-dataflash won't behave.  (Or some other workaround.)
> 
> - Dave
> 
> 
> >                 .max_speed_hz   = 15 * 1000 * 1000,
> >         },
> > };
> > 
> > snip from .config:
> > 
> > CONFIG_MTD_DATAFLASH=y
> > 
> > # 
> > # SPI support
> > # 
> > CONFIG_SPI=y
> > CONFIG_SPI_DEBUG=y
> > CONFIG_SPI_MASTER=y
> > 
> > #
> > # SPI Master Controller Drivers
> > # 
> > CONFIG_SPI_ATMEL=y
> > # CONFIG_SPI_BITBANG is not set
> > CONFIG_SPI_AT91_MANUAL_CS=y
> > #
> > # SPI Protocol Masters
> > #
> > # CONFIG_SPI_AT25 is not set
> > # CONFIG_SPI_SPIDEV is not set
> > 
> > While boot, the board stumbles on SPI initialization:
> > 
> > Uncompressing Linux....................................................................... done, booting the kernel.
> > Linux version 2.6.22-rc1 (vano@newbox) (gcc version 3.4.2) #12 Wed May 23 14:05:30 EEST 2007
> > CPU: ARM920T [41129200] revision 0 (ARMv4T), cr=c0007177
> > Machine: Promwad Chub
> > ---snip----
> > eth0: Link now 100-FullDuplex
> > eth0: AT91 ethernet at 0xfefbc000 int=24 100-FullDuplex (00:12:34:56:78:9a)
> > eth0: National Semiconductor DP83848 PHY
> > NAND device: Manufacturer ID: 0xec, Chip ID: 0x76 (Samsung NAND 64MiB 3,3V 8-bit)
> > Scanning device for bad blocks
> > Creating 1 MTD partitions on "NAND 64MiB 3,3V 8-bit":
> > 0x00000000-0x04000000 : "NAND Partition 1"
> > atmel_spi atmel_spi.0: Atmel SPI Controller at 0xfffe0000 (irq 13)
> > 
> > Not booting further. Timer led is still blinking. Is atmel_spi usable?
> > I have working setup on 2.6.20 + corresponding patch from
> > maxim.org.za/at91_26.html +  legacy "at91_dataflash" + legacy "at91_spi" 
> > 
> > Best regards, Ivan
> > 
> > 
> > 

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