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

[David Brownell <david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>]

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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