[U-Boot] [PATCH] usb: ci_udc: fix interaction with CONFIG_USB_ETH_CDC

[Jörg Krause]

On 06/30/2014 11:15 PM, Marek Vasut wrote:
> On Monday, June 30, 2014 at 10:55:37 PM, Jörg Krause wrote:
> [...]
>>>>> 2) You applied "allow multiple buffer allocs per ep"
>>>> Setting #define CONFIG_SYS_CACHELINE_SIZE 32 to my config file helped
>>>> here. But still timeouts. First run almost always runs fine, only
>>>> sometimes timeouts while receiving a packet, but always running to the
>>>> end. Running tftp after this a second time and more fails with a ERROR:
>>>> The remote end did not respond in time. at
>>>> drivers/usb/gadget/ether.c:2388/usb_eth_init(), but sometimes it works.
>>>>
>>>> Setting CONFIG_SYS_CACHELINE_SIZE 32 does not make it better (as I
>>>> previously wrote it).
>> Sorry, this is a typo. It should be CONFIG_SYS_CACHELINE_SIZE 16 (not 32).
> MX28 has 32b-long cachelines. Setting this to 16 is nonsense.
> [...]
Yes it is. But if I do not set cacheline size to 32 in my config header 
file it will be 64, as I stated in a previous mail.

    I checked this and I found that ARCH_DMA_MINALIGN is set to 64,
    which is not true for Freescale i.MX28. This processor has an
    ARM926EJ-S, which has an cache line size of 32. In
    arch/arm/include/asm/cache.h the macro ARCH_DMA_MINALIGN is defined
    as followed:
    #ifdef CONFIG_SYS_CACHELINE_SIZE
    #define ARCH_DMA_MINALIGN    CONFIG_SYS_CACHELINE_SIZE
    #else
    #define ARCH_DMA_MINALIGN    64
    #endif

    And in /arch/arm/cpu/arm926ejs/cache.c as followed:
    #ifndef CONFIG_SYS_CACHELINE_SIZE
    #define CONFIG_SYS_CACHELINE_SIZE    32
    #endif

    arch/arm/include/asm/cache.h does not see the definition of
    CONFIG_SYS_CACHELINE_SIZE in /arch/arm/cpu/arm926ejs/cache.c, so
    it's a bad place to put it in there.


I was just curious of the impact on the behaviour of the USB ethernet 
gadget driver.
>
> Best regards,
> Marek Vasut