[U-Boot] [RFC] MUSB-UDC issues and fixes

[Tom <Tom.Rix@windriver.com>]

Juha Kuikka wrote:
> Hi,
> 
> I ran into some issues with the MUSB-UDC support while adding a new
> Davinci DM850/OMAP-L138 board:
> 
> 1. Move endpoint count into SoC specific musb-header file. This
> implementation only has 4 instead of 15 OMAP2/3 has.
> 2. On DM850 the MUSB interrupts are read from a wrapper, not from MUSB
> block . Add optional interface function to read-and-clear interrupts.
> 3. Problem setting FADDR - in udc_irq() the
> musb_peri_ep0_set_address() gets called on the same run as the ep0
> SET_ADDRESS request is handled. This causes the FADDR to change before
> the status stage interrupt is received and USB session fails. Fixed by
> removing extra call to musb_peri_ep0() from udc_irq(). It should only
> be called when EP0 interrupt is present.
> 4. udc_setup_ep() has a problem when id != 0, epinfo[] is indexed too
> far, this results in wrong EPs configured.
> 
> This is not a final patch, just asking for comments.
> 
> I am investigating another issue where rx endpoint stops receiving
> data when CDC ACM console is used. This happens under heavy inbound
> data conditions, namely using "loads".
> 
> -------------------------
> diff --git a/drivers/usb/musb/musb_udc.c b/drivers/usb/musb/musb_udc.c
> index fc43cf4..b6f9bff 100644
> --- a/drivers/usb/musb/musb_udc.c
> +++ b/drivers/usb/musb/musb_udc.c
> @@ -65,8 +65,6 @@
>  /* #define MUSB_DEBUG */
>  #include "musb_debug.h"
> 
> -#define MAX_ENDPOINT 15
> -
>  #define GET_ENDPOINT(dev,ep)						\
>  (((struct usb_device_instance *)(dev))->bus->endpoint_array + ep)
> 
> @@ -157,6 +155,17 @@ static void musb_db_regs(void)
>  #define musb_db_regs()
>  #endif /* DEBUG_MUSB */
> 
> +#ifndef CONFIG_MUSB_SOC_IRQ
> +static void musb_get_interrupts(u8 *usb, u16 *rx, u16 *tx)
> +{
> +	*usb = readb(&musbr->intrusb);
> +	*rx = readw(&musbr->intrrx);
> +	*tx = readw(&musbr->intrtx);
> +}
> +#else
> +extern void musb_get_interrupts(u8 *usb, u16 *rx, u16 *tx);
> +#endif
> +

The reading of INT registers clears them.
If all you want in the usb INT's, you will wipe out the rx/tx to
get them.

Tom