[ECOS] Chaining DSRs in Different Drivers

Douglas Bush dbush@extremeeng.com
Thu Jan 31 17:01:00 GMT 2002


Folks,

Is there a good mechanism for chaining device driver DSRs?

Currently, I have a PCMCIA driver for the CL-PS6700 which receives all
the interrupts coming through the PCMCIA interface.  (In this case a
Wavelan 802.11 card.)

The CL-PS6700 DSR calls the (I believe) appropriate handler, then
re-enables interrupts. (The code is abbreviated below.)

// This DSR handles the card interrupt
static void cf_irq_dsr(cyg_vector_t vector, cyg_ucount32 count,
cyg_addrword_t data)
{
    struct cf_slot *slot = (struct cf_slot *)data;

    // Process interrupt
    (slot->irq_handler.handler)(vector, count, slot->irq_handler.param);

    /* 
        clear all interrupts that occured in the controller
        except for CD1 and CD2
    */
    *(unsigned volatile*)PCICR = ~EDB7XXX_CF_DETECT_MASK;
 
    // Clear interrupt
    cyg_drv_interrupt_acknowledge(EDB7XXX_CF_IRQ);

    // Allow interrupts to happen again
    cyg_drv_interrupt_unmask(EDB7XXX_CF_IRQ);
}

The (slot->irq_handler.handler)(xxx) call actually calls eth_drv_dsr
(bottom of the eth_drv.c file) which schedules a timer but doesn't
actually call the Wavelan driver DSR until sometime later.

The PCMCIA DSR then re-enables interrupts to the PCMCIA port BEFORE the
Wavelan DSR has run, the PCMCIA driver therefore goes into near
continuous interrupt.

Is there a better mechanism for chaining DSRs from one driver (PCMCIA)
to another (Ethernet)?  Preferably from the context of the original DSR?

Regards,
 
Douglas Bush
Extreme Engineering
#17, 6025 - 12 St. SE
Calgary, Alberta, Canada
T2H 2K1

Phone: 403 640 9494 ext-208
Fax: 403 640 9599

http://www.extremeeng.com




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