On Mon, 15 Oct 2007 09:33:49 -0700
Jiri Slaby <[email protected]> wrote:
> phantom, improved data passing
>
> this new version guarantees amb_bit switch in small enough intervals, so
> that the device won't stop working in the middle of a movement anymore.
> However it preserves old (openhaptics) functionality.
>
> ...
>
> +
> + /* preserve amp bit (don't allow to change it when in NOT_OH) */
> + if (r.reg == PHN_CONTROL && (dev->status & PHB_NOT_OH))
> + dev->ctl_reg = r.value = (r.value & ~PHN_CTL_AMP) |
> + (dev->ctl_reg & PHN_CTL_AMP);
hm, is that coded as clearly and as simply as possible? Don't think so :(
> + spin_lock_irqsave(&dev->regs_lock, flags);
> + if (dev->status & PHB_NOT_OH)
> + memcpy(&dev->oregs, &rs, sizeof(rs));
> + else {
> + for (i = 0; i < min(rs.count, 8U); i++)
We evaluate min() each time around the loop. Doesn't matter much here I guess.
> + if (rs.mask & BIT(i))
> + iowrite32(rs.values[i], dev->oaddr + i);
> + ioread32(dev->iaddr); /* PCI posting */
> + }
> + spin_unlock_irqrestore(&dev->regs_lock, flags);
> break;
> case PHN_GET_REG:
> if (copy_from_user(&r, argp, sizeof(r)))
>
> ...
>
> static irqreturn_t phantom_isr(int irq, void *data)
> {
> struct phantom_device *dev = data;
> + unsigned int i;
> + u32 ctl;
>
> - if (!(ioread32(dev->iaddr + PHN_CONTROL) & PHN_CTL_IRQ))
> + spin_lock(&dev->regs_lock);
> + ctl = ioread32(dev->iaddr + PHN_CONTROL);
> + if (!(ctl & PHN_CTL_IRQ)) {
> + spin_unlock(&dev->regs_lock);
> return IRQ_NONE;
> + }
>
> iowrite32(0, dev->iaddr);
> iowrite32(0xc0, dev->iaddr);
> +
> + if (dev->status & PHB_NOT_OH)
> + for (i = 0; i < min(dev->oregs.count, 8U); i++)
But this is the interrupt handler, and there's a pointer chase as well as
the min() each time around the loop (I assume). I doubt if the world will
end, but it seems a bit lazy?
> + if (dev->oregs.mask & BIT(i))
> + iowrite32(dev->oregs.values[i], dev->oaddr + i);
> +
> + dev->ctl_reg ^= PHN_CTL_AMP;
> + iowrite32(dev->ctl_reg, dev->iaddr + PHN_CONTROL);
> + spin_unlock(&dev->regs_lock);
> +
-
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