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    SubjectRe: [PATCH v2 2/2] irqchip: Add Qualcomm MPM controller driver
    On Tue, Nov 30, 2021 at 01:19:48PM +0530, Maulik Shah wrote:
    > Hi Shawn,
    >
    > On 11/30/2021 8:01 AM, Shawn Guo wrote:
    >
    > + do {
    > + r_val = readl(priv->base + offset);
    > + udelay(5);
    > + } while (r_val != val);
    >
    > What? Is this waiting for a bit to clear? Why isn't this one of the
    > read*_poll_timeout*() function instead? Surely you can't wait forever
    > here.
    >
    > This is taken from downstream, and it seems to double check the written
    > value by reading it back. But to be honest, I'm not really this is
    > necessary. I will do some testing with the read-back check dropped.
    >
    > How about asking for specs instead? There are QC people on Cc, and
    > many more reading the list. Hopefully they can explain what this is
    > all about.
    >
    > Maulik,
    >
    > If you have some information about this, that would be great.
    >
    > This can be converted to read poll_timeout(). This was introduced in
    > place of wmb() to make sure writes are completed.

    Hmm, in this case, writel() will just do the right thing, as it wraps
    wmb() there. Or am I missing something?

    Shawn

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