On Fri, Jan 27, 2017 at 2:08 AM, Jonathan Richardson
<jonathan.richardson@xxxxxxxxxxxx> wrote:
> +static int iproc_mbox_send_data_m0(struct mbox_chan *chan, void *data)
> +{
> + struct iproc_mbox *mbox = dev_get_drvdata(chan->mbox->dev);
> + struct iproc_mbox_msg *msg = (struct iproc_mbox_msg *)data;
> + unsigned long flags;
> + int err = 0;
> + const int poll_period_us = 5;
> + const int max_retries = (MAX_M0_TIMEOUT_MS * 1000) / poll_period_us;
> +
> + if (!msg)
> + return -EINVAL;
> +
> + spin_lock_irqsave(&mbox->lock, flags);
> +
> + dev_dbg(mbox->dev, "Send msg to M0: cmd=0x%x, param=0x%x, wait_ack=%d\n",
> + msg->cmd, msg->param, msg->wait_ack);
> +
prints should be outside the spinlocks.
> + writel(msg->cmd, mbox->base + IPROC_CRMU_MAILBOX0_OFFSET);
> + writel(msg->param, mbox->base + IPROC_CRMU_MAILBOX1_OFFSET);
> +
> + if (msg->wait_ack) {
> + int retries;
> +
move poll_period_us and max_retries in here or just define' them
> + err = msg->reply_code = -ETIMEDOUT;
> + for (retries = 0; retries < max_retries; retries++) {
> + u32 val = readl(
> + mbox->base + IPROC_CRMU_MAILBOX0_OFFSET);
> + if (val & M0_IPC_CMD_DONE_MASK) {
> + /*
> + * M0 replied - save reply code and
> + * clear error.
> + */
> + msg->reply_code = (val &
> + M0_IPC_CMD_REPLY_MASK) >>
> + M0_IPC_CMD_REPLY_SHIFT;
> + err = 0;
> + break;
> + }
> + udelay(poll_period_us);
>
potentially 2ms inside spin_lock_irqsave. Alternative is to implement
a simple 'peek_data' and call it for requests with 'wait_ack'
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