Messages in this thread | | | Subject | Re: [PATCH] bus: sunxi-rsb: Make interrupt handling more robust | From | Samuel Holland <> | Date | Mon, 7 Oct 2019 07:08:32 -0500 |
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Hello,
On 8/24/19 12:50 PM, Samuel Holland wrote: > The RSB controller has two registers for controlling interrupt inputs: > RSB_INTE, which has bits for each possible interrupt, and the global > interrupt enable bit in RSB_CTRL. > > Currently, we enable the bits in RSB_INTE before each transfer, but this > is unnecessary because we never disable them. Move the initialization of > RSB_INTE so it is done only once. > > We also set the global interrupt enable bit before each transfer. Unlike > other bits in RSB_CTRL, this bit is cleared by writing a zero. Thus, we > clear the bit in the post-timeout cleanup code, so I note that in the > comment. > > However, if we do receive an interrupt, we do not clear the bit. Nor do > we clear interrupt statuses before starting a transfer. Thus, if some > other driver uses the RSB bus while Linux is suspended (as both Trusted > Firmware and SCP firmware do to control the PMIC), we receive spurious > interrupts upon resume. This causes false completion of a transfer, and > the next transfer starts prematurely, causing a LOAD_BSY condition. The > end result is that some transfers at resume fail with -EBUSY. > > With this patch, all transfers reliably succeed during/after resume. > > Signed-off-by: Samuel Holland <samuel@sholland.org>
Ping? Any comments?
> --- > drivers/bus/sunxi-rsb.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/drivers/bus/sunxi-rsb.c b/drivers/bus/sunxi-rsb.c > index be79d6c6a4e4..b8043b58568a 100644 > --- a/drivers/bus/sunxi-rsb.c > +++ b/drivers/bus/sunxi-rsb.c > @@ -274,7 +274,7 @@ static int _sunxi_rsb_run_xfer(struct sunxi_rsb *rsb) > reinit_completion(&rsb->complete); > > writel(RSB_INTS_LOAD_BSY | RSB_INTS_TRANS_ERR | RSB_INTS_TRANS_OVER, > - rsb->regs + RSB_INTE); > + rsb->regs + RSB_INTS); > writel(RSB_CTRL_START_TRANS | RSB_CTRL_GLOBAL_INT_ENB, > rsb->regs + RSB_CTRL); > > @@ -282,7 +282,7 @@ static int _sunxi_rsb_run_xfer(struct sunxi_rsb *rsb) > msecs_to_jiffies(100))) { > dev_dbg(rsb->dev, "RSB timeout\n"); > > - /* abort the transfer */ > + /* abort the transfer and disable interrupts */ > writel(RSB_CTRL_ABORT_TRANS, rsb->regs + RSB_CTRL); > > /* clear any interrupt flags */ > @@ -480,6 +480,9 @@ static irqreturn_t sunxi_rsb_irq(int irq, void *dev_id) > status = readl(rsb->regs + RSB_INTS); > rsb->status = status; > > + /* Disable any further interrupts */ > + writel(0, rsb->regs + RSB_CTRL); > + > /* Clear interrupts */ > status &= (RSB_INTS_LOAD_BSY | RSB_INTS_TRANS_ERR | > RSB_INTS_TRANS_OVER); > @@ -718,6 +721,9 @@ static int sunxi_rsb_probe(struct platform_device *pdev) > goto err_reset_assert; > } > > + writel(RSB_INTS_LOAD_BSY | RSB_INTS_TRANS_ERR | RSB_INTS_TRANS_OVER, > + rsb->regs + RSB_INTE); > + > /* initialize all devices on the bus into RSB mode */ > ret = sunxi_rsb_init_device_mode(rsb); > if (ret) >
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