Re: [PATCH v6] arm pl011 serial: support multi-irq request
From: Robin Murphy
Date: Fri Aug 13 2021 - 11:21:46 EST
On 2021-08-13 16:04, Greg KH wrote:
On Fri, Aug 13, 2021 at 03:08:48PM +0100, Robin Murphy wrote:
Hi Greg,
On 2021-08-13 09:17, Greg KH wrote:
On Fri, Aug 13, 2021 at 03:56:01PM +0800, Bing Fan wrote:
在 8/13/2021 15:19, Greg KH 写道:
On Fri, Aug 13, 2021 at 11:31:30AM +0800, Bing Fan wrote:
From: Bing Fan <tombinfan@xxxxxxxxxxx>
In order to make pl011 work better, multiple interrupts are
required, such as TXIM, RXIM, RTIM, error interrupt(FE/PE/BE/OE);
at the same time, pl011 to GIC does not merge the interrupt
lines(each serial-interrupt corresponding to different GIC hardware
interrupt), so need to enable and request multiple gic interrupt
numbers in the driver.
Signed-off-by: Bing Fan <tombinfan@xxxxxxxxxxx>
---
drivers/tty/serial/amba-pl011.c | 39 +++++++++++++++++++++++++++++++--
1 file changed, 37 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index e14f3378b8a0..eaac3431459c 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -1701,6 +1701,41 @@ static void pl011_write_lcr_h(struct uart_amba_port *uap, unsigned int lcr_h)
}
}
+static void pl011_release_multi_irqs(struct uart_amba_port *uap, unsigned int max_cnt)
+{
+ struct amba_device *amba_dev = container_of(uap->port.dev, struct amba_device, dev);
+ int i;
+
+ for (i = 0; i < max_cnt; i++)
+ if (amba_dev->irq[i])
+ free_irq(amba_dev->irq[i], uap);
+}
+
+static int pl011_allocate_multi_irqs(struct uart_amba_port *uap)
+{
+ int ret = 0;
+ int i;
+ unsigned int virq;
+ struct amba_device *amba_dev = container_of(uap->port.dev, struct amba_device, dev);
+
+ pl011_write(uap->im, uap, REG_IMSC);
+
+ for (i = 0; i < AMBA_NR_IRQS; i++) {
+ virq = amba_dev->irq[i];
+ if (virq == 0)
+ break;
+
+ ret = request_irq(virq, pl011_int, IRQF_SHARED, dev_name(&amba_dev->dev), uap);
+ if (ret) {
+ dev_err(uap->port.dev, "request %u interrupt failed\n", virq);
+ pl011_release_multi_irqs(uap, i - 1);
+ break;
+ }
+ }
+
+ return ret;
+}
This function looks identical to pl011_allocate_irq(), so what is the
difference here? Why is this still needed at all? What does it do that
is different from pl011_allocate_irq()?
The v6-patch is based on master of
git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git, not tty-next.
Always submit patches based on tty-next if you want them accepted into
that tree.
As below, the pl011_allocate_irq function supports single irq request only,
which different from pl011_allocate_multi_irqs.
static int pl011_allocate_irq(struct uart_amba_port *uap)
{
pl011_write(uap->im, uap, REG_IMSC);
return request_irq(uap->port.irq, pl011_int, IRQF_SHARED, "uart-pl011",
uap);
}
Ok, but that does not reflect what is in my tree to be merged for
5.15-rc1. What is wrong with the code in there that is incorrect and
needs to be changed?
As reported by Qian Cai, it blows up on ACPI-based systems by assuming
port.dev is an amba_device when in fact in that situation it's a
platform_device. If you're able to drop the current patch from your tree
that would probably be the best thing to do for the moment.
I have not seen any such bug report.
It's the thread on the v5 patch that you've just replied to ;)
If something needs to be reverted in linux-next, (i.e. in my tty-next
branch), please let me know. Ideally by sending a pathc to do so...
Since I'm only really involved here off the back of a drive-by review
comment, I'll leave that up to Qian.
Cheers,
Robin.