On 2021-08-16 08:42, Bing Fan wrote:
At present, i think a focus of our discussion is whether this patch is
necessary.
As for the other points you mentioned, I think they can be used as code
review comments.
Yes, as you described below, most dts files have only one interrupt, but
not all platforms are like this.
The scene I'm encountering now is the latter: the interrupt lines of the
uart is connected to the gic separately
so the dts should be define like this:
duart1: serial@5E139000 {
compatible = "arm,pl011", "arm,primecell";
reg = <0x00 0x5E139000 0x0 0x1000>;
interrupts = <GIC_SPI 178 IRQ_TYPE_LEVEL_HIGH>,
<GIC_SPI 179 IRQ_TYPE_LEVEL_HIGH>,
<GIC_SPI 180 IRQ_TYPE_LEVEL_HIGH>,
<GIC_SPI 181 IRQ_TYPE_LEVEL_HIGH>;
clocks = <&sysclk>;
clock-names = "apb_pclk";
};
Apologies for being unclear - the point I was implying is that of course
you can do that in practice, but if you run that DTS through `make
dtbs_check` it will fail. The binding needs extending to make it valid
to specify more than one interrupt, and that's a separate patch and
discussion in itself (simply increasing "maxitems" for the "interrupts"
property is not enough to be robust).
Robin.
The current tty-master code cannot meet this scenario, so I submitted
this patch.
在 2021/8/13 下午10:37, Robin Murphy 写道:
[ +Russell as the listed PL011 maintainer ]
On 2021-08-13 04:31, 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);
When you request the IRQs you break at the first zero, so this could
potentially try to free IRQs that you haven't requested, if there
happen to be any nonzero values beyond that. Maybe that can never
happen, but there seems little need for deliberate inconsistency here.
+}
+
+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++) {
It's not clear where these extra IRQs are expected to come from given
that the DT binding explicitly defines only one :/
+ virq = amba_dev->irq[i];
+ if (virq == 0)
+ break;
+
+ ret = request_irq(virq, pl011_int, IRQF_SHARED,
dev_name(&amba_dev->dev), uap);
Note that using dev_name() here technically breaks user ABI - scripts
looking in /proc for an irq named "uart-pl011" will no longer find it.
Furthermore, the "dev" cookie passed to request_irq is supposed to be
globally unique, which "uap" isn't once you start registering it
multiple times. If firmware did describe all the individual PL011 IRQ
outputs on a system where they are muxed to the same physical IRQ
anyway, you'd end up registering ambiguous IRQ actions here. Of course
in practice you might still get away with that, but it is technically
wrong.
Robin.
+ if (ret) {
+ dev_err(uap->port.dev, "request %u interrupt failed\n",
virq);
+ pl011_release_multi_irqs(uap, i - 1);
+ break;
+ }
+ }
+
+ return ret;
+}
+
static int pl011_allocate_irq(struct uart_amba_port *uap)
{
pl011_write(uap->im, uap, REG_IMSC);
@@ -1753,7 +1788,7 @@ static int pl011_startup(struct uart_port *port)
if (retval)
goto clk_dis;
- retval = pl011_allocate_irq(uap);
+ retval = pl011_allocate_multi_irqs(uap);
if (retval)
goto clk_dis;
@@ -1864,7 +1899,7 @@ static void pl011_shutdown(struct uart_port
*port)
pl011_dma_shutdown(uap);
- free_irq(uap->port.irq, uap);
+ pl011_release_multi_irqs(uap, AMBA_NR_IRQS);
pl011_disable_uart(uap);
