[PATCH] arm pl011 serial: support multi-irq request

[PATCH] arm pl011 serial: support multi-irq request

[Bing Fan]

From: Bing Fan <tombinfan@tencent.com>

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@tencent.com>
---
 drivers/tty/serial/amba-pl011.c | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 78682c12156a..b63164e89903 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -1703,9 +1703,30 @@ static void pl011_write_lcr_h(struct uart_amba_port *uap, unsigned int lcr_h)
 
 static int pl011_allocate_irq(struct uart_amba_port *uap)
 {
+	int ret = -1;
+	int i = 0;
+	unsigned int virq = 0;
+	struct amba_device *amba_dev = (struct amba_device *)uap->port.dev;
+
+	if (!amba_dev)
+		return -1;
+
 	pl011_write(uap->im, uap, REG_IMSC);
 
-	return request_irq(uap->port.irq, pl011_int, IRQF_SHARED, "uart-pl011", uap);
+	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, "uart-pl011-*", uap);
+		if (ret < 0) {
+			dev_info(uap->port.dev, "%s %d request %u interrupt failed\n",
+					__func__, __LINE__, virq);
+			break;
+		}
+	}
+
+	return ret;
 }
 
 /*
-- 
2.17.1

Re: [PATCH] arm pl011 serial: support multi-irq request

[Greg KH]

On Tue, Jun 29, 2021 at 09:29:24AM +0800, Bing Fan wrote:
> From: Bing Fan <tombinfan@tencent.com>
> 
> 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@tencent.com>
> ---
>  drivers/tty/serial/amba-pl011.c | 23 ++++++++++++++++++++++-
>  1 file changed, 22 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
> index 78682c12156a..b63164e89903 100644
> --- a/drivers/tty/serial/amba-pl011.c
> +++ b/drivers/tty/serial/amba-pl011.c
> @@ -1703,9 +1703,30 @@ static void pl011_write_lcr_h(struct uart_amba_port *uap, unsigned int lcr_h)
>  
>  static int pl011_allocate_irq(struct uart_amba_port *uap)
>  {
> +	int ret = -1;

Pick a real error value.

> +	int i = 0;

Why is this initialized?

> +	unsigned int virq = 0;

Why is this initialized?

> +	struct amba_device *amba_dev = (struct amba_device *)uap->port.dev;

Are you sure you can just cast this like this?  Did you test this?

> +
> +	if (!amba_dev)
> +		return -1;

Do not make up error numbers, return a specific -ERR* value.

And how can this happen?

> +
>  	pl011_write(uap->im, uap, REG_IMSC);
>  
> -	return request_irq(uap->port.irq, pl011_int, IRQF_SHARED, "uart-pl011", uap);
> +	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, "uart-pl011-*", uap);
> +		if (ret < 0) {
> +			dev_info(uap->port.dev, "%s %d request %u interrupt failed\n",
> +					__func__, __LINE__, virq);

dev_err() is for errors, not dev_info().

And no need for __func__ and __LINE__ for the dev_* calls.



> +			break;
> +		}
> +	}
> +
> +	return ret;
>  }
>  
>  /*
> -- 
> 2.17.1
> 

Re: [PATCH] arm pl011 serial: support multi-irq request

[Greg KH]

On Tue, Jun 29, 2021 at 07:32:36PM +0800, Bing Fan wrote:
> hello,
> 
> replied as below.
> 
> and new patch is at the bottom.

Please submit this properly as the documentation says to do so, I can't
take an attachment :(

> > > +	struct amba_device *amba_dev = (struct amba_device *)uap->port.dev;
> > Are you sure you can just cast this like this?  Did you test this?
> 
> 
> Yes, i have tested and applied in my project.
> 
> The function pl011_probe calls pl011_setup_port with &amba_dev->dev and uap
> params;
> 
> and pl011_setup_port set uap->port.dev to the address of amba_dev->dev;
> 
> the two structs' relationship is:
> 
>     struct amba_device {
> 
>         struct device dev;
> 
>         ……
> 
>     };
> 
> When pointer(uap->port.dev) points to amba_dev->dev address, the momery
> actully stores
> 
> content of struct amba_device; so the cast assignment can be forced to
> amba_dev.

That is now how this should work, use the correct container_of() cast
instead.  That will always work no matter where struct device is in the
structure.  You got lucky here :)

> > > +
> > > +	if (!amba_dev)
> > > +		return -1;
> > Do not make up error numbers, return a specific -ERR* value.
> 
> changed to "return -ENODEV"

So this changed the logic of this function, is that ok?

> > 
> > And how can this happen?
> 
> The function pl011_setup_port isn't called, event pl011_probe isn't called.

And how can that ever happen?


thanks,

greg k-h

Re: [PATCH] arm pl011 serial: support multi-irq request

[Greg KH]

On Tue, Jun 29, 2021 at 08:31:00PM +0800, Bing Fan wrote:
> hello,
> 
> 
> 在 6/29/2021 20:18, Greg KH 写道:
> > On Tue, Jun 29, 2021 at 07:32:36PM +0800, Bing Fan wrote:
> > > hello, replied as below. and new patch is at the bottom.
> > Please submit this properly as the documentation says to do so, I can't
> > take an attachment :(
> Ok.
> > > > > + struct amba_device *amba_dev = (struct amba_device *)uap->port.dev;
> > > > Are you sure you can just cast this like this? Did you test this?
> > > Yes, i have tested and applied in my project. The function
> > > pl011_probe calls pl011_setup_port with &amba_dev->dev and uap
> > > params; and pl011_setup_port set uap->port.dev to the address of
> > > amba_dev->dev; the two structs' relationship is:     struct
> > > amba_device {         struct device dev;         ……     }; When
> > > pointer(uap->port.dev) points to amba_dev->dev address, the momery
> > > actully stores content of struct amba_device; so the cast assignment
> > > can be forced to amba_dev.
> > That is now how this should work, use the correct container_of() cast
> > instead. That will always work no matter where struct device is in the
> > structure. You got lucky here :)
> 
> changed to "struct amba_device *amba_dev = container_of(uap->port.dev, struct amba_device, dev);"
> 
> 
> > > > > + + if (!amba_dev) + return -1;
> > > > Do not make up error numbers, return a specific -ERR* value.
> > > changed to "return -ENODEV"
> > So this changed the logic of this function, is that ok?
> 
> No, just sanity check.

If it can never happen, no need to check for it.

> > > > And how can this happen?
> > > The function pl011_setup_port isn't called, event pl011_probe isn't
> > > called.
> > And how can that ever happen?
> 
> If there is no pl011 device.

How can that happen here?

thanks,

greg k-h

[PATCH] arm pl011 serial: support multi-irq request

[bing fan]

From: Bing Fan <tombinfan@tencent.com>

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 <hptsfb@gmail.com>
---
 drivers/tty/serial/amba-pl011.c | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 78682c12156a..2b6f43c27dea 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -1703,9 +1703,30 @@ static void pl011_write_lcr_h(struct
uart_amba_port *uap, unsigned int lcr_h)

 static int pl011_allocate_irq(struct uart_amba_port *uap)
 {
+       int ret = -1;
+       int i = 0;
+       unsigned int virq = 0;
+       struct amba_device *amba_dev = (struct amba_device *)uap->port.dev;
+
+       if (!amba_dev)
+               return -1;
+
        pl011_write(uap->im, uap, REG_IMSC);

-       return request_irq(uap->port.irq, pl011_int, IRQF_SHARED,
"uart-pl011", uap);
+       for (i = 0; i < AMBA_NR_IRQS; i++) {
+               virq = amba_dev->irq[i];
+               if (virq == 0)          // request irq until virq is 0
+                       break;
+
+               ret = request_irq(virq, pl011_int, IRQF_SHARED,
"uart-pl011-*", uap);
+               if (ret < 0) {
+                       dev_info(uap->port.dev, "%s %d request %u
interrupt failed\n",
+                                       __func__, __LINE__, virq);
+                       break;
+               }
+       }
+
+       return ret;
 }

 /*
-- 
2.17.1

Re: [PATCH] arm pl011 serial: support multi-irq request

[Greg Kroah-Hartman]

On Mon, Jun 28, 2021 at 03:19:13PM +0800, bing fan wrote:
> From: Bing Fan <tombinfan@tencent.com>
> 
> 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 <hptsfb@gmail.com>
> ---
>  drivers/tty/serial/amba-pl011.c | 23 ++++++++++++++++++++++-
>  1 file changed, 22 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
> index 78682c12156a..2b6f43c27dea 100644
> --- a/drivers/tty/serial/amba-pl011.c
> +++ b/drivers/tty/serial/amba-pl011.c
> @@ -1703,9 +1703,30 @@ static void pl011_write_lcr_h(struct
> uart_amba_port *uap, unsigned int lcr_h)
> 
>  static int pl011_allocate_irq(struct uart_amba_port *uap)
>  {
> +       int ret = -1;
> +       int i = 0;
> +       unsigned int virq = 0;
> +       struct amba_device *amba_dev = (struct amba_device *)uap->port.dev;
> +
> +       if (!amba_dev)
> +               return -1;
> +
>         pl011_write(uap->im, uap, REG_IMSC);
> 
> -       return request_irq(uap->port.irq, pl011_int, IRQF_SHARED,
> "uart-pl011", uap);
> +       for (i = 0; i < AMBA_NR_IRQS; i++) {
> +               virq = amba_dev->irq[i];
> +               if (virq == 0)          // request irq until virq is 0
> +                       break;
> +
> +               ret = request_irq(virq, pl011_int, IRQF_SHARED,
> "uart-pl011-*", uap);
> +               if (ret < 0) {
> +                       dev_info(uap->port.dev, "%s %d request %u
> interrupt failed\n",
> +                                       __func__, __LINE__, virq);
> +                       break;
> +               }
> +       }
> +
> +       return ret;
>  }
> 
>  /*
> -- 
> 2.17.1


Hi,

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