[RFC PATCH 0/2] Add ability to handle nodes with interrupts-extended property

[RFC PATCH 0/2] Add ability to handle nodes with interrupts-extended property

[Oleksandr Tyshchenko]

From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>

Hello, all.

The purpose of this small series is to add minimal required support for Xen to be able to
handle device-tree nodes with "interrupts-extended" property [1].

The reason:
Xen expects to see "interrupts" property when parsing host device-tree.
But, there are cases when some device nodes contain "interrupts-extended" property instead.
    
The good example here is arch timer node for R-Car Gen3/Gen2 family [2], which is mandatory device
for Xen usage on ARM. And without ability to handle such nodes, Xen fails to operate:
    
(XEN) ****************************************
(XEN) Panic on CPU 0:
(XEN) Timer: Unable to retrieve IRQ 0 from the device tree
(XEN) ****************************************

----------

Preliminary tested on R-Car Gen3 based board. Log (with debug enabled) shows that Xen recognized arch timer
interrupts represented with "interrupts-extended" property:

timer {
	compatible = "arm,armv8-timer";
	interrupts-extended = <&gic GIC_PPI 13 (GIC_CPU_MASK_SIMPLE(8) | IRQ_TYPE_LEVEL_LOW)>,
			      <&gic GIC_PPI 14 (GIC_CPU_MASK_SIMPLE(8) | IRQ_TYPE_LEVEL_LOW)>,
			      <&gic GIC_PPI 11 (GIC_CPU_MASK_SIMPLE(8) | IRQ_TYPE_LEVEL_LOW)>,
			      <&gic GIC_PPI 10 (GIC_CPU_MASK_SIMPLE(8) | IRQ_TYPE_LEVEL_LOW)>;
};

...
(XEN) dt_device_get_raw_irq: dev=/timer, index=0
(XEN)  intspec=1 intsize=3
(XEN) dt_irq_map_raw: par=/soc/interrupt-controller@f1010000,intspec=[0x00000001 0x0000000d...],ointsize=3
(XEN) dt_irq_map_raw: ipar=/soc/interrupt-controller@f1010000, size=3
(XEN)  -> addrsize=0
(XEN)  -> got it !
(XEN) dt_device_get_raw_irq: dev=/timer, index=1
(XEN)  intspec=1 intsize=3
(XEN) dt_irq_map_raw: par=/soc/interrupt-controller@f1010000,intspec=[0x00000001 0x0000000e...],ointsize=3
(XEN) dt_irq_map_raw: ipar=/soc/interrupt-controller@f1010000, size=3
(XEN)  -> addrsize=0
(XEN)  -> got it !
(XEN) dt_device_get_raw_irq: dev=/timer, index=2
(XEN)  intspec=1 intsize=3
(XEN) dt_irq_map_raw: par=/soc/interrupt-controller@f1010000,intspec=[0x00000001 0x0000000b...],ointsize=3
(XEN) dt_irq_map_raw: ipar=/soc/interrupt-controller@f1010000, size=3
(XEN)  -> addrsize=0
(XEN)  -> got it !
(XEN) dt_device_get_raw_irq: dev=/timer, index=3
(XEN)  intspec=1 intsize=3
(XEN) dt_irq_map_raw: par=/soc/interrupt-controller@f1010000,intspec=[0x00000001 0x0000000a...],ointsize=3
(XEN) dt_irq_map_raw: ipar=/soc/interrupt-controller@f1010000, size=3
(XEN)  -> addrsize=0
(XEN)  -> got it !
(XEN) Generic Timer IRQ: phys=30 hyp=26 virt=27 Freq: 8333 KHz
...

----------
The first patch had Julien's R-B some time ago, but I dropped it.  


[1]
https://elixir.bootlin.com/linux/v5.1-rc7/source/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt

[2]
https://elixir.bootlin.com/linux/v5.1-rc7/source/arch/arm64/boot/dts/renesas/r8a7795.dtsi#L3185
https://elixir.bootlin.com/linux/v5.1-rc7/source/arch/arm/boot/dts/r8a7790.dtsi#L1856

Oleksandr Tyshchenko (2):
  xen/device-tree: Add dt_count_phandle_with_args helper
  xen/device-tree: Add ability to handle nodes with interrupts-extended
    prop

 xen/common/device_tree.c      | 39 ++++++++++++++++++++++++++++++++++++---
 xen/include/xen/device_tree.h | 19 +++++++++++++++++++
 2 files changed, 55 insertions(+), 3 deletions(-)

-- 
2.7.4


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[Xen-devel] [RFC PATCH 0/2] Add ability to handle nodes with interrupts-extended property

[Oleksandr Tyshchenko]

From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>

Hello, all.

The purpose of this small series is to add minimal required support for Xen to be able to
handle device-tree nodes with "interrupts-extended" property [1].

The reason:
Xen expects to see "interrupts" property when parsing host device-tree.
But, there are cases when some device nodes contain "interrupts-extended" property instead.
    
The good example here is arch timer node for R-Car Gen3/Gen2 family [2], which is mandatory device
for Xen usage on ARM. And without ability to handle such nodes, Xen fails to operate:
    
(XEN) ****************************************
(XEN) Panic on CPU 0:
(XEN) Timer: Unable to retrieve IRQ 0 from the device tree
(XEN) ****************************************

----------

Preliminary tested on R-Car Gen3 based board. Log (with debug enabled) shows that Xen recognized arch timer
interrupts represented with "interrupts-extended" property:

timer {
	compatible = "arm,armv8-timer";
	interrupts-extended = <&gic GIC_PPI 13 (GIC_CPU_MASK_SIMPLE(8) | IRQ_TYPE_LEVEL_LOW)>,
			      <&gic GIC_PPI 14 (GIC_CPU_MASK_SIMPLE(8) | IRQ_TYPE_LEVEL_LOW)>,
			      <&gic GIC_PPI 11 (GIC_CPU_MASK_SIMPLE(8) | IRQ_TYPE_LEVEL_LOW)>,
			      <&gic GIC_PPI 10 (GIC_CPU_MASK_SIMPLE(8) | IRQ_TYPE_LEVEL_LOW)>;
};

...
(XEN) dt_device_get_raw_irq: dev=/timer, index=0
(XEN)  intspec=1 intsize=3
(XEN) dt_irq_map_raw: par=/soc/interrupt-controller@f1010000,intspec=[0x00000001 0x0000000d...],ointsize=3
(XEN) dt_irq_map_raw: ipar=/soc/interrupt-controller@f1010000, size=3
(XEN)  -> addrsize=0
(XEN)  -> got it !
(XEN) dt_device_get_raw_irq: dev=/timer, index=1
(XEN)  intspec=1 intsize=3
(XEN) dt_irq_map_raw: par=/soc/interrupt-controller@f1010000,intspec=[0x00000001 0x0000000e...],ointsize=3
(XEN) dt_irq_map_raw: ipar=/soc/interrupt-controller@f1010000, size=3
(XEN)  -> addrsize=0
(XEN)  -> got it !
(XEN) dt_device_get_raw_irq: dev=/timer, index=2
(XEN)  intspec=1 intsize=3
(XEN) dt_irq_map_raw: par=/soc/interrupt-controller@f1010000,intspec=[0x00000001 0x0000000b...],ointsize=3
(XEN) dt_irq_map_raw: ipar=/soc/interrupt-controller@f1010000, size=3
(XEN)  -> addrsize=0
(XEN)  -> got it !
(XEN) dt_device_get_raw_irq: dev=/timer, index=3
(XEN)  intspec=1 intsize=3
(XEN) dt_irq_map_raw: par=/soc/interrupt-controller@f1010000,intspec=[0x00000001 0x0000000a...],ointsize=3
(XEN) dt_irq_map_raw: ipar=/soc/interrupt-controller@f1010000, size=3
(XEN)  -> addrsize=0
(XEN)  -> got it !
(XEN) Generic Timer IRQ: phys=30 hyp=26 virt=27 Freq: 8333 KHz
...

----------
The first patch had Julien's R-B some time ago, but I dropped it.  


[1]
https://elixir.bootlin.com/linux/v5.1-rc7/source/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt

[2]
https://elixir.bootlin.com/linux/v5.1-rc7/source/arch/arm64/boot/dts/renesas/r8a7795.dtsi#L3185
https://elixir.bootlin.com/linux/v5.1-rc7/source/arch/arm/boot/dts/r8a7790.dtsi#L1856

Oleksandr Tyshchenko (2):
  xen/device-tree: Add dt_count_phandle_with_args helper
  xen/device-tree: Add ability to handle nodes with interrupts-extended
    prop

 xen/common/device_tree.c      | 39 ++++++++++++++++++++++++++++++++++++---
 xen/include/xen/device_tree.h | 19 +++++++++++++++++++
 2 files changed, 55 insertions(+), 3 deletions(-)

-- 
2.7.4


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[RFC PATCH 1/2] xen/device-tree: Add dt_count_phandle_with_args helper

[Oleksandr Tyshchenko]

From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>

Port Linux helper of_count_phandle_with_args for counting
number of phandles in a property.

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
---
 xen/common/device_tree.c      |  7 +++++++
 xen/include/xen/device_tree.h | 19 +++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
index 8fc401d..65862b5 100644
--- a/xen/common/device_tree.c
+++ b/xen/common/device_tree.c
@@ -1663,6 +1663,13 @@ int dt_parse_phandle_with_args(const struct dt_device_node *np,
                                         index, out_args);
 }
 
+int dt_count_phandle_with_args(const struct dt_device_node *np,
+                               const char *list_name,
+                               const char *cells_name)
+{
+    return __dt_parse_phandle_with_args(np, list_name, cells_name, 0, -1, NULL);
+}
+
 /**
  * unflatten_dt_node - Alloc and populate a device_node from the flat tree
  * @fdt: The parent device tree blob
diff --git a/xen/include/xen/device_tree.h b/xen/include/xen/device_tree.h
index 7408a6c..8315629 100644
--- a/xen/include/xen/device_tree.h
+++ b/xen/include/xen/device_tree.h
@@ -738,6 +738,25 @@ int dt_parse_phandle_with_args(const struct dt_device_node *np,
                                const char *cells_name, int index,
                                struct dt_phandle_args *out_args);
 
+/**
+ * dt_count_phandle_with_args() - Find the number of phandles references in a property
+ * @np: pointer to a device tree node containing a list
+ * @list_name: property name that contains a list
+ * @cells_name: property name that specifies phandles' arguments count
+ *
+ * Returns the number of phandle + argument tuples within a property. It
+ * is a typical pattern to encode a list of phandle and variable
+ * arguments into a single property. The number of arguments is encoded
+ * by a property in the phandle-target node. For example, a gpios
+ * property would contain a list of GPIO specifies consisting of a
+ * phandle and 1 or more arguments. The number of arguments are
+ * determined by the #gpio-cells property in the node pointed to by the
+ * phandle.
+ */
+int dt_count_phandle_with_args(const struct dt_device_node *np,
+                               const char *list_name,
+                               const char *cells_name);
+
 #ifdef CONFIG_DEVICE_TREE_DEBUG
 #define dt_dprintk(fmt, args...)  \
     printk(XENLOG_DEBUG fmt, ## args)
-- 
2.7.4


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[Xen-devel] [RFC PATCH 1/2] xen/device-tree: Add dt_count_phandle_with_args helper

[Oleksandr Tyshchenko]

From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>

Port Linux helper of_count_phandle_with_args for counting
number of phandles in a property.

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
---
 xen/common/device_tree.c      |  7 +++++++
 xen/include/xen/device_tree.h | 19 +++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
index 8fc401d..65862b5 100644
--- a/xen/common/device_tree.c
+++ b/xen/common/device_tree.c
@@ -1663,6 +1663,13 @@ int dt_parse_phandle_with_args(const struct dt_device_node *np,
                                         index, out_args);
 }
 
+int dt_count_phandle_with_args(const struct dt_device_node *np,
+                               const char *list_name,
+                               const char *cells_name)
+{
+    return __dt_parse_phandle_with_args(np, list_name, cells_name, 0, -1, NULL);
+}
+
 /**
  * unflatten_dt_node - Alloc and populate a device_node from the flat tree
  * @fdt: The parent device tree blob
diff --git a/xen/include/xen/device_tree.h b/xen/include/xen/device_tree.h
index 7408a6c..8315629 100644
--- a/xen/include/xen/device_tree.h
+++ b/xen/include/xen/device_tree.h
@@ -738,6 +738,25 @@ int dt_parse_phandle_with_args(const struct dt_device_node *np,
                                const char *cells_name, int index,
                                struct dt_phandle_args *out_args);
 
+/**
+ * dt_count_phandle_with_args() - Find the number of phandles references in a property
+ * @np: pointer to a device tree node containing a list
+ * @list_name: property name that contains a list
+ * @cells_name: property name that specifies phandles' arguments count
+ *
+ * Returns the number of phandle + argument tuples within a property. It
+ * is a typical pattern to encode a list of phandle and variable
+ * arguments into a single property. The number of arguments is encoded
+ * by a property in the phandle-target node. For example, a gpios
+ * property would contain a list of GPIO specifies consisting of a
+ * phandle and 1 or more arguments. The number of arguments are
+ * determined by the #gpio-cells property in the node pointed to by the
+ * phandle.
+ */
+int dt_count_phandle_with_args(const struct dt_device_node *np,
+                               const char *list_name,
+                               const char *cells_name);
+
 #ifdef CONFIG_DEVICE_TREE_DEBUG
 #define dt_dprintk(fmt, args...)  \
     printk(XENLOG_DEBUG fmt, ## args)
-- 
2.7.4


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[RFC PATCH 2/2] xen/device-tree: Add ability to handle nodes with interrupts-extended prop

[Oleksandr Tyshchenko]

From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>

Xen expects to see "interrupts" property when parsing host
device-tree. But, there are cases when some device nodes contain
"interrupts-extended" property instead.

The good example here is arch timer node for R-Car Gen3/Gen2 family,
which is mandatory device for Xen usage on ARM. And without ability
to handle such nodes, Xen fails to operate:

(XEN) ****************************************
(XEN) Panic on CPU 0:
(XEN) Timer: Unable to retrieve IRQ 0 from the device tree
(XEN) ****************************************

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
---
 xen/common/device_tree.c | 32 +++++++++++++++++++++++++++++---
 1 file changed, 29 insertions(+), 3 deletions(-)

diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
index 65862b5..00ada6e 100644
--- a/xen/common/device_tree.c
+++ b/xen/common/device_tree.c
@@ -987,9 +987,19 @@ unsigned int dt_number_of_irq(const struct dt_device_node *device)
     const struct dt_device_node *p;
     const __be32 *intspec, *tmp;
     u32 intsize, intlen;
+    int intnum;
 
     dt_dprintk("dt_irq_number: dev=%s\n", device->full_name);
 
+    /* Try the new-style interrupts-extended first */
+    intnum = dt_count_phandle_with_args(device, "interrupts-extended",
+                                        "#interrupt-cells");
+    if ( intnum > 0 )
+    {
+        dt_dprintk(" intnum=%d\n", intnum);
+        return intnum;
+    }
+
     /* Get the interrupts property */
     intspec = dt_get_property(device, "interrupts", &intlen);
     if ( intspec == NULL )
@@ -1420,10 +1430,29 @@ int dt_device_get_raw_irq(const struct dt_device_node *device,
     const __be32 *intspec, *tmp, *addr;
     u32 intsize, intlen;
     int res = -EINVAL;
+    struct dt_phandle_args args;
+    int i;
 
     dt_dprintk("dt_device_get_raw_irq: dev=%s, index=%u\n",
                device->full_name, index);
 
+    /* Get the reg property (if any) */
+    addr = dt_get_property(device, "reg", NULL);
+
+    /* Try the new-style interrupts-extended first */
+    res = dt_parse_phandle_with_args(device, "interrupts-extended",
+                                     "#interrupt-cells", index, &args);
+    if ( !res )
+    {
+        dt_dprintk(" intspec=%d intsize=%d\n", args.args[0], args.args_count);
+
+        for ( i = 0; i < args.args_count; i++ )
+            args.args[i] = cpu_to_be32(args.args[i]);
+
+        return dt_irq_map_raw(args.np, args.args, args.args_count,
+                              addr, out_irq);
+    }
+
     /* Get the interrupts property */
     intspec = dt_get_property(device, "interrupts", &intlen);
     if ( intspec == NULL )
@@ -1432,9 +1461,6 @@ int dt_device_get_raw_irq(const struct dt_device_node *device,
 
     dt_dprintk(" intspec=%d intlen=%d\n", be32_to_cpup(intspec), intlen);
 
-    /* Get the reg property (if any) */
-    addr = dt_get_property(device, "reg", NULL);
-
     /* Look for the interrupt parent. */
     p = dt_irq_find_parent(device);
     if ( p == NULL )
-- 
2.7.4


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[Xen-devel] [RFC PATCH 2/2] xen/device-tree: Add ability to handle nodes with interrupts-extended prop

[Oleksandr Tyshchenko]

From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>

Xen expects to see "interrupts" property when parsing host
device-tree. But, there are cases when some device nodes contain
"interrupts-extended" property instead.

The good example here is arch timer node for R-Car Gen3/Gen2 family,
which is mandatory device for Xen usage on ARM. And without ability
to handle such nodes, Xen fails to operate:

(XEN) ****************************************
(XEN) Panic on CPU 0:
(XEN) Timer: Unable to retrieve IRQ 0 from the device tree
(XEN) ****************************************

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
---
 xen/common/device_tree.c | 32 +++++++++++++++++++++++++++++---
 1 file changed, 29 insertions(+), 3 deletions(-)

diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
index 65862b5..00ada6e 100644
--- a/xen/common/device_tree.c
+++ b/xen/common/device_tree.c
@@ -987,9 +987,19 @@ unsigned int dt_number_of_irq(const struct dt_device_node *device)
     const struct dt_device_node *p;
     const __be32 *intspec, *tmp;
     u32 intsize, intlen;
+    int intnum;
 
     dt_dprintk("dt_irq_number: dev=%s\n", device->full_name);
 
+    /* Try the new-style interrupts-extended first */
+    intnum = dt_count_phandle_with_args(device, "interrupts-extended",
+                                        "#interrupt-cells");
+    if ( intnum > 0 )
+    {
+        dt_dprintk(" intnum=%d\n", intnum);
+        return intnum;
+    }
+
     /* Get the interrupts property */
     intspec = dt_get_property(device, "interrupts", &intlen);
     if ( intspec == NULL )
@@ -1420,10 +1430,29 @@ int dt_device_get_raw_irq(const struct dt_device_node *device,
     const __be32 *intspec, *tmp, *addr;
     u32 intsize, intlen;
     int res = -EINVAL;
+    struct dt_phandle_args args;
+    int i;
 
     dt_dprintk("dt_device_get_raw_irq: dev=%s, index=%u\n",
                device->full_name, index);
 
+    /* Get the reg property (if any) */
+    addr = dt_get_property(device, "reg", NULL);
+
+    /* Try the new-style interrupts-extended first */
+    res = dt_parse_phandle_with_args(device, "interrupts-extended",
+                                     "#interrupt-cells", index, &args);
+    if ( !res )
+    {
+        dt_dprintk(" intspec=%d intsize=%d\n", args.args[0], args.args_count);
+
+        for ( i = 0; i < args.args_count; i++ )
+            args.args[i] = cpu_to_be32(args.args[i]);
+
+        return dt_irq_map_raw(args.np, args.args, args.args_count,
+                              addr, out_irq);
+    }
+
     /* Get the interrupts property */
     intspec = dt_get_property(device, "interrupts", &intlen);
     if ( intspec == NULL )
@@ -1432,9 +1461,6 @@ int dt_device_get_raw_irq(const struct dt_device_node *device,
 
     dt_dprintk(" intspec=%d intlen=%d\n", be32_to_cpup(intspec), intlen);
 
-    /* Get the reg property (if any) */
-    addr = dt_get_property(device, "reg", NULL);
-
     /* Look for the interrupt parent. */
     p = dt_irq_find_parent(device);
     if ( p == NULL )
-- 
2.7.4


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Re: [RFC PATCH 0/2] Add ability to handle nodes with interrupts-extended property

[Oleksandr]

Hello, all


gentle reminder...


-- 
Regards,

Oleksandr Tyshchenko


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Re: [Xen-devel] [RFC PATCH 0/2] Add ability to handle nodes with interrupts-extended property

[Oleksandr]

Hello, all


gentle reminder...


-- 
Regards,

Oleksandr Tyshchenko


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Re: [RFC PATCH 0/2] Add ability to handle nodes with interrupts-extended property

[Julien Grall]

On 10/05/2019 16:29, Oleksandr wrote:
> 
> Hello, all
> 
> 
> gentle reminder...

This is on my long queue of patches to review. Any help reviewing the on-going 
series will help.

Cheers,

-- 
Julien Grall

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Re: [Xen-devel] [RFC PATCH 0/2] Add ability to handle nodes with interrupts-extended property

[Julien Grall]

On 10/05/2019 16:29, Oleksandr wrote:
> 
> Hello, all
> 
> 
> gentle reminder...

This is on my long queue of patches to review. Any help reviewing the on-going 
series will help.

Cheers,

-- 
Julien Grall

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Re: [RFC PATCH 0/2] Add ability to handle nodes with interrupts-extended property

[Oleksandr]

On 10.05.19 18:45, Julien Grall wrote:

Hi, Julien

>
>
> On 10/05/2019 16:29, Oleksandr wrote:
>>
>> Hello, all
>>
>>
>> gentle reminder...
>
> This is on my long queue of patches to review. Any help reviewing the 
> on-going series will help.

Oh, I see. Fair enough.


>
> Cheers,
>
-- 
Regards,

Oleksandr Tyshchenko


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Re: [Xen-devel] [RFC PATCH 0/2] Add ability to handle nodes with interrupts-extended property

[Oleksandr]

On 10.05.19 18:45, Julien Grall wrote:

Hi, Julien

>
>
> On 10/05/2019 16:29, Oleksandr wrote:
>>
>> Hello, all
>>
>>
>> gentle reminder...
>
> This is on my long queue of patches to review. Any help reviewing the 
> on-going series will help.

Oh, I see. Fair enough.


>
> Cheers,
>
-- 
Regards,

Oleksandr Tyshchenko


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Re: [RFC PATCH 1/2] xen/device-tree: Add dt_count_phandle_with_args helper

[Julien Grall]

Hi,

On 02/05/2019 15:13, Oleksandr Tyshchenko wrote:
> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
> 
> Port Linux helper of_count_phandle_with_args for counting
> number of phandles in a property.

Linux 5.1 uses a completely different implementation for 
of_count_phandle_with_args. So which version of Linux did you port from?

Cheers,

-- 
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Re: [Xen-devel] [RFC PATCH 1/2] xen/device-tree: Add dt_count_phandle_with_args helper

[Julien Grall]

Hi,

On 02/05/2019 15:13, Oleksandr Tyshchenko wrote:
> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
> 
> Port Linux helper of_count_phandle_with_args for counting
> number of phandles in a property.

Linux 5.1 uses a completely different implementation for 
of_count_phandle_with_args. So which version of Linux did you port from?

Cheers,

-- 
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Re: [RFC PATCH 2/2] xen/device-tree: Add ability to handle nodes with interrupts-extended prop

[Julien Grall]

Hi,

On 02/05/2019 15:13, Oleksandr Tyshchenko wrote:
> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
> 
> Xen expects to see "interrupts" property when parsing host
> device-tree. But, there are cases when some device nodes contain
> "interrupts-extended" property instead.
> 
> The good example here is arch timer node for R-Car Gen3/Gen2 family,
> which is mandatory device for Xen usage on ARM. And without ability
> to handle such nodes, Xen fails to operate:

Per the binding documentation [1], the interrupts-extend property should only be 
used when a device has multiple interrupt parents. This is not the case of the 
arch timer, so why is it used there?

Don't get me wrong, I am fine with the idea of adding "interrupts-extend". 
However, the commit message should give some ground why a new property has been 
introduced/used over the current one.

> 
> (XEN) ****************************************
> (XEN) Panic on CPU 0:
> (XEN) Timer: Unable to retrieve IRQ 0 from the device tree
> (XEN) ****************************************
> 
> Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
> ---
>   xen/common/device_tree.c | 32 +++++++++++++++++++++++++++++---
>   1 file changed, 29 insertions(+), 3 deletions(-)
> 
> diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
> index 65862b5..00ada6e 100644
> --- a/xen/common/device_tree.c
> +++ b/xen/common/device_tree.c
> @@ -987,9 +987,19 @@ unsigned int dt_number_of_irq(const struct dt_device_node *device)
>       const struct dt_device_node *p;
>       const __be32 *intspec, *tmp;
>       u32 intsize, intlen;
> +    int intnum;
>   
>       dt_dprintk("dt_irq_number: dev=%s\n", device->full_name);
>   

> +    /* Try the new-style interrupts-extended first */
> +    intnum = dt_count_phandle_with_args(device, "interrupts-extended",
> +                                        "#interrupt-cells");
> +    if ( intnum > 0 )

IIUC dt_count_phandle_with_args, 0 would means the property is present but 
doesn't contain any interrupts. I do agree this is a probably a wrong 
device-tree, but technically I am not sure we should try to look for 
"#interrupts" if intnum = 0.

> +    {
> +        dt_dprintk(" intnum=%d\n", intnum);

You are re-using the exact same debug message as for "interrupts". So it would 
be difficult for a developer to know exactly which path is used. Could we print 
message regarding whether "interrupts-extended" or "interrupts" is used?

> +        return intnum;
> +    }
> +
>       /* Get the interrupts property */
>       intspec = dt_get_property(device, "interrupts", &intlen);
>       if ( intspec == NULL )
> @@ -1420,10 +1430,29 @@ int dt_device_get_raw_irq(const struct dt_device_node *device,
>       const __be32 *intspec, *tmp, *addr;
>       u32 intsize, intlen;
>       int res = -EINVAL;
> +    struct dt_phandle_args args;
> +    int i;
>   
>       dt_dprintk("dt_device_get_raw_irq: dev=%s, index=%u\n",
>                  device->full_name, index);
>   
> +    /* Get the reg property (if any) */
> +    addr = dt_get_property(device, "reg", NULL);
> +
> +    /* Try the new-style interrupts-extended first */
> +    res = dt_parse_phandle_with_args(device, "interrupts-extended",
> +                                     "#interrupt-cells", index, &args);
> +    if ( !res )

I don't think the check is correct. dt_parse_phandle_with_args may return a 
negative value in case of an error. So we likely want "res >= 0" here.

> +    {
> +        dt_dprintk(" intspec=%d intsize=%d\n", args.args[0], args.args_count);

Same remark for the message here.

> +
> +        for ( i = 0; i < args.args_count; i++ )
> +            args.args[i] = cpu_to_be32(args.args[i]);
> +
> +        return dt_irq_map_raw(args.np, args.args, args.args_count,
> +                              addr, out_irq);
> +    }
> +
>       /* Get the interrupts property */
>       intspec = dt_get_property(device, "interrupts", &intlen);
>       if ( intspec == NULL )
> @@ -1432,9 +1461,6 @@ int dt_device_get_raw_irq(const struct dt_device_node *device,
>   
>       dt_dprintk(" intspec=%d intlen=%d\n", be32_to_cpup(intspec), intlen);
>   
> -    /* Get the reg property (if any) */
> -    addr = dt_get_property(device, "reg", NULL);
> -
>       /* Look for the interrupt parent. */
>       p = dt_irq_find_parent(device);
>       if ( p == NULL )
> 

Cheers,

[1] linux/Documentation/devicetree/bindings/interrupt-controller

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Re: [Xen-devel] [RFC PATCH 2/2] xen/device-tree: Add ability to handle nodes with interrupts-extended prop

[Julien Grall]

Hi,

On 02/05/2019 15:13, Oleksandr Tyshchenko wrote:
> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
> 
> Xen expects to see "interrupts" property when parsing host
> device-tree. But, there are cases when some device nodes contain
> "interrupts-extended" property instead.
> 
> The good example here is arch timer node for R-Car Gen3/Gen2 family,
> which is mandatory device for Xen usage on ARM. And without ability
> to handle such nodes, Xen fails to operate:

Per the binding documentation [1], the interrupts-extend property should only be 
used when a device has multiple interrupt parents. This is not the case of the 
arch timer, so why is it used there?

Don't get me wrong, I am fine with the idea of adding "interrupts-extend". 
However, the commit message should give some ground why a new property has been 
introduced/used over the current one.

> 
> (XEN) ****************************************
> (XEN) Panic on CPU 0:
> (XEN) Timer: Unable to retrieve IRQ 0 from the device tree
> (XEN) ****************************************
> 
> Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
> ---
>   xen/common/device_tree.c | 32 +++++++++++++++++++++++++++++---
>   1 file changed, 29 insertions(+), 3 deletions(-)
> 
> diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
> index 65862b5..00ada6e 100644
> --- a/xen/common/device_tree.c
> +++ b/xen/common/device_tree.c
> @@ -987,9 +987,19 @@ unsigned int dt_number_of_irq(const struct dt_device_node *device)
>       const struct dt_device_node *p;
>       const __be32 *intspec, *tmp;
>       u32 intsize, intlen;
> +    int intnum;
>   
>       dt_dprintk("dt_irq_number: dev=%s\n", device->full_name);
>   

> +    /* Try the new-style interrupts-extended first */
> +    intnum = dt_count_phandle_with_args(device, "interrupts-extended",
> +                                        "#interrupt-cells");
> +    if ( intnum > 0 )

IIUC dt_count_phandle_with_args, 0 would means the property is present but 
doesn't contain any interrupts. I do agree this is a probably a wrong 
device-tree, but technically I am not sure we should try to look for 
"#interrupts" if intnum = 0.

> +    {
> +        dt_dprintk(" intnum=%d\n", intnum);

You are re-using the exact same debug message as for "interrupts". So it would 
be difficult for a developer to know exactly which path is used. Could we print 
message regarding whether "interrupts-extended" or "interrupts" is used?

> +        return intnum;
> +    }
> +
>       /* Get the interrupts property */
>       intspec = dt_get_property(device, "interrupts", &intlen);
>       if ( intspec == NULL )
> @@ -1420,10 +1430,29 @@ int dt_device_get_raw_irq(const struct dt_device_node *device,
>       const __be32 *intspec, *tmp, *addr;
>       u32 intsize, intlen;
>       int res = -EINVAL;
> +    struct dt_phandle_args args;
> +    int i;
>   
>       dt_dprintk("dt_device_get_raw_irq: dev=%s, index=%u\n",
>                  device->full_name, index);
>   
> +    /* Get the reg property (if any) */
> +    addr = dt_get_property(device, "reg", NULL);
> +
> +    /* Try the new-style interrupts-extended first */
> +    res = dt_parse_phandle_with_args(device, "interrupts-extended",
> +                                     "#interrupt-cells", index, &args);
> +    if ( !res )

I don't think the check is correct. dt_parse_phandle_with_args may return a 
negative value in case of an error. So we likely want "res >= 0" here.

> +    {
> +        dt_dprintk(" intspec=%d intsize=%d\n", args.args[0], args.args_count);

Same remark for the message here.

> +
> +        for ( i = 0; i < args.args_count; i++ )
> +            args.args[i] = cpu_to_be32(args.args[i]);
> +
> +        return dt_irq_map_raw(args.np, args.args, args.args_count,
> +                              addr, out_irq);
> +    }
> +
>       /* Get the interrupts property */
>       intspec = dt_get_property(device, "interrupts", &intlen);
>       if ( intspec == NULL )
> @@ -1432,9 +1461,6 @@ int dt_device_get_raw_irq(const struct dt_device_node *device,
>   
>       dt_dprintk(" intspec=%d intlen=%d\n", be32_to_cpup(intspec), intlen);
>   
> -    /* Get the reg property (if any) */
> -    addr = dt_get_property(device, "reg", NULL);
> -
>       /* Look for the interrupt parent. */
>       p = dt_irq_find_parent(device);
>       if ( p == NULL )
> 

Cheers,

[1] linux/Documentation/devicetree/bindings/interrupt-controller

-- 
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Re: [RFC PATCH 1/2] xen/device-tree: Add dt_count_phandle_with_args helper

[Oleksandr]

On 20.05.19 14:03, Julien Grall wrote:
> Hi,

Hi, Julien


>
> On 02/05/2019 15:13, Oleksandr Tyshchenko wrote:
>> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
>>
>> Port Linux helper of_count_phandle_with_args for counting
>> number of phandles in a property.
>
> Linux 5.1 uses a completely different implementation for 
> of_count_phandle_with_args. So which version of Linux did you port from?

This patch is exactly the same one [1], I did more than 2 years ago in 
the context of non-shared IOMMU patch series. Likely, I was based on v4.4.

Sorry for the confusing description.


You are right, current implementation of_count_phandle_with_args is 
completely different, and I am afraid, is not easily back-portable to Xen.

If the implementation "v4.4" looks correct and fits in current Xen 
codebase, I can recollect an exact version and update the patch 
description.

What do you think?


[1] https://patchwork.kernel.org/patch/9862557/

>
> Cheers,
>
-- 
Regards,

Oleksandr Tyshchenko


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Re: [Xen-devel] [RFC PATCH 1/2] xen/device-tree: Add dt_count_phandle_with_args helper

[Oleksandr]

On 20.05.19 14:03, Julien Grall wrote:
> Hi,

Hi, Julien


>
> On 02/05/2019 15:13, Oleksandr Tyshchenko wrote:
>> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
>>
>> Port Linux helper of_count_phandle_with_args for counting
>> number of phandles in a property.
>
> Linux 5.1 uses a completely different implementation for 
> of_count_phandle_with_args. So which version of Linux did you port from?

This patch is exactly the same one [1], I did more than 2 years ago in 
the context of non-shared IOMMU patch series. Likely, I was based on v4.4.

Sorry for the confusing description.


You are right, current implementation of_count_phandle_with_args is 
completely different, and I am afraid, is not easily back-portable to Xen.

If the implementation "v4.4" looks correct and fits in current Xen 
codebase, I can recollect an exact version and update the patch 
description.

What do you think?


[1] https://patchwork.kernel.org/patch/9862557/

>
> Cheers,
>
-- 
Regards,

Oleksandr Tyshchenko


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Re: [RFC PATCH 1/2] xen/device-tree: Add dt_count_phandle_with_args helper

[Julien Grall]

On 20/05/2019 14:48, Oleksandr wrote:
> 
> On 20.05.19 14:03, Julien Grall wrote:
>> Hi,
> 
> Hi, Julien
> 
> 
>>
>> On 02/05/2019 15:13, Oleksandr Tyshchenko wrote:
>>> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
>>>
>>> Port Linux helper of_count_phandle_with_args for counting
>>> number of phandles in a property.
>>
>> Linux 5.1 uses a completely different implementation for 
>> of_count_phandle_with_args. So which version of Linux did you port from?
> 
> This patch is exactly the same one [1], I did more than 2 years ago in the 
> context of non-shared IOMMU patch series. Likely, I was based on v4.4.
> 
> Sorry for the confusing description.
> 
> 
> You are right, current implementation of_count_phandle_with_args is completely 
> different, and I am afraid, is not easily back-portable to Xen.
> 
> If the implementation "v4.4" looks correct and fits in current Xen codebase, I 
> can recollect an exact version and update the patch description.
> 
> What do you think?

The current implementation looks correct. So the commit message needs to be updated.

Cheers,

-- 
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Re: [Xen-devel] [RFC PATCH 1/2] xen/device-tree: Add dt_count_phandle_with_args helper

[Julien Grall]

On 20/05/2019 14:48, Oleksandr wrote:
> 
> On 20.05.19 14:03, Julien Grall wrote:
>> Hi,
> 
> Hi, Julien
> 
> 
>>
>> On 02/05/2019 15:13, Oleksandr Tyshchenko wrote:
>>> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
>>>
>>> Port Linux helper of_count_phandle_with_args for counting
>>> number of phandles in a property.
>>
>> Linux 5.1 uses a completely different implementation for 
>> of_count_phandle_with_args. So which version of Linux did you port from?
> 
> This patch is exactly the same one [1], I did more than 2 years ago in the 
> context of non-shared IOMMU patch series. Likely, I was based on v4.4.
> 
> Sorry for the confusing description.
> 
> 
> You are right, current implementation of_count_phandle_with_args is completely 
> different, and I am afraid, is not easily back-portable to Xen.
> 
> If the implementation "v4.4" looks correct and fits in current Xen codebase, I 
> can recollect an exact version and update the patch description.
> 
> What do you think?

The current implementation looks correct. So the commit message needs to be updated.

Cheers,

-- 
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Re: [RFC PATCH 2/2] xen/device-tree: Add ability to handle nodes with interrupts-extended prop

[Oleksandr]

On 20.05.19 15:25, Julien Grall wrote:
> Hi,

Hi, Julien.


>
> On 02/05/2019 15:13, Oleksandr Tyshchenko wrote:
>> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
>>
>> Xen expects to see "interrupts" property when parsing host
>> device-tree. But, there are cases when some device nodes contain
>> "interrupts-extended" property instead.
>>
>> The good example here is arch timer node for R-Car Gen3/Gen2 family,
>> which is mandatory device for Xen usage on ARM. And without ability
>> to handle such nodes, Xen fails to operate:
>
> Per the binding documentation [1], the interrupts-extend property 
> should only be used when a device has multiple interrupt parents. This 
> is not the case of the arch timer, so why is it used there?
> Don't get me wrong, I am fine with the idea of adding 
> "interrupts-extend". However, the commit message should give some 
> ground why a new property has been introduced/used over the current one.

Have just grepped, looks like, R-Car Gen2/Gen3 dtsi files are not the 
only single users of "interrupts-extended" property for a device with a 
single interrupt parent...

Unfortunately, I don't know the real reason, can guess only that for a 
device (with a single interrupt parent) outside "/soc" container the 
usage of single "interrupts-extended" property is more simpler/cleaner 
than usage of pairs ("interrupt-parent" + "interrupts").  Looks like, 
the patch "ARM: dts: r8a7790: add soc node" from this series [1] started 
using "interrupts-extended" property for ARCH timer node. I will mention 
that in patch description.


>> +    /* Try the new-style interrupts-extended first */
>> +    intnum = dt_count_phandle_with_args(device, "interrupts-extended",
>> +                                        "#interrupt-cells");
>> +    if ( intnum > 0 )
>
> IIUC dt_count_phandle_with_args, 0 would means the property is present 
> but doesn't contain any interrupts. I do agree this is a probably a 
> wrong device-tree, but technically I am not sure we should try to look 
> for "#interrupts" if intnum = 0.

agree, will return 0 if intnum == 0


>
>> +    {
>> +        dt_dprintk(" intnum=%d\n", intnum);
>
> You are re-using the exact same debug message as for "interrupts". So 
> it would be difficult for a developer to know exactly which path is 
> used. Could we print message regarding whether "interrupts-extended" 
> or "interrupts" is used?

I couldn't find where else the same debug message was used, could you, 
please, point me? But, I don't mind to add some indicator. For 
"interrupts-extended" path (newly added prints) I can add the 
corresponding prefix...


>
>
>> +        return intnum;
>> +    }
>> +
>>       /* Get the interrupts property */
>>       intspec = dt_get_property(device, "interrupts", &intlen);
>>       if ( intspec == NULL )
>> @@ -1420,10 +1430,29 @@ int dt_device_get_raw_irq(const struct 
>> dt_device_node *device,
>>       const __be32 *intspec, *tmp, *addr;
>>       u32 intsize, intlen;
>>       int res = -EINVAL;
>> +    struct dt_phandle_args args;
>> +    int i;
>>         dt_dprintk("dt_device_get_raw_irq: dev=%s, index=%u\n",
>>                  device->full_name, index);
>>   +    /* Get the reg property (if any) */
>> +    addr = dt_get_property(device, "reg", NULL);
>> +
>> +    /* Try the new-style interrupts-extended first */
>> +    res = dt_parse_phandle_with_args(device, "interrupts-extended",
>> +                                     "#interrupt-cells", index, &args);
>> +    if ( !res )
>
> I don't think the check is correct. dt_parse_phandle_with_args may 
> return a negative value in case of an error. So we likely want "res >= 
> 0" here.

I am not sure I understand your point correctly. Why do we need to check 
for res > 0 as well?

If index is not -1, then function will return either 0 (on success) or 
-ERR_XXX.


>
>
>> +    {
>> +        dt_dprintk(" intspec=%d intsize=%d\n", args.args[0], 
>> args.args_count);
>
> Same remark for the message here.

agree.


[1] https://www.spinics.net/lists/linux-renesas-soc/msg22539.html

-- 
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Oleksandr Tyshchenko


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Re: [Xen-devel] [RFC PATCH 2/2] xen/device-tree: Add ability to handle nodes with interrupts-extended prop

[Oleksandr]

On 20.05.19 15:25, Julien Grall wrote:
> Hi,

Hi, Julien.


>
> On 02/05/2019 15:13, Oleksandr Tyshchenko wrote:
>> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
>>
>> Xen expects to see "interrupts" property when parsing host
>> device-tree. But, there are cases when some device nodes contain
>> "interrupts-extended" property instead.
>>
>> The good example here is arch timer node for R-Car Gen3/Gen2 family,
>> which is mandatory device for Xen usage on ARM. And without ability
>> to handle such nodes, Xen fails to operate:
>
> Per the binding documentation [1], the interrupts-extend property 
> should only be used when a device has multiple interrupt parents. This 
> is not the case of the arch timer, so why is it used there?
> Don't get me wrong, I am fine with the idea of adding 
> "interrupts-extend". However, the commit message should give some 
> ground why a new property has been introduced/used over the current one.

Have just grepped, looks like, R-Car Gen2/Gen3 dtsi files are not the 
only single users of "interrupts-extended" property for a device with a 
single interrupt parent...

Unfortunately, I don't know the real reason, can guess only that for a 
device (with a single interrupt parent) outside "/soc" container the 
usage of single "interrupts-extended" property is more simpler/cleaner 
than usage of pairs ("interrupt-parent" + "interrupts").  Looks like, 
the patch "ARM: dts: r8a7790: add soc node" from this series [1] started 
using "interrupts-extended" property for ARCH timer node. I will mention 
that in patch description.


>> +    /* Try the new-style interrupts-extended first */
>> +    intnum = dt_count_phandle_with_args(device, "interrupts-extended",
>> +                                        "#interrupt-cells");
>> +    if ( intnum > 0 )
>
> IIUC dt_count_phandle_with_args, 0 would means the property is present 
> but doesn't contain any interrupts. I do agree this is a probably a 
> wrong device-tree, but technically I am not sure we should try to look 
> for "#interrupts" if intnum = 0.

agree, will return 0 if intnum == 0


>
>> +    {
>> +        dt_dprintk(" intnum=%d\n", intnum);
>
> You are re-using the exact same debug message as for "interrupts". So 
> it would be difficult for a developer to know exactly which path is 
> used. Could we print message regarding whether "interrupts-extended" 
> or "interrupts" is used?

I couldn't find where else the same debug message was used, could you, 
please, point me? But, I don't mind to add some indicator. For 
"interrupts-extended" path (newly added prints) I can add the 
corresponding prefix...


>
>
>> +        return intnum;
>> +    }
>> +
>>       /* Get the interrupts property */
>>       intspec = dt_get_property(device, "interrupts", &intlen);
>>       if ( intspec == NULL )
>> @@ -1420,10 +1430,29 @@ int dt_device_get_raw_irq(const struct 
>> dt_device_node *device,
>>       const __be32 *intspec, *tmp, *addr;
>>       u32 intsize, intlen;
>>       int res = -EINVAL;
>> +    struct dt_phandle_args args;
>> +    int i;
>>         dt_dprintk("dt_device_get_raw_irq: dev=%s, index=%u\n",
>>                  device->full_name, index);
>>   +    /* Get the reg property (if any) */
>> +    addr = dt_get_property(device, "reg", NULL);
>> +
>> +    /* Try the new-style interrupts-extended first */
>> +    res = dt_parse_phandle_with_args(device, "interrupts-extended",
>> +                                     "#interrupt-cells", index, &args);
>> +    if ( !res )
>
> I don't think the check is correct. dt_parse_phandle_with_args may 
> return a negative value in case of an error. So we likely want "res >= 
> 0" here.

I am not sure I understand your point correctly. Why do we need to check 
for res > 0 as well?

If index is not -1, then function will return either 0 (on success) or 
-ERR_XXX.


>
>
>> +    {
>> +        dt_dprintk(" intspec=%d intsize=%d\n", args.args[0], 
>> args.args_count);
>
> Same remark for the message here.

agree.


[1] https://www.spinics.net/lists/linux-renesas-soc/msg22539.html

-- 
Regards,

Oleksandr Tyshchenko


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Re: [RFC PATCH 2/2] xen/device-tree: Add ability to handle nodes with interrupts-extended prop

[Julien Grall]

On 20/05/2019 17:10, Oleksandr wrote:
> 
> On 20.05.19 15:25, Julien Grall wrote:
>> Hi,
> 
> Hi, Julien.
> 
> 
>>
>> On 02/05/2019 15:13, Oleksandr Tyshchenko wrote:
>>> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
>>>
>>> Xen expects to see "interrupts" property when parsing host
>>> device-tree. But, there are cases when some device nodes contain
>>> "interrupts-extended" property instead.
>>>
>>> The good example here is arch timer node for R-Car Gen3/Gen2 family,
>>> which is mandatory device for Xen usage on ARM. And without ability
>>> to handle such nodes, Xen fails to operate:
>>
>> Per the binding documentation [1], the interrupts-extend property should only 
>> be used when a device has multiple interrupt parents. This is not the case of 
>> the arch timer, so why is it used there?
>> Don't get me wrong, I am fine with the idea of adding "interrupts-extend". 
>> However, the commit message should give some ground why a new property has 
>> been introduced/used over the current one.
> 
> Have just grepped, looks like, R-Car Gen2/Gen3 dtsi files are not the only 
> single users of "interrupts-extended" property for a device with a single 
> interrupt parent...
> 
> Unfortunately, I don't know the real reason, can guess only that for a device 
> (with a single interrupt parent) outside "/soc" container the usage of single 
> "interrupts-extended" property is more simpler/cleaner than usage of pairs 
> ("interrupt-parent" + "interrupts").  Looks like, the patch "ARM: dts: r8a7790: 
> add soc node" from this series [1] started using "interrupts-extended" property 
> for ARCH timer node. I will mention that in patch description.

I don't think it is important to know why Renesas is using it. What matter is 
the property allows to describe in DT a device with interrupts coming from 
multiple interrupt controllers.

In other words, what I ask is explaining in the commit message what this 
property is used for and properly a pointer to the bindings helping the reviewer 
to find out what you speak about.

> 
> 
>>> +    /* Try the new-style interrupts-extended first */
>>> +    intnum = dt_count_phandle_with_args(device, "interrupts-extended",
>>> +                                        "#interrupt-cells");
>>> +    if ( intnum > 0 )
>>
>> IIUC dt_count_phandle_with_args, 0 would means the property is present but 
>> doesn't contain any interrupts. I do agree this is a probably a wrong 
>> device-tree, but technically I am not sure we should try to look for 
>> "#interrupts" if intnum = 0.
> 
> agree, will return 0 if intnum == 0
> 
> 
>>
>>> +    {
>>> +        dt_dprintk(" intnum=%d\n", intnum);
>>
>> You are re-using the exact same debug message as for "interrupts". So it would 
>> be difficult for a developer to know exactly which path is used. Could we 
>> print message regarding whether "interrupts-extended" or "interrupts" is used?
> 
> I couldn't find where else the same debug message was used, could you, please, 
> point me? But, I don't mind to add some indicator. For "interrupts-extended" 
> path (newly added prints) I can add the corresponding prefix...

Sorry, I thought the message was duplicated. However, I still think a message 
telling which property is used would be useful.

> 
> 
>>
>>
>>> +        return intnum;
>>> +    }
>>> +
>>>       /* Get the interrupts property */
>>>       intspec = dt_get_property(device, "interrupts", &intlen);
>>>       if ( intspec == NULL )
>>> @@ -1420,10 +1430,29 @@ int dt_device_get_raw_irq(const struct dt_device_node 
>>> *device,
>>>       const __be32 *intspec, *tmp, *addr;
>>>       u32 intsize, intlen;
>>>       int res = -EINVAL;
>>> +    struct dt_phandle_args args;
>>> +    int i;
>>>         dt_dprintk("dt_device_get_raw_irq: dev=%s, index=%u\n",
>>>                  device->full_name, index);
>>>   +    /* Get the reg property (if any) */
>>> +    addr = dt_get_property(device, "reg", NULL);
>>> +
>>> +    /* Try the new-style interrupts-extended first */
>>> +    res = dt_parse_phandle_with_args(device, "interrupts-extended",
>>> +                                     "#interrupt-cells", index, &args);
>>> +    if ( !res )
>>
>> I don't think the check is correct. dt_parse_phandle_with_args may return a 
>> negative value in case of an error. So we likely want "res >= 0" here.
> 
> I am not sure I understand your point correctly. Why do we need to check for res 
>  > 0 as well?
> 
> If index is not -1, then function will return either 0 (on success) or -ERR_XXX.

But I misread the code. Sorry for the noise.

Cheers,

-- 
Julien Grall

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Re: [Xen-devel] [RFC PATCH 2/2] xen/device-tree: Add ability to handle nodes with interrupts-extended prop

[Julien Grall]

On 20/05/2019 17:10, Oleksandr wrote:
> 
> On 20.05.19 15:25, Julien Grall wrote:
>> Hi,
> 
> Hi, Julien.
> 
> 
>>
>> On 02/05/2019 15:13, Oleksandr Tyshchenko wrote:
>>> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
>>>
>>> Xen expects to see "interrupts" property when parsing host
>>> device-tree. But, there are cases when some device nodes contain
>>> "interrupts-extended" property instead.
>>>
>>> The good example here is arch timer node for R-Car Gen3/Gen2 family,
>>> which is mandatory device for Xen usage on ARM. And without ability
>>> to handle such nodes, Xen fails to operate:
>>
>> Per the binding documentation [1], the interrupts-extend property should only 
>> be used when a device has multiple interrupt parents. This is not the case of 
>> the arch timer, so why is it used there?
>> Don't get me wrong, I am fine with the idea of adding "interrupts-extend". 
>> However, the commit message should give some ground why a new property has 
>> been introduced/used over the current one.
> 
> Have just grepped, looks like, R-Car Gen2/Gen3 dtsi files are not the only 
> single users of "interrupts-extended" property for a device with a single 
> interrupt parent...
> 
> Unfortunately, I don't know the real reason, can guess only that for a device 
> (with a single interrupt parent) outside "/soc" container the usage of single 
> "interrupts-extended" property is more simpler/cleaner than usage of pairs 
> ("interrupt-parent" + "interrupts").  Looks like, the patch "ARM: dts: r8a7790: 
> add soc node" from this series [1] started using "interrupts-extended" property 
> for ARCH timer node. I will mention that in patch description.

I don't think it is important to know why Renesas is using it. What matter is 
the property allows to describe in DT a device with interrupts coming from 
multiple interrupt controllers.

In other words, what I ask is explaining in the commit message what this 
property is used for and properly a pointer to the bindings helping the reviewer 
to find out what you speak about.

> 
> 
>>> +    /* Try the new-style interrupts-extended first */
>>> +    intnum = dt_count_phandle_with_args(device, "interrupts-extended",
>>> +                                        "#interrupt-cells");
>>> +    if ( intnum > 0 )
>>
>> IIUC dt_count_phandle_with_args, 0 would means the property is present but 
>> doesn't contain any interrupts. I do agree this is a probably a wrong 
>> device-tree, but technically I am not sure we should try to look for 
>> "#interrupts" if intnum = 0.
> 
> agree, will return 0 if intnum == 0
> 
> 
>>
>>> +    {
>>> +        dt_dprintk(" intnum=%d\n", intnum);
>>
>> You are re-using the exact same debug message as for "interrupts". So it would 
>> be difficult for a developer to know exactly which path is used. Could we 
>> print message regarding whether "interrupts-extended" or "interrupts" is used?
> 
> I couldn't find where else the same debug message was used, could you, please, 
> point me? But, I don't mind to add some indicator. For "interrupts-extended" 
> path (newly added prints) I can add the corresponding prefix...

Sorry, I thought the message was duplicated. However, I still think a message 
telling which property is used would be useful.

> 
> 
>>
>>
>>> +        return intnum;
>>> +    }
>>> +
>>>       /* Get the interrupts property */
>>>       intspec = dt_get_property(device, "interrupts", &intlen);
>>>       if ( intspec == NULL )
>>> @@ -1420,10 +1430,29 @@ int dt_device_get_raw_irq(const struct dt_device_node 
>>> *device,
>>>       const __be32 *intspec, *tmp, *addr;
>>>       u32 intsize, intlen;
>>>       int res = -EINVAL;
>>> +    struct dt_phandle_args args;
>>> +    int i;
>>>         dt_dprintk("dt_device_get_raw_irq: dev=%s, index=%u\n",
>>>                  device->full_name, index);
>>>   +    /* Get the reg property (if any) */
>>> +    addr = dt_get_property(device, "reg", NULL);
>>> +
>>> +    /* Try the new-style interrupts-extended first */
>>> +    res = dt_parse_phandle_with_args(device, "interrupts-extended",
>>> +                                     "#interrupt-cells", index, &args);
>>> +    if ( !res )
>>
>> I don't think the check is correct. dt_parse_phandle_with_args may return a 
>> negative value in case of an error. So we likely want "res >= 0" here.
> 
> I am not sure I understand your point correctly. Why do we need to check for res 
>  > 0 as well?
> 
> If index is not -1, then function will return either 0 (on success) or -ERR_XXX.

But I misread the code. Sorry for the noise.

Cheers,

-- 
Julien Grall

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Re: [RFC PATCH 2/2] xen/device-tree: Add ability to handle nodes with interrupts-extended prop

[Oleksandr]

Hi, Julien


>>
>>
>>>
>>> On 02/05/2019 15:13, Oleksandr Tyshchenko wrote:
>>>> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
>>>>
>>>> Xen expects to see "interrupts" property when parsing host
>>>> device-tree. But, there are cases when some device nodes contain
>>>> "interrupts-extended" property instead.
>>>>
>>>> The good example here is arch timer node for R-Car Gen3/Gen2 family,
>>>> which is mandatory device for Xen usage on ARM. And without ability
>>>> to handle such nodes, Xen fails to operate:
>>>
>>> Per the binding documentation [1], the interrupts-extend property 
>>> should only be used when a device has multiple interrupt parents. 
>>> This is not the case of the arch timer, so why is it used there?
>>> Don't get me wrong, I am fine with the idea of adding 
>>> "interrupts-extend". However, the commit message should give some 
>>> ground why a new property has been introduced/used over the current 
>>> one.
>>
>> Have just grepped, looks like, R-Car Gen2/Gen3 dtsi files are not the 
>> only single users of "interrupts-extended" property for a device with 
>> a single interrupt parent...
>>
>> Unfortunately, I don't know the real reason, can guess only that for 
>> a device (with a single interrupt parent) outside "/soc" container 
>> the usage of single "interrupts-extended" property is more 
>> simpler/cleaner than usage of pairs ("interrupt-parent" + 
>> "interrupts").  Looks like, the patch "ARM: dts: r8a7790: add soc 
>> node" from this series [1] started using "interrupts-extended" 
>> property for ARCH timer node. I will mention that in patch description.
>
> I don't think it is important to know why Renesas is using it. What 
> matter is the property allows to describe in DT a device with 
> interrupts coming from multiple interrupt controllers.
>
> In other words, what I ask is explaining in the commit message what 
> this property is used for and properly a pointer to the bindings 
> helping the reviewer to find out what you speak about.

OK. Sounds reasonable. Will add an information regarding the property 
itself with link. Should I retain the original sentences (regarding ARCH 
timer on R-Car uses it, etc) as well?


>>
>>
>>>
>>>> +    {
>>>> +        dt_dprintk(" intnum=%d\n", intnum);
>>>
>>> You are re-using the exact same debug message as for "interrupts". 
>>> So it would be difficult for a developer to know exactly which path 
>>> is used. Could we print message regarding whether 
>>> "interrupts-extended" or "interrupts" is used?
>>
>> I couldn't find where else the same debug message was used, could 
>> you, please, point me? But, I don't mind to add some indicator. For 
>> "interrupts-extended" path (newly added prints) I can add the 
>> corresponding prefix...
>
> Sorry, I thought the message was duplicated. However, I still think a 
> message telling which property is used would be useful.

Just to clarify: should I add for the newly added messages 
("interrupts-extended" path) only? Or I should modify existing messages 
for "interrupts" path also?


-- 
Regards,

Oleksandr Tyshchenko


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Re: [Xen-devel] [RFC PATCH 2/2] xen/device-tree: Add ability to handle nodes with interrupts-extended prop

[Oleksandr]

Hi, Julien


>>
>>
>>>
>>> On 02/05/2019 15:13, Oleksandr Tyshchenko wrote:
>>>> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
>>>>
>>>> Xen expects to see "interrupts" property when parsing host
>>>> device-tree. But, there are cases when some device nodes contain
>>>> "interrupts-extended" property instead.
>>>>
>>>> The good example here is arch timer node for R-Car Gen3/Gen2 family,
>>>> which is mandatory device for Xen usage on ARM. And without ability
>>>> to handle such nodes, Xen fails to operate:
>>>
>>> Per the binding documentation [1], the interrupts-extend property 
>>> should only be used when a device has multiple interrupt parents. 
>>> This is not the case of the arch timer, so why is it used there?
>>> Don't get me wrong, I am fine with the idea of adding 
>>> "interrupts-extend". However, the commit message should give some 
>>> ground why a new property has been introduced/used over the current 
>>> one.
>>
>> Have just grepped, looks like, R-Car Gen2/Gen3 dtsi files are not the 
>> only single users of "interrupts-extended" property for a device with 
>> a single interrupt parent...
>>
>> Unfortunately, I don't know the real reason, can guess only that for 
>> a device (with a single interrupt parent) outside "/soc" container 
>> the usage of single "interrupts-extended" property is more 
>> simpler/cleaner than usage of pairs ("interrupt-parent" + 
>> "interrupts").  Looks like, the patch "ARM: dts: r8a7790: add soc 
>> node" from this series [1] started using "interrupts-extended" 
>> property for ARCH timer node. I will mention that in patch description.
>
> I don't think it is important to know why Renesas is using it. What 
> matter is the property allows to describe in DT a device with 
> interrupts coming from multiple interrupt controllers.
>
> In other words, what I ask is explaining in the commit message what 
> this property is used for and properly a pointer to the bindings 
> helping the reviewer to find out what you speak about.

OK. Sounds reasonable. Will add an information regarding the property 
itself with link. Should I retain the original sentences (regarding ARCH 
timer on R-Car uses it, etc) as well?


>>
>>
>>>
>>>> +    {
>>>> +        dt_dprintk(" intnum=%d\n", intnum);
>>>
>>> You are re-using the exact same debug message as for "interrupts". 
>>> So it would be difficult for a developer to know exactly which path 
>>> is used. Could we print message regarding whether 
>>> "interrupts-extended" or "interrupts" is used?
>>
>> I couldn't find where else the same debug message was used, could 
>> you, please, point me? But, I don't mind to add some indicator. For 
>> "interrupts-extended" path (newly added prints) I can add the 
>> corresponding prefix...
>
> Sorry, I thought the message was duplicated. However, I still think a 
> message telling which property is used would be useful.

Just to clarify: should I add for the newly added messages 
("interrupts-extended" path) only? Or I should modify existing messages 
for "interrupts" path also?


-- 
Regards,

Oleksandr Tyshchenko


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