[PATCH 0/3] raspi: cleanup of vc fixups

[PATCH 0/3] raspi: cleanup of vc fixups

[Jonas Richardsen]

This patch series contains a few changes to the video core fixups where
the desired behaviour is obvious from raspberry device trees. These were
tested on a Raspberry Pi 4B. There's a few more differences between the
video core device tree and the one provided by barebox for which a
discussion is welcome:

- After a [recent change][link1] the `/chosen` node of the device tree
  is now fully copied from the video core device tree. This could
  possibly be restricted to only copy relevant properties.
- The properties `memreserve` and `serial-number` of the root node are
  added by the video core and could also be copied. 
- The property `model` of the root node is updated with the specific
  hardware revision of the pi.
- The video core adds the two aliases `i2c_arm` and `i2c_vc` (as
  properties to the `/aliases` node). As the [raspberrypi
  documentation][link2] suggests to use the former for writing overlays,
  it should maybe also be copied as a fixup.

[link1]: https://git.pengutronix.de/cgit/barebox/commit/?id=30754085bdba91853acbb3973ce348bf5aa2c9e7
[link2]: https://www.raspberrypi.com/documentation/computers/configuration.html#part3.3

Jonas Richardsen (3):
  raspi: add fixup method for specific properties
  raspi: override properties in /reserved-memory node of device tree
  raspi: add a fixup for the `dma-ranges` property of the `/emmc2bus` dt
    node

 arch/arm/boards/raspberry-pi/rpi-common.c | 50 ++++++++++++++++++++++-
 1 file changed, 49 insertions(+), 1 deletion(-)

-- 
2.42.0

[PATCH 1/3] raspi: add fixup method for specific properties

[Jonas Richardsen]

Add `rpi_vc_property_fixup` method to allow for fixups of specific
properties, i.e., copy a property of some node from the video core
device tree. Notably, this does override the property if it already
existed (as opposed to `rpi_vc_fixup`, which copies an entire node, but
does not override existing properties).

Signed-off-by: Jonas Richardsen <jonasrichardsen@emlix.com>
---
 arch/arm/boards/raspberry-pi/rpi-common.c | 46 +++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/arch/arm/boards/raspberry-pi/rpi-common.c b/arch/arm/boards/raspberry-pi/rpi-common.c
index 7c82c740e2..2245c36cbe 100644
--- a/arch/arm/boards/raspberry-pi/rpi-common.c
+++ b/arch/arm/boards/raspberry-pi/rpi-common.c
@@ -60,6 +60,11 @@ struct rpi_priv {
 	const char *name;
 };
 
+struct rpi_property_fixup_data {
+    const struct device_node* vc_node;
+    const char *propname;
+};
+
 static void rpi_set_usbethaddr(void)
 {
 	u8 mac[ETH_ALEN];
@@ -301,6 +306,47 @@ static struct device_node *register_vc_fixup(struct device_node *root,
 	return ret;
 }
 
+static int rpi_vc_fdt_fixup_property(struct device_node *root, void *data)
+{
+	const struct rpi_property_fixup_data *fixup = data;
+	struct device_node *node;
+	struct property *prop;
+
+	node = of_create_node(root, fixup->vc_node->full_name);
+	if (!node)
+		return -ENOMEM;
+
+	prop = of_find_property(fixup->vc_node, fixup->propname, NULL);
+	if (!prop)
+		return -ENOENT;
+
+	return of_set_property(node, prop->name,
+						   of_property_get_value(prop), prop->length, 1);
+}
+
+static int register_vc_property_fixup(struct device_node *root,
+						 const char *path, const char *propname)
+{
+	struct device_node *node, *tmp;
+	struct rpi_property_fixup_data* fixup_data;
+
+	node = of_find_node_by_path_from(root, path);
+	if (node) {
+		tmp = of_dup(node);
+		tmp->full_name = xstrdup(node->full_name);
+		fixup_data = xzalloc(sizeof(*fixup_data));
+		fixup_data->vc_node = tmp;
+		fixup_data->propname = xstrdup(propname);
+
+		of_register_fixup(rpi_vc_fdt_fixup_property, fixup_data);
+	} else {
+		pr_info("no '%s' node found in vc fdt\n", path);
+		return -ENOENT;
+	}
+
+	return 0;
+}
+
 static u32 rpi_boot_mode, rpi_boot_part;
 /* Extract useful information from the VideoCore FDT we got.
  * Some parameters are defined here:
-- 
2.42.0

[PATCH 2/3] raspi: override properties in /reserved-memory node of device tree

[Jonas Richardsen]

Previously, the fixups in rpi-common.c only tries to copy the
`/reserved-memory` node from the video core. As explained in
`bcm2711-rpi.dtsi`, line 58, the video core does only update the
placement information of the `/reserved-memory/nvram@0` subnode:
> /*
>  * RPi4's co-processor will copy the board's bootloader configuration
>  * into memory for the OS to consume. It'll also update this node with
>  * its placement information.
>  */
This behaviour is not achieved by the previous fixup, as this fixup
operates on the wrong node and, even if applied to
"/reserved-memory/nvram@0" would not override the already existing
properties of this node. Instead, we can use the previously added
`register_vc_property_fixup` method to achieve the desired behaviour.

Signed-off-by: Jonas Richardsen <jonasrichardsen@emlix.com>
---
 arch/arm/boards/raspberry-pi/rpi-common.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm/boards/raspberry-pi/rpi-common.c b/arch/arm/boards/raspberry-pi/rpi-common.c
index 2245c36cbe..3c685852d3 100644
--- a/arch/arm/boards/raspberry-pi/rpi-common.c
+++ b/arch/arm/boards/raspberry-pi/rpi-common.c
@@ -372,7 +372,8 @@ static void rpi_vc_fdt_parse(struct device_node *root)
 
 	register_vc_fixup(root, "/system");
 	register_vc_fixup(root, "/axi");
-	register_vc_fixup(root, "/reserved-memory");
+	register_vc_property_fixup(root, "/reserved-memory/nvram@0", "reg");
+	register_vc_property_fixup(root, "/reserved-memory/nvram@0", "status");
 	register_vc_fixup(root, "/hat");
 	register_vc_fixup(root, "/chosen/bootloader");
 	chosen = register_vc_fixup(root, "/chosen");
-- 
2.42.0

[PATCH 3/3] raspi: add a fixup for the `dma-ranges` property of the `/emmc2bus` dt node

[Jonas Richardsen]

As mentioned in `bcm2711.dtsi`, line 412, the `dma-ranges` property
of the `/emmc2bus` node is overridden by the video core firmware:
> /*
>  * emmc2 has different DMA constraints based on SoC revisions. It was
>  * moved into its own bus, so as for RPi4's firmware to update them.
>  * The firmware will find whether the emmc2bus alias is defined, and if
>  * so, it'll edit the dma-ranges property below accordingly.
>  */
This change adds a fixup that copies the correct value of this property
from the video core device tree.

Signed-off-by: Jonas Richardsen <jonasrichardsen@emlix.com>
---
 arch/arm/boards/raspberry-pi/rpi-common.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/boards/raspberry-pi/rpi-common.c b/arch/arm/boards/raspberry-pi/rpi-common.c
index 3c685852d3..04e1a899f1 100644
--- a/arch/arm/boards/raspberry-pi/rpi-common.c
+++ b/arch/arm/boards/raspberry-pi/rpi-common.c
@@ -375,6 +375,7 @@ static void rpi_vc_fdt_parse(struct device_node *root)
 	register_vc_property_fixup(root, "/reserved-memory/nvram@0", "reg");
 	register_vc_property_fixup(root, "/reserved-memory/nvram@0", "status");
 	register_vc_fixup(root, "/hat");
+	register_vc_property_fixup(root, "/emmc2bus", "dma-ranges");
 	register_vc_fixup(root, "/chosen/bootloader");
 	chosen = register_vc_fixup(root, "/chosen");
 	if (!chosen) {
-- 
2.42.0

Re: [PATCH 0/3] raspi: cleanup of vc fixups

[Sascha Hauer]

On Mon, 22 Apr 2024 10:16:46 +0000, Jonas Richardsen wrote:
> This patch series contains a few changes to the video core fixups where
> the desired behaviour is obvious from raspberry device trees. These were
> tested on a Raspberry Pi 4B. There's a few more differences between the
> video core device tree and the one provided by barebox for which a
> discussion is welcome:
> 
> - After a [recent change][link1] the `/chosen` node of the device tree
>   is now fully copied from the video core device tree. This could
>   possibly be restricted to only copy relevant properties.
> - The properties `memreserve` and `serial-number` of the root node are
>   added by the video core and could also be copied.
> - The property `model` of the root node is updated with the specific
>   hardware revision of the pi.
> - The video core adds the two aliases `i2c_arm` and `i2c_vc` (as
>   properties to the `/aliases` node). As the [raspberrypi
>   documentation][link2] suggests to use the former for writing overlays,
>   it should maybe also be copied as a fixup.
> 
> [...]

Applied, thanks!

[1/3] raspi: add fixup method for specific properties
      https://git.pengutronix.de/cgit/barebox/commit/?id=dcb947764491 (link may not be stable)
[2/3] raspi: override properties in /reserved-memory node of device tree
      https://git.pengutronix.de/cgit/barebox/commit/?id=3cf4417d0045 (link may not be stable)
[3/3] raspi: add a fixup for the `dma-ranges` property of the `/emmc2bus` dt node
      https://git.pengutronix.de/cgit/barebox/commit/?id=3f9788433919 (link may not be stable)

Best regards,
-- 
Sascha Hauer <s.hauer@pengutronix.de>