Backport RPi patches for PIO/RP1 firmware probing errors (#3972)

One of the reason for failures after update to OS 15.0 was missing support for
the kernel PIO driver in EEPROM firmware. Backport upstream patches from
raspberrypi/linux#6645 and raspberrypi/linux#6642 that handle this situation
more gracefully. These patches could be dropped after the next RPi kernel
release.

Refs #3943

buildroot-external/board/raspberrypi/patches/linux/0005-misc-rp1-pio-Error-out-on-incompatible-firmware.patch

@@ -0,0 +1,44 @@
+From ab1d73e2b5101689fcd1737e588119b4fde3a5ff Mon Sep 17 00:00:00 2001
+From: Phil Elwell <phil@raspberrypi.com>
+Date: Mon, 3 Feb 2025 14:44:08 +0000
+Subject: [PATCH] misc: rp1-pio: Error out on incompatible firmware
+
+If the RP1 firmware has reported an error then return that from the PIO
+probe function, otherwise defer the probing.
+
+Link: https://github.com/raspberrypi/linux/issues/6642
+
+Signed-off-by: Phil Elwell <phil@raspberrypi.com>
+---
+ drivers/misc/rp1-pio.c | 11 +++++++++--
+ 1 file changed, 9 insertions(+), 2 deletions(-)
+
+diff --git a/drivers/misc/rp1-pio.c b/drivers/misc/rp1-pio.c
+index dbf69279e313d..7e875811509f8 100644
+--- a/drivers/misc/rp1-pio.c
++++ b/drivers/misc/rp1-pio.c
+@@ -1268,8 +1268,10 @@ static int rp1_pio_probe(struct platform_device *pdev)
+ 		return dev_err_probe(dev, pdev->id, "alias is missing\n");
+ 
+ 	fw = devm_rp1_firmware_get(dev, dev->of_node);
+-	if (IS_ERR_OR_NULL(fw))
+-		return dev_err_probe(dev, -ENOENT, "failed to contact RP1 firmware\n");
++	if (!fw)
++		return dev_err_probe(dev, -EPROBE_DEFER, "failed to find RP1 firmware driver\n");
++	if (IS_ERR(fw))
++		return dev_err_probe(dev, PTR_ERR(fw), "failed to contact RP1 firmware\n");
+ 	ret = rp1_firmware_get_feature(fw, FOURCC_PIO, &op_base, &op_count);
+ 	if (ret < 0)
+ 		return ret;
+@@ -1346,6 +1348,11 @@ static void rp1_pio_remove(struct platform_device *pdev)
+ 
+ 	if (g_pio == pio)
+ 		g_pio = NULL;
++
++	device_destroy(pio->dev_class, pio->dev_num);
++	cdev_del(&pio->cdev);
++	class_destroy(pio->dev_class);
++	unregister_chrdev_region(pio->dev_num, 1);
+ }
+ 
+ static const struct of_device_id rp1_pio_ids[] = {

buildroot-external/board/raspberrypi/patches/linux/0006-firmware-rp1-Linger-on-firmware-failure.patch

@@ -0,0 +1,105 @@
+From b1bcedb44c54a65a8e494158385eb23199572217 Mon Sep 17 00:00:00 2001
+From: Phil Elwell <phil@raspberrypi.com>
+Date: Mon, 3 Feb 2025 14:51:52 +0000
+Subject: [PATCH] firmware: rp1: Linger on firmware failure
+
+To avoid pointless retries, let the probe function succeed if the
+firmware interface is configured correctly but the firmware is
+incompatible. The value of the private drvdata field holds the outcome.
+
+Link: https://github.com/raspberrypi/linux/issues/6642
+
+Signed-off-by: Phil Elwell <phil@raspberrypi.com>
+---
+ drivers/firmware/rp1.c | 28 ++++++++++++++--------------
+ 1 file changed, 14 insertions(+), 14 deletions(-)
+
+diff --git a/drivers/firmware/rp1.c b/drivers/firmware/rp1.c
+index 0b0760ca77764..a258452c8b33e 100644
+--- a/drivers/firmware/rp1.c
++++ b/drivers/firmware/rp1.c
+@@ -114,7 +114,8 @@ static void rp1_firmware_delete(struct kref *kref)
+ 
+ void rp1_firmware_put(struct rp1_firmware *fw)
+ {
+-	kref_put(&fw->consumers, rp1_firmware_delete);
++	if (!IS_ERR_OR_NULL(fw))
++		kref_put(&fw->consumers, rp1_firmware_delete);
+ }
+ EXPORT_SYMBOL_GPL(rp1_firmware_put);
+ 
+@@ -157,7 +158,7 @@ struct rp1_firmware *rp1_firmware_get(struct device_node *client)
+ 	const char *match = rp1_firmware_of_match[0].compatible;
+ 	struct platform_device *pdev;
+ 	struct device_node *fwnode;
+-	struct rp1_firmware *fw;
++	struct rp1_firmware *fw = NULL;
+ 
+ 	if (!client)
+ 		return NULL;
+@@ -166,17 +167,17 @@ struct rp1_firmware *rp1_firmware_get(struct device_node *client)
+ 		return NULL;
+ 	if (!of_device_is_compatible(fwnode, match)) {
+ 		of_node_put(fwnode);
+-		return NULL;
++		return ERR_PTR(-ENXIO);
+ 	}
+ 
+ 	pdev = of_find_device_by_node(fwnode);
+ 	of_node_put(fwnode);
+ 
+ 	if (!pdev)
+-		goto err_exit;
++		return ERR_PTR(-ENXIO);
+ 
+ 	fw = platform_get_drvdata(pdev);
+-	if (!fw)
++	if (IS_ERR_OR_NULL(fw))
+ 		goto err_exit;
+ 
+ 	if (!kref_get_unless_zero(&fw->consumers))
+@@ -188,7 +189,7 @@ struct rp1_firmware *rp1_firmware_get(struct device_node *client)
+ 
+ err_exit:
+ 	put_device(&pdev->dev);
+-	return NULL;
++	return fw;
+ }
+ EXPORT_SYMBOL_GPL(rp1_firmware_get);
+ 
+@@ -204,8 +205,8 @@ struct rp1_firmware *devm_rp1_firmware_get(struct device *dev, struct device_nod
+ 	int ret;
+ 
+ 	fw = rp1_firmware_get(client);
+-	if (!fw)
+-		return NULL;
++	if (IS_ERR_OR_NULL(fw))
++		return fw;
+ 
+ 	ret = devm_add_action_or_reset(dev, devm_rp1_firmware_put, fw);
+ 	if (ret)
+@@ -270,19 +271,18 @@ static int rp1_firmware_probe(struct platform_device *pdev)
+ 	init_completion(&fw->c);
+ 	kref_init(&fw->consumers);
+ 
+-	platform_set_drvdata(pdev, fw);
+-
+ 	ret = rp1_firmware_message(fw, GET_FIRMWARE_VERSION,
+ 				   NULL, 0, &version, sizeof(version));
+ 	if (ret == sizeof(version)) {
+ 		dev_info(dev, "RP1 Firmware version %08x%08x%08x%08x%08x\n",
+ 			 version[0], version[1], version[2], version[3], version[4]);
+-		ret = 0;
+-	} else if (ret >= 0) {
+-		ret = -EIO;
++		platform_set_drvdata(pdev, fw);
++	} else {
++		rp1_firmware_put(fw);
++		platform_set_drvdata(pdev, ERR_PTR(-ENOENT));
+ 	}
+ 
+-	return ret;
++	return 0;
+ }
+ 
+ static int rp1_firmware_remove(struct platform_device *pdev)

buildroot-external/board/raspberrypi/patches/linux/0007-mailbox-rp1-Don-t-claim-channels-in-of_xlate.patch

@@ -0,0 +1,32 @@
+From 97e6955cef61340165e8ec276084841d335335e9 Mon Sep 17 00:00:00 2001
+From: Phil Elwell <phil@raspberrypi.com>
+Date: Tue, 4 Feb 2025 13:18:45 +0000
+Subject: [PATCH] mailbox: rp1: Don't claim channels in of_xlate
+
+The of_xlate method saves the calculated event mask in the con_priv
+field. It also rejects subsequent attempt to use that channel because
+the mask is non-zero, which causes a repeated instantiation of a client
+driver to fail.
+
+The of_xlate method is not meant to be a point of resource acquisition.
+Leave the con_priv initialisation, but drop the test that it was
+previously zero.
+
+Signed-off-by: Phil Elwell <phil@raspberrypi.com>
+---
+ drivers/mailbox/rp1-mailbox.c | 2 --
+ 1 file changed, 2 deletions(-)
+
+diff --git a/drivers/mailbox/rp1-mailbox.c b/drivers/mailbox/rp1-mailbox.c
+index bf71db1dd9fae..0e8af098b62b2 100644
+--- a/drivers/mailbox/rp1-mailbox.c
++++ b/drivers/mailbox/rp1-mailbox.c
+@@ -133,8 +133,6 @@ static struct mbox_chan *rp1_mbox_xlate(struct mbox_controller *mbox,
+ 		return ERR_PTR(-EINVAL);
+ 
+ 	chan = &mbox->chans[doorbell];
+-	if (chan->con_priv)
+-		return ERR_PTR(-EBUSY);
+ 
+ 	chan->con_priv = (void *)(uintptr_t)(1 << doorbell);
+ 

buildroot-external/board/raspberrypi/patches/linux/0008-misc-rp1-pio-Demote-fw-probe-error-to-warning.patch

@@ -0,0 +1,34 @@
+From c8cf0694d8ecd5acaa03c26fc404e66dea9308fd Mon Sep 17 00:00:00 2001
+From: Phil Elwell <phil@raspberrypi.com>
+Date: Tue, 25 Feb 2025 12:16:33 +0000
+Subject: [PATCH] misc: rp1-pio: Demote fw probe error to warning
+
+Support for the RP1 firmware mailbox API is rolling out to Pi 5 EEPROM
+images. For most users, the fact that the PIO is not available is no
+cause for alarm. Change the message to a warning, so that it does not
+appear with "quiet" in cmdline.txt.
+
+Link: https://github.com/raspberrypi/linux/issues/6642
+
+Signed-off-by: Phil Elwell <phil@raspberrypi.com>
+---
+ drivers/misc/rp1-pio.c | 6 ++++--
+ 1 file changed, 4 insertions(+), 2 deletions(-)
+
+diff --git a/drivers/misc/rp1-pio.c b/drivers/misc/rp1-pio.c
+index 7e875811509f8..a04dc8edcf5b8 100644
+--- a/drivers/misc/rp1-pio.c
++++ b/drivers/misc/rp1-pio.c
+@@ -1270,8 +1270,10 @@ static int rp1_pio_probe(struct platform_device *pdev)
+ 	fw = devm_rp1_firmware_get(dev, dev->of_node);
+ 	if (!fw)
+ 		return dev_err_probe(dev, -EPROBE_DEFER, "failed to find RP1 firmware driver\n");
+-	if (IS_ERR(fw))
+-		return dev_err_probe(dev, PTR_ERR(fw), "failed to contact RP1 firmware\n");
++	if (IS_ERR(fw)) {
++		dev_warn(dev, "failed to contact RP1 firmware\n");
++		return PTR_ERR(fw);
++	}
+ 	ret = rp1_firmware_get_feature(fw, FOURCC_PIO, &op_base, &op_count);
+ 	if (ret < 0)
+ 		return ret;