change system file

hc

2024-10-09 244b2c5ca8b14627e4a17755e5922221e121c771

 kernel/drivers/firmware/raspberrypi.c
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..
@@ -1,15 +1,13 @@
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+// SPDX-License-Identifier: GPL-2.0
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 /*
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  * Defines interfaces for interacting wtih the Raspberry Pi firmware's
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  * property channel.
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  *
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  * Copyright © 2015 Broadcom
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- *
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- * This program is free software; you can redistribute it and/or modify
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- * it under the terms of the GNU General Public License version 2 as
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- * published by the Free Software Foundation.
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  */
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 #include <linux/dma-mapping.h>
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+#include <linux/kref.h>
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 #include <linux/mailbox_client.h>
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 #include <linux/module.h>
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 #include <linux/of_platform.h>
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@@ -23,12 +21,15 @@
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 #define MBOX_CHAN_PROPERTY		8
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 static struct platform_device *rpi_hwmon;
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+static struct platform_device *rpi_clk;
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 struct rpi_firmware {
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 	struct mbox_client cl;
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 	struct mbox_chan *chan; /* The property channel. */
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 	struct completion c;
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 	u32 enabled;
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+
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+	struct kref consumers;
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 };
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 static DEFINE_MUTEX(transaction_lock);
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@@ -55,8 +56,12 @@
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 	reinit_completion(&fw->c);
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 	ret = mbox_send_message(fw->chan, &message);
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 	if (ret >= 0) {
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-		wait_for_completion(&fw->c);
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-		ret = 0;
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+		if (wait_for_completion_timeout(&fw->c, HZ)) {
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+			ret = 0;
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+		} else {
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+			ret = -ETIMEDOUT;
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+			WARN_ONCE(1, "Firmware transaction timeout");
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+		}
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 	} else {
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 		dev_err(fw->cl.dev, "mbox_send_message returned %d\n", ret);
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 	}
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@@ -175,21 +180,18 @@
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 static void
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 rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
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 {
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+	time64_t date_and_time;
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 	u32 packet;
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 	int ret = rpi_firmware_property(fw,
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 					RPI_FIRMWARE_GET_FIRMWARE_REVISION,
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 					&packet, sizeof(packet));
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-	if (ret == 0) {
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-		struct tm tm;
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+	if (ret)
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+		return;
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-		time64_to_tm(packet, 0, &tm);
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-
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-		dev_info(fw->cl.dev,
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-			 "Attached to firmware from %04ld-%02d-%02d %02d:%02d\n",
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-			 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
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-			 tm.tm_hour, tm.tm_min);
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-	}
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+	/* This is not compatible with y2038 */
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+	date_and_time = packet;
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+	dev_info(fw->cl.dev, "Attached to firmware from %ptT\n", &date_and_time);
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 }
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 static void
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@@ -206,12 +208,58 @@
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 						  -1, NULL, 0);
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 }
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+static void rpi_register_clk_driver(struct device *dev)
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+{
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+	struct device_node *firmware;
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+
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+	/*
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+	 * Earlier DTs don't have a node for the firmware clocks but
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+	 * rely on us creating a platform device by hand. If we do
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+	 * have a node for the firmware clocks, just bail out here.
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+	 */
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+	firmware = of_get_compatible_child(dev->of_node,
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+					   "raspberrypi,firmware-clocks");
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+	if (firmware) {
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+		of_node_put(firmware);
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+		return;
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+	}
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+
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+	rpi_clk = platform_device_register_data(dev, "raspberrypi-clk",
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+						-1, NULL, 0);
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+}
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+
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+static void rpi_firmware_delete(struct kref *kref)
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+{
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+	struct rpi_firmware *fw = container_of(kref, struct rpi_firmware,
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+					       consumers);
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+
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+	mbox_free_channel(fw->chan);
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+	kfree(fw);
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+}
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+
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+void rpi_firmware_put(struct rpi_firmware *fw)
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+{
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+	kref_put(&fw->consumers, rpi_firmware_delete);
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+}
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+EXPORT_SYMBOL_GPL(rpi_firmware_put);
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+
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+static void devm_rpi_firmware_put(void *data)
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+{
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+	struct rpi_firmware *fw = data;
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+
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+	rpi_firmware_put(fw);
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+}
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+
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 static int rpi_firmware_probe(struct platform_device *pdev)
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 {
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 	struct device *dev = &pdev->dev;
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 	struct rpi_firmware *fw;
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-	fw = devm_kzalloc(dev, sizeof(*fw), GFP_KERNEL);
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+	/*
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+	 * Memory will be freed by rpi_firmware_delete() once all users have
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+	 * released their firmware handles. Don't use devm_kzalloc() here.
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+	 */
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+	fw = kzalloc(sizeof(*fw), GFP_KERNEL);
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 	if (!fw)
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 		return -ENOMEM;
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@@ -224,17 +272,30 @@
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 		int ret = PTR_ERR(fw->chan);
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 		if (ret != -EPROBE_DEFER)
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 			dev_err(dev, "Failed to get mbox channel: %d\n", ret);
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+		kfree(fw);
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 		return ret;
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 	}
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 	init_completion(&fw->c);
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+	kref_init(&fw->consumers);
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 	platform_set_drvdata(pdev, fw);
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 	rpi_firmware_print_firmware_revision(fw);
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 	rpi_register_hwmon_driver(dev, fw);
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+	rpi_register_clk_driver(dev);
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 	return 0;
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+}
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+
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+static void rpi_firmware_shutdown(struct platform_device *pdev)
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+{
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+	struct rpi_firmware *fw = platform_get_drvdata(pdev);
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+
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+	if (!fw)
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+		return;
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+
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+	rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_REBOOT, NULL, 0);
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 }
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 static int rpi_firmware_remove(struct platform_device *pdev)
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@@ -243,7 +304,10 @@
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 	platform_device_unregister(rpi_hwmon);
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 	rpi_hwmon = NULL;
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-	mbox_free_channel(fw->chan);
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+	platform_device_unregister(rpi_clk);
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+	rpi_clk = NULL;
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+
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+	rpi_firmware_put(fw);
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 	return 0;
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 }
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@@ -252,18 +316,56 @@
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  * rpi_firmware_get - Get pointer to rpi_firmware structure.
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  * @firmware_node:    Pointer to the firmware Device Tree node.
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  *
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+ * The reference to rpi_firmware has to be released with rpi_firmware_put().
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+ *
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  * Returns NULL is the firmware device is not ready.
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  */
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 struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
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 {
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 	struct platform_device *pdev = of_find_device_by_node(firmware_node);
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+	struct rpi_firmware *fw;
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 	if (!pdev)
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 		return NULL;
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-	return platform_get_drvdata(pdev);
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+	fw = platform_get_drvdata(pdev);
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+	if (!fw)
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+		goto err_put_device;
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+
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+	if (!kref_get_unless_zero(&fw->consumers))
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+		goto err_put_device;
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+
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+	put_device(&pdev->dev);
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+
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+	return fw;
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+
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+err_put_device:
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+	put_device(&pdev->dev);
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+	return NULL;
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 }
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 EXPORT_SYMBOL_GPL(rpi_firmware_get);
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+
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+/**
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+ * devm_rpi_firmware_get - Get pointer to rpi_firmware structure.
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+ * @firmware_node:    Pointer to the firmware Device Tree node.
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+ *
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+ * Returns NULL is the firmware device is not ready.
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+ */
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+struct rpi_firmware *devm_rpi_firmware_get(struct device *dev,
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+					   struct device_node *firmware_node)
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+{
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+	struct rpi_firmware *fw;
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+
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+	fw = rpi_firmware_get(firmware_node);
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+	if (!fw)
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+		return NULL;
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+
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+	if (devm_add_action_or_reset(dev, devm_rpi_firmware_put, fw))
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+		return NULL;
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+
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+	return fw;
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+}
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+EXPORT_SYMBOL_GPL(devm_rpi_firmware_get);
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 static const struct of_device_id rpi_firmware_of_match[] = {
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 	{ .compatible = "raspberrypi,bcm2835-firmware", },
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@@ -277,6 +379,7 @@
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 		.of_match_table = rpi_firmware_of_match,
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 	},
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 	.probe		= rpi_firmware_probe,
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+	.shutdown	= rpi_firmware_shutdown,
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 	.remove		= rpi_firmware_remove,
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 };
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 module_platform_driver(rpi_firmware_driver);