1 files changed, 155 insertions, 27 deletions

diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c
index a13558154ac3..7ecde6921a0a 100644
--- a/drivers/firmware/raspberrypi.c
+++ b/drivers/firmware/raspberrypi.c
@@ -1,14 +1,17 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * Defines interfaces for interacting wtih the Raspberry Pi firmware's
+ * Defines interfaces for interacting with the Raspberry Pi firmware's
  * property channel.
  *
  * Copyright © 2015 Broadcom
  */
 
 #include <linux/dma-mapping.h>
+#include <linux/kref.h>
 #include <linux/mailbox_client.h>
+#include <linux/mailbox_controller.h>
 #include <linux/module.h>
+#include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
@@ -20,12 +23,15 @@
 #define MBOX_CHAN_PROPERTY		8
 
 static struct platform_device *rpi_hwmon;
+static struct platform_device *rpi_clk;
 
 struct rpi_firmware {
 	struct mbox_client cl;
 	struct mbox_chan *chan; /* The property channel. */
 	struct completion c;
 	u32 enabled;
+
+	struct kref consumers;
 };
 
 static DEFINE_MUTEX(transaction_lock);
@@ -56,7 +62,6 @@ rpi_firmware_transaction(struct rpi_firmware *fw, u32 chan, u32 data)
 			ret = 0;
 		} else {
 			ret = -ETIMEDOUT;
-			WARN_ONCE(1, "Firmware transaction timeout");
 		}
 	} else {
 		dev_err(fw->cl.dev, "mbox_send_message returned %d\n", ret);
@@ -92,8 +97,8 @@ int rpi_firmware_property_list(struct rpi_firmware *fw,
 	if (size & 3)
 		return -EINVAL;
 
-	buf = dma_alloc_coherent(fw->cl.dev, PAGE_ALIGN(size), &bus_addr,
-				 GFP_ATOMIC);
+	buf = dma_alloc_coherent(fw->chan->mbox->dev, PAGE_ALIGN(size),
+				 &bus_addr, GFP_ATOMIC);
 	if (!buf)
 		return -ENOMEM;
 
@@ -119,9 +124,11 @@ int rpi_firmware_property_list(struct rpi_firmware *fw,
 		dev_err(fw->cl.dev, "Request 0x%08x returned status 0x%08x\n",
 			buf[2], buf[1]);
 		ret = -EINVAL;
+	} else if (ret == -ETIMEDOUT) {
+		WARN_ONCE(1, "Firmware transaction 0x%08x timeout", buf[2]);
 	}
 
-	dma_free_coherent(fw->cl.dev, PAGE_ALIGN(size), buf, bus_addr);
+	dma_free_coherent(fw->chan->mbox->dev, PAGE_ALIGN(size), buf, bus_addr);
 
 	return ret;
 }
@@ -176,21 +183,18 @@ EXPORT_SYMBOL_GPL(rpi_firmware_property);
 static void
 rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
 {
+	time64_t date_and_time;
 	u32 packet;
 	int ret = rpi_firmware_property(fw,
 					RPI_FIRMWARE_GET_FIRMWARE_REVISION,
 					&packet, sizeof(packet));
 
-	if (ret == 0) {
-		struct tm tm;
-
-		time64_to_tm(packet, 0, &tm);
+	if (ret)
+		return;
 
-		dev_info(fw->cl.dev,
-			 "Attached to firmware from %04ld-%02d-%02d %02d:%02d\n",
-			 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
-			 tm.tm_hour, tm.tm_min);
-	}
+	/* This is not compatible with y2038 */
+	date_and_time = packet;
+	dev_info(fw->cl.dev, "Attached to firmware from %ptT\n", &date_and_time);
 }
 
 static void
@@ -207,12 +211,78 @@ rpi_register_hwmon_driver(struct device *dev, struct rpi_firmware *fw)
 						  -1, NULL, 0);
 }
 
+static void rpi_register_clk_driver(struct device *dev)
+{
+	struct device_node *firmware;
+
+	/*
+	 * Earlier DTs don't have a node for the firmware clocks but
+	 * rely on us creating a platform device by hand. If we do
+	 * have a node for the firmware clocks, just bail out here.
+	 */
+	firmware = of_get_compatible_child(dev->of_node,
+					   "raspberrypi,firmware-clocks");
+	if (firmware) {
+		of_node_put(firmware);
+		return;
+	}
+
+	rpi_clk = platform_device_register_data(dev, "raspberrypi-clk",
+						-1, NULL, 0);
+}
+
+unsigned int rpi_firmware_clk_get_max_rate(struct rpi_firmware *fw, unsigned int id)
+{
+	struct rpi_firmware_clk_rate_request msg =
+		RPI_FIRMWARE_CLK_RATE_REQUEST(id);
+	int ret;
+
+	ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_MAX_CLOCK_RATE,
+				    &msg, sizeof(msg));
+	if (ret)
+		/*
+		 * If our firmware doesn't support that operation, or fails, we
+		 * assume the maximum clock rate is absolute maximum we can
+		 * store over our type.
+		 */
+		 return UINT_MAX;
+
+	return le32_to_cpu(msg.rate);
+}
+EXPORT_SYMBOL_GPL(rpi_firmware_clk_get_max_rate);
+
+static void rpi_firmware_delete(struct kref *kref)
+{
+	struct rpi_firmware *fw = container_of(kref, struct rpi_firmware,
+					       consumers);
+
+	mbox_free_channel(fw->chan);
+	kfree(fw);
+}
+
+void rpi_firmware_put(struct rpi_firmware *fw)
+{
+	kref_put(&fw->consumers, rpi_firmware_delete);
+}
+EXPORT_SYMBOL_GPL(rpi_firmware_put);
+
+static void devm_rpi_firmware_put(void *data)
+{
+	struct rpi_firmware *fw = data;
+
+	rpi_firmware_put(fw);
+}
+
 static int rpi_firmware_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct rpi_firmware *fw;
 
-	fw = devm_kzalloc(dev, sizeof(*fw), GFP_KERNEL);
+	/*
+	 * Memory will be freed by rpi_firmware_delete() once all users have
+	 * released their firmware handles. Don't use devm_kzalloc() here.
+	 */
+	fw = kzalloc(sizeof(*fw), GFP_KERNEL);
 	if (!fw)
 		return -ENOMEM;
 
@@ -223,54 +293,111 @@ static int rpi_firmware_probe(struct platform_device *pdev)
 	fw->chan = mbox_request_channel(&fw->cl, 0);
 	if (IS_ERR(fw->chan)) {
 		int ret = PTR_ERR(fw->chan);
-		if (ret != -EPROBE_DEFER)
-			dev_err(dev, "Failed to get mbox channel: %d\n", ret);
-		return ret;
+		kfree(fw);
+		return dev_err_probe(dev, ret, "Failed to get mbox channel\n");
 	}
 
 	init_completion(&fw->c);
+	kref_init(&fw->consumers);
 
 	platform_set_drvdata(pdev, fw);
 
 	rpi_firmware_print_firmware_revision(fw);
 	rpi_register_hwmon_driver(dev, fw);
+	rpi_register_clk_driver(dev);
 
 	return 0;
 }
 
-static int rpi_firmware_remove(struct platform_device *pdev)
+static void rpi_firmware_shutdown(struct platform_device *pdev)
+{
+	struct rpi_firmware *fw = platform_get_drvdata(pdev);
+
+	if (!fw)
+		return;
+
+	rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_REBOOT, NULL, 0);
+}
+
+static void rpi_firmware_remove(struct platform_device *pdev)
 {
 	struct rpi_firmware *fw = platform_get_drvdata(pdev);
 
 	platform_device_unregister(rpi_hwmon);
 	rpi_hwmon = NULL;
-	mbox_free_channel(fw->chan);
+	platform_device_unregister(rpi_clk);
+	rpi_clk = NULL;
 
-	return 0;
+	rpi_firmware_put(fw);
+}
+
+static const struct of_device_id rpi_firmware_of_match[] = {
+	{ .compatible = "raspberrypi,bcm2835-firmware", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);
+
+struct device_node *rpi_firmware_find_node(void)
+{
+	return of_find_matching_node(NULL, rpi_firmware_of_match);
 }
+EXPORT_SYMBOL_GPL(rpi_firmware_find_node);
 
 /**
  * rpi_firmware_get - Get pointer to rpi_firmware structure.
  * @firmware_node:    Pointer to the firmware Device Tree node.
  *
+ * The reference to rpi_firmware has to be released with rpi_firmware_put().
+ *
  * Returns NULL is the firmware device is not ready.
  */
 struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
 {
 	struct platform_device *pdev = of_find_device_by_node(firmware_node);
+	struct rpi_firmware *fw;
 
 	if (!pdev)
 		return NULL;
 
-	return platform_get_drvdata(pdev);
+	fw = platform_get_drvdata(pdev);
+	if (!fw)
+		goto err_put_device;
+
+	if (!kref_get_unless_zero(&fw->consumers))
+		goto err_put_device;
+
+	put_device(&pdev->dev);
+
+	return fw;
+
+err_put_device:
+	put_device(&pdev->dev);
+	return NULL;
 }
 EXPORT_SYMBOL_GPL(rpi_firmware_get);
 
-static const struct of_device_id rpi_firmware_of_match[] = {
-	{ .compatible = "raspberrypi,bcm2835-firmware", },
-	{},
-};
-MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);
+/**
+ * devm_rpi_firmware_get - Get pointer to rpi_firmware structure.
+ * @dev:              The firmware device structure
+ * @firmware_node:    Pointer to the firmware Device Tree node.
+ *
+ * Returns NULL is the firmware device is not ready.
+ */
+struct rpi_firmware *devm_rpi_firmware_get(struct device *dev,
+					   struct device_node *firmware_node)
+{
+	struct rpi_firmware *fw;
+
+	fw = rpi_firmware_get(firmware_node);
+	if (!fw)
+		return NULL;
+
+	if (devm_add_action_or_reset(dev, devm_rpi_firmware_put, fw))
+		return NULL;
+
+	return fw;
+}
+EXPORT_SYMBOL_GPL(devm_rpi_firmware_get);
 
 static struct platform_driver rpi_firmware_driver = {
 	.driver = {
@@ -278,6 +405,7 @@ static struct platform_driver rpi_firmware_driver = {
 		.of_match_table = rpi_firmware_of_match,
 	},
 	.probe		= rpi_firmware_probe,
+	.shutdown	= rpi_firmware_shutdown,
 	.remove		= rpi_firmware_remove,
 };
 module_platform_driver(rpi_firmware_driver);