From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/drivers/firmware/raspberrypi.c | 139 ++++++++++++++++++++++++++++++++++++++++------
1 files changed, 121 insertions(+), 18 deletions(-)
diff --git a/kernel/drivers/firmware/raspberrypi.c b/kernel/drivers/firmware/raspberrypi.c
index 44eb998..45ff03d 100644
--- a/kernel/drivers/firmware/raspberrypi.c
+++ b/kernel/drivers/firmware/raspberrypi.c
@@ -1,15 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0
/*
* Defines interfaces for interacting wtih the Raspberry Pi firmware's
* property channel.
*
* Copyright © 2015 Broadcom
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
*/
#include <linux/dma-mapping.h>
+#include <linux/kref.h>
#include <linux/mailbox_client.h>
#include <linux/module.h>
#include <linux/of_platform.h>
@@ -23,12 +21,15 @@
#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);
@@ -55,8 +56,12 @@
reinit_completion(&fw->c);
ret = mbox_send_message(fw->chan, &message);
if (ret >= 0) {
- wait_for_completion(&fw->c);
- ret = 0;
+ if (wait_for_completion_timeout(&fw->c, HZ)) {
+ ret = 0;
+ } else {
+ ret = -ETIMEDOUT;
+ WARN_ONCE(1, "Firmware transaction timeout");
+ }
} else {
dev_err(fw->cl.dev, "mbox_send_message returned %d\n", ret);
}
@@ -175,21 +180,18 @@
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;
+ if (ret)
+ return;
- time64_to_tm(packet, 0, &tm);
-
- 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
@@ -206,12 +208,58 @@
-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);
+}
+
+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;
@@ -224,17 +272,30 @@
int ret = PTR_ERR(fw->chan);
if (ret != -EPROBE_DEFER)
dev_err(dev, "Failed to get mbox channel: %d\n", ret);
+ kfree(fw);
return ret;
}
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 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 int rpi_firmware_remove(struct platform_device *pdev)
@@ -243,7 +304,10 @@
platform_device_unregister(rpi_hwmon);
rpi_hwmon = NULL;
- mbox_free_channel(fw->chan);
+ platform_device_unregister(rpi_clk);
+ rpi_clk = NULL;
+
+ rpi_firmware_put(fw);
return 0;
}
@@ -252,18 +316,56 @@
* 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);
+
+/**
+ * devm_rpi_firmware_get - Get pointer to rpi_firmware 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 const struct of_device_id rpi_firmware_of_match[] = {
{ .compatible = "raspberrypi,bcm2835-firmware", },
@@ -277,6 +379,7 @@
.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);
--
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