1 files changed, 175 insertions, 0 deletions

diff --git a/drivers/hwspinlock/stm32_hwspinlock.c b/drivers/hwspinlock/stm32_hwspinlock.c
new file mode 100644
index 000000000..bb5c7e5f7
--- /dev/null
+++ b/drivers/hwspinlock/stm32_hwspinlock.c
@@ -0,0 +1,175 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) STMicroelectronics SA 2018
+ * Author: Benjamin Gaignard <benjamin.gaignard@st.com> for STMicroelectronics.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/hwspinlock.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+
+#include "hwspinlock_internal.h"
+
+#define STM32_MUTEX_COREID	BIT(8)
+#define STM32_MUTEX_LOCK_BIT	BIT(31)
+#define STM32_MUTEX_NUM_LOCKS	32
+
+struct stm32_hwspinlock {
+	struct clk *clk;
+	struct hwspinlock_device bank;
+};
+
+static int stm32_hwspinlock_trylock(struct hwspinlock *lock)
+{
+	void __iomem *lock_addr = lock->priv;
+	u32 status;
+
+	writel(STM32_MUTEX_LOCK_BIT | STM32_MUTEX_COREID, lock_addr);
+	status = readl(lock_addr);
+
+	return status == (STM32_MUTEX_LOCK_BIT | STM32_MUTEX_COREID);
+}
+
+static void stm32_hwspinlock_unlock(struct hwspinlock *lock)
+{
+	void __iomem *lock_addr = lock->priv;
+
+	writel(STM32_MUTEX_COREID, lock_addr);
+}
+
+static void stm32_hwspinlock_relax(struct hwspinlock *lock)
+{
+	ndelay(50);
+}
+
+static const struct hwspinlock_ops stm32_hwspinlock_ops = {
+	.trylock	= stm32_hwspinlock_trylock,
+	.unlock		= stm32_hwspinlock_unlock,
+	.relax		= stm32_hwspinlock_relax,
+};
+
+static void stm32_hwspinlock_disable_clk(void *data)
+{
+	struct platform_device *pdev = data;
+	struct stm32_hwspinlock *hw = platform_get_drvdata(pdev);
+	struct device *dev = &pdev->dev;
+
+	pm_runtime_get_sync(dev);
+	pm_runtime_disable(dev);
+	pm_runtime_set_suspended(dev);
+	pm_runtime_put_noidle(dev);
+
+	clk_disable_unprepare(hw->clk);
+}
+
+static int stm32_hwspinlock_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct stm32_hwspinlock *hw;
+	void __iomem *io_base;
+	int i, ret;
+
+	io_base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(io_base))
+		return PTR_ERR(io_base);
+
+	hw = devm_kzalloc(dev, struct_size(hw, bank.lock, STM32_MUTEX_NUM_LOCKS), GFP_KERNEL);
+	if (!hw)
+		return -ENOMEM;
+
+	hw->clk = devm_clk_get(dev, "hsem");
+	if (IS_ERR(hw->clk))
+		return PTR_ERR(hw->clk);
+
+	ret = clk_prepare_enable(hw->clk);
+	if (ret) {
+		dev_err(dev, "Failed to prepare_enable clock\n");
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, hw);
+
+	pm_runtime_get_noresume(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+	pm_runtime_put(dev);
+
+	ret = devm_add_action_or_reset(dev, stm32_hwspinlock_disable_clk, pdev);
+	if (ret) {
+		dev_err(dev, "Failed to register action\n");
+		return ret;
+	}
+
+	for (i = 0; i < STM32_MUTEX_NUM_LOCKS; i++)
+		hw->bank.lock[i].priv = io_base + i * sizeof(u32);
+
+	ret = devm_hwspin_lock_register(dev, &hw->bank, &stm32_hwspinlock_ops,
+					0, STM32_MUTEX_NUM_LOCKS);
+
+	if (ret)
+		dev_err(dev, "Failed to register hwspinlock\n");
+
+	return ret;
+}
+
+static int __maybe_unused stm32_hwspinlock_runtime_suspend(struct device *dev)
+{
+	struct stm32_hwspinlock *hw = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(hw->clk);
+
+	return 0;
+}
+
+static int __maybe_unused stm32_hwspinlock_runtime_resume(struct device *dev)
+{
+	struct stm32_hwspinlock *hw = dev_get_drvdata(dev);
+
+	clk_prepare_enable(hw->clk);
+
+	return 0;
+}
+
+static const struct dev_pm_ops stm32_hwspinlock_pm_ops = {
+	SET_RUNTIME_PM_OPS(stm32_hwspinlock_runtime_suspend,
+			   stm32_hwspinlock_runtime_resume,
+			   NULL)
+};
+
+static const struct of_device_id stm32_hwpinlock_ids[] = {
+	{ .compatible = "st,stm32-hwspinlock", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, stm32_hwpinlock_ids);
+
+static struct platform_driver stm32_hwspinlock_driver = {
+	.probe		= stm32_hwspinlock_probe,
+	.driver		= {
+		.name	= "stm32_hwspinlock",
+		.of_match_table = stm32_hwpinlock_ids,
+		.pm	= &stm32_hwspinlock_pm_ops,
+	},
+};
+
+static int __init stm32_hwspinlock_init(void)
+{
+	return platform_driver_register(&stm32_hwspinlock_driver);
+}
+/* board init code might need to reserve hwspinlocks for predefined purposes */
+postcore_initcall(stm32_hwspinlock_init);
+
+static void __exit stm32_hwspinlock_exit(void)
+{
+	platform_driver_unregister(&stm32_hwspinlock_driver);
+}
+module_exit(stm32_hwspinlock_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Hardware spinlock driver for STM32 SoCs");
+MODULE_AUTHOR("Benjamin Gaignard <benjamin.gaignard@st.com>");