[PATCH v4 2/4] hwspinlock: add STM32 hwspinlock device

[Benjamin Gaignard]

From: Benjamin Gaignard <benjamin.gaignard@xxxxxx>

This patch adds support of hardware semaphores for stm32mp1 SoC.
The hardware block provides 32 semaphores.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxx>
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxx>
---
version 4:
- add Linaro SoB

version 3 :
- use postcore_initcall() instead of module_platform_driver()
  
version 2 :
- change clock name from hwspinlock to hsem to be align with hardware
  documentation
- remove useless licence terms from header
- fix alphabetic order issues
- do not abort remove function if hwspin_lock_unregister() failed

 drivers/hwspinlock/Kconfig            |   9 ++
 drivers/hwspinlock/Makefile           |   1 +
 drivers/hwspinlock/stm32_hwspinlock.c | 156 ++++++++++++++++++++++++++++++++++
 3 files changed, 166 insertions(+)
 create mode 100644 drivers/hwspinlock/stm32_hwspinlock.c

diff --git a/drivers/hwspinlock/Kconfig b/drivers/hwspinlock/Kconfig
index e895d29500ee..7869c67e5b6b 100644
--- a/drivers/hwspinlock/Kconfig
+++ b/drivers/hwspinlock/Kconfig
@@ -49,6 +49,15 @@ config HWSPINLOCK_SPRD
 
 	  If unsure, say N.
 
+config HWSPINLOCK_STM32
+	tristate "STM32 Hardware Spinlock device"
+	depends on MACH_STM32MP157
+	depends on HWSPINLOCK
+	help
+	  Say y here to support the STM32 Hardware Spinlock device.
+
+	  If unsure, say N.
+
 config HSEM_U8500
 	tristate "STE Hardware Semaphore functionality"
 	depends on HWSPINLOCK
diff --git a/drivers/hwspinlock/Makefile b/drivers/hwspinlock/Makefile
index b87c01a506a4..ed053e3f02be 100644
--- a/drivers/hwspinlock/Makefile
+++ b/drivers/hwspinlock/Makefile
@@ -8,4 +8,5 @@ obj-$(CONFIG_HWSPINLOCK_OMAP)		+= omap_hwspinlock.o
 obj-$(CONFIG_HWSPINLOCK_QCOM)		+= qcom_hwspinlock.o
 obj-$(CONFIG_HWSPINLOCK_SIRF)		+= sirf_hwspinlock.o
 obj-$(CONFIG_HWSPINLOCK_SPRD)		+= sprd_hwspinlock.o
+obj-$(CONFIG_HWSPINLOCK_STM32)		+= stm32_hwspinlock.o
 obj-$(CONFIG_HSEM_U8500)		+= u8500_hsem.o
diff --git a/drivers/hwspinlock/stm32_hwspinlock.c b/drivers/hwspinlock/stm32_hwspinlock.c
new file mode 100644
index 000000000000..34a8e009dc93
--- /dev/null
+++ b/drivers/hwspinlock/stm32_hwspinlock.c
@@ -0,0 +1,156 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) STMicroelectronics SA 2018
+ * Author: Benjamin Gaignard <benjamin.gaignard@xxxxxx> for STMicroelectronics.
+ */
+
+#include <linux/clk.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 const struct hwspinlock_ops stm32_hwspinlock_ops = {
+	.trylock	= stm32_hwspinlock_trylock,
+	.unlock		= stm32_hwspinlock_unlock,
+};
+
+static int stm32_hwspinlock_probe(struct platform_device *pdev)
+{
+	struct stm32_hwspinlock *hw;
+	void __iomem *io_base;
+	struct resource *res;
+	size_t array_size;
+	int i, ret;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	io_base = devm_ioremap_resource(&pdev->dev, res);
+	if (!io_base)
+		return -ENOMEM;
+
+	array_size = STM32_MUTEX_NUM_LOCKS * sizeof(struct hwspinlock);
+	hw = devm_kzalloc(&pdev->dev, sizeof(*hw) + array_size, GFP_KERNEL);
+	if (!hw)
+		return -ENOMEM;
+
+	hw->clk = devm_clk_get(&pdev->dev, "hsem");
+	if (IS_ERR(hw->clk))
+		return PTR_ERR(hw->clk);
+
+	for (i = 0; i < STM32_MUTEX_NUM_LOCKS; i++)
+		hw->bank.lock[i].priv = io_base + i * sizeof(u32);
+
+	platform_set_drvdata(pdev, hw);
+	pm_runtime_enable(&pdev->dev);
+
+	ret = hwspin_lock_register(&hw->bank, &pdev->dev, &stm32_hwspinlock_ops,
+				   0, STM32_MUTEX_NUM_LOCKS);
+
+	if (ret)
+		pm_runtime_disable(&pdev->dev);
+
+	return ret;
+}
+
+static int stm32_hwspinlock_remove(struct platform_device *pdev)
+{
+	struct stm32_hwspinlock *hw = platform_get_drvdata(pdev);
+	int ret;
+
+	ret = hwspin_lock_unregister(&hw->bank);
+	if (ret)
+		dev_err(&pdev->dev, "%s failed: %d\n", __func__, ret);
+
+	pm_runtime_disable(&pdev->dev);
+
+	return 0;
+}
+
+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,
+	.remove		= stm32_hwspinlock_remove,
+	.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@xxxxxx>");
-- 
2.15.0