hwspinlock: add STM32 hwspinlock device

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

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

3 files changed, 166 insertions, 0 deletions

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@st.com> 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@st.com>");