Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 157 insertions, 0 deletions

diff --git a/drivers/hwspinlock/u8500_hsem.c b/drivers/hwspinlock/u8500_hsem.c
new file mode 100644
index 000000000..67845c0c9
--- /dev/null
+++ b/drivers/hwspinlock/u8500_hsem.c
@@ -0,0 +1,157 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * u8500 HWSEM driver
+ *
+ * Copyright (C) 2010-2011 ST-Ericsson
+ *
+ * Implements u8500 semaphore handling for protocol 1, no interrupts.
+ *
+ * Author: Mathieu Poirier <mathieu.poirier@linaro.org>
+ * Heavily borrowed from the work of :
+ *   Simon Que <sque@ti.com>
+ *   Hari Kanigeri <h-kanigeri2@ti.com>
+ *   Ohad Ben-Cohen <ohad@wizery.com>
+ */
+
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/hwspinlock.h>
+#include <linux/platform_device.h>
+
+#include "hwspinlock_internal.h"
+
+/*
+ * Implementation of STE's HSem protocol 1 without interrutps.
+ * The only masterID we allow is '0x01' to force people to use
+ * HSems for synchronisation between processors rather than processes
+ * on the ARM core.
+ */
+
+#define U8500_MAX_SEMAPHORE		32	/* a total of 32 semaphore */
+#define RESET_SEMAPHORE			(0)	/* free */
+
+/*
+ * CPU ID for master running u8500 kernel.
+ * Hswpinlocks should only be used to synchonise operations
+ * between the Cortex A9 core and the other CPUs.  Hence
+ * forcing the masterID to a preset value.
+ */
+#define HSEM_MASTER_ID			0x01
+
+#define HSEM_REGISTER_OFFSET		0x08
+
+#define HSEM_CTRL_REG			0x00
+#define HSEM_ICRALL			0x90
+#define HSEM_PROTOCOL_1			0x01
+
+static int u8500_hsem_trylock(struct hwspinlock *lock)
+{
+	void __iomem *lock_addr = lock->priv;
+
+	writel(HSEM_MASTER_ID, lock_addr);
+
+	/* get only first 4 bit and compare to masterID.
+	 * if equal, we have the semaphore, otherwise
+	 * someone else has it.
+	 */
+	return (HSEM_MASTER_ID == (0x0F & readl(lock_addr)));
+}
+
+static void u8500_hsem_unlock(struct hwspinlock *lock)
+{
+	void __iomem *lock_addr = lock->priv;
+
+	/* release the lock by writing 0 to it */
+	writel(RESET_SEMAPHORE, lock_addr);
+}
+
+/*
+ * u8500: what value is recommended here ?
+ */
+static void u8500_hsem_relax(struct hwspinlock *lock)
+{
+	ndelay(50);
+}
+
+static const struct hwspinlock_ops u8500_hwspinlock_ops = {
+	.trylock	= u8500_hsem_trylock,
+	.unlock		= u8500_hsem_unlock,
+	.relax		= u8500_hsem_relax,
+};
+
+static int u8500_hsem_probe(struct platform_device *pdev)
+{
+	struct hwspinlock_pdata *pdata = pdev->dev.platform_data;
+	struct hwspinlock_device *bank;
+	struct hwspinlock *hwlock;
+	void __iomem *io_base;
+	int i, num_locks = U8500_MAX_SEMAPHORE;
+	ulong val;
+
+	if (!pdata)
+		return -ENODEV;
+
+	io_base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(io_base))
+		return PTR_ERR(io_base);
+
+	/* make sure protocol 1 is selected */
+	val = readl(io_base + HSEM_CTRL_REG);
+	writel((val & ~HSEM_PROTOCOL_1), io_base + HSEM_CTRL_REG);
+
+	/* clear all interrupts */
+	writel(0xFFFF, io_base + HSEM_ICRALL);
+
+	bank = devm_kzalloc(&pdev->dev, struct_size(bank, lock, num_locks),
+			    GFP_KERNEL);
+	if (!bank)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, bank);
+
+	for (i = 0, hwlock = &bank->lock[0]; i < num_locks; i++, hwlock++)
+		hwlock->priv = io_base + HSEM_REGISTER_OFFSET + sizeof(u32) * i;
+
+	return devm_hwspin_lock_register(&pdev->dev, bank,
+					 &u8500_hwspinlock_ops,
+					 pdata->base_id, num_locks);
+}
+
+static int u8500_hsem_remove(struct platform_device *pdev)
+{
+	struct hwspinlock_device *bank = platform_get_drvdata(pdev);
+	void __iomem *io_base = bank->lock[0].priv - HSEM_REGISTER_OFFSET;
+
+	/* clear all interrupts */
+	writel(0xFFFF, io_base + HSEM_ICRALL);
+
+	return 0;
+}
+
+static struct platform_driver u8500_hsem_driver = {
+	.probe		= u8500_hsem_probe,
+	.remove		= u8500_hsem_remove,
+	.driver		= {
+		.name	= "u8500_hsem",
+	},
+};
+
+static int __init u8500_hsem_init(void)
+{
+	return platform_driver_register(&u8500_hsem_driver);
+}
+/* board init code might need to reserve hwspinlocks for predefined purposes */
+postcore_initcall(u8500_hsem_init);
+
+static void __exit u8500_hsem_exit(void)
+{
+	platform_driver_unregister(&u8500_hsem_driver);
+}
+module_exit(u8500_hsem_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Hardware Spinlock driver for u8500");
+MODULE_AUTHOR("Mathieu Poirier <mathieu.poirier@linaro.org>");