hwspinlock: add a CSR atlas7 driver

Add hwspinlock support for the CSR atlas7 SoC.

The Hardware Spinlock device on atlas7 provides hardware assistance
for synchronization between the multiple processors in the system
(dual Cortex-A7, CAN bus Cortex-M3 and audio DSP).
Reviewed-by: Suman Anna <s-anna@ti.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Signed-off-by: Wei Chen <wei.chen@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>

drivers/hwspinlock/Kconfig

@@ -30,6 +30,18 @@ config HWSPINLOCK_QCOM
 
 	  If unsure, say N.
 
+config HWSPINLOCK_SIRF
+	tristate "SIRF Hardware Spinlock device"
+	depends on ARCH_SIRF
+	select HWSPINLOCK
+	help
+	  Say y here to support the SIRF Hardware Spinlock device, which
+	  provides a synchronisation mechanism for the various processors
+	  on the SoC.
+
+	  It's safe to say n here if you're not interested in SIRF hardware
+	  spinlock or just want a bare minimum kernel.
+
 config HSEM_U8500
 	tristate "STE Hardware Semaphore functionality"
 	depends on ARCH_U8500

drivers/hwspinlock/Makefile

@@ -5,4 +5,5 @@
 obj-$(CONFIG_HWSPINLOCK)		+= hwspinlock_core.o
 obj-$(CONFIG_HWSPINLOCK_OMAP)		+= omap_hwspinlock.o
 obj-$(CONFIG_HWSPINLOCK_QCOM)		+= qcom_hwspinlock.o
+obj-$(CONFIG_HWSPINLOCK_SIRF)		+= sirf_hwspinlock.o
 obj-$(CONFIG_HSEM_U8500)		+= u8500_hsem.o

drivers/hwspinlock/sirf_hwspinlock.c

+/*
+ * SIRF hardware spinlock driver
+ *
+ * Copyright (c) 2015 Cambridge Silicon Radio Limited, a CSR plc group company.
+ *
+ * Licensed under GPLv2.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/hwspinlock.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+
+#include "hwspinlock_internal.h"
+
+struct sirf_hwspinlock {
+	void __iomem *io_base;
+	struct hwspinlock_device bank;
+};
+
+/* Number of Hardware Spinlocks*/
+#define	HW_SPINLOCK_NUMBER	30
+
+/* Hardware spinlock register offsets */
+#define HW_SPINLOCK_BASE	0x404
+#define HW_SPINLOCK_OFFSET(x)	(HW_SPINLOCK_BASE + 0x4 * (x))
+
+static int sirf_hwspinlock_trylock(struct hwspinlock *lock)
+{
+	void __iomem *lock_addr = lock->priv;
+
+	/* attempt to acquire the lock by reading value == 1 from it */
+	return !!readl(lock_addr);
+}
+
+static void sirf_hwspinlock_unlock(struct hwspinlock *lock)
+{
+	void __iomem *lock_addr = lock->priv;
+
+	/* release the lock by writing 0 to it */
+	writel(0, lock_addr);
+}
+
+static const struct hwspinlock_ops sirf_hwspinlock_ops = {
+	.trylock = sirf_hwspinlock_trylock,
+	.unlock = sirf_hwspinlock_unlock,
+};
+
+static int sirf_hwspinlock_probe(struct platform_device *pdev)
+{
+	struct sirf_hwspinlock *hwspin;
+	struct hwspinlock *hwlock;
+	int idx, ret;
+
+	if (!pdev->dev.of_node)
+		return -ENODEV;
+
+	hwspin = devm_kzalloc(&pdev->dev, sizeof(*hwspin) +
+			sizeof(*hwlock) * HW_SPINLOCK_NUMBER, GFP_KERNEL);
+	if (!hwspin)
+		return -ENOMEM;
+
+	/* retrieve io base */
+	hwspin->io_base = of_iomap(pdev->dev.of_node, 0);
+	if (!hwspin->io_base)
+		return -ENOMEM;
+
+	for (idx = 0; idx < HW_SPINLOCK_NUMBER; idx++) {
+		hwlock = &hwspin->bank.lock[idx];
+		hwlock->priv = hwspin->io_base + HW_SPINLOCK_OFFSET(idx);
+	}
+
+	platform_set_drvdata(pdev, hwspin);
+
+	pm_runtime_enable(&pdev->dev);
+
+	ret = hwspin_lock_register(&hwspin->bank, &pdev->dev,
+				   &sirf_hwspinlock_ops, 0,
+				   HW_SPINLOCK_NUMBER);
+	if (ret)
+		goto reg_failed;
+
+	return 0;
+
+reg_failed:
+	pm_runtime_disable(&pdev->dev);
+	iounmap(hwspin->io_base);
+
+	return ret;
+}
+
+static int sirf_hwspinlock_remove(struct platform_device *pdev)
+{
+	struct sirf_hwspinlock *hwspin = platform_get_drvdata(pdev);
+	int ret;
+
+	ret = hwspin_lock_unregister(&hwspin->bank);
+	if (ret) {
+		dev_err(&pdev->dev, "%s failed: %d\n", __func__, ret);
+		return ret;
+	}
+
+	pm_runtime_disable(&pdev->dev);
+
+	iounmap(hwspin->io_base);
+
+	return 0;
+}
+
+static const struct of_device_id sirf_hwpinlock_ids[] = {
+	{ .compatible = "sirf,hwspinlock", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, sirf_hwpinlock_ids);
+
+static struct platform_driver sirf_hwspinlock_driver = {
+	.probe = sirf_hwspinlock_probe,
+	.remove = sirf_hwspinlock_remove,
+	.driver = {
+		.name = "atlas7_hwspinlock",
+		.of_match_table = of_match_ptr(sirf_hwpinlock_ids),
+	},
+};
+
+module_platform_driver(sirf_hwspinlock_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("SIRF Hardware spinlock driver");
+MODULE_AUTHOR("Wei Chen <wei.chen@csr.com>");