Date:   Tue, 16 May 2017 15:54:01 +0800
From:   Baolin Wang <baolin.wang@...aro.org>
To:     ohad@...ery.com, bjorn.andersson@...aro.org
Cc:     linux-kernel@...r.kernel.org, linux-remoteproc@...r.kernel.org,
        broonie@...nel.org, baolin.wang@...aro.org,
        baolin.wang@...eadtrum.com
Subject: [PATCH] hwspinlock: sprd: Add hardware spinlock driver

The Spreadtrum hardware spinlock device can provide hardware assistance
for synchronization between the multiple subsystems.

Signed-off-by: Baolin Wang <baolin.wang@...eadtrum.com>
---
 drivers/hwspinlock/Kconfig           |    9 ++
 drivers/hwspinlock/Makefile          |    1 +
 drivers/hwspinlock/sprd_hwspinlock.c |  243 ++++++++++++++++++++++++++++++++++
 3 files changed, 253 insertions(+)
 create mode 100644 drivers/hwspinlock/sprd_hwspinlock.c

diff --git a/drivers/hwspinlock/Kconfig b/drivers/hwspinlock/Kconfig
index 73a4016..25304e0 100644
--- a/drivers/hwspinlock/Kconfig
+++ b/drivers/hwspinlock/Kconfig
@@ -53,4 +53,13 @@ config HSEM_U8500
 
 	  If unsure, say N.
 
+config HWSPINLOCK_SPRD
+	tristate "SPRD Hardware Spinlock device"
+	depends on ARCH_SPRD
+	select HWSPINLOCK
+	help
+	  Say y here to support the SPRD Hardware Spinlock device.
+
+	  If unsure, say N.
+
 endmenu
diff --git a/drivers/hwspinlock/Makefile b/drivers/hwspinlock/Makefile
index 6b59cb5a..03c442f 100644
--- a/drivers/hwspinlock/Makefile
+++ b/drivers/hwspinlock/Makefile
@@ -7,3 +7,4 @@ 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
+obj-$(CONFIG_HWSPINLOCK_SPRD)		+= sprd_hwspinlock.o
diff --git a/drivers/hwspinlock/sprd_hwspinlock.c b/drivers/hwspinlock/sprd_hwspinlock.c
new file mode 100644
index 0000000..898738f
--- /dev/null
+++ b/drivers/hwspinlock/sprd_hwspinlock.c
@@ -0,0 +1,243 @@
+/*
+ * Spreadtrum hardware spinlock driver
+ * Copyright (C) 2017 Spreadtrum  - http://www.spreadtrum.com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/hwspinlock.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include "hwspinlock_internal.h"
+
+/* hwspinlock registers definition */
+#define HWSPINLOCK_RECCTRL		0x4
+#define HWSPINLOCK_TTLSTS		0x8
+#define HWSPINLOCK_FLAG0		0x10
+#define HWSPINLOCK_FLAG1		0x14
+#define HWSPINLOCK_FLAG2		0x18
+#define HWSPINLOCK_FLAG3		0x1c
+#define HWSPINLOCK_MASTERID(_X_)	(0x80 + 0x4 * (_X_))
+#define HWSPINLOCK_TOKEN(_X_)		(0x800 + 0x4 * (_X_))
+#define HWSPINLOCK_VERID		0xFFC
+
+/* untoken lock value */
+#define HWSPINLOCK_NOTTAKEN		0x55aa10c5
+/* bits definition of RECCTRL reg */
+#define HWSPINLOCK_ID			0x0
+#define HWSPINLOCK_USER_BITS		0x1
+
+/* hwspinlock number */
+#define SPRD_HWLOCKS_NUM		32
+
+struct sprd_hwspinlock_dev {
+	void __iomem *base;
+	struct clk *clk;
+	unsigned char status[SPRD_HWLOCKS_NUM];
+	struct hwspinlock_device bank;
+};
+
+static const struct of_device_id sprd_hwspinlock_of_match[] = {
+	{ .compatible = "sprd,hwspinlock-r3p0",},
+	{ /* sentinel */ }
+};
+
+static struct sprd_hwspinlock_dev *sprd_lock_to_dev(struct hwspinlock *lock)
+{
+	struct hwspinlock_device *hwbank;
+	unsigned int lock_id = hwlock_to_id(lock);
+
+	hwbank = container_of(lock, struct hwspinlock_device, lock[lock_id]);
+	return container_of(hwbank, struct sprd_hwspinlock_dev, bank);
+}
+
+/* set the hardware spinlock record type */
+static void sprd_set_hwspinlock_record(struct sprd_hwspinlock_dev *sprd_hwlock,
+				       unsigned int type)
+{
+	writel_relaxed(type, sprd_hwlock->base + HWSPINLOCK_RECCTRL);
+}
+
+/* get the hardware spinlock master/user id */
+static unsigned int sprd_get_hwspinlock_id(struct sprd_hwspinlock_dev *sprd_hwlock,
+					   unsigned int lock_id)
+{
+	return readl_relaxed(sprd_hwlock->base + HWSPINLOCK_MASTERID(lock_id));
+}
+
+/* record the hardware spinlock status */
+static int sprd_record_hwspinlock_sts(struct hwspinlock *lock)
+{
+	struct sprd_hwspinlock_dev *sprd_hwlock = sprd_lock_to_dev(lock);
+	unsigned int lock_id = hwlock_to_id(lock);
+	unsigned char status;
+
+	if (lock_id >= SPRD_HWLOCKS_NUM) {
+		dev_err(sprd_hwlock->bank.dev, "lock id is out of the range\n");
+		return -ENXIO;
+	}
+
+	/* get the hardware spinlock status */
+	status = !!(readl_relaxed(sprd_hwlock->base + HWSPINLOCK_TTLSTS) &
+		    BIT(lock_id));
+
+	sprd_hwlock->status[lock_id] = status;
+	return 0;
+}
+
+/* try to lock the hardware spinlock */
+static int sprd_hwspinlock_trylock(struct hwspinlock *lock)
+{
+	struct sprd_hwspinlock_dev *sprd_hwlock = sprd_lock_to_dev(lock);
+	void __iomem *addr = lock->priv;
+
+	if (!readl_relaxed(addr))
+		goto locked;
+
+	dev_warn(sprd_hwlock->bank.dev,
+		 "hwspinlock [%d] lock failed and master/user id = %d!\n",
+		 hwlock_to_id(lock),
+		 sprd_get_hwspinlock_id(sprd_hwlock, hwlock_to_id(lock)));
+	return 0;
+
+locked:
+	sprd_record_hwspinlock_sts(lock);
+	return 1;
+}
+
+/* unlock the hardware spinlock */
+static void sprd_hwspinlock_unlock(struct hwspinlock *lock)
+{
+	void __iomem *lock_addr = lock->priv;
+
+	writel_relaxed(HWSPINLOCK_NOTTAKEN, lock_addr);
+	sprd_record_hwspinlock_sts(lock);
+}
+
+/* The specs recommended below number as the retry delay time */
+static void sprd_hwspinlock_relax(struct hwspinlock *lock)
+{
+	ndelay(10);
+}
+
+static const struct hwspinlock_ops sprd_hwspinlock_ops = {
+	.trylock = sprd_hwspinlock_trylock,
+	.unlock = sprd_hwspinlock_unlock,
+	.relax = sprd_hwspinlock_relax,
+};
+
+static int sprd_hwspinlock_probe(struct platform_device *pdev)
+{
+	struct sprd_hwspinlock_dev *sprd_hwlock;
+	struct hwspinlock *lock;
+	struct resource *res;
+	int i, ret;
+
+	if (!pdev->dev.of_node)
+		return -ENODEV;
+
+	sprd_hwlock = devm_kzalloc(&pdev->dev,
+				   sizeof(struct sprd_hwspinlock_dev) +
+				   SPRD_HWLOCKS_NUM * sizeof(*lock),
+				   GFP_KERNEL);
+	if (!sprd_hwlock)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	sprd_hwlock->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(sprd_hwlock->base))
+		return PTR_ERR(sprd_hwlock->base);
+
+	sprd_hwlock->clk = of_clk_get_by_name(pdev->dev.of_node, "enable");
+	if (IS_ERR(sprd_hwlock->clk)) {
+		dev_err(&pdev->dev, "get hwspinlock clock failed!\n");
+		return PTR_ERR(sprd_hwlock->clk);
+	}
+
+	clk_prepare_enable(sprd_hwlock->clk);
+
+	/* set the hwspinlock to record user id to identify subsystems */
+	sprd_set_hwspinlock_record(sprd_hwlock, HWSPINLOCK_USER_BITS);
+
+	for (i = 0; i < SPRD_HWLOCKS_NUM; i++) {
+		lock = &sprd_hwlock->bank.lock[i];
+		lock->priv = sprd_hwlock->base + HWSPINLOCK_TOKEN(i);
+	}
+
+	platform_set_drvdata(pdev, sprd_hwlock);
+	pm_runtime_enable(&pdev->dev);
+
+	ret = hwspin_lock_register(&sprd_hwlock->bank, &pdev->dev,
+				   &sprd_hwspinlock_ops, 0, SPRD_HWLOCKS_NUM);
+	if (ret) {
+		dev_err(&pdev->dev, "hwspinlock register failed!\n");
+		pm_runtime_disable(&pdev->dev);
+		clk_disable_unprepare(sprd_hwlock->clk);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int sprd_hwspinlock_remove(struct platform_device *pdev)
+{
+	struct sprd_hwspinlock_dev *sprd_hwlock = platform_get_drvdata(pdev);
+	int ret;
+
+	ret = hwspin_lock_unregister(&sprd_hwlock->bank);
+	if (ret) {
+		dev_err(&pdev->dev, "hwspinlock unregister failed: %d\n", ret);
+		return ret;
+	}
+
+	pm_runtime_disable(&pdev->dev);
+	clk_disable_unprepare(sprd_hwlock->clk);
+	return 0;
+}
+
+static struct platform_driver sprd_hwspinlock_driver = {
+	.probe = sprd_hwspinlock_probe,
+	.remove = sprd_hwspinlock_remove,
+	.driver = {
+		.name = "sprd_hwspinlock",
+		.owner = THIS_MODULE,
+		.of_match_table = of_match_ptr(sprd_hwspinlock_of_match),
+	},
+};
+
+static int __init sprd_hwspinlock_init(void)
+{
+	return platform_driver_register(&sprd_hwspinlock_driver);
+}
+postcore_initcall(sprd_hwspinlock_init);
+
+static void __exit sprd_hwspinlock_exit(void)
+{
+	platform_driver_unregister(&sprd_hwspinlock_driver);
+}
+module_exit(sprd_hwspinlock_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Hardware spinlock driver for Spreadtrum");
+MODULE_AUTHOR("Baolin Wang <baolin.wang@...eadtrum.com>");
+MODULE_AUTHOR("Lanqing Liu <lanqing.liu@...eadtrum.com>");
+MODULE_AUTHOR("Long Cheng <aiden.cheng@...eadtrum.com>");
-- 
1.7.9.5

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