[PATCH v8 2/2] hwspinlock: qcom: Add support for Qualcomm HW Mutex block

[Bjorn Andersson <bjorn.andersson@sonymobile.com>]

Add driver for Qualcomm Hardware Mutex block found in many Qualcomm
SoCs.

Based on initial effort by Kumar Gala <galak@codeaurora.org>

Reviewed-by: Andy Gross <agross@codeaurora.org>
Reviewed-by: Jeffrey Hugo <jhugo@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
---

Changes since v7:
- None (DT binding only)

Changes since v6:
- Added missing select of MFD_SYSCON

Changes since v5:
- Dropped all but hwspinlock specific dt bindings
- Hardcoded the number of locks (there is 32)
- Rework to sit ontop of syscon

Changes since v4:
- Aligned with devicetree support in hwlock framework and hence depends on [1]

Changes since v3:
- Reverted back to getting stride from of_match, per Kumars request

Changes since v2:
- MODULE_DEVICE_TABLE
- Changed prefix to qcom
- Cleaned up includes
- Rely on reg and num-locks to figure out stride, instead of of_match data

Changes since v1:
- Added the pm_runtime calls needed to be able to boot a kernel with
  pm_runtime and this driver, patch from Courtney.
- Added sfpb-mutex compatible, for re-use of the driver in family A platforms.
- Updated formatting of DT binding documentation, while adding the extra
  compatible.
- Dropped Stephen Boyds Reviewed-by due to these changes.

 drivers/hwspinlock/Kconfig           |  12 +++
 drivers/hwspinlock/Makefile          |   1 +
 drivers/hwspinlock/qcom_hwspinlock.c | 181 +++++++++++++++++++++++++++++++++++
 3 files changed, 194 insertions(+)
 create mode 100644 drivers/hwspinlock/qcom_hwspinlock.c

diff --git a/drivers/hwspinlock/Kconfig b/drivers/hwspinlock/Kconfig
index 3612cb5..b5b4f52 100644
--- a/drivers/hwspinlock/Kconfig
+++ b/drivers/hwspinlock/Kconfig
@@ -18,6 +18,18 @@ config HWSPINLOCK_OMAP
 
 	  If unsure, say N.
 
+config HWSPINLOCK_QCOM
+	tristate "Qualcomm Hardware Spinlock device"
+	depends on ARCH_QCOM
+	select HWSPINLOCK
+	select MFD_SYSCON
+	help
+	  Say y here to support the Qualcomm Hardware Mutex functionality, which
+	  provides a synchronisation mechanism for the various processors on
+	  the SoC.
+
+	  If unsure, say N.
+
 config HSEM_U8500
 	tristate "STE Hardware Semaphore functionality"
 	depends on ARCH_U8500
diff --git a/drivers/hwspinlock/Makefile b/drivers/hwspinlock/Makefile
index 93eb64b..68f95d9 100644
--- a/drivers/hwspinlock/Makefile
+++ b/drivers/hwspinlock/Makefile
@@ -4,4 +4,5 @@
 
 obj-$(CONFIG_HWSPINLOCK)		+= hwspinlock_core.o
 obj-$(CONFIG_HWSPINLOCK_OMAP)		+= omap_hwspinlock.o
+obj-$(CONFIG_HWSPINLOCK_QCOM)		+= qcom_hwspinlock.o
 obj-$(CONFIG_HSEM_U8500)		+= u8500_hsem.o
diff --git a/drivers/hwspinlock/qcom_hwspinlock.c b/drivers/hwspinlock/qcom_hwspinlock.c
new file mode 100644
index 0000000..93b62e0
--- /dev/null
+++ b/drivers/hwspinlock/qcom_hwspinlock.c
@@ -0,0 +1,181 @@
+/*
+ * Copyright (c) 2013, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2015, Sony Mobile Communications AB
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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/hwspinlock.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.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/regmap.h>
+
+#include "hwspinlock_internal.h"
+
+#define QCOM_MUTEX_APPS_PROC_ID	1
+#define QCOM_MUTEX_NUM_LOCKS	32
+
+static int qcom_hwspinlock_trylock(struct hwspinlock *lock)
+{
+	struct regmap_field *field = lock->priv;
+	u32 lock_owner;
+	int ret;
+
+	ret = regmap_field_write(field, QCOM_MUTEX_APPS_PROC_ID);
+	if (ret)
+		return ret;
+
+	ret = regmap_field_read(field, &lock_owner);
+	if (ret)
+		return ret;
+
+	return lock_owner == QCOM_MUTEX_APPS_PROC_ID;
+}
+
+static void qcom_hwspinlock_unlock(struct hwspinlock *lock)
+{
+	struct regmap_field *field = lock->priv;
+	u32 lock_owner;
+	int ret;
+
+	ret = regmap_field_read(field, &lock_owner);
+	if (ret) {
+		pr_err("%s: unable to query spinlock owner\n", __func__);
+		return;
+	}
+
+	if (lock_owner != QCOM_MUTEX_APPS_PROC_ID) {
+		pr_err("%s: spinlock not owned by us (actual owner is %d)\n",
+				__func__, lock_owner);
+	}
+
+	ret = regmap_field_write(field, 0);
+	if (ret)
+		pr_err("%s: failed to unlock spinlock\n", __func__);
+}
+
+static const struct hwspinlock_ops qcom_hwspinlock_ops = {
+	.trylock	= qcom_hwspinlock_trylock,
+	.unlock		= qcom_hwspinlock_unlock,
+};
+
+static const struct of_device_id qcom_hwspinlock_of_match[] = {
+	{ .compatible = "qcom,sfpb-mutex" },
+	{ .compatible = "qcom,tcsr-mutex" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, qcom_hwspinlock_of_match);
+
+static int qcom_hwspinlock_probe(struct platform_device *pdev)
+{
+	struct hwspinlock_device *bank;
+	struct device_node *syscon;
+	struct reg_field field;
+	struct regmap *regmap;
+	size_t array_size;
+	u32 stride;
+	u32 base;
+	int ret;
+	int i;
+
+	syscon = of_parse_phandle(pdev->dev.of_node, "syscon", 0);
+	if (!syscon) {
+		dev_err(&pdev->dev, "no syscon property\n");
+		return -ENODEV;
+	}
+
+	regmap = syscon_node_to_regmap(syscon);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	ret = of_property_read_u32_index(pdev->dev.of_node, "syscon", 1, &base);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "no offset in syscon\n");
+		return -EINVAL;
+	}
+
+	ret = of_property_read_u32_index(pdev->dev.of_node, "syscon", 2, &stride);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "no stride syscon\n");
+		return -EINVAL;
+	}
+
+	array_size = QCOM_MUTEX_NUM_LOCKS * sizeof(struct hwspinlock);
+	bank = devm_kzalloc(&pdev->dev, sizeof(*bank) + array_size, GFP_KERNEL);
+	if (!bank)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, bank);
+
+	for (i = 0; i < QCOM_MUTEX_NUM_LOCKS; i++) {
+		field.reg = base + i * stride;
+		field.lsb = 0;
+		field.msb = 32;
+
+		bank->lock[i].priv = devm_regmap_field_alloc(&pdev->dev,
+							     regmap, field);
+	}
+
+	pm_runtime_enable(&pdev->dev);
+
+	ret = hwspin_lock_register(bank, &pdev->dev, &qcom_hwspinlock_ops,
+				   0, QCOM_MUTEX_NUM_LOCKS);
+	if (ret)
+		pm_runtime_disable(&pdev->dev);
+
+	return ret;
+}
+
+static int qcom_hwspinlock_remove(struct platform_device *pdev)
+{
+	struct hwspinlock_device *bank = platform_get_drvdata(pdev);
+	int ret;
+
+	ret = hwspin_lock_unregister(bank);
+	if (ret) {
+		dev_err(&pdev->dev, "%s failed: %d\n", __func__, ret);
+		return ret;
+	}
+
+	pm_runtime_disable(&pdev->dev);
+
+	return 0;
+}
+
+static struct platform_driver qcom_hwspinlock_driver = {
+	.probe		= qcom_hwspinlock_probe,
+	.remove		= qcom_hwspinlock_remove,
+	.driver		= {
+		.name	= "qcom_hwspinlock",
+		.of_match_table = qcom_hwspinlock_of_match,
+	},
+};
+
+static int __init qcom_hwspinlock_init(void)
+{
+	return platform_driver_register(&qcom_hwspinlock_driver);
+}
+/* board init code might need to reserve hwspinlocks for predefined purposes */
+postcore_initcall(qcom_hwspinlock_init);
+
+static void __exit qcom_hwspinlock_exit(void)
+{
+	platform_driver_unregister(&qcom_hwspinlock_driver);
+}
+module_exit(qcom_hwspinlock_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Hardware spinlock driver for Qualcomm SoCs");
-- 
1.8.2.2