[PATCH 2/2] hwspinlock: add SUNXI implementation

fuyao
2020-11-19T06:45:34Z

From: fuyao <fuyao@allwinnertech.com>

Add hwspinlock support for the SUNXI Hardware Spinlock device.

The Hardware Spinlock device on SUNXI provides hardware assistance
for synchronization between the multiple processors in the system
(Cortex-A7, or1k, Xtensa DSP, Cortex-A53)

Signed-off-by: fuyao <fuyao@allwinnertech.com>
---
MAINTAINERS | 6 +
drivers/hwspinlock/Kconfig | 10 ++
drivers/hwspinlock/Makefile | 1 +
drivers/hwspinlock/sunxi_hwspinlock.c | 205 ++++++++++++++++++++++++++
4 files changed, 222 insertions(+)
create mode 100644 drivers/hwspinlock/sunxi_hwspinlock.c

diff --git a/MAINTAINERS b/MAINTAINERS
index e451dcce054f0..68d25574432d0 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -737,6 +737,12 @@ L: linux-media@vger.kernel.org
S: Maintained
F: drivers/staging/media/sunxi/cedrus/

+ALLWINNER HWSPINLOCK DRIVER
+M: fuyao <fuyao@allwinnertech.com>
+S: Maintained
+F: drivers/hwspinlock/sunxi_hwspinlock.c
+F: Documentation/devicetree/bindings/hwlock/sunxi,hwspinlock.yaml
+
ALPHA PORT
M: Richard Henderson <rth@twiddle.net>
M: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
diff --git a/drivers/hwspinlock/Kconfig b/drivers/hwspinlock/Kconfig
index 32cd26352f381..4d0d516dcb544 100644
--- a/drivers/hwspinlock/Kconfig
+++ b/drivers/hwspinlock/Kconfig
@@ -55,6 +55,16 @@ config HWSPINLOCK_STM32

If unsure, say N.

+config HWSPINLOCK_SUNXI
+ tristate "SUNXI Hardware Spinlock device"
+ depends on ARCH_SUNXI || COMPILE_TEST
+ help
+ Say y here to support the SUNXI Hardware Semaphore functionality, which
+ provides a synchronisation mechanism for the various processor on the
+ SoC.
+
+ If unsure, say N.
+
config HSEM_U8500
tristate "STE Hardware Semaphore functionality"
depends on ARCH_U8500 || COMPILE_TEST
diff --git a/drivers/hwspinlock/Makefile b/drivers/hwspinlock/Makefile
index ed053e3f02be4..839a053205f73 100644
--- a/drivers/hwspinlock/Makefile
+++ b/drivers/hwspinlock/Makefile
@@ -10,3 +10,4 @@ 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
+obj-$(CONFIG_HWSPINLOCK_SUNXI) += sunxi_hwspinlock.o
diff --git a/drivers/hwspinlock/sunxi_hwspinlock.c b/drivers/hwspinlock/sunxi_hwspinlock.c
new file mode 100644
index 0000000000000..2c3dc148c9b72
--- /dev/null
+++ b/drivers/hwspinlock/sunxi_hwspinlock.c
@@ -0,0 +1,205 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * SUNXI hardware spinlock driver
+ *
+ * Copyright (C) 2020 Allwinnertech - http://www.allwinnertech.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/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/bitops.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/hwspinlock.h>
+#include <linux/clk.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/err.h>
+#include <linux/reset.h>
+
+#include "hwspinlock_internal.h"
+
+/* hardware spinlock register list */
+#define LOCK_SYS_STATUS_REG (0x0000)
+#define LOCK_STATUS_REG (0x0010)
+#define LOCK_BASE_OFFSET (0x0100)
+#define LOCK_BASE_ID (0)
+
+/* Possible values of SPINLOCK_LOCK_REG */
+#define SPINLOCK_NOTTAKEN (0) /* free */
+#define SPINLOCK_TAKEN (1) /* locked */
+
+struct sunxi_spinlock_config {
+ int nspin;
+};
+
+static int sunxi_hwspinlock_trylock(struct hwspinlock *lock)
+{
+ void __iomem *lock_addr = lock->priv;
+
+ /* attempt to acquire the lock by reading its value */
+ return (readl(lock_addr) == SPINLOCK_NOTTAKEN);
+}
+
+static void sunxi_hwspinlock_unlock(struct hwspinlock *lock)
+{
+ void __iomem *lock_addr = lock->priv;
+
+ /* release the lock by writing 0 to it */
+ writel(SPINLOCK_NOTTAKEN, lock_addr);
+}
+
+/*
+ * relax the SUNXI interconnect while spinning on it.
+ *
+ * The specs recommended that the retry delay time will be
+ * just over half of the time that a requester would be
+ * expected to hold the lock.
+ *
+ * in sunxi spinlock time less then 200 cycles
+ *
+ * The number below is taken from an hardware specs example,
+ * obviously it is somewhat arbitrary.
+ */
+static void sunxi_hwspinlock_relax(struct hwspinlock *lock)
+{
+ ndelay(50);
+}
+
+static const struct hwspinlock_ops sunxi_hwspinlock_ops = {
+ .trylock = sunxi_hwspinlock_trylock,
+ .unlock = sunxi_hwspinlock_unlock,
+ .relax = sunxi_hwspinlock_relax,
+};
+
+struct sunxi_hwspinlock_device {
+ struct hwspinlock_device *bank;
+ struct clk *bus_clk;
+ struct reset_control *reset;
+};
+
+static void sunxi_hwspinlock_clk_init(struct platform_device *pdev,
+ struct sunxi_hwspinlock_device *private)
+{
+ private->bus_clk = devm_clk_get(&pdev->dev, NULL);
+ private->reset = devm_reset_control_get(&pdev->dev, NULL);
+
+ if (private->reset)
+ reset_control_deassert(private->reset);
+ if (private->bus_clk)
+ clk_prepare_enable(private->bus_clk);
+}
+
+static void sunxi_hwspinlock_clk_dinit(struct sunxi_hwspinlock_device *private)
+{
+ if (private->reset)
+ reset_control_assert(private->reset);
+ if (private->bus_clk)
+ clk_disable(private->bus_clk);
+}
+
+static const struct sunxi_spinlock_config spin_ver_1 = {
+ .nspin = 32,
+};
+
+static const struct of_device_id sunxi_hwspinlock_of_match[] = {
+ {
+ .compatible = "allwinner,h3-hwspinlock",
+ .data = &spin_ver_1,
+ },
+ {
+ .compatible = "allwinner,h6-hwspinlock",
+ .data = &spin_ver_1,
+ },
+ { /* Sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, sunxi_hwspinlock_of_match);
+
+static int sunxi_hwspinlock_probe(struct platform_device *pdev)
+{
+ struct sunxi_hwspinlock_device *private;
+ struct hwspinlock_device *bank;
+ struct hwspinlock *hwlock;
+ const struct sunxi_spinlock_config *config;
+ const struct of_device_id *match;
+ void __iomem *iobase;
+ int num_locks, i, ret;
+
+ iobase = devm_platform_ioremap_resource(pdev, 0);
+ if (PTR_ERR(iobase))
+ return PTR_ERR(iobase);
+
+ match = of_match_device(of_match_ptr(sunxi_hwspinlock_of_match),
+ &pdev->dev);
+ if (!match)
+ return -ENODEV;
+
+ config = match->data;
+ num_locks = config->nspin;
+
+ private = devm_kzalloc(&pdev->dev, sizeof(*private), GFP_KERNEL);
+ if (!private)
+ return -ENOMEM;
+
+ bank = devm_kzalloc(&pdev->dev,
+ sizeof(*bank) + num_locks * sizeof(*hwlock),
+ GFP_KERNEL);
+ if (!bank)
+ return -ENOMEM;
+
+ private->bank = bank;
+ sunxi_hwspinlock_clk_init(pdev, private);
+
+ platform_set_drvdata(pdev, private);
+
+ for (i = 0, hwlock = &bank->lock[0]; i < num_locks; i++, hwlock++)
+ hwlock->priv = iobase + LOCK_BASE_OFFSET + sizeof(u32) * i;
+
+ ret = devm_hwspin_lock_register(&pdev->dev, bank, &sunxi_hwspinlock_ops,
+ LOCK_BASE_ID, num_locks);
+ if (ret)
+ return ret;
+
+
+ return 0;
+}
+
+static int sunxi_hwspinlock_remove(struct platform_device *pdev)
+{
+ struct sunxi_hwspinlock_device *private = platform_get_drvdata(pdev);
+
+ sunxi_hwspinlock_clk_dinit(private);
+
+ return 0;
+}
+
+static struct platform_driver sunxi_hwspinlock_driver = {
+ .probe = sunxi_hwspinlock_probe,
+ .remove = sunxi_hwspinlock_remove,
+ .driver = {
+ .name = "sunxi-hwspinlock",
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(sunxi_hwspinlock_of_match),
+ },
+};
+
+module_platform_driver(sunxi_hwspinlock_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Hardware spinlock driver for SUNXI");
+MODULE_AUTHOR("fuyao <fuyao@allwinnertech.com>");
--
2.29.2