On Jul 29, 2013, at 4:40 PM, Stephen Boyd wrote:

On 07/29, Kumar Gala wrote:

quoted

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diff --git a/Documentation/devicetree/bindings/arm/msm/tcsr-mutex.txt b/Documentation/devicetree/bindings/arm/msm/tcsr-mutex.txt
new file mode 100644
index 0000000..ddd6889
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/msm/tcsr-mutex.txt

Maybe this should go under a new hwspinlock directory?

Will look for Ohad to comment on this.

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@@ -0,0 +1,20 @@
+Qualcomm MSM Hardware Mutex Block:
+
+The hardware block provides mutexes utilized between different processors
+on the SoC as part of the communication protocol used by these processors.
+
+Required properties:
+- compatible: should be "qcom,tcsr-mutex"
+- reg: Should contain registers location and length of mutex registers
+- reg-names:
+	"mutex-base"  - string to identify mutex registers
+- qcom,num-locks: the number of locks/mutexes supported
+
+Example:
+
+	qcom,tcsr-mutex@fd484000 {

Maybe it should be hw-mutex@fd484000?

again, will look for Ohad to make some comment on this.

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+		compatible = "qcom,tcsr-mutex";
+		reg = <0xfd484000 0x1000>;
+		reg-names = "mutex-base";
+		qcom,num-locks = <32>;
+	};

diff --git a/drivers/hwspinlock/msm_hwspinlock.c b/drivers/hwspinlock/msm_hwspinlock.c
new file mode 100644
index 0000000..c7d80c5
--- /dev/null
+++ b/drivers/hwspinlock/msm_hwspinlock.c

@@ -0,0 +1,150 @@
+/*
+ * Copyright (c) 2013, The Linux Foundation. All rights reserved.
+ *
+ * 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/err.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/hwspinlock.h>
+
+#include <asm/io.h>

<linux/io.h> please.

will change, I choice <asm/io.h> since *_relaxed are arm specific.

quoted

quoted

+
+#include "hwspinlock_internal.h"
+
+#define SPINLOCK_ID_APPS_PROC	1
+#define BASE_ID			0
+
+static int msm_hwspinlock_trylock(struct hwspinlock *lock)
+{
+	void __iomem *lock_addr = lock->priv;
+
+	writel_relaxed(SPINLOCK_ID_APPS_PROC, lock_addr);
+	smp_mb();

Are you sure you don't want mb() instead? What is this barrier
for? Comment please.

Hopefully, Eric or Jeff can comment.

quoted

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+	return readl_relaxed(lock_addr) == SPINLOCK_ID_APPS_PROC;
+}
+
+static void msm_hwspinlock_unlock(struct hwspinlock *lock)
+{
+	int lock_owner;
+	void __iomem *lock_addr = lock->priv;
+
+	lock_owner = readl_relaxed(lock_addr);
+	if (lock_owner != SPINLOCK_ID_APPS_PROC) {
+		pr_err("%s: spinlock not owned by Apps (actual owner is %d)\n",
+				__func__, lock_owner);
+	}
+
+	writel_relaxed(0, lock_addr);
+	smp_mb();

Same here. What is smp_mb() for?

Hopefully, Eric or Jeff can comment.

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+}
+
+static const struct hwspinlock_ops msm_hwspinlock_ops = {
+	.trylock	= msm_hwspinlock_trylock,
+	.unlock		= msm_hwspinlock_unlock,
+};
+
+static struct of_device_id msm_hwspinlock_of_match[];

Why not just put the match table here then? Also, can it be
const?

Will change and make const

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+static int msm_hwspinlock_probe(struct platform_device *pdev)
+{
+	int ret, i, stride;
+	u32 num_locks;
+	struct hwspinlock_device *bank;
+	struct hwspinlock *hwlock;
+	struct resource *res;
+	void __iomem *iobase;
+	struct device_node *node = pdev->dev.of_node;
+	const struct of_device_id *match;
+
+	match = of_match_device(msm_hwspinlock_of_match, &pdev->dev);
+	if (!match)
+		return -EINVAL;
+
+	ret = of_property_read_u32(node, "qcom,num-locks", &num_locks);
+	if (ret || (num_locks == 0))

Drop useless ().

done

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+		return -ENODEV;
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "mutex-base");
+	iobase = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(iobase))
+		return PTR_ERR(iobase);
+
+	bank = devm_kzalloc(&pdev->dev,
+		 sizeof(*bank) + num_locks * sizeof(*hwlock), GFP_KERNEL);
+	if (!bank)
+		return -ENOMEM;
+

Style Nit: Maybe we could grow a local variable to get this to be
one line.

	size_t array_size;

	array_size = num_lock * sizeof(*hwlock);
	bank = devm_kzalloc(&pdev->dev, sizeof(*bank) + array_size, GFP_KERNEL);

done

- k

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