On 8/12/2013 10:35 AM, Stephen Boyd wrote:
On 07/29/13 15:00, Kumar Gala wrote:
diff --git a/drivers/hwspinlock/msm_hwspinlock.c b/drivers/hwspinlock/msm_hwspinlock.c
new file mode 100644
index 0000000..dbd9a69
--- /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 <linux/io.h>
+
+#include "hwspinlock_internal.h"
+
+#define SPINLOCK_ID_APPS_PROC 1
Is this id only for the apps processor? What about hexagon? Does it need
a different number?
Yes, hexagon would need a different id based on what job that particular
hexagon processor is doing. I'm not currently aware of a hexagon
usecase, but I believe modifying the DT binding in the future would
cover the usecase if it comes up.
+#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();
+ return readl_relaxed(lock_addr) == SPINLOCK_ID_APPS_PROC;
+}
+
+static void msm_hwspinlock_unlock(struct hwspinlock *lock)
+{
+ int lock_owner;
This should probably be u32 to be explicit about the size of the register.
+ 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",
Maybe you should just say "spinlock not owned by us (actual owner is
%d)" so that this driver is agnostic to the processor it runs on?
+ __func__, lock_owner);
+ }
+
+ writel_relaxed(0, lock_addr);
+ smp_mb();
+}
Jeffrey Hugo
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