1 files changed, 243 insertions, 0 deletions

diff --git a/arch/arm/mach-tegra/arb_sema.c b/arch/arm/mach-tegra/arb_sema.c
new file mode 100644
index 00000000000..eecdee5967c
--- /dev/null
+++ b/arch/arm/mach-tegra/arb_sema.c
@@ -0,0 +1,243 @@
+/*
+ * Copyright (C) 2010, NVIDIA Corporation
+ *
+ * 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/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/io.h>
+#include <linux/mutex.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+#include <linux/completion.h>
+
+#include <mach/arb_sema.h>
+#include <mach/irqs.h>
+#include <mach/iomap.h>
+
+#define TEGRA_RPC_MAX_SEM 32
+
+/* arb_gnt ictrl */
+#define ARB_CPU_INT_EN          0x4
+
+/* arb_sema */
+#define ARB_GRANT_STATUS        0x0
+#define ARB_GRANT_REQUEST       0x4
+#define ARB_GRANT_RELEASE       0x8
+#define ARB_GRANT_PENDING       0xC
+
+struct tegra_arb_dev {
+        void __iomem    *sema_base;
+        void __iomem    *gnt_base;
+        spinlock_t lock;
+        struct completion arb_gnt_complete[TEGRA_RPC_MAX_SEM];
+        struct mutex mutexes[TEGRA_RPC_MAX_SEM];
+        int irq;
+        int status;
+        bool suspended;
+};
+
+static struct tegra_arb_dev *arb;
+
+static inline u32 arb_sema_read(u32 offset)
+{
+        return readl(arb->sema_base + offset);
+}
+
+static inline void arb_sema_write(u32 value, u32 offset)
+{
+        writel(value, arb->sema_base + offset);
+}
+
+static inline u32 arb_gnt_read(u32 offset)
+{
+        return readl(arb->gnt_base + offset);
+}
+
+static inline void arb_gnt_write(u32 value, u32 offset)
+{
+        writel(value, arb->gnt_base + offset);
+}
+
+static void request_arb_sem(enum tegra_arb_module lock)
+{
+        unsigned long flags;
+        u32 value;
+
+        spin_lock_irqsave(&arb->lock, flags);
+
+        arb_sema_write(1 << lock, ARB_GRANT_REQUEST);
+        value = arb_gnt_read(ARB_CPU_INT_EN);
+        value |= (1 << lock);
+        arb_gnt_write(value, ARB_CPU_INT_EN);
+
+        spin_unlock_irqrestore(&arb->lock, flags);
+}
+
+static void cancel_arb_sem(enum tegra_arb_module lock)
+{
+        unsigned long flags;
+        u32 value;
+
+        spin_lock_irqsave(&arb->lock, flags);
+
+        arb_sema_write(1 << lock, ARB_GRANT_RELEASE);
+        value = arb_gnt_read(ARB_CPU_INT_EN);
+        value &= ~(1 << lock);
+        arb_gnt_write(value, ARB_CPU_INT_EN);
+
+        spin_unlock_irqrestore(&arb->lock, flags);
+}
+
+int tegra_arb_mutex_lock_timeout(enum tegra_arb_module lock, int msecs)
+{
+        int ret;
+
+        if (!arb)
+                return -ENODEV;
+
+        if (arb->suspended) {
+                pr_err("device in suspend\n");
+                return -ETIMEDOUT;
+        }
+
+        mutex_lock(&arb->mutexes[lock]);
+        INIT_COMPLETION(arb->arb_gnt_complete[lock]);
+        request_arb_sem(lock);
+        ret = wait_for_completion_timeout(&arb->arb_gnt_complete[lock], msecs_to_jiffies(msecs));
+        if (ret == 0) {
+                pr_err("timed out. pending:0x%x\n", arb_sema_read(ARB_GRANT_PENDING));
+                cancel_arb_sem(lock);
+                mutex_unlock(&arb->mutexes[lock]);
+                return -ETIMEDOUT;
+        }
+
+        return 0;
+}
+EXPORT_SYMBOL(tegra_arb_mutex_lock_timeout);
+
+int tegra_arb_mutex_unlock(enum tegra_arb_module lock)
+{
+        if (!arb)
+                return -ENODEV;
+
+        if (arb->suspended) {
+                pr_err("device in suspend\n");
+                return -ETIMEDOUT;
+        }
+
+        cancel_arb_sem(lock);
+        mutex_unlock(&arb->mutexes[lock]);
+        return 0;
+}
+EXPORT_SYMBOL(tegra_arb_mutex_unlock);
+
+static irqreturn_t arb_gnt_isr(int irq, void *dev_id)
+{
+        struct tegra_arb_dev *dev = dev_id;
+        unsigned long status;
+        u32 cpu_int_en;
+        unsigned int bit;
+        unsigned long flags;
+
+        spin_lock_irqsave(&arb->lock, flags);
+
+        status = arb_sema_read(ARB_GRANT_STATUS);
+        pr_debug("%s: 0x%lx\n", __func__, status);
+
+        /* disable the arb semaphores which were signalled */
+        cpu_int_en = arb_gnt_read(ARB_CPU_INT_EN);
+        arb_gnt_write((cpu_int_en & ~(status & cpu_int_en)),
+                ARB_CPU_INT_EN);
+
+        status &= cpu_int_en;
+        for_each_set_bit(bit, &status, BITS_PER_LONG)
+                complete(&dev->arb_gnt_complete[bit]);
+
+        spin_unlock_irqrestore(&arb->lock, flags);
+        return IRQ_HANDLED;
+}
+
+int tegra_arb_suspend(void)
+{
+        unsigned long status = arb_sema_read(ARB_GRANT_STATUS);
+
+        if (WARN_ON(status != 0)) {
+                pr_err("%s: suspending while holding arbitration "
+                       "semaphore: %08lx\n", __func__, status);
+        }
+        arb->suspended = true;
+
+        return status ? -EBUSY : 0;
+}
+
+int tegra_arb_resume(void)
+{
+        arb->suspended = false;
+        return 0;
+}
+
+static int __init tegra_arb_init(void)
+{
+        struct tegra_arb_dev *dev = NULL;
+        int err, i;
+
+        dev = kzalloc(sizeof(struct tegra_arb_dev), GFP_KERNEL);
+        if (dev == NULL) {
+                pr_err("%s: unable to alloc data struct.\n", __func__);
+                return -ENOMEM;
+        }
+
+        for (i = 0; i < TEGRA_RPC_MAX_SEM; i++) {
+                mutex_init(&dev->mutexes[i]);
+                init_completion(&dev->arb_gnt_complete[i]);
+        }
+
+        dev->sema_base = IO_ADDRESS(TEGRA_ARB_SEMA_BASE);
+        if (!dev->sema_base) {
+                pr_err("%s: can't get arb sema_base\n", __func__);
+                err = -ENOMEM;
+                goto out;
+        }
+
+        dev->gnt_base = IO_ADDRESS(TEGRA_ARBGNT_ICTLR_BASE);
+        if (!dev->gnt_base) {
+                pr_err("%s: can't ioremap gnt_base\n", __func__);
+                err = -ENOMEM;
+                goto out;
+        }
+
+        dev->irq = INT_GNT_1;
+        err = request_irq(dev->irq, arb_gnt_isr, 0, "rpc-arbsema", dev);
+        if (err) {
+                pr_err("%s: request_irq(%d) failed(%d)\n", __func__,
+                        dev->irq, err);
+                goto out;
+        }
+
+        spin_lock_init(&dev->lock);
+        arb = dev;
+
+        pr_info("%s: initialized\n", __func__);
+        return 0;
+
+out:
+        kfree(dev);
+        pr_err("%s: initialization failed.\n", __func__);
+        return err;
+}
+subsys_initcall(tegra_arb_init);
+
+MODULE_LICENSE("GPLv2");