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/*
* 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");
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