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/*
* header goes here
*/
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/device.h>
#include <linux/sched.h>
#include <mach/mvf.h>
#define NUM_GATES 16
#define MASK_FROM_GATE(gate_num) ((u32)(1 << (NUM_GATES*2 - 1 - idx[gate_num])))
#define THIS_CORE (0)
#define LOCK_VALUE (THIS_CORE + 1)
#define SEMA4_CP0INE (MVF_SEMA4_BASE_ADDR + 0x40)
#define SEMA4_CP0NTF (MVF_SEMA4_BASE_ADDR + 0x80)
//#if 0
#include <linux/mm.h>
#include <linux/version.h>
#include <linux/kdev_t.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <mach/hardware.h>
#include <linux/string.h>
#include <linux/uaccess.h>
#include <linux/delay.h>
#include <linux/time.h>
//#endif
#include <linux/debugfs.h>
#include <linux/mvf_sema4.h>
// ************************************ Local Data *************************************************
static MVF_SEMA4* gates[NUM_GATES];
static bool initialized = false;
// account for the way the bits are set / returned in CP0INE and CP0NTF
static const int idx[16] = {3, 2, 1, 0, 7, 6, 5, 4, 11, 10, 9, 8, 15, 14, 13, 12};
// debugfs
#define DEBUGFS_DIR "mvf_sema4"
static struct dentry *debugfs_dir;
// ************************************ Interrupt handler *************************************************
static irqreturn_t sema4_irq_handler(int irq, void *dev_id)
{
int gate_num;
u32 cp0ntf = readl(MVF_IO_ADDRESS(SEMA4_CP0NTF));
for(gate_num=0; gate_num<NUM_GATES; gate_num++)
{
// interrupt from this gate?
if(cp0ntf & MASK_FROM_GATE(gate_num))
{
// grab the gate to stop the interrupts
writeb(LOCK_VALUE, MVF_IO_ADDRESS(MVF_SEMA4_BASE_ADDR) + gate_num);
// make sure there's a gate assigned
if(gates[gate_num])
{
if(gates[gate_num]->use_interrupts) {
// wake up whoever was aiting
wake_up_interruptible(&(gates[gate_num]->wait_queue));
// bump stats
gates[gate_num]->interrupts++;
}
}
}
}
return IRQ_HANDLED;
}
// ************************************ Utility functions *************************************************
static int initialize(void)
{
int i;
// clear the gates table
for(i=0; i<NUM_GATES; i++)
gates[i] = NULL;
// clear out all notification requests
writel(0, MVF_IO_ADDRESS(SEMA4_CP0INE));
//Register the interrupt handler
if (request_irq(MVF_INT_SEMA4, sema4_irq_handler, 0, "mvf_sema4_handler", NULL) != 0)
{
printk(KERN_ERR "Failed to register MVF_INT_SEMA4 interrupt.\n");
return -EIO;
}
// debugfs
debugfs_dir = debugfs_create_dir(DEBUGFS_DIR, NULL);
initialized = true;
return 0;
}
int mvf_sema4_assign(int gate_num, bool use_interrupts, MVF_SEMA4** sema4_p)
{
int retval;
u32 cp0ine;
unsigned long irq_flags;
char debugfs_gatedir[4];
// take the opportunity to initialize the whole sub-system
if(!initialized)
{
retval = initialize();
if(retval)
return retval;
}
if((gate_num < 0) || (gate_num >= NUM_GATES))
return -EINVAL;
if(gates[gate_num])
return -EBUSY;
*sema4_p = (MVF_SEMA4 *)kmalloc(sizeof(MVF_SEMA4), GFP_KERNEL);
if(*sema4_p == NULL)
return -ENOMEM;
memset(*sema4_p, 0, sizeof(MVF_SEMA4));
gates[gate_num] = *sema4_p;
(*sema4_p)->gate_num = gate_num;
(*sema4_p)->use_interrupts = use_interrupts;
if(use_interrupts)
{
init_waitqueue_head(&((*sema4_p)->wait_queue));
local_irq_save(irq_flags);
cp0ine = readl(MVF_IO_ADDRESS(SEMA4_CP0INE));
cp0ine |= MASK_FROM_GATE(gate_num);
writel(cp0ine, MVF_IO_ADDRESS(SEMA4_CP0INE));
local_irq_restore(irq_flags);
}
// debugfs
sprintf(debugfs_gatedir, "%d", gate_num);
debugfs_dir = debugfs_create_dir(debugfs_gatedir, debugfs_dir);
debugfs_create_u32("attempts", 0444, debugfs_dir, &(*sema4_p)->attempts);
debugfs_create_u32("interrupts", 0444, debugfs_dir, &(*sema4_p)->interrupts);
return 0;
}
int mvf_sema4_deassign(MVF_SEMA4 *sema4)
{
u32 cp0ine;
unsigned long irq_flags;
int gate_num;
if(!sema4)
return -EINVAL;
gate_num = sema4->gate_num;
if(sema4->use_interrupts)
{
local_irq_save(irq_flags);
cp0ine = readl(MVF_IO_ADDRESS(SEMA4_CP0INE));
cp0ine &= ~MASK_FROM_GATE(gate_num);
writel(cp0ine, MVF_IO_ADDRESS(SEMA4_CP0INE));
local_irq_restore(irq_flags);
}
kfree(sema4);
gates[gate_num] = NULL;
return 0;
}
int mvf_sema4_lock(MVF_SEMA4 *sema4, unsigned int timeout_us)
{
int retval;
int gate_num;
if(!sema4)
return -EINVAL;
gate_num = sema4->gate_num;
// cant use timeouts if not using interruppts
// TODO use spin lock if not using interrupts
if((!sema4->use_interrupts) && timeout_us)
return -EINVAL;
// bump stats
gates[gate_num]->attempts++;
// try to grab it
writeb(LOCK_VALUE, MVF_IO_ADDRESS(MVF_SEMA4_BASE_ADDR) + gate_num);
if(readb(MVF_IO_ADDRESS(MVF_SEMA4_BASE_ADDR) + gate_num) == LOCK_VALUE)
return 0;
// no timeout, fail
if(!timeout_us)
return -EBUSY;
// wait forever?
if(timeout_us == 0xffffffff)
{
if(wait_event_interruptible(sema4->wait_queue, (readb(MVF_IO_ADDRESS(MVF_SEMA4_BASE_ADDR) + gate_num) == LOCK_VALUE)))
return -ERESTARTSYS;
}
else
{
// return: 0 = timeout, >0 = woke up with that many jiffies left, <0 = error
retval = wait_event_interruptible_timeout(sema4->wait_queue,
(readb(MVF_IO_ADDRESS(MVF_SEMA4_BASE_ADDR) + gate_num) == LOCK_VALUE),
usecs_to_jiffies(timeout_us));
if(retval == 0)
return -ETIME;
else if(retval < 0)
return retval;
}
return 0;
}
int mvf_sema4_unlock(MVF_SEMA4 *sema4)
{
if(!sema4)
return -EINVAL;
// unlock it
writeb(0, MVF_IO_ADDRESS(MVF_SEMA4_BASE_ADDR) + sema4->gate_num);
return 0;
}
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