diff options
Diffstat (limited to 'arch/arm/mach-mvf/mvf_sema4.c')
| -rw-r--r-- | arch/arm/mach-mvf/mvf_sema4.c | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/arch/arm/mach-mvf/mvf_sema4.c b/arch/arm/mach-mvf/mvf_sema4.c new file mode 100644 index 000000000000..311b56a69d73 --- /dev/null +++ b/arch/arm/mach-mvf/mvf_sema4.c @@ -0,0 +1,234 @@ +/* +* 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/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}; + + +// ************************************ 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)); + } + } + } + + return IRQ_HANDLED; +} + +// ************************************ Utility functions ************************************************* + +static int find_sema4(MVF_SEMA4 *sema4) +{ + int i; + + for(i=0; i<NUM_GATES; i++) + { + if(gates[i] == sema4) + return i; + } + + return -EINVAL; +} + +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; + } + + 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; + + // 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; + + 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); + } + + return 0; +} + +int mvf_sema4_deassign(MVF_SEMA4 *sema4) +{ + u32 cp0ine; + unsigned long irq_flags; + + int gate_num = find_sema4(sema4); + if(gate_num < 0) + return 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 = find_sema4(sema4); + if(gate_num < 0) + return 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; + + // 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) +{ + int gate_num = find_sema4(sema4); + if(gate_num < 0) + return gate_num; + + // unlock it + writeb(0, MVF_IO_ADDRESS(MVF_SEMA4_BASE_ADDR) + gate_num); + + return 0; +} + |