arch/mips/kernel/rtlx-mt.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 2005 MIPS Technologies, Inc.  All rights reserved.
   7  * Copyright (C) 2013 Imagination Technologies Ltd.
   8  */
   9 #include <linux/device.h>
  10 #include <linux/fs.h>
  11 #include <linux/err.h>
  12 #include <linux/wait.h>
  13 #include <linux/sched.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/irq.h>
  16
  17 #include <asm/mips_mt.h>
  18 #include <asm/vpe.h>
  19 #include <asm/rtlx.h>
  20
  21 static int major;
  22
  23 static void rtlx_dispatch(void)
  24 {
  25         if (read_c0_cause() & read_c0_status() & C_SW0)
  26                 do_IRQ(MIPS_CPU_IRQ_BASE + MIPS_CPU_RTLX_IRQ);
  27 }
  28
  29 /*
  30  * Interrupt handler may be called before rtlx_init has otherwise had
  31  * a chance to run.
  32  */
  33 static irqreturn_t rtlx_interrupt(int irq, void *dev_id)
  34 {
  35         unsigned int vpeflags;
  36         unsigned long flags;
  37         int i;
  38
  39         local_irq_save(flags);
  40         vpeflags = dvpe();
  41         set_c0_status(0x100 << MIPS_CPU_RTLX_IRQ);
  42         irq_enable_hazard();
  43         evpe(vpeflags);
  44         local_irq_restore(flags);
  45
  46         for (i = 0; i < RTLX_CHANNELS; i++) {
  47                 wake_up(&channel_wqs[i].lx_queue);
  48                 wake_up(&channel_wqs[i].rt_queue);
  49         }
  50
  51         return IRQ_HANDLED;
  52 }
  53
  54 static int rtlx_irq_num = MIPS_CPU_IRQ_BASE + MIPS_CPU_RTLX_IRQ;
  55
  56 void _interrupt_sp(void)
  57 {
  58         unsigned long flags;
  59
  60         local_irq_save(flags);
  61         dvpe();
  62         settc(1);
  63         write_vpe_c0_cause(read_vpe_c0_cause() | C_SW0);
  64         evpe(EVPE_ENABLE);
  65         local_irq_restore(flags);
  66 }
  67
  68 int __init rtlx_module_init(void)
  69 {
  70         struct device *dev;
  71         int i, err;
  72
  73         if (!cpu_has_mipsmt) {
  74                 pr_warn("VPE loader: not a MIPS MT capable processor\n");
  75                 return -ENODEV;
  76         }
  77
  78         if (aprp_cpu_index() == 0) {
  79                 pr_warn("No TCs reserved for AP/SP, not initializing RTLX.\n"
  80                         "Pass maxtcs=<n> argument as kernel argument\n");
  81
  82                 return -ENODEV;
  83         }
  84
  85         major = register_chrdev(0, RTLX_MODULE_NAME, &rtlx_fops);
  86         if (major < 0) {
  87                 pr_err("rtlx_module_init: unable to register device\n");
  88                 return major;
  89         }
  90
  91         /* initialise the wait queues */
  92         for (i = 0; i < RTLX_CHANNELS; i++) {
  93                 init_waitqueue_head(&channel_wqs[i].rt_queue);
  94                 init_waitqueue_head(&channel_wqs[i].lx_queue);
  95                 atomic_set(&channel_wqs[i].in_open, 0);
  96                 mutex_init(&channel_wqs[i].mutex);
  97
  98                 dev = device_create(&mt_class, NULL, MKDEV(major, i), NULL,
  99                                     "%s%d", RTLX_MODULE_NAME, i);
 100                 if (IS_ERR(dev)) {
 101                         while (i--)
 102                                 device_destroy(&mt_class, MKDEV(major, i));
 103
 104                         err = PTR_ERR(dev);
 105                         goto out_chrdev;
 106                 }
 107         }
 108
 109         /* set up notifiers */
 110         rtlx_notify.start = rtlx_starting;
 111         rtlx_notify.stop = rtlx_stopping;
 112         vpe_notify(aprp_cpu_index(), &rtlx_notify);
 113
 114         if (cpu_has_vint) {
 115                 aprp_hook = rtlx_dispatch;
 116         } else {
 117                 pr_err("APRP RTLX init on non-vectored-interrupt processor\n");
 118                 err = -ENODEV;
 119                 goto out_class;
 120         }
 121
 122         err = request_irq(rtlx_irq_num, rtlx_interrupt, 0, "RTLX", rtlx);
 123         if (err)
 124                 goto out_class;
 125
 126         return 0;
 127
 128 out_class:
 129         for (i = 0; i < RTLX_CHANNELS; i++)
 130                 device_destroy(&mt_class, MKDEV(major, i));
 131 out_chrdev:
 132         unregister_chrdev(major, RTLX_MODULE_NAME);
 133
 134         return err;
 135 }
 136
 137 void __exit rtlx_module_exit(void)
 138 {
 139         int i;
 140
 141         for (i = 0; i < RTLX_CHANNELS; i++)
 142                 device_destroy(&mt_class, MKDEV(major, i));
 143
 144         unregister_chrdev(major, RTLX_MODULE_NAME);
 145
 146         aprp_hook = NULL;
 147 }