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 struct irqaction rtlx_irq = {
  55         .handler        = rtlx_interrupt,
  56         .name           = "RTLX",
  57 };
  58
  59 static int rtlx_irq_num = MIPS_CPU_IRQ_BASE + MIPS_CPU_RTLX_IRQ;
  60
  61 void _interrupt_sp(void)
  62 {
  63         unsigned long flags;
  64
  65         local_irq_save(flags);
  66         dvpe();
  67         settc(1);
  68         write_vpe_c0_cause(read_vpe_c0_cause() | C_SW0);
  69         evpe(EVPE_ENABLE);
  70         local_irq_restore(flags);
  71 }
  72
  73 int __init rtlx_module_init(void)
  74 {
  75         struct device *dev;
  76         int i, err;
  77
  78         if (!cpu_has_mipsmt) {
  79                 pr_warn("VPE loader: not a MIPS MT capable processor\n");
  80                 return -ENODEV;
  81         }
  82
  83         if (aprp_cpu_index() == 0) {
  84                 pr_warn("No TCs reserved for AP/SP, not initializing RTLX.\n"
  85                         "Pass maxtcs=<n> argument as kernel argument\n");
  86
  87                 return -ENODEV;
  88         }
  89
  90         major = register_chrdev(0, RTLX_MODULE_NAME, &rtlx_fops);
  91         if (major < 0) {
  92                 pr_err("rtlx_module_init: unable to register device\n");
  93                 return major;
  94         }
  95
  96         /* initialise the wait queues */
  97         for (i = 0; i < RTLX_CHANNELS; i++) {
  98                 init_waitqueue_head(&channel_wqs[i].rt_queue);
  99                 init_waitqueue_head(&channel_wqs[i].lx_queue);
 100                 atomic_set(&channel_wqs[i].in_open, 0);
 101                 mutex_init(&channel_wqs[i].mutex);
 102
 103                 dev = device_create(mt_class, NULL, MKDEV(major, i), NULL,
 104                                     "%s%d", RTLX_MODULE_NAME, i);
 105                 if (IS_ERR(dev)) {
 106                         while (i--)
 107                                 device_destroy(mt_class, MKDEV(major, i));
 108
 109                         err = PTR_ERR(dev);
 110                         goto out_chrdev;
 111                 }
 112         }
 113
 114         /* set up notifiers */
 115         rtlx_notify.start = rtlx_starting;
 116         rtlx_notify.stop = rtlx_stopping;
 117         vpe_notify(aprp_cpu_index(), &rtlx_notify);
 118
 119         if (cpu_has_vint) {
 120                 aprp_hook = rtlx_dispatch;
 121         } else {
 122                 pr_err("APRP RTLX init on non-vectored-interrupt processor\n");
 123                 err = -ENODEV;
 124                 goto out_class;
 125         }
 126
 127         rtlx_irq.dev_id = rtlx;
 128         err = setup_irq(rtlx_irq_num, &rtlx_irq);
 129         if (err)
 130                 goto out_class;
 131
 132         return 0;
 133
 134 out_class:
 135         for (i = 0; i < RTLX_CHANNELS; i++)
 136                 device_destroy(mt_class, MKDEV(major, i));
 137 out_chrdev:
 138         unregister_chrdev(major, RTLX_MODULE_NAME);
 139
 140         return err;
 141 }
 142
 143 void __exit rtlx_module_exit(void)
 144 {
 145         int i;
 146
 147         for (i = 0; i < RTLX_CHANNELS; i++)
 148                 device_destroy(mt_class, MKDEV(major, i));
 149
 150         unregister_chrdev(major, RTLX_MODULE_NAME);
 151
 152         aprp_hook = NULL;
 153 }