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         /* Ought not to be strictly necessary for SMTC builds */
  40         local_irq_save(flags);
  41         vpeflags = dvpe();
  42         set_c0_status(0x100 << MIPS_CPU_RTLX_IRQ);
  43         irq_enable_hazard();
  44         evpe(vpeflags);
  45         local_irq_restore(flags);
  46
  47         for (i = 0; i < RTLX_CHANNELS; i++) {
  48                 wake_up(&channel_wqs[i].lx_queue);
  49                 wake_up(&channel_wqs[i].rt_queue);
  50         }
  51
  52         return IRQ_HANDLED;
  53 }
  54
  55 static struct irqaction rtlx_irq = {
  56         .handler        = rtlx_interrupt,
  57         .name           = "RTLX",
  58 };
  59
  60 static int rtlx_irq_num = MIPS_CPU_IRQ_BASE + MIPS_CPU_RTLX_IRQ;
  61
  62 void _interrupt_sp(void)
  63 {
  64         unsigned long flags;
  65
  66         local_irq_save(flags);
  67         dvpe();
  68         settc(1);
  69         write_vpe_c0_cause(read_vpe_c0_cause() | C_SW0);
  70         evpe(EVPE_ENABLE);
  71         local_irq_restore(flags);
  72 }
  73
  74 int __init rtlx_module_init(void)
  75 {
  76         struct device *dev;
  77         int i, err;
  78
  79         if (!cpu_has_mipsmt) {
  80                 pr_warn("VPE loader: not a MIPS MT capable processor\n");
  81                 return -ENODEV;
  82         }
  83
  84         if (aprp_cpu_index() == 0) {
  85                 pr_warn("No TCs reserved for AP/SP, not initializing RTLX.\n"
  86                         "Pass maxtcs=<n> argument as kernel argument\n");
  87
  88                 return -ENODEV;
  89         }
  90
  91         major = register_chrdev(0, RTLX_MODULE_NAME, &rtlx_fops);
  92         if (major < 0) {
  93                 pr_err("rtlx_module_init: unable to register device\n");
  94                 return major;
  95         }
  96
  97         /* initialise the wait queues */
  98         for (i = 0; i < RTLX_CHANNELS; i++) {
  99                 init_waitqueue_head(&channel_wqs[i].rt_queue);
 100                 init_waitqueue_head(&channel_wqs[i].lx_queue);
 101                 atomic_set(&channel_wqs[i].in_open, 0);
 102                 mutex_init(&channel_wqs[i].mutex);
 103
 104                 dev = device_create(mt_class, NULL, MKDEV(major, i), NULL,
 105                                     "%s%d", RTLX_MODULE_NAME, i);
 106                 if (IS_ERR(dev)) {
 107                         err = PTR_ERR(dev);
 108                         goto out_chrdev;
 109                 }
 110         }
 111
 112         /* set up notifiers */
 113         rtlx_notify.start = rtlx_starting;
 114         rtlx_notify.stop = rtlx_stopping;
 115         vpe_notify(aprp_cpu_index(), &rtlx_notify);
 116
 117         if (cpu_has_vint) {
 118                 aprp_hook = rtlx_dispatch;
 119         } else {
 120                 pr_err("APRP RTLX init on non-vectored-interrupt processor\n");
 121                 err = -ENODEV;
 122                 goto out_class;
 123         }
 124
 125         rtlx_irq.dev_id = rtlx;
 126         err = setup_irq(rtlx_irq_num, &rtlx_irq);
 127         if (err)
 128                 goto out_class;
 129
 130         return 0;
 131
 132 out_class:
 133         for (i = 0; i < RTLX_CHANNELS; i++)
 134                 device_destroy(mt_class, MKDEV(major, i));
 135 out_chrdev:
 136         unregister_chrdev(major, RTLX_MODULE_NAME);
 137
 138         return err;
 139 }
 140
 141 void __exit rtlx_module_exit(void)
 142 {
 143         int i;
 144
 145         for (i = 0; i < RTLX_CHANNELS; i++)
 146                 device_destroy(mt_class, MKDEV(major, i));
 147
 148         unregister_chrdev(major, RTLX_MODULE_NAME);
 149
 150         aprp_hook = NULL;
 151 }