arch/powerpc/sysdev/mpic_msgr.c

   1 /*
   2  * Copyright 2011-2012, Meador Inge, Mentor Graphics Corporation.
   3  *
   4  * Some ideas based on un-pushed work done by Vivek Mahajan, Jason Jin, and
   5  * Mingkai Hu from Freescale Semiconductor, Inc.
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; version 2 of the
  10  * License.
  11  *
  12  */
  13
  14 #include <linux/list.h>
  15 #include <linux/of_platform.h>
  16 #include <linux/errno.h>
  17 #include <asm/prom.h>
  18 #include <asm/hw_irq.h>
  19 #include <asm/ppc-pci.h>
  20 #include <asm/mpic_msgr.h>
  21
  22 #define MPIC_MSGR_REGISTERS_PER_BLOCK   4
  23 #define MPIC_MSGR_STRIDE                0x10
  24 #define MPIC_MSGR_MER_OFFSET            0x100
  25 #define MSGR_INUSE                      0
  26 #define MSGR_FREE                       1
  27
  28 static struct mpic_msgr **mpic_msgrs;
  29 static unsigned int mpic_msgr_count;
  30 static DEFINE_RAW_SPINLOCK(msgrs_lock);
  31
  32 static inline void _mpic_msgr_mer_write(struct mpic_msgr *msgr, u32 value)
  33 {
  34         out_be32(msgr->mer, value);
  35 }
  36
  37 static inline u32 _mpic_msgr_mer_read(struct mpic_msgr *msgr)
  38 {
  39         return in_be32(msgr->mer);
  40 }
  41
  42 static inline void _mpic_msgr_disable(struct mpic_msgr *msgr)
  43 {
  44         u32 mer = _mpic_msgr_mer_read(msgr);
  45
  46         _mpic_msgr_mer_write(msgr, mer & ~(1 << msgr->num));
  47 }
  48
  49 struct mpic_msgr *mpic_msgr_get(unsigned int reg_num)
  50 {
  51         unsigned long flags;
  52         struct mpic_msgr *msgr;
  53
  54         /* Assume busy until proven otherwise.  */
  55         msgr = ERR_PTR(-EBUSY);
  56
  57         if (reg_num >= mpic_msgr_count)
  58                 return ERR_PTR(-ENODEV);
  59
  60         raw_spin_lock_irqsave(&msgrs_lock, flags);
  61         msgr = mpic_msgrs[reg_num];
  62         if (msgr->in_use == MSGR_FREE)
  63                 msgr->in_use = MSGR_INUSE;
  64         raw_spin_unlock_irqrestore(&msgrs_lock, flags);
  65
  66         return msgr;
  67 }
  68 EXPORT_SYMBOL_GPL(mpic_msgr_get);
  69
  70 void mpic_msgr_put(struct mpic_msgr *msgr)
  71 {
  72         unsigned long flags;
  73
  74         raw_spin_lock_irqsave(&msgr->lock, flags);
  75         msgr->in_use = MSGR_FREE;
  76         _mpic_msgr_disable(msgr);
  77         raw_spin_unlock_irqrestore(&msgr->lock, flags);
  78 }
  79 EXPORT_SYMBOL_GPL(mpic_msgr_put);
  80
  81 void mpic_msgr_enable(struct mpic_msgr *msgr)
  82 {
  83         unsigned long flags;
  84         u32 mer;
  85
  86         raw_spin_lock_irqsave(&msgr->lock, flags);
  87         mer = _mpic_msgr_mer_read(msgr);
  88         _mpic_msgr_mer_write(msgr, mer | (1 << msgr->num));
  89         raw_spin_unlock_irqrestore(&msgr->lock, flags);
  90 }
  91 EXPORT_SYMBOL_GPL(mpic_msgr_enable);
  92
  93 void mpic_msgr_disable(struct mpic_msgr *msgr)
  94 {
  95         unsigned long flags;
  96
  97         raw_spin_lock_irqsave(&msgr->lock, flags);
  98         _mpic_msgr_disable(msgr);
  99         raw_spin_unlock_irqrestore(&msgr->lock, flags);
 100 }
 101 EXPORT_SYMBOL_GPL(mpic_msgr_disable);
 102
 103 /* The following three functions are used to compute the order and number of
 104  * the message register blocks.  They are clearly very inefficent.  However,
 105  * they are called *only* a few times during device initialization.
 106  */
 107 static unsigned int mpic_msgr_number_of_blocks(void)
 108 {
 109         unsigned int count;
 110         struct device_node *aliases;
 111
 112         count = 0;
 113         aliases = of_find_node_by_name(NULL, "aliases");
 114
 115         if (aliases) {
 116                 char buf[32];
 117
 118                 for (;;) {
 119                         snprintf(buf, sizeof(buf), "mpic-msgr-block%d", count);
 120                         if (!of_find_property(aliases, buf, NULL))
 121                                 break;
 122
 123                         count += 1;
 124                 }
 125         }
 126
 127         return count;
 128 }
 129
 130 static unsigned int mpic_msgr_number_of_registers(void)
 131 {
 132         return mpic_msgr_number_of_blocks() * MPIC_MSGR_REGISTERS_PER_BLOCK;
 133 }
 134
 135 static int mpic_msgr_block_number(struct device_node *node)
 136 {
 137         struct device_node *aliases;
 138         unsigned int index, number_of_blocks;
 139         char buf[64];
 140
 141         number_of_blocks = mpic_msgr_number_of_blocks();
 142         aliases = of_find_node_by_name(NULL, "aliases");
 143         if (!aliases)
 144                 return -1;
 145
 146         for (index = 0; index < number_of_blocks; ++index) {
 147                 struct property *prop;
 148
 149                 snprintf(buf, sizeof(buf), "mpic-msgr-block%d", index);
 150                 prop = of_find_property(aliases, buf, NULL);
 151                 if (node == of_find_node_by_path(prop->value))
 152                         break;
 153         }
 154
 155         return index == number_of_blocks ? -1 : index;
 156 }
 157
 158 /* The probe function for a single message register block.
 159  */
 160 static __devinit int mpic_msgr_probe(struct platform_device *dev)
 161 {
 162         void __iomem *msgr_block_addr;
 163         int block_number;
 164         struct resource rsrc;
 165         unsigned int i;
 166         unsigned int irq_index;
 167         struct device_node *np = dev->dev.of_node;
 168         unsigned int receive_mask;
 169         const unsigned int *prop;
 170
 171         if (!np) {
 172                 dev_err(&dev->dev, "Device OF-Node is NULL");
 173                 return -EFAULT;
 174         }
 175
 176         /* Allocate the message register array upon the first device
 177          * registered.
 178          */
 179         if (!mpic_msgrs) {
 180                 mpic_msgr_count = mpic_msgr_number_of_registers();
 181                 dev_info(&dev->dev, "Found %d message registers\n",
 182                                 mpic_msgr_count);
 183
 184                 mpic_msgrs = kzalloc(sizeof(struct mpic_msgr) * mpic_msgr_count,
 185                                                          GFP_KERNEL);
 186                 if (!mpic_msgrs) {
 187                         dev_err(&dev->dev,
 188                                 "No memory for message register blocks\n");
 189                         return -ENOMEM;
 190                 }
 191         }
 192         dev_info(&dev->dev, "Of-device full name %s\n", np->full_name);
 193
 194         /* IO map the message register block. */
 195         of_address_to_resource(np, 0, &rsrc);
 196         msgr_block_addr = ioremap(rsrc.start, rsrc.end - rsrc.start);
 197         if (!msgr_block_addr) {
 198                 dev_err(&dev->dev, "Failed to iomap MPIC message registers");
 199                 return -EFAULT;
 200         }
 201
 202         /* Ensure the block has a defined order. */
 203         block_number = mpic_msgr_block_number(np);
 204         if (block_number < 0) {
 205                 dev_err(&dev->dev,
 206                         "Failed to find message register block alias\n");
 207                 return -ENODEV;
 208         }
 209         dev_info(&dev->dev, "Setting up message register block %d\n",
 210                         block_number);
 211
 212         /* Grab the receive mask which specifies what registers can receive
 213          * interrupts.
 214          */
 215         prop = of_get_property(np, "mpic-msgr-receive-mask", NULL);
 216         receive_mask = (prop) ? *prop : 0xF;
 217
 218         /* Build up the appropriate message register data structures. */
 219         for (i = 0, irq_index = 0; i < MPIC_MSGR_REGISTERS_PER_BLOCK; ++i) {
 220                 struct mpic_msgr *msgr;
 221                 unsigned int reg_number;
 222
 223                 msgr = kzalloc(sizeof(struct mpic_msgr), GFP_KERNEL);
 224                 if (!msgr) {
 225                         dev_err(&dev->dev, "No memory for message register\n");
 226                         return -ENOMEM;
 227                 }
 228
 229                 reg_number = block_number * MPIC_MSGR_REGISTERS_PER_BLOCK + i;
 230                 msgr->base = msgr_block_addr + i * MPIC_MSGR_STRIDE;
 231                 msgr->mer = (u32 *)((u8 *)msgr->base + MPIC_MSGR_MER_OFFSET);
 232                 msgr->in_use = MSGR_FREE;
 233                 msgr->num = i;
 234                 raw_spin_lock_init(&msgr->lock);
 235
 236                 if (receive_mask & (1 << i)) {
 237                         struct resource irq;
 238
 239                         if (of_irq_to_resource(np, irq_index, &irq) == NO_IRQ) {
 240                                 dev_err(&dev->dev,
 241                                                 "Missing interrupt specifier");
 242                                 kfree(msgr);
 243                                 return -EFAULT;
 244                         }
 245                         msgr->irq = irq.start;
 246                         irq_index += 1;
 247                 } else {
 248                         msgr->irq = NO_IRQ;
 249                 }
 250
 251                 mpic_msgrs[reg_number] = msgr;
 252                 mpic_msgr_disable(msgr);
 253                 dev_info(&dev->dev, "Register %d initialized: irq %d\n",
 254                                 reg_number, msgr->irq);
 255
 256         }
 257
 258         return 0;
 259 }
 260
 261 static const struct of_device_id mpic_msgr_ids[] = {
 262         {
 263                 .compatible = "fsl,mpic-v3.1-msgr",
 264                 .data = NULL,
 265         },
 266         {}
 267 };
 268
 269 static struct platform_driver mpic_msgr_driver = {
 270         .driver = {
 271                 .name = "mpic-msgr",
 272                 .owner = THIS_MODULE,
 273                 .of_match_table = mpic_msgr_ids,
 274         },
 275         .probe = mpic_msgr_probe,
 276 };
 277
 278 static __init int mpic_msgr_init(void)
 279 {
 280         return platform_driver_register(&mpic_msgr_driver);
 281 }
 282 subsys_initcall(mpic_msgr_init);