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