root/arch/powerpc/platforms/52xx/mpc52xx_pic.c

DEFINITIONS

1. io_be_setbit
2. io_be_clrbit
3. mpc52xx_extirq_mask
4. mpc52xx_extirq_unmask
5. mpc52xx_extirq_ack
6. mpc52xx_extirq_set_type
7. mpc52xx_null_set_type
8. mpc52xx_main_mask
9. mpc52xx_main_unmask
10. mpc52xx_periph_mask
11. mpc52xx_periph_unmask
12. mpc52xx_sdma_mask
13. mpc52xx_sdma_unmask
14. mpc52xx_sdma_ack
15. mpc52xx_is_extirq
16. mpc52xx_irqhost_xlate
17. mpc52xx_irqhost_map
18. mpc52xx_init_irq
19. mpc52xx_get_irq

   1 /*
   2  *
   3  * Programmable Interrupt Controller functions for the Freescale MPC52xx.
   4  *
   5  * Copyright (C) 2008 Secret Lab Technologies Ltd.
   6  * Copyright (C) 2006 bplan GmbH
   7  * Copyright (C) 2004 Sylvain Munaut <tnt@246tNt.com>
   8  * Copyright (C) 2003 Montavista Software, Inc
   9  *
  10  * Based on the code from the 2.4 kernel by
  11  * Dale Farnsworth <dfarnsworth@mvista.com> and Kent Borg.
  12  *
  13  * This file is licensed under the terms of the GNU General Public License
  14  * version 2. This program is licensed "as is" without any warranty of any
  15  * kind, whether express or implied.
  16  *
  17  */
  18 
  19 /*
  20  * This is the device driver for the MPC5200 interrupt controller.
  21  *
  22  * hardware overview
  23  * -----------------
  24  * The MPC5200 interrupt controller groups the all interrupt sources into
  25  * three groups called 'critical', 'main', and 'peripheral'.  The critical
  26  * group has 3 irqs, External IRQ0, slice timer 0 irq, and wake from deep
  27  * sleep.  Main group include the other 3 external IRQs, slice timer 1, RTC,
  28  * gpios, and the general purpose timers.  Peripheral group contains the
  29  * remaining irq sources from all of the on-chip peripherals (PSCs, Ethernet,
  30  * USB, DMA, etc).
  31  *
  32  * virqs
  33  * -----
  34  * The Linux IRQ subsystem requires that each irq source be assigned a
  35  * system wide unique IRQ number starting at 1 (0 means no irq).  Since
  36  * systems can have multiple interrupt controllers, the virtual IRQ (virq)
  37  * infrastructure lets each interrupt controller to define a local set
  38  * of IRQ numbers and the virq infrastructure maps those numbers into
  39  * a unique range of the global IRQ# space.
  40  *
  41  * To define a range of virq numbers for this controller, this driver first
  42  * assigns a number to each of the irq groups (called the level 1 or L1
  43  * value).  Within each group individual irq sources are also assigned a
  44  * number, as defined by the MPC5200 user guide, and refers to it as the
  45  * level 2 or L2 value.  The virq number is determined by shifting up the
  46  * L1 value by MPC52xx_IRQ_L1_OFFSET and ORing it with the L2 value.
  47  *
  48  * For example, the TMR0 interrupt is irq 9 in the main group.  The
  49  * virq for TMR0 is calculated by ((1 << MPC52xx_IRQ_L1_OFFSET) | 9).
  50  *
  51  * The observant reader will also notice that this driver defines a 4th
  52  * interrupt group called 'bestcomm'.  The bestcomm group isn't physically
  53  * part of the MPC5200 interrupt controller, but it is used here to assign
  54  * a separate virq number for each bestcomm task (since any of the 16
  55  * bestcomm tasks can cause the bestcomm interrupt to be raised).  When a
  56  * bestcomm interrupt occurs (peripheral group, irq 0) this driver determines
  57  * which task needs servicing and returns the irq number for that task.  This
  58  * allows drivers which use bestcomm to define their own interrupt handlers.
  59  *
  60  * irq_chip structures
  61  * -------------------
  62  * For actually manipulating IRQs (masking, enabling, clearing, etc) this
  63  * driver defines four separate 'irq_chip' structures, one for the main
  64  * group, one for the peripherals group, one for the bestcomm group and one
  65  * for external interrupts.  The irq_chip structures provide the hooks needed
  66  * to manipulate each IRQ source, and since each group is has a separate set
  67  * of registers for controlling the irq, it makes sense to divide up the
  68  * hooks along those lines.
  69  *
  70  * You'll notice that there is not an irq_chip for the critical group and
  71  * you'll also notice that there is an irq_chip defined for external
  72  * interrupts even though there is no external interrupt group.  The reason
  73  * for this is that the four external interrupts are all managed with the same
  74  * register even though one of the external IRQs is in the critical group and
  75  * the other three are in the main group.  For this reason it makes sense for
  76  * the 4 external irqs to be managed using a separate set of hooks.  The
  77  * reason there is no crit irq_chip is that of the 3 irqs in the critical
  78  * group, only external interrupt is actually support at this time by this
  79  * driver and since external interrupt is the only one used, it can just
  80  * be directed to make use of the external irq irq_chip.
  81  *
  82  * device tree bindings
  83  * --------------------
  84  * The device tree bindings for this controller reflect the two level
  85  * organization of irqs in the device.  #interrupt-cells = <3> where the
  86  * first cell is the group number [0..3], the second cell is the irq
  87  * number in the group, and the third cell is the sense type (level/edge).
  88  * For reference, the following is a list of the interrupt property values
  89  * associated with external interrupt sources on the MPC5200 (just because
  90  * it is non-obvious to determine what the interrupts property should be
  91  * when reading the mpc5200 manual and it is a frequently asked question).
  92  *
  93  * External interrupts:
  94  * <0 0 n>      external irq0, n is sense       (n=0: level high,
  95  * <1 1 n>      external irq1, n is sense        n=1: edge rising,
  96  * <1 2 n>      external irq2, n is sense        n=2: edge falling,
  97  * <1 3 n>      external irq3, n is sense        n=3: level low)
  98  */
  99 #undef DEBUG
 100 
 101 #include <linux/interrupt.h>
 102 #include <linux/irq.h>
 103 #include <linux/of.h>
 104 #include <asm/io.h>
 105 #include <asm/prom.h>
 106 #include <asm/mpc52xx.h>
 107 
 108 /* HW IRQ mapping */
 109 #define MPC52xx_IRQ_L1_CRIT     (0)
 110 #define MPC52xx_IRQ_L1_MAIN     (1)
 111 #define MPC52xx_IRQ_L1_PERP     (2)
 112 #define MPC52xx_IRQ_L1_SDMA     (3)
 113 
 114 #define MPC52xx_IRQ_L1_OFFSET   (6)
 115 #define MPC52xx_IRQ_L1_MASK     (0x00c0)
 116 #define MPC52xx_IRQ_L2_MASK     (0x003f)
 117 
 118 #define MPC52xx_IRQ_HIGHTESTHWIRQ (0xd0)
 119 
 120 
 121 /* MPC5200 device tree match tables */
 122 static const struct of_device_id mpc52xx_pic_ids[] __initconst = {
 123         { .compatible = "fsl,mpc5200-pic", },
 124         { .compatible = "mpc5200-pic", },
 125         {}
 126 };
 127 static const struct of_device_id mpc52xx_sdma_ids[] __initconst = {
 128         { .compatible = "fsl,mpc5200-bestcomm", },
 129         { .compatible = "mpc5200-bestcomm", },
 130         {}
 131 };
 132 
 133 static struct mpc52xx_intr __iomem *intr;
 134 static struct mpc52xx_sdma __iomem *sdma;
 135 static struct irq_domain *mpc52xx_irqhost = NULL;
 136 
 137 static unsigned char mpc52xx_map_senses[4] = {
 138         IRQ_TYPE_LEVEL_HIGH,
 139         IRQ_TYPE_EDGE_RISING,
 140         IRQ_TYPE_EDGE_FALLING,
 141         IRQ_TYPE_LEVEL_LOW,
 142 };
 143 
 144 /* Utility functions */
 145 static inline void io_be_setbit(u32 __iomem *addr, int bitno)
 146 {
 147         out_be32(addr, in_be32(addr) | (1 << bitno));
 148 }
 149 
 150 static inline void io_be_clrbit(u32 __iomem *addr, int bitno)
 151 {
 152         out_be32(addr, in_be32(addr) & ~(1 << bitno));
 153 }
 154 
 155 /*
 156  * IRQ[0-3] interrupt irq_chip
 157  */
 158 static void mpc52xx_extirq_mask(struct irq_data *d)
 159 {
 160         int l2irq = irqd_to_hwirq(d) & MPC52xx_IRQ_L2_MASK;
 161         io_be_clrbit(&intr->ctrl, 11 - l2irq);
 162 }
 163 
 164 static void mpc52xx_extirq_unmask(struct irq_data *d)
 165 {
 166         int l2irq = irqd_to_hwirq(d) & MPC52xx_IRQ_L2_MASK;
 167         io_be_setbit(&intr->ctrl, 11 - l2irq);
 168 }
 169 
 170 static void mpc52xx_extirq_ack(struct irq_data *d)
 171 {
 172         int l2irq = irqd_to_hwirq(d) & MPC52xx_IRQ_L2_MASK;
 173         io_be_setbit(&intr->ctrl, 27-l2irq);
 174 }
 175 
 176 static int mpc52xx_extirq_set_type(struct irq_data *d, unsigned int flow_type)
 177 {
 178         u32 ctrl_reg, type;
 179         int l2irq = irqd_to_hwirq(d) & MPC52xx_IRQ_L2_MASK;
 180         void *handler = handle_level_irq;
 181 
 182         pr_debug("%s: irq=%x. l2=%d flow_type=%d\n", __func__,
 183                 (int) irqd_to_hwirq(d), l2irq, flow_type);
 184 
 185         switch (flow_type) {
 186         case IRQF_TRIGGER_HIGH: type = 0; break;
 187         case IRQF_TRIGGER_RISING: type = 1; handler = handle_edge_irq; break;
 188         case IRQF_TRIGGER_FALLING: type = 2; handler = handle_edge_irq; break;
 189         case IRQF_TRIGGER_LOW: type = 3; break;
 190         default:
 191                 type = 0;
 192         }
 193 
 194         ctrl_reg = in_be32(&intr->ctrl);
 195         ctrl_reg &= ~(0x3 << (22 - (l2irq * 2)));
 196         ctrl_reg |= (type << (22 - (l2irq * 2)));
 197         out_be32(&intr->ctrl, ctrl_reg);
 198 
 199         irq_set_handler_locked(d, handler);
 200 
 201         return 0;
 202 }
 203 
 204 static struct irq_chip mpc52xx_extirq_irqchip = {
 205         .name = "MPC52xx External",
 206         .irq_mask = mpc52xx_extirq_mask,
 207         .irq_unmask = mpc52xx_extirq_unmask,
 208         .irq_ack = mpc52xx_extirq_ack,
 209         .irq_set_type = mpc52xx_extirq_set_type,
 210 };
 211 
 212 /*
 213  * Main interrupt irq_chip
 214  */
 215 static int mpc52xx_null_set_type(struct irq_data *d, unsigned int flow_type)
 216 {
 217         return 0; /* Do nothing so that the sense mask will get updated */
 218 }
 219 
 220 static void mpc52xx_main_mask(struct irq_data *d)
 221 {
 222         int l2irq = irqd_to_hwirq(d) & MPC52xx_IRQ_L2_MASK;
 223         io_be_setbit(&intr->main_mask, 16 - l2irq);
 224 }
 225 
 226 static void mpc52xx_main_unmask(struct irq_data *d)
 227 {
 228         int l2irq = irqd_to_hwirq(d) & MPC52xx_IRQ_L2_MASK;
 229         io_be_clrbit(&intr->main_mask, 16 - l2irq);
 230 }
 231 
 232 static struct irq_chip mpc52xx_main_irqchip = {
 233         .name = "MPC52xx Main",
 234         .irq_mask = mpc52xx_main_mask,
 235         .irq_mask_ack = mpc52xx_main_mask,
 236         .irq_unmask = mpc52xx_main_unmask,
 237         .irq_set_type = mpc52xx_null_set_type,
 238 };
 239 
 240 /*
 241  * Peripherals interrupt irq_chip
 242  */
 243 static void mpc52xx_periph_mask(struct irq_data *d)
 244 {
 245         int l2irq = irqd_to_hwirq(d) & MPC52xx_IRQ_L2_MASK;
 246         io_be_setbit(&intr->per_mask, 31 - l2irq);
 247 }
 248 
 249 static void mpc52xx_periph_unmask(struct irq_data *d)
 250 {
 251         int l2irq = irqd_to_hwirq(d) & MPC52xx_IRQ_L2_MASK;
 252         io_be_clrbit(&intr->per_mask, 31 - l2irq);
 253 }
 254 
 255 static struct irq_chip mpc52xx_periph_irqchip = {
 256         .name = "MPC52xx Peripherals",
 257         .irq_mask = mpc52xx_periph_mask,
 258         .irq_mask_ack = mpc52xx_periph_mask,
 259         .irq_unmask = mpc52xx_periph_unmask,
 260         .irq_set_type = mpc52xx_null_set_type,
 261 };
 262 
 263 /*
 264  * SDMA interrupt irq_chip
 265  */
 266 static void mpc52xx_sdma_mask(struct irq_data *d)
 267 {
 268         int l2irq = irqd_to_hwirq(d) & MPC52xx_IRQ_L2_MASK;
 269         io_be_setbit(&sdma->IntMask, l2irq);
 270 }
 271 
 272 static void mpc52xx_sdma_unmask(struct irq_data *d)
 273 {
 274         int l2irq = irqd_to_hwirq(d) & MPC52xx_IRQ_L2_MASK;
 275         io_be_clrbit(&sdma->IntMask, l2irq);
 276 }
 277 
 278 static void mpc52xx_sdma_ack(struct irq_data *d)
 279 {
 280         int l2irq = irqd_to_hwirq(d) & MPC52xx_IRQ_L2_MASK;
 281         out_be32(&sdma->IntPend, 1 << l2irq);
 282 }
 283 
 284 static struct irq_chip mpc52xx_sdma_irqchip = {
 285         .name = "MPC52xx SDMA",
 286         .irq_mask = mpc52xx_sdma_mask,
 287         .irq_unmask = mpc52xx_sdma_unmask,
 288         .irq_ack = mpc52xx_sdma_ack,
 289         .irq_set_type = mpc52xx_null_set_type,
 290 };
 291 
 292 /**
 293  * mpc52xx_is_extirq - Returns true if hwirq number is for an external IRQ
 294  */
 295 static int mpc52xx_is_extirq(int l1, int l2)
 296 {
 297         return ((l1 == 0) && (l2 == 0)) ||
 298                ((l1 == 1) && (l2 >= 1) && (l2 <= 3));
 299 }
 300 
 301 /**
 302  * mpc52xx_irqhost_xlate - translate virq# from device tree interrupts property
 303  */
 304 static int mpc52xx_irqhost_xlate(struct irq_domain *h, struct device_node *ct,
 305                                  const u32 *intspec, unsigned int intsize,
 306                                  irq_hw_number_t *out_hwirq,
 307                                  unsigned int *out_flags)
 308 {
 309         int intrvect_l1;
 310         int intrvect_l2;
 311         int intrvect_type;
 312         int intrvect_linux;
 313 
 314         if (intsize != 3)
 315                 return -1;
 316 
 317         intrvect_l1 = (int)intspec[0];
 318         intrvect_l2 = (int)intspec[1];
 319         intrvect_type = (int)intspec[2] & 0x3;
 320 
 321         intrvect_linux = (intrvect_l1 << MPC52xx_IRQ_L1_OFFSET) &
 322                          MPC52xx_IRQ_L1_MASK;
 323         intrvect_linux |= intrvect_l2 & MPC52xx_IRQ_L2_MASK;
 324 
 325         *out_hwirq = intrvect_linux;
 326         *out_flags = IRQ_TYPE_LEVEL_LOW;
 327         if (mpc52xx_is_extirq(intrvect_l1, intrvect_l2))
 328                 *out_flags = mpc52xx_map_senses[intrvect_type];
 329 
 330         pr_debug("return %x, l1=%d, l2=%d\n", intrvect_linux, intrvect_l1,
 331                  intrvect_l2);
 332         return 0;
 333 }
 334 
 335 /**
 336  * mpc52xx_irqhost_map - Hook to map from virq to an irq_chip structure
 337  */
 338 static int mpc52xx_irqhost_map(struct irq_domain *h, unsigned int virq,
 339                                irq_hw_number_t irq)
 340 {
 341         int l1irq;
 342         int l2irq;
 343         struct irq_chip *uninitialized_var(irqchip);
 344         void *hndlr;
 345         int type;
 346         u32 reg;
 347 
 348         l1irq = (irq & MPC52xx_IRQ_L1_MASK) >> MPC52xx_IRQ_L1_OFFSET;
 349         l2irq = irq & MPC52xx_IRQ_L2_MASK;
 350 
 351         /*
 352          * External IRQs are handled differently by the hardware so they are
 353          * handled by a dedicated irq_chip structure.
 354          */
 355         if (mpc52xx_is_extirq(l1irq, l2irq)) {
 356                 reg = in_be32(&intr->ctrl);
 357                 type = mpc52xx_map_senses[(reg >> (22 - l2irq * 2)) & 0x3];
 358                 if ((type == IRQ_TYPE_EDGE_FALLING) ||
 359                     (type == IRQ_TYPE_EDGE_RISING))
 360                         hndlr = handle_edge_irq;
 361                 else
 362                         hndlr = handle_level_irq;
 363 
 364                 irq_set_chip_and_handler(virq, &mpc52xx_extirq_irqchip, hndlr);
 365                 pr_debug("%s: External IRQ%i virq=%x, hw=%x. type=%x\n",
 366                          __func__, l2irq, virq, (int)irq, type);
 367                 return 0;
 368         }
 369 
 370         /* It is an internal SOC irq.  Choose the correct irq_chip */
 371         switch (l1irq) {
 372         case MPC52xx_IRQ_L1_MAIN: irqchip = &mpc52xx_main_irqchip; break;
 373         case MPC52xx_IRQ_L1_PERP: irqchip = &mpc52xx_periph_irqchip; break;
 374         case MPC52xx_IRQ_L1_SDMA: irqchip = &mpc52xx_sdma_irqchip; break;
 375         case MPC52xx_IRQ_L1_CRIT:
 376                 pr_warn("%s: Critical IRQ #%d is unsupported! Nopping it.\n",
 377                         __func__, l2irq);
 378                 irq_set_chip(virq, &no_irq_chip);
 379                 return 0;
 380         }
 381 
 382         irq_set_chip_and_handler(virq, irqchip, handle_level_irq);
 383         pr_debug("%s: virq=%x, l1=%i, l2=%i\n", __func__, virq, l1irq, l2irq);
 384 
 385         return 0;
 386 }
 387 
 388 static const struct irq_domain_ops mpc52xx_irqhost_ops = {
 389         .xlate = mpc52xx_irqhost_xlate,
 390         .map = mpc52xx_irqhost_map,
 391 };
 392 
 393 /**
 394  * mpc52xx_init_irq - Initialize and register with the virq subsystem
 395  *
 396  * Hook for setting up IRQs on an mpc5200 system.  A pointer to this function
 397  * is to be put into the machine definition structure.
 398  *
 399  * This function searches the device tree for an MPC5200 interrupt controller,
 400  * initializes it, and registers it with the virq subsystem.
 401  */
 402 void __init mpc52xx_init_irq(void)
 403 {
 404         u32 intr_ctrl;
 405         struct device_node *picnode;
 406         struct device_node *np;
 407 
 408         /* Remap the necessary zones */
 409         picnode = of_find_matching_node(NULL, mpc52xx_pic_ids);
 410         intr = of_iomap(picnode, 0);
 411         if (!intr)
 412                 panic(__FILE__  ": find_and_map failed on 'mpc5200-pic'. "
 413                                 "Check node !");
 414 
 415         np = of_find_matching_node(NULL, mpc52xx_sdma_ids);
 416         sdma = of_iomap(np, 0);
 417         of_node_put(np);
 418         if (!sdma)
 419                 panic(__FILE__  ": find_and_map failed on 'mpc5200-bestcomm'. "
 420                                 "Check node !");
 421 
 422         pr_debug("MPC5200 IRQ controller mapped to 0x%p\n", intr);
 423 
 424         /* Disable all interrupt sources. */
 425         out_be32(&sdma->IntPend, 0xffffffff);   /* 1 means clear pending */
 426         out_be32(&sdma->IntMask, 0xffffffff);   /* 1 means disabled */
 427         out_be32(&intr->per_mask, 0x7ffffc00);  /* 1 means disabled */
 428         out_be32(&intr->main_mask, 0x00010fff); /* 1 means disabled */
 429         intr_ctrl = in_be32(&intr->ctrl);
 430         intr_ctrl &= 0x00ff0000;        /* Keeps IRQ[0-3] config */
 431         intr_ctrl |=    0x0f000000 |    /* clear IRQ 0-3 */
 432                         0x00001000 |    /* MEE master external enable */
 433                         0x00000000 |    /* 0 means disable IRQ 0-3 */
 434                         0x00000001;     /* CEb route critical normally */
 435         out_be32(&intr->ctrl, intr_ctrl);
 436 
 437         /* Zero a bunch of the priority settings. */
 438         out_be32(&intr->per_pri1, 0);
 439         out_be32(&intr->per_pri2, 0);
 440         out_be32(&intr->per_pri3, 0);
 441         out_be32(&intr->main_pri1, 0);
 442         out_be32(&intr->main_pri2, 0);
 443 
 444         /*
 445          * As last step, add an irq host to translate the real
 446          * hw irq information provided by the ofw to linux virq
 447          */
 448         mpc52xx_irqhost = irq_domain_add_linear(picnode,
 449                                          MPC52xx_IRQ_HIGHTESTHWIRQ,
 450                                          &mpc52xx_irqhost_ops, NULL);
 451 
 452         if (!mpc52xx_irqhost)
 453                 panic(__FILE__ ": Cannot allocate the IRQ host\n");
 454 
 455         irq_set_default_host(mpc52xx_irqhost);
 456 
 457         pr_info("MPC52xx PIC is up and running!\n");
 458 }
 459 
 460 /**
 461  * mpc52xx_get_irq - Get pending interrupt number hook function
 462  *
 463  * Called by the interrupt handler to determine what IRQ handler needs to be
 464  * executed.
 465  *
 466  * Status of pending interrupts is determined by reading the encoded status
 467  * register.  The encoded status register has three fields; one for each of the
 468  * types of interrupts defined by the controller - 'critical', 'main' and
 469  * 'peripheral'.  This function reads the status register and returns the IRQ
 470  * number associated with the highest priority pending interrupt.  'Critical'
 471  * interrupts have the highest priority, followed by 'main' interrupts, and
 472  * then 'peripheral'.
 473  *
 474  * The mpc5200 interrupt controller can be configured to boost the priority
 475  * of individual 'peripheral' interrupts.  If this is the case then a special
 476  * value will appear in either the crit or main fields indicating a high
 477  * or medium priority peripheral irq has occurred.
 478  *
 479  * This function checks each of the 3 irq request fields and returns the
 480  * first pending interrupt that it finds.
 481  *
 482  * This function also identifies a 4th type of interrupt; 'bestcomm'.  Each
 483  * bestcomm DMA task can raise the bestcomm peripheral interrupt.  When this
 484  * occurs at task-specific IRQ# is decoded so that each task can have its
 485  * own IRQ handler.
 486  */
 487 unsigned int mpc52xx_get_irq(void)
 488 {
 489         u32 status;
 490         int irq;
 491 
 492         status = in_be32(&intr->enc_status);
 493         if (status & 0x00000400) {      /* critical */
 494                 irq = (status >> 8) & 0x3;
 495                 if (irq == 2)   /* high priority peripheral */
 496                         goto peripheral;
 497                 irq |= (MPC52xx_IRQ_L1_CRIT << MPC52xx_IRQ_L1_OFFSET);
 498         } else if (status & 0x00200000) {       /* main */
 499                 irq = (status >> 16) & 0x1f;
 500                 if (irq == 4)   /* low priority peripheral */
 501                         goto peripheral;
 502                 irq |= (MPC52xx_IRQ_L1_MAIN << MPC52xx_IRQ_L1_OFFSET);
 503         } else if (status & 0x20000000) {       /* peripheral */
 504               peripheral:
 505                 irq = (status >> 24) & 0x1f;
 506                 if (irq == 0) { /* bestcomm */
 507                         status = in_be32(&sdma->IntPend);
 508                         irq = ffs(status) - 1;
 509                         irq |= (MPC52xx_IRQ_L1_SDMA << MPC52xx_IRQ_L1_OFFSET);
 510                 } else {
 511                         irq |= (MPC52xx_IRQ_L1_PERP << MPC52xx_IRQ_L1_OFFSET);
 512                 }
 513         } else {
 514                 return 0;
 515         }
 516 
 517         return irq_linear_revmap(mpc52xx_irqhost, irq);
 518 }