arch/powerpc/sysdev/xilinx_intc.c

   1 /*
   2  * Interrupt controller driver for Xilinx Virtex FPGAs
   3  *
   4  * Copyright (C) 2007 Secret Lab Technologies Ltd.
   5  *
   6  * This file is licensed under the terms of the GNU General Public License
   7  * version 2. This program is licensed "as is" without any warranty of any
   8  * kind, whether express or implied.
   9  *
  10  */
  11
  12 /*
  13  * This is a driver for the interrupt controller typically found in
  14  * Xilinx Virtex FPGA designs.
  15  *
  16  * The interrupt sense levels are hard coded into the FPGA design with
  17  * typically a 1:1 relationship between irq lines and devices (no shared
  18  * irq lines).  Therefore, this driver does not attempt to handle edge
  19  * and level interrupts differently.
  20  */
  21 #undef DEBUG
  22
  23 #include <linux/kernel.h>
  24 #include <linux/irq.h>
  25 #include <linux/of.h>
  26 #include <asm/io.h>
  27 #include <asm/processor.h>
  28 #include <asm/i8259.h>
  29 #include <asm/irq.h>
  30
  31 /*
  32  * INTC Registers
  33  */
  34 #define XINTC_ISR       0       /* Interrupt Status */
  35 #define XINTC_IPR       4       /* Interrupt Pending */
  36 #define XINTC_IER       8       /* Interrupt Enable */
  37 #define XINTC_IAR       12      /* Interrupt Acknowledge */
  38 #define XINTC_SIE       16      /* Set Interrupt Enable bits */
  39 #define XINTC_CIE       20      /* Clear Interrupt Enable bits */
  40 #define XINTC_IVR       24      /* Interrupt Vector */
  41 #define XINTC_MER       28      /* Master Enable */
  42
  43 static struct irq_host *master_irqhost;
  44
  45 #define XILINX_INTC_MAXIRQS     (32)
  46
  47 /* The following table allows the interrupt type, edge or level,
  48  * to be cached after being read from the device tree until the interrupt
  49  * is mapped
  50  */
  51 static int xilinx_intc_typetable[XILINX_INTC_MAXIRQS];
  52
  53 /* Map the interrupt type from the device tree to the interrupt types
  54  * used by the interrupt subsystem
  55  */
  56 static unsigned char xilinx_intc_map_senses[] = {
  57         IRQ_TYPE_EDGE_RISING,
  58         IRQ_TYPE_EDGE_FALLING,
  59         IRQ_TYPE_LEVEL_HIGH,
  60         IRQ_TYPE_LEVEL_LOW,
  61 };
  62
  63 /*
  64  * The interrupt controller is setup such that it doesn't work well with
  65  * the level interrupt handler in the kernel because the handler acks the
  66  * interrupt before calling the application interrupt handler. To deal with
  67  * that, we use 2 different irq chips so that different functions can be
  68  * used for level and edge type interrupts.
  69  *
  70  * IRQ Chip common (across level and edge) operations
  71  */
  72 static void xilinx_intc_mask(struct irq_data *d)
  73 {
  74         int irq = irqd_to_hwirq(d);
  75         void * regs = irq_data_get_irq_chip_data(d);
  76         pr_debug("mask: %d\n", irq);
  77         out_be32(regs + XINTC_CIE, 1 << irq);
  78 }
  79
  80 static int xilinx_intc_set_type(struct irq_data *d, unsigned int flow_type)
  81 {
  82         return 0;
  83 }
  84
  85 /*
  86  * IRQ Chip level operations
  87  */
  88 static void xilinx_intc_level_unmask(struct irq_data *d)
  89 {
  90         int irq = irqd_to_hwirq(d);
  91         void * regs = irq_data_get_irq_chip_data(d);
  92         pr_debug("unmask: %d\n", irq);
  93         out_be32(regs + XINTC_SIE, 1 << irq);
  94
  95         /* ack level irqs because they can't be acked during
  96          * ack function since the handle_level_irq function
  97          * acks the irq before calling the inerrupt handler
  98          */
  99         out_be32(regs + XINTC_IAR, 1 << irq);
 100 }
 101
 102 static struct irq_chip xilinx_intc_level_irqchip = {
 103         .name = "Xilinx Level INTC",
 104         .irq_mask = xilinx_intc_mask,
 105         .irq_mask_ack = xilinx_intc_mask,
 106         .irq_unmask = xilinx_intc_level_unmask,
 107         .irq_set_type = xilinx_intc_set_type,
 108 };
 109
 110 /*
 111  * IRQ Chip edge operations
 112  */
 113 static void xilinx_intc_edge_unmask(struct irq_data *d)
 114 {
 115         int irq = irqd_to_hwirq(d);
 116         void *regs = irq_data_get_irq_chip_data(d);
 117         pr_debug("unmask: %d\n", irq);
 118         out_be32(regs + XINTC_SIE, 1 << irq);
 119 }
 120
 121 static void xilinx_intc_edge_ack(struct irq_data *d)
 122 {
 123         int irq = irqd_to_hwirq(d);
 124         void * regs = irq_data_get_irq_chip_data(d);
 125         pr_debug("ack: %d\n", irq);
 126         out_be32(regs + XINTC_IAR, 1 << irq);
 127 }
 128
 129 static struct irq_chip xilinx_intc_edge_irqchip = {
 130         .name = "Xilinx Edge  INTC",
 131         .irq_mask = xilinx_intc_mask,
 132         .irq_unmask = xilinx_intc_edge_unmask,
 133         .irq_ack = xilinx_intc_edge_ack,
 134         .irq_set_type = xilinx_intc_set_type,
 135 };
 136
 137 /*
 138  * IRQ Host operations
 139  */
 140
 141 /**
 142  * xilinx_intc_xlate - translate virq# from device tree interrupts property
 143  */
 144 static int xilinx_intc_xlate(struct irq_host *h, struct device_node *ct,
 145                                 const u32 *intspec, unsigned int intsize,
 146                                 irq_hw_number_t *out_hwirq,
 147                                 unsigned int *out_flags)
 148 {
 149         if ((intsize < 2) || (intspec[0] >= XILINX_INTC_MAXIRQS))
 150                 return -EINVAL;
 151
 152         /* keep a copy of the interrupt type til the interrupt is mapped
 153          */
 154         xilinx_intc_typetable[intspec[0]] = xilinx_intc_map_senses[intspec[1]];
 155
 156         /* Xilinx uses 2 interrupt entries, the 1st being the h/w
 157          * interrupt number, the 2nd being the interrupt type, edge or level
 158          */
 159         *out_hwirq = intspec[0];
 160         *out_flags = xilinx_intc_map_senses[intspec[1]];
 161
 162         return 0;
 163 }
 164 static int xilinx_intc_map(struct irq_host *h, unsigned int virq,
 165                                   irq_hw_number_t irq)
 166 {
 167         irq_set_chip_data(virq, h->host_data);
 168
 169         if (xilinx_intc_typetable[irq] == IRQ_TYPE_LEVEL_HIGH ||
 170             xilinx_intc_typetable[irq] == IRQ_TYPE_LEVEL_LOW) {
 171                 irq_set_chip_and_handler(virq, &xilinx_intc_level_irqchip,
 172                                          handle_level_irq);
 173         } else {
 174                 irq_set_chip_and_handler(virq, &xilinx_intc_edge_irqchip,
 175                                          handle_edge_irq);
 176         }
 177         return 0;
 178 }
 179
 180 static struct irq_host_ops xilinx_intc_ops = {
 181         .map = xilinx_intc_map,
 182         .xlate = xilinx_intc_xlate,
 183 };
 184
 185 struct irq_host * __init
 186 xilinx_intc_init(struct device_node *np)
 187 {
 188         struct irq_host * irq;
 189         void * regs;
 190
 191         /* Find and map the intc registers */
 192         regs = of_iomap(np, 0);
 193         if (!regs) {
 194                 pr_err("xilinx_intc: could not map registers\n");
 195                 return NULL;
 196         }
 197
 198         /* Setup interrupt controller */
 199         out_be32(regs + XINTC_IER, 0); /* disable all irqs */
 200         out_be32(regs + XINTC_IAR, ~(u32) 0); /* Acknowledge pending irqs */
 201         out_be32(regs + XINTC_MER, 0x3UL); /* Turn on the Master Enable. */
 202
 203         /* Allocate and initialize an irq_host structure. */
 204         irq = irq_alloc_host(np, IRQ_HOST_MAP_LINEAR, XILINX_INTC_MAXIRQS,
 205                              &xilinx_intc_ops, -1);
 206         if (!irq)
 207                 panic(__FILE__ ": Cannot allocate IRQ host\n");
 208         irq->host_data = regs;
 209
 210         return irq;
 211 }
 212
 213 int xilinx_intc_get_irq(void)
 214 {
 215         void * regs = master_irqhost->host_data;
 216         pr_debug("get_irq:\n");
 217         return irq_linear_revmap(master_irqhost, in_be32(regs + XINTC_IVR));
 218 }
 219
 220 #if defined(CONFIG_PPC_I8259)
 221 /*
 222  * Support code for cascading to 8259 interrupt controllers
 223  */
 224 static void xilinx_i8259_cascade(unsigned int irq, struct irq_desc *desc)
 225 {
 226         struct irq_chip *chip = irq_desc_get_chip(desc);
 227         unsigned int cascade_irq = i8259_irq();
 228
 229         if (cascade_irq)
 230                 generic_handle_irq(cascade_irq);
 231
 232         /* Let xilinx_intc end the interrupt */
 233         chip->irq_unmask(&desc->irq_data);
 234 }
 235
 236 static void __init xilinx_i8259_setup_cascade(void)
 237 {
 238         struct device_node *cascade_node;
 239         int cascade_irq;
 240
 241         /* Initialize i8259 controller */
 242         cascade_node = of_find_compatible_node(NULL, NULL, "chrp,iic");
 243         if (!cascade_node)
 244                 return;
 245
 246         cascade_irq = irq_of_parse_and_map(cascade_node, 0);
 247         if (!cascade_irq) {
 248                 pr_err("virtex_ml510: Failed to map cascade interrupt\n");
 249                 goto out;
 250         }
 251
 252         i8259_init(cascade_node, 0);
 253         irq_set_chained_handler(cascade_irq, xilinx_i8259_cascade);
 254
 255         /* Program irq 7 (usb/audio), 14/15 (ide) to level sensitive */
 256         /* This looks like a dirty hack to me --gcl */
 257         outb(0xc0, 0x4d0);
 258         outb(0xc0, 0x4d1);
 259
 260  out:
 261         of_node_put(cascade_node);
 262 }
 263 #else
 264 static inline void xilinx_i8259_setup_cascade(void) { return; }
 265 #endif /* defined(CONFIG_PPC_I8259) */
 266
 267 static struct of_device_id xilinx_intc_match[] __initconst = {
 268         { .compatible = "xlnx,opb-intc-1.00.c", },
 269         { .compatible = "xlnx,xps-intc-1.00.a", },
 270         {}
 271 };
 272
 273 /*
 274  * Initialize master Xilinx interrupt controller
 275  */
 276 void __init xilinx_intc_init_tree(void)
 277 {
 278         struct device_node *np;
 279
 280         /* find top level interrupt controller */
 281         for_each_matching_node(np, xilinx_intc_match) {
 282                 if (!of_get_property(np, "interrupts", NULL))
 283                         break;
 284         }
 285         BUG_ON(!np);
 286
 287         master_irqhost = xilinx_intc_init(np);
 288         BUG_ON(!master_irqhost);
 289
 290         irq_set_default_host(master_irqhost);
 291         of_node_put(np);
 292
 293         xilinx_i8259_setup_cascade();
 294 }