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(unsigned int virq)
  73 {
  74         int irq = virq_to_hw(virq);
  75         void * regs = get_irq_chip_data(virq);
  76         pr_debug("mask: %d\n", irq);
  77         out_be32(regs + XINTC_CIE, 1 << irq);
  78 }
  79
  80 static int xilinx_intc_set_type(unsigned int virq, unsigned int flow_type)
  81 {
  82         struct irq_desc *desc = get_irq_desc(virq);
  83
  84         desc->status &= ~(IRQ_TYPE_SENSE_MASK | IRQ_LEVEL);
  85         desc->status |= flow_type & IRQ_TYPE_SENSE_MASK;
  86         if (flow_type & (IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW))
  87                 desc->status |= IRQ_LEVEL;
  88         return 0;
  89 }
  90
  91 /*
  92  * IRQ Chip level operations
  93  */
  94 static void xilinx_intc_level_unmask(unsigned int virq)
  95 {
  96         int irq = virq_to_hw(virq);
  97         void * regs = get_irq_chip_data(virq);
  98         pr_debug("unmask: %d\n", irq);
  99         out_be32(regs + XINTC_SIE, 1 << irq);
 100
 101         /* ack level irqs because they can't be acked during
 102          * ack function since the handle_level_irq function
 103          * acks the irq before calling the inerrupt handler
 104          */
 105         out_be32(regs + XINTC_IAR, 1 << irq);
 106 }
 107
 108 static struct irq_chip xilinx_intc_level_irqchip = {
 109         .typename = "Xilinx Level INTC",
 110         .mask = xilinx_intc_mask,
 111         .mask_ack = xilinx_intc_mask,
 112         .unmask = xilinx_intc_level_unmask,
 113         .set_type = xilinx_intc_set_type,
 114 };
 115
 116 /*
 117  * IRQ Chip edge operations
 118  */
 119 static void xilinx_intc_edge_unmask(unsigned int virq)
 120 {
 121         int irq = virq_to_hw(virq);
 122         void *regs = get_irq_chip_data(virq);
 123         pr_debug("unmask: %d\n", irq);
 124         out_be32(regs + XINTC_SIE, 1 << irq);
 125 }
 126
 127 static void xilinx_intc_edge_ack(unsigned int virq)
 128 {
 129         int irq = virq_to_hw(virq);
 130         void * regs = get_irq_chip_data(virq);
 131         pr_debug("ack: %d\n", irq);
 132         out_be32(regs + XINTC_IAR, 1 << irq);
 133 }
 134
 135 static struct irq_chip xilinx_intc_edge_irqchip = {
 136         .typename = "Xilinx Edge  INTC",
 137         .mask = xilinx_intc_mask,
 138         .unmask = xilinx_intc_edge_unmask,
 139         .ack = xilinx_intc_edge_ack,
 140         .set_type = xilinx_intc_set_type,
 141 };
 142
 143 /*
 144  * IRQ Host operations
 145  */
 146
 147 /**
 148  * xilinx_intc_xlate - translate virq# from device tree interrupts property
 149  */
 150 static int xilinx_intc_xlate(struct irq_host *h, struct device_node *ct,
 151                                 u32 *intspec, unsigned int intsize,
 152                                 irq_hw_number_t *out_hwirq,
 153                                 unsigned int *out_flags)
 154 {
 155         if ((intsize < 2) || (intspec[0] >= XILINX_INTC_MAXIRQS))
 156                 return -EINVAL;
 157
 158         /* keep a copy of the interrupt type til the interrupt is mapped
 159          */
 160         xilinx_intc_typetable[intspec[0]] = xilinx_intc_map_senses[intspec[1]];
 161
 162         /* Xilinx uses 2 interrupt entries, the 1st being the h/w
 163          * interrupt number, the 2nd being the interrupt type, edge or level
 164          */
 165         *out_hwirq = intspec[0];
 166         *out_flags = xilinx_intc_map_senses[intspec[1]];
 167
 168         return 0;
 169 }
 170 static int xilinx_intc_map(struct irq_host *h, unsigned int virq,
 171                                   irq_hw_number_t irq)
 172 {
 173         set_irq_chip_data(virq, h->host_data);
 174
 175         if (xilinx_intc_typetable[irq] == IRQ_TYPE_LEVEL_HIGH ||
 176             xilinx_intc_typetable[irq] == IRQ_TYPE_LEVEL_LOW) {
 177                 set_irq_chip_and_handler(virq, &xilinx_intc_level_irqchip,
 178                         handle_level_irq);
 179         } else {
 180                 set_irq_chip_and_handler(virq, &xilinx_intc_edge_irqchip,
 181                         handle_edge_irq);
 182         }
 183         return 0;
 184 }
 185
 186 static struct irq_host_ops xilinx_intc_ops = {
 187         .map = xilinx_intc_map,
 188         .xlate = xilinx_intc_xlate,
 189 };
 190
 191 struct irq_host * __init
 192 xilinx_intc_init(struct device_node *np)
 193 {
 194         struct irq_host * irq;
 195         void * regs;
 196
 197         /* Find and map the intc registers */
 198         regs = of_iomap(np, 0);
 199         if (!regs) {
 200                 pr_err("xilinx_intc: could not map registers\n");
 201                 return NULL;
 202         }
 203
 204         /* Setup interrupt controller */
 205         out_be32(regs + XINTC_IER, 0); /* disable all irqs */
 206         out_be32(regs + XINTC_IAR, ~(u32) 0); /* Acknowledge pending irqs */
 207         out_be32(regs + XINTC_MER, 0x3UL); /* Turn on the Master Enable. */
 208
 209         /* Allocate and initialize an irq_host structure. */
 210         irq = irq_alloc_host(np, IRQ_HOST_MAP_LINEAR, XILINX_INTC_MAXIRQS,
 211                              &xilinx_intc_ops, -1);
 212         if (!irq)
 213                 panic(__FILE__ ": Cannot allocate IRQ host\n");
 214         irq->host_data = regs;
 215
 216         return irq;
 217 }
 218
 219 int xilinx_intc_get_irq(void)
 220 {
 221         void * regs = master_irqhost->host_data;
 222         pr_debug("get_irq:\n");
 223         return irq_linear_revmap(master_irqhost, in_be32(regs + XINTC_IVR));
 224 }
 225
 226 #if defined(CONFIG_PPC_I8259)
 227 /*
 228  * Support code for cascading to 8259 interrupt controllers
 229  */
 230 static void xilinx_i8259_cascade(unsigned int irq, struct irq_desc *desc)
 231 {
 232         unsigned int cascade_irq = i8259_irq();
 233         if (cascade_irq)
 234                 generic_handle_irq(cascade_irq);
 235
 236         /* Let xilinx_intc end the interrupt */
 237         desc->chip->unmask(irq);
 238 }
 239
 240 static void __init xilinx_i8259_setup_cascade(void)
 241 {
 242         struct device_node *cascade_node;
 243         int cascade_irq;
 244
 245         /* Initialize i8259 controller */
 246         cascade_node = of_find_compatible_node(NULL, NULL, "chrp,iic");
 247         if (!cascade_node)
 248                 return;
 249
 250         cascade_irq = irq_of_parse_and_map(cascade_node, 0);
 251         if (!cascade_irq) {
 252                 pr_err("virtex_ml510: Failed to map cascade interrupt\n");
 253                 goto out;
 254         }
 255
 256         i8259_init(cascade_node, 0);
 257         set_irq_chained_handler(cascade_irq, xilinx_i8259_cascade);
 258
 259         /* Program irq 7 (usb/audio), 14/15 (ide) to level sensitive */
 260         /* This looks like a dirty hack to me --gcl */
 261         outb(0xc0, 0x4d0);
 262         outb(0xc0, 0x4d1);
 263
 264  out:
 265         of_node_put(cascade_node);
 266 }
 267 #else
 268 static inline void xilinx_i8259_setup_cascade(void) { return; }
 269 #endif /* defined(CONFIG_PPC_I8259) */
 270
 271 static struct of_device_id xilinx_intc_match[] __initconst = {
 272         { .compatible = "xlnx,opb-intc-1.00.c", },
 273         { .compatible = "xlnx,xps-intc-1.00.a", },
 274         {}
 275 };
 276
 277 /*
 278  * Initialize master Xilinx interrupt controller
 279  */
 280 void __init xilinx_intc_init_tree(void)
 281 {
 282         struct device_node *np;
 283
 284         /* find top level interrupt controller */
 285         for_each_matching_node(np, xilinx_intc_match) {
 286                 if (!of_get_property(np, "interrupts", NULL))
 287                         break;
 288         }
 289         BUG_ON(!np);
 290
 291         master_irqhost = xilinx_intc_init(np);
 292         BUG_ON(!master_irqhost);
 293
 294         irq_set_default_host(master_irqhost);
 295         of_node_put(np);
 296
 297         xilinx_i8259_setup_cascade();
 298 }