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/irq.h>
  29
  30 /*
  31  * INTC Registers
  32  */
  33 #define XINTC_ISR       0       /* Interrupt Status */
  34 #define XINTC_IPR       4       /* Interrupt Pending */
  35 #define XINTC_IER       8       /* Interrupt Enable */
  36 #define XINTC_IAR       12      /* Interrupt Acknowledge */
  37 #define XINTC_SIE       16      /* Set Interrupt Enable bits */
  38 #define XINTC_CIE       20      /* Clear Interrupt Enable bits */
  39 #define XINTC_IVR       24      /* Interrupt Vector */
  40 #define XINTC_MER       28      /* Master Enable */
  41
  42 static struct irq_host *master_irqhost;
  43
  44 /*
  45  * IRQ Chip operations
  46  */
  47 static void xilinx_intc_mask(unsigned int virq)
  48 {
  49         int irq = virq_to_hw(virq);
  50         void * regs = get_irq_chip_data(virq);
  51         pr_debug("mask: %d\n", irq);
  52         out_be32(regs + XINTC_CIE, 1 << irq);
  53 }
  54
  55 static void xilinx_intc_unmask(unsigned int virq)
  56 {
  57         int irq = virq_to_hw(virq);
  58         void * regs = get_irq_chip_data(virq);
  59         pr_debug("unmask: %d\n", irq);
  60         out_be32(regs + XINTC_SIE, 1 << irq);
  61 }
  62
  63 static void xilinx_intc_ack(unsigned int virq)
  64 {
  65         int irq = virq_to_hw(virq);
  66         void * regs = get_irq_chip_data(virq);
  67         pr_debug("ack: %d\n", irq);
  68         out_be32(regs + XINTC_IAR, 1 << irq);
  69 }
  70
  71 static struct irq_chip xilinx_intc_irqchip = {
  72         .typename = "Xilinx INTC",
  73         .mask = xilinx_intc_mask,
  74         .unmask = xilinx_intc_unmask,
  75         .ack = xilinx_intc_ack,
  76 };
  77
  78 /*
  79  * IRQ Host operations
  80  */
  81 static int xilinx_intc_map(struct irq_host *h, unsigned int virq,
  82                                   irq_hw_number_t irq)
  83 {
  84         set_irq_chip_data(virq, h->host_data);
  85         set_irq_chip_and_handler(virq, &xilinx_intc_irqchip, handle_level_irq);
  86         set_irq_type(virq, IRQ_TYPE_NONE);
  87         return 0;
  88 }
  89
  90 static struct irq_host_ops xilinx_intc_ops = {
  91         .map = xilinx_intc_map,
  92 };
  93
  94 struct irq_host * __init
  95 xilinx_intc_init(struct device_node *np)
  96 {
  97         struct irq_host * irq;
  98         struct resource res;
  99         void * regs;
 100         int rc;
 101
 102         /* Find and map the intc registers */
 103         rc = of_address_to_resource(np, 0, &res);
 104         if (rc) {
 105                 printk(KERN_ERR __FILE__ ": of_address_to_resource() failed\n");
 106                 return NULL;
 107         }
 108         regs = ioremap(res.start, 32);
 109
 110         printk(KERN_INFO "Xilinx intc at 0x%08X mapped to 0x%p\n",
 111                 res.start, regs);
 112
 113         /* Setup interrupt controller */
 114         out_be32(regs + XINTC_IER, 0); /* disable all irqs */
 115         out_be32(regs + XINTC_IAR, ~(u32) 0); /* Acknowledge pending irqs */
 116         out_be32(regs + XINTC_MER, 0x3UL); /* Turn on the Master Enable. */
 117
 118         /* Allocate and initialize an irq_host structure. */
 119         irq = irq_alloc_host(np, IRQ_HOST_MAP_LINEAR, 32, &xilinx_intc_ops, -1);
 120         if (!irq)
 121                 panic(__FILE__ ": Cannot allocate IRQ host\n");
 122         irq->host_data = regs;
 123         return irq;
 124 }
 125
 126 int xilinx_intc_get_irq(void)
 127 {
 128         void * regs = master_irqhost->host_data;
 129         pr_debug("get_irq:\n");
 130         return irq_linear_revmap(master_irqhost, in_be32(regs + XINTC_IVR));
 131 }
 132
 133 void __init xilinx_intc_init_tree(void)
 134 {
 135         struct device_node *np;
 136
 137         /* find top level interrupt controller */
 138         for_each_compatible_node(np, NULL, "xilinx,intc") {
 139                 if (!of_get_property(np, "interrupts", NULL))
 140                         break;
 141         }
 142
 143         /* xilinx interrupt controller needs to be top level */
 144         BUG_ON(!np);
 145
 146         master_irqhost = xilinx_intc_init(np);
 147         BUG_ON(!master_irqhost);
 148
 149         irq_set_default_host(master_irqhost);
 150         of_node_put(np);
 151 }