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 <linux/of_address.h>
  27 #include <linux/of_irq.h>
  28 #include <asm/io.h>
  29 #include <asm/processor.h>
  30 #include <asm/i8259.h>
  31 #include <asm/irq.h>
  32 #include <linux/irqchip.h>
  33
  34 #if defined(CONFIG_PPC_I8259)
  35 /*
  36  * Support code for cascading to 8259 interrupt controllers
  37  */
  38 static void xilinx_i8259_cascade(struct irq_desc *desc)
  39 {
  40         struct irq_chip *chip = irq_desc_get_chip(desc);
  41         unsigned int cascade_irq = i8259_irq();
  42
  43         if (cascade_irq)
  44                 generic_handle_irq(cascade_irq);
  45
  46         /* Let xilinx_intc end the interrupt */
  47         chip->irq_unmask(&desc->irq_data);
  48 }
  49
  50 static void __init xilinx_i8259_setup_cascade(void)
  51 {
  52         struct device_node *cascade_node;
  53         int cascade_irq;
  54
  55         /* Initialize i8259 controller */
  56         cascade_node = of_find_compatible_node(NULL, NULL, "chrp,iic");
  57         if (!cascade_node)
  58                 return;
  59
  60         cascade_irq = irq_of_parse_and_map(cascade_node, 0);
  61         if (!cascade_irq) {
  62                 pr_err("virtex_ml510: Failed to map cascade interrupt\n");
  63                 goto out;
  64         }
  65
  66         i8259_init(cascade_node, 0);
  67         irq_set_chained_handler(cascade_irq, xilinx_i8259_cascade);
  68
  69         /* Program irq 7 (usb/audio), 14/15 (ide) to level sensitive */
  70         /* This looks like a dirty hack to me --gcl */
  71         outb(0xc0, 0x4d0);
  72         outb(0xc0, 0x4d1);
  73
  74  out:
  75         of_node_put(cascade_node);
  76 }
  77 #else
  78 static inline void xilinx_i8259_setup_cascade(void) { return; }
  79 #endif /* defined(CONFIG_PPC_I8259) */
  80
  81 /*
  82  * Initialize master Xilinx interrupt controller
  83  */
  84 void __init xilinx_intc_init_tree(void)
  85 {
  86         irqchip_init();
  87         xilinx_i8259_setup_cascade();
  88 }