arch/arm/plat-samsung/irq-uart.c

   1 /* arch/arm/plat-samsung/irq-uart.c
   2  *      originally part of arch/arm/plat-s3c64xx/irq.c
   3  *
   4  * Copyright 2008 Openmoko, Inc.
   5  * Copyright 2008 Simtec Electronics
   6  *      Ben Dooks <ben@simtec.co.uk>
   7  *      http://armlinux.simtec.co.uk/
   8  *
   9  * Samsung- UART Interrupt handling
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/serial_core.h>
  19 #include <linux/irq.h>
  20 #include <linux/io.h>
  21
  22 #include <asm/mach/irq.h>
  23
  24 #include <mach/map.h>
  25 #include <plat/irq-uart.h>
  26 #include <plat/regs-serial.h>
  27 #include <plat/cpu.h>
  28
  29 /* Note, we make use of the fact that the parent IRQs, IRQ_UART[0..3]
  30  * are consecutive when looking up the interrupt in the demux routines.
  31  */
  32 static void s3c_irq_demux_uart(unsigned int irq, struct irq_desc *desc)
  33 {
  34         struct s3c_uart_irq *uirq = desc->irq_data.handler_data;
  35         struct irq_chip *chip = irq_get_chip(irq);
  36         u32 pend = __raw_readl(uirq->regs + S3C64XX_UINTP);
  37         int base = uirq->base_irq;
  38
  39         chained_irq_enter(chip, desc);
  40
  41         if (pend & (1 << 0))
  42                 generic_handle_irq(base);
  43         if (pend & (1 << 1))
  44                 generic_handle_irq(base + 1);
  45         if (pend & (1 << 2))
  46                 generic_handle_irq(base + 2);
  47         if (pend & (1 << 3))
  48                 generic_handle_irq(base + 3);
  49
  50         chained_irq_exit(chip, desc);
  51 }
  52
  53 static void __init s3c_init_uart_irq(struct s3c_uart_irq *uirq)
  54 {
  55         void __iomem *reg_base = uirq->regs;
  56         struct irq_chip_generic *gc;
  57         struct irq_chip_type *ct;
  58
  59         /* mask all interrupts at the start. */
  60         __raw_writel(0xf, reg_base + S3C64XX_UINTM);
  61
  62         gc = irq_alloc_generic_chip("s3c-uart", 1, uirq->base_irq, reg_base,
  63                                     handle_level_irq);
  64
  65         if (!gc) {
  66                 pr_err("%s: irq_alloc_generic_chip for IRQ %u failed\n",
  67                        __func__, uirq->base_irq);
  68                 return;
  69         }
  70
  71         ct = gc->chip_types;
  72         ct->chip.irq_ack = irq_gc_ack_set_bit;
  73         ct->chip.irq_mask = irq_gc_mask_set_bit;
  74         ct->chip.irq_unmask = irq_gc_mask_clr_bit;
  75         ct->regs.ack = S3C64XX_UINTP;
  76         ct->regs.mask = S3C64XX_UINTM;
  77         irq_setup_generic_chip(gc, IRQ_MSK(4), IRQ_GC_INIT_MASK_CACHE,
  78                                IRQ_NOREQUEST | IRQ_NOPROBE, 0);
  79
  80         irq_set_handler_data(uirq->parent_irq, uirq);
  81         irq_set_chained_handler(uirq->parent_irq, s3c_irq_demux_uart);
  82 }
  83
  84 /**
  85  * s3c_init_uart_irqs() - initialise UART IRQs and the necessary demuxing
  86  * @irq: The interrupt data for registering
  87  * @nr_irqs: The number of interrupt descriptions in @irq.
  88  *
  89  * Register the UART interrupts specified by @irq including the demuxing
  90  * routines. This supports the S3C6400 and newer style of devices.
  91  */
  92 void __init s3c_init_uart_irqs(struct s3c_uart_irq *irq, unsigned int nr_irqs)
  93 {
  94         for (; nr_irqs > 0; nr_irqs--, irq++)
  95                 s3c_init_uart_irq(irq);
  96 }