drivers/irqchip/irq-ath79-cpu.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  Atheros AR71xx/AR724x/AR913x specific interrupt handling
   4  *
   5  *  Copyright (C) 2015 Alban Bedel <albeu@free.fr>
   6  *  Copyright (C) 2010-2011 Jaiganesh Narayanan <jnarayanan@atheros.com>
   7  *  Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
   8  *  Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
   9  *
  10  *  Parts of this file are based on Atheros' 2.6.15/2.6.31 BSP
  11  */
  12
  13 #include <linux/interrupt.h>
  14 #include <linux/irqchip.h>
  15 #include <linux/of.h>
  16
  17 #include <asm/irq_cpu.h>
  18 #include <asm/mach-ath79/ath79.h>
  19
  20 /*
  21  * The IP2/IP3 lines are tied to a PCI/WMAC/USB device. Drivers for
  22  * these devices typically allocate coherent DMA memory, however the
  23  * DMA controller may still have some unsynchronized data in the FIFO.
  24  * Issue a flush in the handlers to ensure that the driver sees
  25  * the update.
  26  *
  27  * This array map the interrupt lines to the DDR write buffer channels.
  28  */
  29
  30 static unsigned irq_wb_chan[8] = {
  31         -1, -1, -1, -1, -1, -1, -1, -1,
  32 };
  33
  34 asmlinkage void plat_irq_dispatch(void)
  35 {
  36         unsigned long pending;
  37         int irq;
  38
  39         pending = read_c0_status() & read_c0_cause() & ST0_IM;
  40
  41         if (!pending) {
  42                 spurious_interrupt();
  43                 return;
  44         }
  45
  46         pending >>= CAUSEB_IP;
  47         while (pending) {
  48                 irq = fls(pending) - 1;
  49                 if (irq < ARRAY_SIZE(irq_wb_chan) && irq_wb_chan[irq] != -1)
  50                         ath79_ddr_wb_flush(irq_wb_chan[irq]);
  51                 do_IRQ(MIPS_CPU_IRQ_BASE + irq);
  52                 pending &= ~BIT(irq);
  53         }
  54 }
  55
  56 static int __init ar79_cpu_intc_of_init(
  57         struct device_node *node, struct device_node *parent)
  58 {
  59         int err, i, count;
  60
  61         /* Fill the irq_wb_chan table */
  62         count = of_count_phandle_with_args(
  63                 node, "qca,ddr-wb-channels", "#qca,ddr-wb-channel-cells");
  64
  65         for (i = 0; i < count; i++) {
  66                 struct of_phandle_args args;
  67                 u32 irq = i;
  68
  69                 of_property_read_u32_index(
  70                         node, "qca,ddr-wb-channel-interrupts", i, &irq);
  71                 if (irq >= ARRAY_SIZE(irq_wb_chan))
  72                         continue;
  73
  74                 err = of_parse_phandle_with_args(
  75                         node, "qca,ddr-wb-channels",
  76                         "#qca,ddr-wb-channel-cells",
  77                         i, &args);
  78                 if (err)
  79                         return err;
  80
  81                 irq_wb_chan[irq] = args.args[0];
  82         }
  83
  84         return mips_cpu_irq_of_init(node, parent);
  85 }
  86 IRQCHIP_DECLARE(ar79_cpu_intc, "qca,ar7100-cpu-intc",
  87                 ar79_cpu_intc_of_init);
  88
  89 void __init ath79_cpu_irq_init(unsigned irq_wb_chan2, unsigned irq_wb_chan3)
  90 {
  91         irq_wb_chan[2] = irq_wb_chan2;
  92         irq_wb_chan[3] = irq_wb_chan3;
  93         mips_cpu_irq_init();
  94 }