ARM: 6414/1: ux500: DB5500 generic modem IRQ handler

/*

 * Copyright (C) ST-Ericsson SA 2010

 * Author: Stefan Nilsson <stefan.xk.nilsson@stericsson.com> for ST-Ericsson.

 * Author: Martin Persson <martin.persson@stericsson.com> for ST-Ericsson.

 * License terms: GNU General Public License (GPL), version 2.

 */

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/irq.h>

#include <linux/interrupt.h>

#include <linux/io.h>

#include <linux/slab.h>

#define MODEM_INTCON_BASE_ADDR 0xBFFD3000

#define MODEM_INTCON_SIZE 0xFFF

#define DEST_IRQ41_OFFSET 0x2A4

#define DEST_IRQ43_OFFSET 0x2AC

#define DEST_IRQ45_OFFSET 0x2B4

#define PRIO_IRQ41_OFFSET 0x6A4

#define PRIO_IRQ43_OFFSET 0x6AC

#define PRIO_IRQ45_OFFSET 0x6B4

#define ALLOW_IRQ_OFFSET 0x104

#define MODEM_INTCON_CPU_NBR 0x1

#define MODEM_INTCON_PRIO_HIGH 0x0

#define MODEM_INTCON_ALLOW_IRQ41 0x0200

#define MODEM_INTCON_ALLOW_IRQ43 0x0800

#define MODEM_INTCON_ALLOW_IRQ45 0x2000

#define MODEM_IRQ_REG_OFFSET 0x4

struct modem_irq {

	void __iomem *modem_intcon_base;

};

static void setup_modem_intcon(void __iomem *modem_intcon_base)

{

	/* IC_DESTINATION_BASE_ARRAY - Which CPU to receive the IRQ */

	writel(MODEM_INTCON_CPU_NBR, modem_intcon_base + DEST_IRQ41_OFFSET);

	writel(MODEM_INTCON_CPU_NBR, modem_intcon_base + DEST_IRQ43_OFFSET);

	writel(MODEM_INTCON_CPU_NBR, modem_intcon_base + DEST_IRQ45_OFFSET);

	/* IC_PRIORITY_BASE_ARRAY - IRQ priority in modem IRQ controller */

	writel(MODEM_INTCON_PRIO_HIGH, modem_intcon_base + PRIO_IRQ41_OFFSET);

	writel(MODEM_INTCON_PRIO_HIGH, modem_intcon_base + PRIO_IRQ43_OFFSET);

	writel(MODEM_INTCON_PRIO_HIGH, modem_intcon_base + PRIO_IRQ45_OFFSET);

	/* IC_ALLOW_ARRAY - IRQ enable */

	writel(MODEM_INTCON_ALLOW_IRQ41 |

		   MODEM_INTCON_ALLOW_IRQ43 |

		   MODEM_INTCON_ALLOW_IRQ45,

		   modem_intcon_base + ALLOW_IRQ_OFFSET);

}

static irqreturn_t modem_cpu_irq_handler(int irq, void *data)

{

	int real_irq;

	int virt_irq;

	struct modem_irq *mi = (struct modem_irq *)data;

	/* Read modem side IRQ number from modem IRQ controller */

	real_irq = readl(mi->modem_intcon_base + MODEM_IRQ_REG_OFFSET) & 0xFF;

	virt_irq = IRQ_MODEM_EVENTS_BASE + real_irq;

	pr_debug("modem_irq: Worker read addr 0x%X and got value 0x%X "

		 "which will be 0x%X (%d) which translates to "

		 "virtual IRQ 0x%X (%d)!\n",

		   (u32)mi->modem_intcon_base + MODEM_IRQ_REG_OFFSET,

		   real_irq,

		   real_irq & 0xFF,

		   real_irq & 0xFF,

		   virt_irq,

		   virt_irq);

	if (virt_irq != 0)

		generic_handle_irq(virt_irq);

	pr_debug("modem_irq: Done handling virtual IRQ %d!\n", virt_irq);

	return IRQ_HANDLED;

}

static void create_virtual_irq(int irq, struct irq_chip *modem_irq_chip)

{

	set_irq_chip(irq, modem_irq_chip);

	set_irq_handler(irq, handle_simple_irq);

	set_irq_flags(irq, IRQF_VALID);

	pr_debug("modem_irq: Created virtual IRQ %d\n", irq);

}

static int modem_irq_init(void)

{

	int err;

	static struct irq_chip  modem_irq_chip;

	struct modem_irq *mi;

	pr_info("modem_irq: Set up IRQ handler for incoming modem IRQ %d\n",

		   IRQ_DB5500_MODEM);

	mi = kmalloc(sizeof(struct modem_irq), GFP_KERNEL);

	if (!mi) {

		pr_err("modem_irq: Could not allocate device\n");

		return -ENOMEM;

	}

	mi->modem_intcon_base =

		ioremap(MODEM_INTCON_BASE_ADDR, MODEM_INTCON_SIZE);

	pr_debug("modem_irq: ioremapped modem_intcon_base from "

		 "phy 0x%x to virt 0x%x\n", MODEM_INTCON_BASE_ADDR,

		 (u32)mi->modem_intcon_base);

	setup_modem_intcon(mi->modem_intcon_base);

	modem_irq_chip = dummy_irq_chip;

	modem_irq_chip.name = "modem_irq";

	/* Create the virtual IRQ:s needed */

	create_virtual_irq(MBOX_PAIR0_VIRT_IRQ, &modem_irq_chip);

	create_virtual_irq(MBOX_PAIR1_VIRT_IRQ, &modem_irq_chip);

	create_virtual_irq(MBOX_PAIR2_VIRT_IRQ, &modem_irq_chip);

	err = request_threaded_irq(IRQ_DB5500_MODEM, NULL,

				   modem_cpu_irq_handler, IRQF_ONESHOT,

				   "modem_irq", mi);

	if (err)

		pr_err("modem_irq: Could not register IRQ %d\n",

		       IRQ_DB5500_MODEM);

	return 0;

}

arch_initcall(modem_irq_init);