arch/x86/platform/intel-mid/device_libs/platform_mrfld_wdt.c

   1 /*
   2  * Intel Merrifield watchdog platform device library file
   3  *
   4  * (C) Copyright 2014 Intel Corporation
   5  * Author: David Cohen <david.a.cohen@linux.intel.com>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; version 2
  10  * of the License.
  11  */
  12
  13 #include <linux/init.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/platform_data/intel-mid_wdt.h>
  17
  18 #include <asm/intel-mid.h>
  19 #include <asm/intel_scu_ipc.h>
  20 #include <asm/io_apic.h>
  21 #include <asm/hw_irq.h>
  22
  23 #define TANGIER_EXT_TIMER0_MSI 12
  24
  25 static struct platform_device wdt_dev = {
  26         .name = "intel_mid_wdt",
  27         .id = -1,
  28 };
  29
  30 static int tangier_probe(struct platform_device *pdev)
  31 {
  32         struct irq_alloc_info info;
  33         struct intel_mid_wdt_pdata *pdata = pdev->dev.platform_data;
  34         int gsi = TANGIER_EXT_TIMER0_MSI;
  35         int irq;
  36
  37         if (!pdata)
  38                 return -EINVAL;
  39
  40         /* IOAPIC builds identity mapping between GSI and IRQ on MID */
  41         ioapic_set_alloc_attr(&info, cpu_to_node(0), 1, 0);
  42         irq = mp_map_gsi_to_irq(gsi, IOAPIC_MAP_ALLOC, &info);
  43         if (irq < 0) {
  44                 dev_warn(&pdev->dev, "cannot find interrupt %d in ioapic\n", gsi);
  45                 return irq;
  46         }
  47
  48         pdata->irq = irq;
  49         return 0;
  50 }
  51
  52 static struct intel_mid_wdt_pdata tangier_pdata = {
  53         .probe = tangier_probe,
  54 };
  55
  56 static int wdt_scu_status_change(struct notifier_block *nb,
  57                                  unsigned long code, void *data)
  58 {
  59         if (code == SCU_DOWN) {
  60                 platform_device_unregister(&wdt_dev);
  61                 return 0;
  62         }
  63
  64         return platform_device_register(&wdt_dev);
  65 }
  66
  67 static struct notifier_block wdt_scu_notifier = {
  68         .notifier_call  = wdt_scu_status_change,
  69 };
  70
  71 static int __init register_mid_wdt(void)
  72 {
  73         if (intel_mid_identify_cpu() != INTEL_MID_CPU_CHIP_TANGIER)
  74                 return -ENODEV;
  75
  76         wdt_dev.dev.platform_data = &tangier_pdata;
  77
  78         /*
  79          * We need to be sure that the SCU IPC is ready before watchdog device
  80          * can be registered:
  81          */
  82         intel_scu_notifier_add(&wdt_scu_notifier);
  83
  84         return 0;
  85 }
  86 arch_initcall(register_mid_wdt);