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

DEFINITIONS

1. tangier_probe
2. wdt_scu_status_change
3. register_mid_wdt

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Intel Merrifield watchdog platform device library file
   4  *
   5  * (C) Copyright 2014 Intel Corporation
   6  * Author: David Cohen <david.a.cohen@linux.intel.com>
   7  */
   8 
   9 #include <linux/init.h>
  10 #include <linux/interrupt.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/platform_data/intel-mid_wdt.h>
  13 
  14 #include <asm/intel-mid.h>
  15 #include <asm/intel_scu_ipc.h>
  16 #include <asm/io_apic.h>
  17 #include <asm/hw_irq.h>
  18 
  19 #define TANGIER_EXT_TIMER0_MSI 12
  20 
  21 static struct platform_device wdt_dev = {
  22         .name = "intel_mid_wdt",
  23         .id = -1,
  24 };
  25 
  26 static int tangier_probe(struct platform_device *pdev)
  27 {
  28         struct irq_alloc_info info;
  29         struct intel_mid_wdt_pdata *pdata = pdev->dev.platform_data;
  30         int gsi = TANGIER_EXT_TIMER0_MSI;
  31         int irq;
  32 
  33         if (!pdata)
  34                 return -EINVAL;
  35 
  36         /* IOAPIC builds identity mapping between GSI and IRQ on MID */
  37         ioapic_set_alloc_attr(&info, cpu_to_node(0), 1, 0);
  38         irq = mp_map_gsi_to_irq(gsi, IOAPIC_MAP_ALLOC, &info);
  39         if (irq < 0) {
  40                 dev_warn(&pdev->dev, "cannot find interrupt %d in ioapic\n", gsi);
  41                 return irq;
  42         }
  43 
  44         pdata->irq = irq;
  45         return 0;
  46 }
  47 
  48 static struct intel_mid_wdt_pdata tangier_pdata = {
  49         .probe = tangier_probe,
  50 };
  51 
  52 static int wdt_scu_status_change(struct notifier_block *nb,
  53                                  unsigned long code, void *data)
  54 {
  55         if (code == SCU_DOWN) {
  56                 platform_device_unregister(&wdt_dev);
  57                 return 0;
  58         }
  59 
  60         return platform_device_register(&wdt_dev);
  61 }
  62 
  63 static struct notifier_block wdt_scu_notifier = {
  64         .notifier_call  = wdt_scu_status_change,
  65 };
  66 
  67 static int __init register_mid_wdt(void)
  68 {
  69         if (intel_mid_identify_cpu() != INTEL_MID_CPU_CHIP_TANGIER)
  70                 return -ENODEV;
  71 
  72         wdt_dev.dev.platform_data = &tangier_pdata;
  73 
  74         /*
  75          * We need to be sure that the SCU IPC is ready before watchdog device
  76          * can be registered:
  77          */
  78         intel_scu_notifier_add(&wdt_scu_notifier);
  79 
  80         return 0;
  81 }
  82 arch_initcall(register_mid_wdt);