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
22 #define TANGIER_EXT_TIMER0_MSI 12
23
24 static struct platform_device wdt_dev = {
25 .name = "intel_mid_wdt",
26 .id = -1,
27 };
28
tangier_probe(struct platform_device * pdev)29 static int tangier_probe(struct platform_device *pdev)
30 {
31 int gsi;
32 struct irq_alloc_info info;
33 struct intel_mid_wdt_pdata *pdata = pdev->dev.platform_data;
34
35 if (!pdata)
36 return -EINVAL;
37
38 /* IOAPIC builds identity mapping between GSI and IRQ on MID */
39 gsi = pdata->irq;
40 ioapic_set_alloc_attr(&info, cpu_to_node(0), 1, 0);
41 if (mp_map_gsi_to_irq(gsi, IOAPIC_MAP_ALLOC, &info) <= 0) {
42 dev_warn(&pdev->dev, "cannot find interrupt %d in ioapic\n",
43 gsi);
44 return -EINVAL;
45 }
46
47 return 0;
48 }
49
50 static struct intel_mid_wdt_pdata tangier_pdata = {
51 .irq = TANGIER_EXT_TIMER0_MSI,
52 .probe = tangier_probe,
53 };
54
wdt_scu_status_change(struct notifier_block * nb,unsigned long code,void * data)55 static int wdt_scu_status_change(struct notifier_block *nb,
56 unsigned long code, void *data)
57 {
58 if (code == SCU_DOWN) {
59 platform_device_unregister(&wdt_dev);
60 return 0;
61 }
62
63 return platform_device_register(&wdt_dev);
64 }
65
66 static struct notifier_block wdt_scu_notifier = {
67 .notifier_call = wdt_scu_status_change,
68 };
69
register_mid_wdt(void)70 static int __init register_mid_wdt(void)
71 {
72 if (intel_mid_identify_cpu() != INTEL_MID_CPU_CHIP_TANGIER)
73 return -ENODEV;
74
75 wdt_dev.dev.platform_data = &tangier_pdata;
76
77 /*
78 * We need to be sure that the SCU IPC is ready before watchdog device
79 * can be registered:
80 */
81 intel_scu_notifier_add(&wdt_scu_notifier);
82
83 return 0;
84 }
85 rootfs_initcall(register_mid_wdt);
86