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
tangier_probe(struct platform_device * pdev)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
wdt_scu_status_change(struct notifier_block * nb,unsigned long code,void * data)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
register_mid_wdt(void)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);
87
