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
tangier_probe(struct platform_device * pdev)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
wdt_scu_status_change(struct notifier_block * nb,unsigned long code,void * data)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
register_mid_wdt(void)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);
83