@samitouri / QOSamiQemu
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1 /*
2 * SBSA GWDT Watchdog Action Table (WDAT)
3 *
4 * Copyright Red Hat, Inc. 2026
5 * Author(s): Igor Mammedov <imammedo@redhat.com>
6 *
7 * SPDX-License-Identifier: GPL-2.0-or-later
8 */
9
10 #include "qemu/osdep.h"
11 #include "hw/acpi/aml-build.h"
12 #include "hw/acpi/wdat-gwdt.h"
13 #include "hw/acpi/wdat.h"
14 #include "hw/watchdog/sbsa_gwdt.h"
15
16 #define GWDT_REG(base, reg_offset, reg_width) { \
17 .space_id = AML_AS_SYSTEM_MEMORY, \
18 .address = base + reg_offset, .bit_width = reg_width, \
19 .access_width = AML_DWORD_ACC };
20
21 /*
22 * "Hardware Watchdog Timers Design Specification"
23 * https://uefi.org/acpi 'Watchdog Action Table (WDAT)'
24 */
25 void build_gwdt_wdat(GArray *table_data, BIOSLinker *linker, const char *oem_id,
26 const char *oem_table_id, uint64_t rbase, uint64_t cbase,
27 uint64_t freq)
28 {
29 AcpiTable table = { .sig = "WDAT", .rev = 1, .oem_id = oem_id,
30 .oem_table_id = oem_table_id };
31
32 struct AcpiGenericAddress wrr = GWDT_REG(rbase, 0x0, 32);
33 struct AcpiGenericAddress wor_l = GWDT_REG(cbase, SBSA_GWDT_WOR, 32);
34 struct AcpiGenericAddress wcs = GWDT_REG(cbase, SBSA_GWDT_WCS, 32);
35
36 acpi_table_begin(&table, table_data);
37 build_append_int_noprefix(table_data, 0x20, 4); /* Watchdog Header Length */
38 /*
39 * PCI location fields are set to 0xff to indicate
40 * that the watchdog is not a PCI device.
41 */
42 build_append_int_noprefix(table_data, 0xff, 2); /* PCI Segment */
43 build_append_int_noprefix(table_data, 0xff, 1); /* PCI Bus Number */
44 build_append_int_noprefix(table_data, 0xff, 1); /* PCI Device Number */
45 build_append_int_noprefix(table_data, 0xff, 1); /* PCI Function Number */
46 build_append_int_noprefix(table_data, 0, 3); /* Reserved */
47 /*
48 * WDAT spec: "The clock interval that the WDT uses must be
49 * greater than or equal to 1 millisecond."
50 */
51 g_assert(freq <= 1000);
52 /* Timer Period, ms */
53 build_append_int_noprefix(table_data, 1000 / freq, 4);
54 /*
55 * WDAT spec: "The time-out period before the WDT fires is recommended
56 * to be at least 5 minutes."
57 * Set max count to 10min and min count to 5sec.
58 */
59 build_append_int_noprefix(table_data, 600 * freq, 4); /* Maximum Count */
60 build_append_int_noprefix(table_data, 5 * freq, 4); /* Minimum Count */
61 /*
62 * WATCHDOG_ENABLED | WATCHDOG_STOPPED_IN_SLEEP_STATE
63 */
64 build_append_int_noprefix(table_data, 0x81, 1); /* Watchdog Flags */
65 build_append_int_noprefix(table_data, 0, 3); /* Reserved */
66 /*
67 * watchdog instruction entries
68 */
69 build_append_int_noprefix(table_data, 8, 4);
70 /* Action table: WCS (control/status) register actions */
71 build_append_wdat_ins(table_data, WDAT_ACTION_QUERY_RUNNING_STATE,
72 WDAT_INS_READ_VALUE,
73 wcs, 0x1, 0x1);
74 build_append_wdat_ins(table_data, WDAT_ACTION_SET_RUNNING_STATE,
75 WDAT_INS_WRITE_VALUE | WDAT_INS_PRESERVE_REGISTER,
76 wcs, 1, 0x00000001);
77 build_append_wdat_ins(table_data, WDAT_ACTION_QUERY_STOPPED_STATE,
78 WDAT_INS_READ_VALUE,
79 wcs, 0x0, 0x00000001);
80 build_append_wdat_ins(table_data, WDAT_ACTION_SET_STOPPED_STATE,
81 WDAT_INS_WRITE_VALUE | WDAT_INS_PRESERVE_REGISTER,
82 wcs, 0x0, 0x00000001);
83 build_append_wdat_ins(table_data, WDAT_ACTION_QUERY_WATCHDOG_STATUS,
84 WDAT_INS_READ_VALUE,
85 wcs, 0x4, 0x00000004);
86 /* WOR (offset) and WRR (refresh) register actions */
87 build_append_wdat_ins(table_data, WDAT_ACTION_SET_COUNTDOWN_PERIOD,
88 WDAT_INS_WRITE_COUNTDOWN,
89 wor_l, 0, 0xffffffff);
90 /* WRR: any write refreshes the watchdog, value is ignored */
91 build_append_wdat_ins(table_data, WDAT_ACTION_RESET,
92 WDAT_INS_WRITE_VALUE,
93 wrr, 0x1, 0x1);
94 build_append_wdat_ins(table_data, WDAT_ACTION_SET_WATCHDOG_STATUS,
95 WDAT_INS_WRITE_VALUE | WDAT_INS_PRESERVE_REGISTER,
96 wrr, 0x4, 0x4);
97
98 acpi_table_end(linker, &table);
99 }