1616#include <linux/acpi.h>
1717#include <linux/io.h>
1818#include <linux/pci.h>
19+ #include <linux/efi.h>
1920
2021int acpi_noirq = 1 ; /* skip ACPI IRQ initialization */
2122int acpi_disabled = 1 ;
@@ -24,6 +25,131 @@ EXPORT_SYMBOL(acpi_disabled);
2425int acpi_pci_disabled = 1 ; /* skip ACPI PCI scan and IRQ initialization */
2526EXPORT_SYMBOL (acpi_pci_disabled );
2627
28+ static bool param_acpi_off __initdata ;
29+ static bool param_acpi_on __initdata ;
30+ static bool param_acpi_force __initdata ;
31+
32+ static int __init parse_acpi (char * arg )
33+ {
34+ if (!arg )
35+ return - EINVAL ;
36+
37+ /* "acpi=off" disables both ACPI table parsing and interpreter */
38+ if (strcmp (arg , "off" ) == 0 )
39+ param_acpi_off = true;
40+ else if (strcmp (arg , "on" ) == 0 ) /* prefer ACPI over DT */
41+ param_acpi_on = true;
42+ else if (strcmp (arg , "force" ) == 0 ) /* force ACPI to be enabled */
43+ param_acpi_force = true;
44+ else
45+ return - EINVAL ; /* Core will print when we return error */
46+
47+ return 0 ;
48+ }
49+ early_param ("acpi" , parse_acpi );
50+
51+ /*
52+ * acpi_fadt_sanity_check() - Check FADT presence and carry out sanity
53+ * checks on it
54+ *
55+ * Return 0 on success, <0 on failure
56+ */
57+ static int __init acpi_fadt_sanity_check (void )
58+ {
59+ struct acpi_table_header * table ;
60+ struct acpi_table_fadt * fadt ;
61+ acpi_status status ;
62+ int ret = 0 ;
63+
64+ /*
65+ * FADT is required on riscv; retrieve it to check its presence
66+ * and carry out revision and ACPI HW reduced compliancy tests
67+ */
68+ status = acpi_get_table (ACPI_SIG_FADT , 0 , & table );
69+ if (ACPI_FAILURE (status )) {
70+ const char * msg = acpi_format_exception (status );
71+
72+ pr_err ("Failed to get FADT table, %s\n" , msg );
73+ return - ENODEV ;
74+ }
75+
76+ fadt = (struct acpi_table_fadt * )table ;
77+
78+ /*
79+ * The revision in the table header is the FADT's Major revision. The
80+ * FADT also has a minor revision, which is stored in the FADT itself.
81+ *
82+ * TODO: Currently, we check for 6.5 as the minimum version to check
83+ * for HW_REDUCED flag. However, once RISC-V updates are released in
84+ * the ACPI spec, we need to update this check for exact minor revision
85+ */
86+ if (table -> revision < 6 || (table -> revision == 6 && fadt -> minor_revision < 5 ))
87+ pr_err (FW_BUG "Unsupported FADT revision %d.%d, should be 6.5+\n" ,
88+ table -> revision , fadt -> minor_revision );
89+
90+ if (!(fadt -> flags & ACPI_FADT_HW_REDUCED )) {
91+ pr_err ("FADT not ACPI hardware reduced compliant\n" );
92+ ret = - EINVAL ;
93+ }
94+
95+ /*
96+ * acpi_get_table() creates FADT table mapping that
97+ * should be released after parsing and before resuming boot
98+ */
99+ acpi_put_table (table );
100+ return ret ;
101+ }
102+
103+ /*
104+ * acpi_boot_table_init() called from setup_arch(), always.
105+ * 1. find RSDP and get its address, and then find XSDT
106+ * 2. extract all tables and checksums them all
107+ * 3. check ACPI FADT HW reduced flag
108+ *
109+ * We can parse ACPI boot-time tables such as MADT after
110+ * this function is called.
111+ *
112+ * On return ACPI is enabled if either:
113+ *
114+ * - ACPI tables are initialized and sanity checks passed
115+ * - acpi=force was passed in the command line and ACPI was not disabled
116+ * explicitly through acpi=off command line parameter
117+ *
118+ * ACPI is disabled on function return otherwise
119+ */
120+ void __init acpi_boot_table_init (void )
121+ {
122+ /*
123+ * Enable ACPI instead of device tree unless
124+ * - ACPI has been disabled explicitly (acpi=off), or
125+ * - firmware has not populated ACPI ptr in EFI system table
126+ * and ACPI has not been [force] enabled (acpi=on|force)
127+ */
128+ if (param_acpi_off ||
129+ (!param_acpi_on && !param_acpi_force &&
130+ efi .acpi20 == EFI_INVALID_TABLE_ADDR ))
131+ return ;
132+
133+ /*
134+ * ACPI is disabled at this point. Enable it in order to parse
135+ * the ACPI tables and carry out sanity checks
136+ */
137+ enable_acpi ();
138+
139+ /*
140+ * If ACPI tables are initialized and FADT sanity checks passed,
141+ * leave ACPI enabled and carry on booting; otherwise disable ACPI
142+ * on initialization error.
143+ * If acpi=force was passed on the command line it forces ACPI
144+ * to be enabled even if its initialization failed.
145+ */
146+ if (acpi_table_init () || acpi_fadt_sanity_check ()) {
147+ pr_err ("Failed to init ACPI tables\n" );
148+ if (!param_acpi_force )
149+ disable_acpi ();
150+ }
151+ }
152+
27153/*
28154 * __acpi_map_table() will be called before paging_init(), so early_ioremap()
29155 * or early_memremap() should be called here to for ACPI table mapping.
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