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ad1696f6 AM |
1 | /* |
2 | * Copyright (c) 2012, Intel Corporation | |
3 | * Copyright (c) 2015, Red Hat, Inc. | |
4 | * Copyright (c) 2015, 2016 Linaro Ltd. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | * | |
10 | */ | |
11 | ||
12 | #define pr_fmt(fmt) "ACPI: SPCR: " fmt | |
13 | ||
14 | #include <linux/acpi.h> | |
15 | #include <linux/console.h> | |
16 | #include <linux/kernel.h> | |
17 | #include <linux/serial_core.h> | |
18 | ||
d8a4995b CC |
19 | /* |
20 | * Some Qualcomm Datacenter Technologies SoCs have a defective UART BUSY bit. | |
21 | * Detect them by examining the OEM fields in the SPCR header, similiar to PCI | |
22 | * quirk detection in pci_mcfg.c. | |
23 | */ | |
24 | static bool qdf2400_erratum_44_present(struct acpi_table_header *h) | |
25 | { | |
26 | if (memcmp(h->oem_id, "QCOM ", ACPI_OEM_ID_SIZE)) | |
27 | return false; | |
28 | ||
29 | if (!memcmp(h->oem_table_id, "QDF2432 ", ACPI_OEM_TABLE_ID_SIZE)) | |
30 | return true; | |
31 | ||
32 | if (!memcmp(h->oem_table_id, "QDF2400 ", ACPI_OEM_TABLE_ID_SIZE) && | |
542ed784 | 33 | h->oem_revision == 1) |
d8a4995b CC |
34 | return true; |
35 | ||
36 | return false; | |
37 | } | |
38 | ||
ad1696f6 AM |
39 | /** |
40 | * parse_spcr() - parse ACPI SPCR table and add preferred console | |
41 | * | |
42 | * @earlycon: set up earlycon for the console specified by the table | |
43 | * | |
44 | * For the architectures with support for ACPI, CONFIG_ACPI_SPCR_TABLE may be | |
45 | * defined to parse ACPI SPCR table. As a result of the parsing preferred | |
46 | * console is registered and if @earlycon is true, earlycon is set up. | |
47 | * | |
48 | * When CONFIG_ACPI_SPCR_TABLE is defined, this function should be called | |
183b8021 | 49 | * from arch initialization code as soon as the DT/ACPI decision is made. |
ad1696f6 AM |
50 | * |
51 | */ | |
52 | int __init parse_spcr(bool earlycon) | |
53 | { | |
54 | static char opts[64]; | |
55 | struct acpi_table_spcr *table; | |
ad1696f6 AM |
56 | acpi_status status; |
57 | char *uart; | |
58 | char *iotype; | |
59 | int baud_rate; | |
60 | int err; | |
61 | ||
62 | if (acpi_disabled) | |
63 | return -ENODEV; | |
64 | ||
6b11d1d6 LZ |
65 | status = acpi_get_table(ACPI_SIG_SPCR, 0, |
66 | (struct acpi_table_header **)&table); | |
ad1696f6 AM |
67 | |
68 | if (ACPI_FAILURE(status)) | |
69 | return -ENOENT; | |
70 | ||
71 | if (table->header.revision < 2) { | |
72 | err = -ENOENT; | |
73 | pr_err("wrong table version\n"); | |
74 | goto done; | |
75 | } | |
76 | ||
77 | iotype = table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY ? | |
78 | "mmio" : "io"; | |
79 | ||
80 | switch (table->interface_type) { | |
81 | case ACPI_DBG2_ARM_SBSA_32BIT: | |
82 | iotype = "mmio32"; | |
83 | /* fall through */ | |
84 | case ACPI_DBG2_ARM_PL011: | |
85 | case ACPI_DBG2_ARM_SBSA_GENERIC: | |
86 | case ACPI_DBG2_BCM2835: | |
87 | uart = "pl011"; | |
88 | break; | |
89 | case ACPI_DBG2_16550_COMPATIBLE: | |
90 | case ACPI_DBG2_16550_SUBSET: | |
91 | uart = "uart"; | |
92 | break; | |
93 | default: | |
94 | err = -ENOENT; | |
95 | goto done; | |
96 | } | |
97 | ||
98 | switch (table->baud_rate) { | |
99 | case 3: | |
100 | baud_rate = 9600; | |
101 | break; | |
102 | case 4: | |
103 | baud_rate = 19200; | |
104 | break; | |
105 | case 6: | |
106 | baud_rate = 57600; | |
107 | break; | |
108 | case 7: | |
109 | baud_rate = 115200; | |
110 | break; | |
111 | default: | |
112 | err = -ENOENT; | |
113 | goto done; | |
114 | } | |
115 | ||
d8a4995b CC |
116 | if (qdf2400_erratum_44_present(&table->header)) |
117 | uart = "qdf2400_e44"; | |
118 | ||
ad1696f6 AM |
119 | snprintf(opts, sizeof(opts), "%s,%s,0x%llx,%d", uart, iotype, |
120 | table->serial_port.address, baud_rate); | |
121 | ||
122 | pr_info("console: %s\n", opts); | |
123 | ||
124 | if (earlycon) | |
125 | setup_earlycon(opts); | |
126 | ||
127 | err = add_preferred_console(uart, 0, opts + strlen(uart) + 1); | |
128 | ||
129 | done: | |
6b11d1d6 | 130 | acpi_put_table((struct acpi_table_header *)table); |
ad1696f6 AM |
131 | return err; |
132 | } |