| Aleksey Makarov | ad1696f | 2016-09-27 23:54:13 +0300 | [diff] [blame^] | 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 | |
| 19 | /** |
| 20 | * parse_spcr() - parse ACPI SPCR table and add preferred console |
| 21 | * |
| 22 | * @earlycon: set up earlycon for the console specified by the table |
| 23 | * |
| 24 | * For the architectures with support for ACPI, CONFIG_ACPI_SPCR_TABLE may be |
| 25 | * defined to parse ACPI SPCR table. As a result of the parsing preferred |
| 26 | * console is registered and if @earlycon is true, earlycon is set up. |
| 27 | * |
| 28 | * When CONFIG_ACPI_SPCR_TABLE is defined, this function should be called |
| 29 | * from arch inintialization code as soon as the DT/ACPI decision is made. |
| 30 | * |
| 31 | */ |
| 32 | int __init parse_spcr(bool earlycon) |
| 33 | { |
| 34 | static char opts[64]; |
| 35 | struct acpi_table_spcr *table; |
| 36 | acpi_size table_size; |
| 37 | acpi_status status; |
| 38 | char *uart; |
| 39 | char *iotype; |
| 40 | int baud_rate; |
| 41 | int err; |
| 42 | |
| 43 | if (acpi_disabled) |
| 44 | return -ENODEV; |
| 45 | |
| 46 | status = acpi_get_table_with_size(ACPI_SIG_SPCR, 0, |
| 47 | (struct acpi_table_header **)&table, |
| 48 | &table_size); |
| 49 | |
| 50 | if (ACPI_FAILURE(status)) |
| 51 | return -ENOENT; |
| 52 | |
| 53 | if (table->header.revision < 2) { |
| 54 | err = -ENOENT; |
| 55 | pr_err("wrong table version\n"); |
| 56 | goto done; |
| 57 | } |
| 58 | |
| 59 | iotype = table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY ? |
| 60 | "mmio" : "io"; |
| 61 | |
| 62 | switch (table->interface_type) { |
| 63 | case ACPI_DBG2_ARM_SBSA_32BIT: |
| 64 | iotype = "mmio32"; |
| 65 | /* fall through */ |
| 66 | case ACPI_DBG2_ARM_PL011: |
| 67 | case ACPI_DBG2_ARM_SBSA_GENERIC: |
| 68 | case ACPI_DBG2_BCM2835: |
| 69 | uart = "pl011"; |
| 70 | break; |
| 71 | case ACPI_DBG2_16550_COMPATIBLE: |
| 72 | case ACPI_DBG2_16550_SUBSET: |
| 73 | uart = "uart"; |
| 74 | break; |
| 75 | default: |
| 76 | err = -ENOENT; |
| 77 | goto done; |
| 78 | } |
| 79 | |
| 80 | switch (table->baud_rate) { |
| 81 | case 3: |
| 82 | baud_rate = 9600; |
| 83 | break; |
| 84 | case 4: |
| 85 | baud_rate = 19200; |
| 86 | break; |
| 87 | case 6: |
| 88 | baud_rate = 57600; |
| 89 | break; |
| 90 | case 7: |
| 91 | baud_rate = 115200; |
| 92 | break; |
| 93 | default: |
| 94 | err = -ENOENT; |
| 95 | goto done; |
| 96 | } |
| 97 | |
| 98 | snprintf(opts, sizeof(opts), "%s,%s,0x%llx,%d", uart, iotype, |
| 99 | table->serial_port.address, baud_rate); |
| 100 | |
| 101 | pr_info("console: %s\n", opts); |
| 102 | |
| 103 | if (earlycon) |
| 104 | setup_earlycon(opts); |
| 105 | |
| 106 | err = add_preferred_console(uart, 0, opts + strlen(uart) + 1); |
| 107 | |
| 108 | done: |
| 109 | early_acpi_os_unmap_memory((void __iomem *)table, table_size); |
| 110 | return err; |
| 111 | } |