/*
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* Copyright (c) 2012, Intel Corporation
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* Copyright (c) 2015, Red Hat, Inc.
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* Copyright (c) 2015, 2016 Linaro Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#define pr_fmt(fmt) "ACPI: SPCR: " fmt
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#include <linux/acpi.h>
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#include <linux/console.h>
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#include <linux/kernel.h>
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#include <linux/serial_core.h>
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/**
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* parse_spcr() - parse ACPI SPCR table and add preferred console
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*
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* @earlycon: set up earlycon for the console specified by the table
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*
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* For the architectures with support for ACPI, CONFIG_ACPI_SPCR_TABLE may be
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* defined to parse ACPI SPCR table. As a result of the parsing preferred
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* console is registered and if @earlycon is true, earlycon is set up.
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*
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* When CONFIG_ACPI_SPCR_TABLE is defined, this function should be called
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* from arch inintialization code as soon as the DT/ACPI decision is made.
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*
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*/
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int __init parse_spcr(bool earlycon)
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{
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static char opts[64];
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struct acpi_table_spcr *table;
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acpi_size table_size;
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acpi_status status;
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char *uart;
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char *iotype;
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int baud_rate;
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int err;
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if (acpi_disabled)
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return -ENODEV;
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status = acpi_get_table_with_size(ACPI_SIG_SPCR, 0,
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(struct acpi_table_header **)&table,
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&table_size);
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if (ACPI_FAILURE(status))
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return -ENOENT;
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if (table->header.revision < 2) {
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err = -ENOENT;
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pr_err("wrong table version\n");
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goto done;
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}
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iotype = table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY ?
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"mmio" : "io";
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switch (table->interface_type) {
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case ACPI_DBG2_ARM_SBSA_32BIT:
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iotype = "mmio32";
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/* fall through */
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case ACPI_DBG2_ARM_PL011:
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case ACPI_DBG2_ARM_SBSA_GENERIC:
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case ACPI_DBG2_BCM2835:
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uart = "pl011";
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break;
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case ACPI_DBG2_16550_COMPATIBLE:
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case ACPI_DBG2_16550_SUBSET:
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uart = "uart";
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break;
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default:
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err = -ENOENT;
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goto done;
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}
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switch (table->baud_rate) {
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case 3:
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baud_rate = 9600;
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break;
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case 4:
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baud_rate = 19200;
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break;
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case 6:
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baud_rate = 57600;
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break;
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case 7:
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baud_rate = 115200;
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break;
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default:
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err = -ENOENT;
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goto done;
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}
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snprintf(opts, sizeof(opts), "%s,%s,0x%llx,%d", uart, iotype,
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table->serial_port.address, baud_rate);
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pr_info("console: %s\n", opts);
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if (earlycon)
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setup_earlycon(opts);
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err = add_preferred_console(uart, 0, opts + strlen(uart) + 1);
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done:
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early_acpi_os_unmap_memory((void __iomem *)table, table_size);
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return err;
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}
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